linux/drivers/block/nbd.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Network block device - make block devices work over TCP
*
* Note that you can not swap over this thing, yet. Seems to work but
* deadlocks sometimes - you can not swap over TCP in general.
*
* Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
* Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
*
* (part of code stolen from loop.c)
*/
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/fs.h>
#include <linux/bio.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/ioctl.h>
#include <linux/mutex.h>
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 11:09:47 +03:00
#include <linux/compiler.h>
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
#include <linux/completion.h>
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 11:09:47 +03:00
#include <linux/err.h>
#include <linux/kernel.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 11:04:11 +03:00
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/net.h>
#include <linux/kthread.h>
#include <linux/types.h>
#include <linux/debugfs.h>
#include <linux/blk-mq.h>
#include <linux/uaccess.h>
#include <asm/types.h>
#include <linux/nbd.h>
#include <linux/nbd-netlink.h>
#include <net/genetlink.h>
#define CREATE_TRACE_POINTS
#include <trace/events/nbd.h>
static DEFINE_IDR(nbd_index_idr);
static DEFINE_MUTEX(nbd_index_mutex);
static int nbd_total_devices = 0;
struct nbd_sock {
struct socket *sock;
struct mutex tx_lock;
struct request *pending;
int sent;
bool dead;
int fallback_index;
int cookie;
};
struct recv_thread_args {
struct work_struct work;
struct nbd_device *nbd;
int index;
};
struct link_dead_args {
struct work_struct work;
int index;
};
#define NBD_RT_TIMEDOUT 0
#define NBD_RT_DISCONNECT_REQUESTED 1
#define NBD_RT_DISCONNECTED 2
#define NBD_RT_HAS_PID_FILE 3
#define NBD_RT_HAS_CONFIG_REF 4
#define NBD_RT_BOUND 5
#define NBD_RT_DESTROY_ON_DISCONNECT 6
#define NBD_RT_DISCONNECT_ON_CLOSE 7
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
#define NBD_DESTROY_ON_DISCONNECT 0
#define NBD_DISCONNECT_REQUESTED 1
struct nbd_config {
u32 flags;
unsigned long runtime_flags;
u64 dead_conn_timeout;
struct nbd_sock **socks;
int num_connections;
atomic_t live_connections;
wait_queue_head_t conn_wait;
atomic_t recv_threads;
wait_queue_head_t recv_wq;
loff_t blksize;
loff_t bytesize;
#if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbg_dir;
#endif
};
struct nbd_device {
struct blk_mq_tag_set tag_set;
int index;
refcount_t config_refs;
refcount_t refs;
struct nbd_config *config;
struct mutex config_lock;
struct gendisk *disk;
struct workqueue_struct *recv_workq;
struct list_head list;
struct task_struct *task_recv;
struct task_struct *task_setup;
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
struct completion *destroy_complete;
unsigned long flags;
};
#define NBD_CMD_REQUEUED 1
struct nbd_cmd {
struct nbd_device *nbd;
struct mutex lock;
int index;
int cookie;
int retries;
blk_status_t status;
unsigned long flags;
u32 cmd_cookie;
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
static struct dentry *nbd_dbg_dir;
#endif
#define nbd_name(nbd) ((nbd)->disk->disk_name)
#define NBD_MAGIC 0x68797548
#define NBD_DEF_BLKSIZE 1024
static unsigned int nbds_max = 16;
static int max_part = 16;
static int part_shift;
static int nbd_dev_dbg_init(struct nbd_device *nbd);
static void nbd_dev_dbg_close(struct nbd_device *nbd);
static void nbd_config_put(struct nbd_device *nbd);
static void nbd_connect_reply(struct genl_info *info, int index);
static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
static void nbd_dead_link_work(struct work_struct *work);
static void nbd_disconnect_and_put(struct nbd_device *nbd);
static inline struct device *nbd_to_dev(struct nbd_device *nbd)
{
return disk_to_dev(nbd->disk);
}
static void nbd_requeue_cmd(struct nbd_cmd *cmd)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
blk_mq_requeue_request(req, true);
}
#define NBD_COOKIE_BITS 32
static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
u32 tag = blk_mq_unique_tag(req);
u64 cookie = cmd->cmd_cookie;
return (cookie << NBD_COOKIE_BITS) | tag;
}
static u32 nbd_handle_to_tag(u64 handle)
{
return (u32)handle;
}
static u32 nbd_handle_to_cookie(u64 handle)
{
return (u32)(handle >> NBD_COOKIE_BITS);
}
static const char *nbdcmd_to_ascii(int cmd)
{
switch (cmd) {
case NBD_CMD_READ: return "read";
case NBD_CMD_WRITE: return "write";
case NBD_CMD_DISC: return "disconnect";
nbd: support FLUSH requests Currently, the NBD device does not accept flush requests from the Linux block layer. If the NBD server opened the target with neither O_SYNC nor O_DSYNC, however, the device will be effectively backed by a writeback cache. Without issuing flushes properly, operation of the NBD device will not be safe against power losses. The NBD protocol has support for both a cache flush command and a FUA command flag; the server will also pass a flag to note its support for these features. This patch adds support for the cache flush command and flag. In the kernel, we receive the flags via the NBD_SET_FLAGS ioctl, and map NBD_FLAG_SEND_FLUSH to the argument of blk_queue_flush. When the flag is active the block layer will send REQ_FLUSH requests, which we translate to NBD_CMD_FLUSH commands. FUA support is not included in this patch because all free software servers implement it with a full fdatasync; thus it has no advantage over supporting flush only. Because I [Paolo] cannot really benchmark it in a realistic scenario, I cannot tell if it is a good idea or not. It is also not clear if it is valid for an NBD server to support FUA but not flush. The Linux block layer gives a warning for this combination, the NBD protocol documentation says nothing about it. The patch also fixes a small problem in the handling of flags: nbd->flags must be cleared at the end of NBD_DO_IT, but the driver was not doing that. The bug manifests itself as follows. Suppose you two different client/server pairs to start the NBD device. Suppose also that the first client supports NBD_SET_FLAGS, and the first server sends NBD_FLAG_SEND_FLUSH; the second pair instead does neither of these two things. Before this patch, the second invocation of NBD_DO_IT will use a stale value of nbd->flags, and the second server will issue an error every time it receives an NBD_CMD_FLUSH command. This bug is pre-existing, but it becomes much more important after this patch; flush failures make the device pretty much unusable, unlike Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alex Bligh <alex@alex.org.uk> Acked-by: Paul Clements <Paul.Clements@steeleye.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 05:05:23 +04:00
case NBD_CMD_FLUSH: return "flush";
case NBD_CMD_TRIM: return "trim/discard";
}
return "invalid";
}
static ssize_t pid_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
}
static const struct device_attribute pid_attr = {
.attr = { .name = "pid", .mode = 0444},
.show = pid_show,
};
static void nbd_dev_remove(struct nbd_device *nbd)
{
struct gendisk *disk = nbd->disk;
struct request_queue *q;
if (disk) {
q = disk->queue;
del_gendisk(disk);
blk_cleanup_queue(q);
blk_mq_free_tag_set(&nbd->tag_set);
disk->private_data = NULL;
put_disk(disk);
}
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
/*
* Place this in the last just before the nbd is freed to
* make sure that the disk and the related kobject are also
* totally removed to avoid duplicate creation of the same
* one.
*/
if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && nbd->destroy_complete)
complete(nbd->destroy_complete);
kfree(nbd);
}
static void nbd_put(struct nbd_device *nbd)
{
if (refcount_dec_and_mutex_lock(&nbd->refs,
&nbd_index_mutex)) {
idr_remove(&nbd_index_idr, nbd->index);
nbd_dev_remove(nbd);
mutex_unlock(&nbd_index_mutex);
}
}
static int nbd_disconnected(struct nbd_config *config)
{
return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
}
static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
int notify)
{
if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
struct link_dead_args *args;
args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
if (args) {
INIT_WORK(&args->work, nbd_dead_link_work);
args->index = nbd->index;
queue_work(system_wq, &args->work);
}
}
if (!nsock->dead) {
kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
if (atomic_dec_return(&nbd->config->live_connections) == 0) {
if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
&nbd->config->runtime_flags)) {
set_bit(NBD_RT_DISCONNECTED,
&nbd->config->runtime_flags);
dev_info(nbd_to_dev(nbd),
"Disconnected due to user request.\n");
}
}
}
nsock->dead = true;
nsock->pending = NULL;
nsock->sent = 0;
}
static void nbd_size_clear(struct nbd_device *nbd)
{
if (nbd->config->bytesize) {
set_capacity(nbd->disk, 0);
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
}
}
static void nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
loff_t blksize)
{
struct block_device *bdev;
nbd->config->bytesize = bytesize;
nbd->config->blksize = blksize;
if (!nbd->task_recv)
return;
if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
nbd->disk->queue->limits.discard_granularity = blksize;
nbd->disk->queue->limits.discard_alignment = blksize;
blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
}
blk_queue_logical_block_size(nbd->disk->queue, blksize);
blk_queue_physical_block_size(nbd->disk->queue, blksize);
set_capacity(nbd->disk, bytesize >> 9);
bdev = bdget_disk(nbd->disk, 0);
if (bdev) {
if (bdev->bd_disk)
bd_set_nr_sectors(bdev, bytesize >> 9);
else
set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
bdput(bdev);
}
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
}
static void nbd_complete_rq(struct request *req)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
cmd->status ? "failed" : "done");
blk_mq_end_request(req, cmd->status);
}
/*
* Forcibly shutdown the socket causing all listeners to error
*/
static void sock_shutdown(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
int i;
if (config->num_connections == 0)
return;
if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
return;
for (i = 0; i < config->num_connections; i++) {
struct nbd_sock *nsock = config->socks[i];
mutex_lock(&nsock->tx_lock);
nbd_mark_nsock_dead(nbd, nsock, 0);
mutex_unlock(&nsock->tx_lock);
}
dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
}
static u32 req_to_nbd_cmd_type(struct request *req)
{
switch (req_op(req)) {
case REQ_OP_DISCARD:
return NBD_CMD_TRIM;
case REQ_OP_FLUSH:
return NBD_CMD_FLUSH;
case REQ_OP_WRITE:
return NBD_CMD_WRITE;
case REQ_OP_READ:
return NBD_CMD_READ;
default:
return U32_MAX;
}
}
static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
bool reserved)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
struct nbd_device *nbd = cmd->nbd;
struct nbd_config *config;
if (!mutex_trylock(&cmd->lock))
return BLK_EH_RESET_TIMER;
if (!refcount_inc_not_zero(&nbd->config_refs)) {
cmd->status = BLK_STS_TIMEOUT;
mutex_unlock(&cmd->lock);
goto done;
}
config = nbd->config;
if (config->num_connections > 1 ||
(config->num_connections == 1 && nbd->tag_set.timeout)) {
dev_err_ratelimited(nbd_to_dev(nbd),
"Connection timed out, retrying (%d/%d alive)\n",
atomic_read(&config->live_connections),
config->num_connections);
/*
* Hooray we have more connections, requeue this IO, the submit
* path will put it on a real connection. Or if only one
* connection is configured, the submit path will wait util
* a new connection is reconfigured or util dead timeout.
*/
if (config->socks) {
if (cmd->index < config->num_connections) {
struct nbd_sock *nsock =
config->socks[cmd->index];
mutex_lock(&nsock->tx_lock);
/* We can have multiple outstanding requests, so
* we don't want to mark the nsock dead if we've
* already reconnected with a new socket, so
* only mark it dead if its the same socket we
* were sent out on.
*/
if (cmd->cookie == nsock->cookie)
nbd_mark_nsock_dead(nbd, nsock, 1);
mutex_unlock(&nsock->tx_lock);
}
mutex_unlock(&cmd->lock);
nbd_requeue_cmd(cmd);
nbd_config_put(nbd);
return BLK_EH_DONE;
}
}
if (!nbd->tag_set.timeout) {
/*
* Userspace sets timeout=0 to disable socket disconnection,
* so just warn and reset the timer.
*/
struct nbd_sock *nsock = config->socks[cmd->index];
cmd->retries++;
dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
(unsigned long long)blk_rq_pos(req) << 9,
blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
mutex_lock(&nsock->tx_lock);
if (cmd->cookie != nsock->cookie) {
nbd_requeue_cmd(cmd);
mutex_unlock(&nsock->tx_lock);
mutex_unlock(&cmd->lock);
nbd_config_put(nbd);
return BLK_EH_DONE;
}
mutex_unlock(&nsock->tx_lock);
mutex_unlock(&cmd->lock);
nbd_config_put(nbd);
return BLK_EH_RESET_TIMER;
}
dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
cmd->status = BLK_STS_IOERR;
mutex_unlock(&cmd->lock);
sock_shutdown(nbd);
nbd_config_put(nbd);
done:
blk_mq_complete_request(req);
return BLK_EH_DONE;
}
/*
* Send or receive packet.
*/
static int sock_xmit(struct nbd_device *nbd, int index, int send,
struct iov_iter *iter, int msg_flags, int *sent)
{
struct nbd_config *config = nbd->config;
struct socket *sock = config->socks[index]->sock;
int result;
struct msghdr msg;
unsigned int noreclaim_flag;
if (unlikely(!sock)) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Attempted %s on closed socket in sock_xmit\n",
(send ? "send" : "recv"));
return -EINVAL;
}
msg.msg_iter = *iter;
noreclaim_flag = memalloc_noreclaim_save();
do {
sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = msg_flags | MSG_NOSIGNAL;
nbd: Fix timeout detection At the moment the nbd timeout just detects hanging tcp operations. This is not enough to detect a hanging or bad connection as expected of a timeout. This patch redesigns the timeout detection to include some more cases. The timeout is now in relation to replies from the server. If the server does not send replies within the timeout the connection will be shut down. The patch adds a continous timer 'timeout_timer' that is setup in one of two cases: - The request list is empty and we are sending the first request out to the server. We want to have a reply within the given timeout, otherwise we consider the connection to be dead. - A server response was received. This means the server is still communicating with us. The timer is reset to the timeout value. The timer is not stopped if the list becomes empty. It will just trigger a timeout which will directly leave the handling routine again as the request list is empty. The whole patch does not use any additional explicit locking. The list_empty() calls are safe to be used concurrently. The timer is locked internally as we just use mod_timer and del_timer_sync(). The patch is based on the idea of Michal Belczyk with a previous different implementation. Cc: Michal Belczyk <belczyk@bsd.krakow.pl> Cc: Hermann Lauer <Hermann.Lauer@iwr.uni-heidelberg.de> Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Tested-by: Hermann Lauer <Hermann.Lauer@iwr.uni-heidelberg.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-17 09:20:00 +03:00
if (send)
result = sock_sendmsg(sock, &msg);
nbd: Fix timeout detection At the moment the nbd timeout just detects hanging tcp operations. This is not enough to detect a hanging or bad connection as expected of a timeout. This patch redesigns the timeout detection to include some more cases. The timeout is now in relation to replies from the server. If the server does not send replies within the timeout the connection will be shut down. The patch adds a continous timer 'timeout_timer' that is setup in one of two cases: - The request list is empty and we are sending the first request out to the server. We want to have a reply within the given timeout, otherwise we consider the connection to be dead. - A server response was received. This means the server is still communicating with us. The timer is reset to the timeout value. The timer is not stopped if the list becomes empty. It will just trigger a timeout which will directly leave the handling routine again as the request list is empty. The whole patch does not use any additional explicit locking. The list_empty() calls are safe to be used concurrently. The timer is locked internally as we just use mod_timer and del_timer_sync(). The patch is based on the idea of Michal Belczyk with a previous different implementation. Cc: Michal Belczyk <belczyk@bsd.krakow.pl> Cc: Hermann Lauer <Hermann.Lauer@iwr.uni-heidelberg.de> Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Tested-by: Hermann Lauer <Hermann.Lauer@iwr.uni-heidelberg.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-17 09:20:00 +03:00
else
result = sock_recvmsg(sock, &msg, msg.msg_flags);
if (result <= 0) {
if (result == 0)
result = -EPIPE; /* short read */
break;
}
if (sent)
*sent += result;
} while (msg_data_left(&msg));
memalloc_noreclaim_restore(noreclaim_flag);
return result;
}
/*
* Different settings for sk->sk_sndtimeo can result in different return values
* if there is a signal pending when we enter sendmsg, because reasons?
*/
static inline int was_interrupted(int result)
{
return result == -ERESTARTSYS || result == -EINTR;
}
/* always call with the tx_lock held */
static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
struct nbd_config *config = nbd->config;
struct nbd_sock *nsock = config->socks[index];
int result;
struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
struct iov_iter from;
unsigned long size = blk_rq_bytes(req);
struct bio *bio;
u64 handle;
u32 type;
u32 nbd_cmd_flags = 0;
int sent = nsock->sent, skip = 0;
iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
type = req_to_nbd_cmd_type(req);
if (type == U32_MAX)
return -EIO;
if (rq_data_dir(req) == WRITE &&
(config->flags & NBD_FLAG_READ_ONLY)) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Write on read-only\n");
return -EIO;
}
if (req->cmd_flags & REQ_FUA)
nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
/* We did a partial send previously, and we at least sent the whole
* request struct, so just go and send the rest of the pages in the
* request.
*/
if (sent) {
if (sent >= sizeof(request)) {
skip = sent - sizeof(request);
/* initialize handle for tracing purposes */
handle = nbd_cmd_handle(cmd);
goto send_pages;
}
iov_iter_advance(&from, sent);
} else {
cmd->cmd_cookie++;
}
cmd->index = index;
cmd->cookie = nsock->cookie;
cmd->retries = 0;
request.type = htonl(type | nbd_cmd_flags);
if (type != NBD_CMD_FLUSH) {
nbd: support FLUSH requests Currently, the NBD device does not accept flush requests from the Linux block layer. If the NBD server opened the target with neither O_SYNC nor O_DSYNC, however, the device will be effectively backed by a writeback cache. Without issuing flushes properly, operation of the NBD device will not be safe against power losses. The NBD protocol has support for both a cache flush command and a FUA command flag; the server will also pass a flag to note its support for these features. This patch adds support for the cache flush command and flag. In the kernel, we receive the flags via the NBD_SET_FLAGS ioctl, and map NBD_FLAG_SEND_FLUSH to the argument of blk_queue_flush. When the flag is active the block layer will send REQ_FLUSH requests, which we translate to NBD_CMD_FLUSH commands. FUA support is not included in this patch because all free software servers implement it with a full fdatasync; thus it has no advantage over supporting flush only. Because I [Paolo] cannot really benchmark it in a realistic scenario, I cannot tell if it is a good idea or not. It is also not clear if it is valid for an NBD server to support FUA but not flush. The Linux block layer gives a warning for this combination, the NBD protocol documentation says nothing about it. The patch also fixes a small problem in the handling of flags: nbd->flags must be cleared at the end of NBD_DO_IT, but the driver was not doing that. The bug manifests itself as follows. Suppose you two different client/server pairs to start the NBD device. Suppose also that the first client supports NBD_SET_FLAGS, and the first server sends NBD_FLAG_SEND_FLUSH; the second pair instead does neither of these two things. Before this patch, the second invocation of NBD_DO_IT will use a stale value of nbd->flags, and the second server will issue an error every time it receives an NBD_CMD_FLUSH command. This bug is pre-existing, but it becomes much more important after this patch; flush failures make the device pretty much unusable, unlike Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Alex Bligh <alex@alex.org.uk> Acked-by: Paul Clements <Paul.Clements@steeleye.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 05:05:23 +04:00
request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
request.len = htonl(size);
}
handle = nbd_cmd_handle(cmd);
memcpy(request.handle, &handle, sizeof(handle));
trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
req, nbdcmd_to_ascii(type),
(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
result = sock_xmit(nbd, index, 1, &from,
(type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
trace_nbd_header_sent(req, handle);
if (result <= 0) {
if (was_interrupted(result)) {
/* If we havne't sent anything we can just return BUSY,
* however if we have sent something we need to make
* sure we only allow this req to be sent until we are
* completely done.
*/
if (sent) {
nsock->pending = req;
nsock->sent = sent;
}
set_bit(NBD_CMD_REQUEUED, &cmd->flags);
return BLK_STS_RESOURCE;
}
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Send control failed (result %d)\n", result);
return -EAGAIN;
}
send_pages:
if (type != NBD_CMD_WRITE)
goto out;
bio = req->bio;
while (bio) {
struct bio *next = bio->bi_next;
struct bvec_iter iter;
block: Convert bio_for_each_segment() to bvec_iter More prep work for immutable biovecs - with immutable bvecs drivers won't be able to use the biovec directly, they'll need to use helpers that take into account bio->bi_iter.bi_bvec_done. This updates callers for the new usage without changing the implementation yet. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Paul Clements <Paul.Clements@steeleye.com> Cc: Jim Paris <jim@jtan.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com> Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Cc: support@lsi.com Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Quoc-Son Anh <quoc-sonx.anh@intel.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jan Kara <jack@suse.cz> Cc: linux-m68k@lists.linux-m68k.org Cc: linuxppc-dev@lists.ozlabs.org Cc: drbd-user@lists.linbit.com Cc: nbd-general@lists.sourceforge.net Cc: cbe-oss-dev@lists.ozlabs.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Cc: linux-raid@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: DL-MPTFusionLinux@lsi.com Cc: linux-scsi@vger.kernel.org Cc: devel@driverdev.osuosl.org Cc: linux-fsdevel@vger.kernel.org Cc: cluster-devel@redhat.com Cc: linux-mm@kvack.org Acked-by: Geoff Levand <geoff@infradead.org>
2013-11-24 05:19:00 +04:00
struct bio_vec bvec;
bio_for_each_segment(bvec, bio, iter) {
bool is_last = !next && bio_iter_last(bvec, iter);
int flags = is_last ? 0 : MSG_MORE;
dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
req, bvec.bv_len);
iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
if (skip) {
if (skip >= iov_iter_count(&from)) {
skip -= iov_iter_count(&from);
continue;
}
iov_iter_advance(&from, skip);
skip = 0;
}
result = sock_xmit(nbd, index, 1, &from, flags, &sent);
if (result <= 0) {
if (was_interrupted(result)) {
/* We've already sent the header, we
* have no choice but to set pending and
* return BUSY.
*/
nsock->pending = req;
nsock->sent = sent;
set_bit(NBD_CMD_REQUEUED, &cmd->flags);
return BLK_STS_RESOURCE;
}
dev_err(disk_to_dev(nbd->disk),
"Send data failed (result %d)\n",
result);
return -EAGAIN;
}
/*
* The completion might already have come in,
* so break for the last one instead of letting
* the iterator do it. This prevents use-after-free
* of the bio.
*/
if (is_last)
break;
}
bio = next;
}
out:
trace_nbd_payload_sent(req, handle);
nsock->pending = NULL;
nsock->sent = 0;
return 0;
}
/* NULL returned = something went wrong, inform userspace */
static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
{
struct nbd_config *config = nbd->config;
int result;
struct nbd_reply reply;
struct nbd_cmd *cmd;
struct request *req = NULL;
u64 handle;
u16 hwq;
u32 tag;
struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
struct iov_iter to;
int ret = 0;
reply.magic = 0;
iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
if (result <= 0) {
if (!nbd_disconnected(config))
dev_err(disk_to_dev(nbd->disk),
"Receive control failed (result %d)\n", result);
return ERR_PTR(result);
}
if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
(unsigned long)ntohl(reply.magic));
return ERR_PTR(-EPROTO);
}
memcpy(&handle, reply.handle, sizeof(handle));
tag = nbd_handle_to_tag(handle);
hwq = blk_mq_unique_tag_to_hwq(tag);
if (hwq < nbd->tag_set.nr_hw_queues)
req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
blk_mq_unique_tag_to_tag(tag));
if (!req || !blk_mq_request_started(req)) {
dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
tag, req);
return ERR_PTR(-ENOENT);
}
trace_nbd_header_received(req, handle);
cmd = blk_mq_rq_to_pdu(req);
mutex_lock(&cmd->lock);
if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
ret = -ENOENT;
goto out;
}
if (cmd->status != BLK_STS_OK) {
dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
req);
ret = -ENOENT;
goto out;
}
if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
req);
ret = -ENOENT;
goto out;
}
if (ntohl(reply.error)) {
dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
ntohl(reply.error));
cmd->status = BLK_STS_IOERR;
goto out;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
if (rq_data_dir(req) != WRITE) {
struct req_iterator iter;
block: Convert bio_for_each_segment() to bvec_iter More prep work for immutable biovecs - with immutable bvecs drivers won't be able to use the biovec directly, they'll need to use helpers that take into account bio->bi_iter.bi_bvec_done. This updates callers for the new usage without changing the implementation yet. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Paul Clements <Paul.Clements@steeleye.com> Cc: Jim Paris <jim@jtan.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com> Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Cc: support@lsi.com Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Quoc-Son Anh <quoc-sonx.anh@intel.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jan Kara <jack@suse.cz> Cc: linux-m68k@lists.linux-m68k.org Cc: linuxppc-dev@lists.ozlabs.org Cc: drbd-user@lists.linbit.com Cc: nbd-general@lists.sourceforge.net Cc: cbe-oss-dev@lists.ozlabs.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Cc: linux-raid@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: DL-MPTFusionLinux@lsi.com Cc: linux-scsi@vger.kernel.org Cc: devel@driverdev.osuosl.org Cc: linux-fsdevel@vger.kernel.org Cc: cluster-devel@redhat.com Cc: linux-mm@kvack.org Acked-by: Geoff Levand <geoff@infradead.org>
2013-11-24 05:19:00 +04:00
struct bio_vec bvec;
rq_for_each_segment(bvec, req, iter) {
iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
if (result <= 0) {
dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
result);
/*
* If we've disconnected, we need to make sure we
* complete this request, otherwise error out
* and let the timeout stuff handle resubmitting
* this request onto another connection.
*/
if (nbd_disconnected(config)) {
cmd->status = BLK_STS_IOERR;
goto out;
}
ret = -EIO;
goto out;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
req, bvec.bv_len);
}
}
out:
trace_nbd_payload_received(req, handle);
mutex_unlock(&cmd->lock);
return ret ? ERR_PTR(ret) : cmd;
}
static void recv_work(struct work_struct *work)
{
struct recv_thread_args *args = container_of(work,
struct recv_thread_args,
work);
struct nbd_device *nbd = args->nbd;
struct nbd_config *config = nbd->config;
struct nbd_cmd *cmd;
struct request *rq;
while (1) {
cmd = nbd_read_stat(nbd, args->index);
if (IS_ERR(cmd)) {
struct nbd_sock *nsock = config->socks[args->index];
mutex_lock(&nsock->tx_lock);
nbd_mark_nsock_dead(nbd, nsock, 1);
mutex_unlock(&nsock->tx_lock);
break;
}
rq = blk_mq_rq_from_pdu(cmd);
if (likely(!blk_should_fake_timeout(rq->q)))
blk_mq_complete_request(rq);
}
nbd_config_put(nbd);
atomic_dec(&config->recv_threads);
wake_up(&config->recv_wq);
kfree(args);
}
static bool nbd_clear_req(struct request *req, void *data, bool reserved)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
mutex_lock(&cmd->lock);
cmd->status = BLK_STS_IOERR;
mutex_unlock(&cmd->lock);
blk_mq_complete_request(req);
return true;
}
static void nbd_clear_que(struct nbd_device *nbd)
{
blk_mq_quiesce_queue(nbd->disk->queue);
blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
blk_mq_unquiesce_queue(nbd->disk->queue);
dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
}
static int find_fallback(struct nbd_device *nbd, int index)
{
struct nbd_config *config = nbd->config;
int new_index = -1;
struct nbd_sock *nsock = config->socks[index];
int fallback = nsock->fallback_index;
if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
return new_index;
if (config->num_connections <= 1) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Dead connection, failed to find a fallback\n");
return new_index;
}
if (fallback >= 0 && fallback < config->num_connections &&
!config->socks[fallback]->dead)
return fallback;
if (nsock->fallback_index < 0 ||
nsock->fallback_index >= config->num_connections ||
config->socks[nsock->fallback_index]->dead) {
int i;
for (i = 0; i < config->num_connections; i++) {
if (i == index)
continue;
if (!config->socks[i]->dead) {
new_index = i;
break;
}
}
nsock->fallback_index = new_index;
if (new_index < 0) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Dead connection, failed to find a fallback\n");
return new_index;
}
}
new_index = nsock->fallback_index;
return new_index;
}
static int wait_for_reconnect(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
if (!config->dead_conn_timeout)
return 0;
if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
return 0;
return wait_event_timeout(config->conn_wait,
atomic_read(&config->live_connections) > 0,
config->dead_conn_timeout) > 0;
}
static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
struct nbd_device *nbd = cmd->nbd;
struct nbd_config *config;
struct nbd_sock *nsock;
int ret;
if (!refcount_inc_not_zero(&nbd->config_refs)) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Socks array is empty\n");
blk_mq_start_request(req);
return -EINVAL;
}
config = nbd->config;
if (index >= config->num_connections) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Attempted send on invalid socket\n");
nbd_config_put(nbd);
blk_mq_start_request(req);
return -EINVAL;
}
cmd->status = BLK_STS_OK;
again:
nsock = config->socks[index];
mutex_lock(&nsock->tx_lock);
if (nsock->dead) {
int old_index = index;
index = find_fallback(nbd, index);
mutex_unlock(&nsock->tx_lock);
if (index < 0) {
if (wait_for_reconnect(nbd)) {
index = old_index;
goto again;
}
/* All the sockets should already be down at this point,
* we just want to make sure that DISCONNECTED is set so
* any requests that come in that were queue'ed waiting
* for the reconnect timer don't trigger the timer again
* and instead just error out.
*/
sock_shutdown(nbd);
nbd_config_put(nbd);
blk_mq_start_request(req);
return -EIO;
}
goto again;
}
/* Handle the case that we have a pending request that was partially
* transmitted that _has_ to be serviced first. We need to call requeue
* here so that it gets put _after_ the request that is already on the
* dispatch list.
*/
blk_mq_start_request(req);
if (unlikely(nsock->pending && nsock->pending != req)) {
nbd_requeue_cmd(cmd);
ret = 0;
goto out;
}
/*
* Some failures are related to the link going down, so anything that
* returns EAGAIN can be retried on a different socket.
*/
ret = nbd_send_cmd(nbd, cmd, index);
if (ret == -EAGAIN) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Request send failed, requeueing\n");
nbd_mark_nsock_dead(nbd, nsock, 1);
nbd_requeue_cmd(cmd);
ret = 0;
}
out:
mutex_unlock(&nsock->tx_lock);
nbd_config_put(nbd);
return ret;
}
static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
int ret;
/*
* Since we look at the bio's to send the request over the network we
* need to make sure the completion work doesn't mark this request done
* before we are done doing our send. This keeps us from dereferencing
* freed data if we have particularly fast completions (ie we get the
* completion before we exit sock_xmit on the last bvec) or in the case
* that the server is misbehaving (or there was an error) before we're
* done sending everything over the wire.
*/
mutex_lock(&cmd->lock);
clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
/* We can be called directly from the user space process, which means we
* could possibly have signals pending so our sendmsg will fail. In
* this case we need to return that we are busy, otherwise error out as
* appropriate.
*/
ret = nbd_handle_cmd(cmd, hctx->queue_num);
if (ret < 0)
ret = BLK_STS_IOERR;
else if (!ret)
ret = BLK_STS_OK;
mutex_unlock(&cmd->lock);
return ret;
}
static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
int *err)
{
struct socket *sock;
*err = 0;
sock = sockfd_lookup(fd, err);
if (!sock)
return NULL;
if (sock->ops->shutdown == sock_no_shutdown) {
dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
*err = -EINVAL;
sockfd_put(sock);
return NULL;
}
return sock;
}
static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
bool netlink)
{
struct nbd_config *config = nbd->config;
struct socket *sock;
struct nbd_sock **socks;
struct nbd_sock *nsock;
int err;
sock = nbd_get_socket(nbd, arg, &err);
if (!sock)
return err;
if (!netlink && !nbd->task_setup &&
!test_bit(NBD_RT_BOUND, &config->runtime_flags))
nbd->task_setup = current;
if (!netlink &&
(nbd->task_setup != current ||
test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
dev_err(disk_to_dev(nbd->disk),
"Device being setup by another task");
err = -EBUSY;
goto put_socket;
}
nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
if (!nsock) {
err = -ENOMEM;
goto put_socket;
}
socks = krealloc(config->socks, (config->num_connections + 1) *
sizeof(struct nbd_sock *), GFP_KERNEL);
if (!socks) {
kfree(nsock);
err = -ENOMEM;
goto put_socket;
}
config->socks = socks;
nsock->fallback_index = -1;
nsock->dead = false;
mutex_init(&nsock->tx_lock);
nsock->sock = sock;
nsock->pending = NULL;
nsock->sent = 0;
nsock->cookie = 0;
socks[config->num_connections++] = nsock;
atomic_inc(&config->live_connections);
return 0;
put_socket:
sockfd_put(sock);
return err;
}
static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
{
struct nbd_config *config = nbd->config;
struct socket *sock, *old;
struct recv_thread_args *args;
int i;
int err;
sock = nbd_get_socket(nbd, arg, &err);
if (!sock)
return err;
args = kzalloc(sizeof(*args), GFP_KERNEL);
if (!args) {
sockfd_put(sock);
return -ENOMEM;
}
for (i = 0; i < config->num_connections; i++) {
struct nbd_sock *nsock = config->socks[i];
if (!nsock->dead)
continue;
mutex_lock(&nsock->tx_lock);
if (!nsock->dead) {
mutex_unlock(&nsock->tx_lock);
continue;
}
sk_set_memalloc(sock->sk);
if (nbd->tag_set.timeout)
sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
atomic_inc(&config->recv_threads);
refcount_inc(&nbd->config_refs);
old = nsock->sock;
nsock->fallback_index = -1;
nsock->sock = sock;
nsock->dead = false;
INIT_WORK(&args->work, recv_work);
args->index = i;
args->nbd = nbd;
nsock->cookie++;
mutex_unlock(&nsock->tx_lock);
sockfd_put(old);
clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
/* We take the tx_mutex in an error path in the recv_work, so we
* need to queue_work outside of the tx_mutex.
*/
queue_work(nbd->recv_workq, &args->work);
atomic_inc(&config->live_connections);
wake_up(&config->conn_wait);
return 0;
}
sockfd_put(sock);
kfree(args);
return -ENOSPC;
}
static void nbd_bdev_reset(struct block_device *bdev)
{
if (bdev->bd_openers > 1)
return;
bd_set_nr_sectors(bdev, 0);
}
static void nbd_parse_flags(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
if (config->flags & NBD_FLAG_READ_ONLY)
set_disk_ro(nbd->disk, true);
else
set_disk_ro(nbd->disk, false);
if (config->flags & NBD_FLAG_SEND_TRIM)
blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
if (config->flags & NBD_FLAG_SEND_FLUSH) {
if (config->flags & NBD_FLAG_SEND_FUA)
blk_queue_write_cache(nbd->disk->queue, true, true);
else
blk_queue_write_cache(nbd->disk->queue, true, false);
}
else
blk_queue_write_cache(nbd->disk->queue, false, false);
}
static void send_disconnects(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
struct nbd_request request = {
.magic = htonl(NBD_REQUEST_MAGIC),
.type = htonl(NBD_CMD_DISC),
};
struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
struct iov_iter from;
int i, ret;
for (i = 0; i < config->num_connections; i++) {
struct nbd_sock *nsock = config->socks[i];
iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
mutex_lock(&nsock->tx_lock);
ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
if (ret <= 0)
dev_err(disk_to_dev(nbd->disk),
"Send disconnect failed %d\n", ret);
mutex_unlock(&nsock->tx_lock);
}
}
static int nbd_disconnect(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
send_disconnects(nbd);
return 0;
}
static void nbd_clear_sock(struct nbd_device *nbd)
{
sock_shutdown(nbd);
nbd_clear_que(nbd);
nbd->task_setup = NULL;
}
static void nbd_config_put(struct nbd_device *nbd)
{
if (refcount_dec_and_mutex_lock(&nbd->config_refs,
&nbd->config_lock)) {
struct nbd_config *config = nbd->config;
nbd_dev_dbg_close(nbd);
nbd_size_clear(nbd);
if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
&config->runtime_flags))
device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
nbd->task_recv = NULL;
nbd_clear_sock(nbd);
if (config->num_connections) {
int i;
for (i = 0; i < config->num_connections; i++) {
sockfd_put(config->socks[i]->sock);
kfree(config->socks[i]);
}
kfree(config->socks);
}
kfree(nbd->config);
nbd->config = NULL;
if (nbd->recv_workq)
destroy_workqueue(nbd->recv_workq);
nbd->recv_workq = NULL;
nbd->tag_set.timeout = 0;
nbd->disk->queue->limits.discard_granularity = 0;
nbd->disk->queue->limits.discard_alignment = 0;
blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
mutex_unlock(&nbd->config_lock);
nbd_put(nbd);
module_put(THIS_MODULE);
}
}
static int nbd_start_device(struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
int num_connections = config->num_connections;
int error = 0, i;
if (nbd->task_recv)
return -EBUSY;
if (!config->socks)
return -EINVAL;
if (num_connections > 1 &&
!(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
return -EINVAL;
}
nbd->recv_workq = alloc_workqueue("knbd%d-recv",
WQ_MEM_RECLAIM | WQ_HIGHPRI |
WQ_UNBOUND, 0, nbd->index);
if (!nbd->recv_workq) {
dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
return -ENOMEM;
}
blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
nbd->task_recv = current;
nbd_parse_flags(nbd);
error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
if (error) {
dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
return error;
}
set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
nbd_dev_dbg_init(nbd);
for (i = 0; i < num_connections; i++) {
struct recv_thread_args *args;
args = kzalloc(sizeof(*args), GFP_KERNEL);
if (!args) {
sock_shutdown(nbd);
/*
* If num_connections is m (2 < m),
* and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
* But NO.(n + 1) failed. We still have n recv threads.
* So, add flush_workqueue here to prevent recv threads
* dropping the last config_refs and trying to destroy
* the workqueue from inside the workqueue.
*/
if (i)
flush_workqueue(nbd->recv_workq);
return -ENOMEM;
}
sk_set_memalloc(config->socks[i]->sock->sk);
if (nbd->tag_set.timeout)
config->socks[i]->sock->sk->sk_sndtimeo =
nbd->tag_set.timeout;
atomic_inc(&config->recv_threads);
refcount_inc(&nbd->config_refs);
INIT_WORK(&args->work, recv_work);
args->nbd = nbd;
args->index = i;
queue_work(nbd->recv_workq, &args->work);
}
nbd_set_size(nbd, config->bytesize, config->blksize);
return error;
}
static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
{
struct nbd_config *config = nbd->config;
int ret;
ret = nbd_start_device(nbd);
if (ret)
return ret;
if (max_part)
set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
mutex_unlock(&nbd->config_lock);
ret = wait_event_interruptible(config->recv_wq,
atomic_read(&config->recv_threads) == 0);
if (ret)
sock_shutdown(nbd);
flush_workqueue(nbd->recv_workq);
mutex_lock(&nbd->config_lock);
nbd_bdev_reset(bdev);
/* user requested, ignore socket errors */
if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
ret = 0;
if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
ret = -ETIMEDOUT;
return ret;
}
static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
struct block_device *bdev)
{
sock_shutdown(nbd);
nbd: replace kill_bdev() with __invalidate_device() again Commit abbbdf12497d ("replace kill_bdev() with __invalidate_device()") once did this, but 29eaadc03649 ("nbd: stop using the bdev everywhere") resurrected kill_bdev() and it has been there since then. So buffer_head mappings still get killed on a server disconnection, and we can still hit the BUG_ON on a filesystem on the top of the nbd device. EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null) block nbd0: Receive control failed (result -32) block nbd0: shutting down sockets print_req_error: I/O error, dev nbd0, sector 66264 flags 3000 EXT4-fs warning (device nbd0): htree_dirblock_to_tree:979: inode #2: lblock 0: comm ls: error -5 reading directory block print_req_error: I/O error, dev nbd0, sector 2264 flags 3000 EXT4-fs error (device nbd0): __ext4_get_inode_loc:4690: inode #2: block 283: comm ls: unable to read itable block EXT4-fs error (device nbd0) in ext4_reserve_inode_write:5894: IO failure ------------[ cut here ]------------ kernel BUG at fs/buffer.c:3057! invalid opcode: 0000 [#1] SMP PTI CPU: 7 PID: 40045 Comm: jbd2/nbd0-8 Not tainted 5.1.0-rc3+ #4 Hardware name: Amazon EC2 m5.12xlarge/, BIOS 1.0 10/16/2017 RIP: 0010:submit_bh_wbc+0x18b/0x190 ... Call Trace: jbd2_write_superblock+0xf1/0x230 [jbd2] ? account_entity_enqueue+0xc5/0xf0 jbd2_journal_update_sb_log_tail+0x94/0xe0 [jbd2] jbd2_journal_commit_transaction+0x12f/0x1d20 [jbd2] ? __switch_to_asm+0x40/0x70 ... ? lock_timer_base+0x67/0x80 kjournald2+0x121/0x360 [jbd2] ? remove_wait_queue+0x60/0x60 kthread+0xf8/0x130 ? commit_timeout+0x10/0x10 [jbd2] ? kthread_bind+0x10/0x10 ret_from_fork+0x35/0x40 With __invalidate_device(), I no longer hit the BUG_ON with sync or unmount on the disconnected device. Fixes: 29eaadc03649 ("nbd: stop using the bdev everywhere") Cc: linux-block@vger.kernel.org Cc: Ratna Manoj Bolla <manoj.br@gmail.com> Cc: nbd@other.debian.org Cc: stable@vger.kernel.org Cc: David Woodhouse <dwmw@amazon.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Munehisa Kamata <kamatam@amazon.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-31 15:13:10 +03:00
__invalidate_device(bdev, true);
nbd_bdev_reset(bdev);
if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
&nbd->config->runtime_flags))
nbd_config_put(nbd);
}
static bool nbd_is_valid_blksize(unsigned long blksize)
{
if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
blksize > PAGE_SIZE)
return false;
return true;
}
static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
{
nbd->tag_set.timeout = timeout * HZ;
if (timeout)
blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
else
blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
}
/* Must be called with config_lock held */
static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
unsigned int cmd, unsigned long arg)
{
struct nbd_config *config = nbd->config;
switch (cmd) {
case NBD_DISCONNECT:
return nbd_disconnect(nbd);
case NBD_CLEAR_SOCK:
nbd_clear_sock_ioctl(nbd, bdev);
return 0;
case NBD_SET_SOCK:
return nbd_add_socket(nbd, arg, false);
case NBD_SET_BLKSIZE:
if (!arg)
arg = NBD_DEF_BLKSIZE;
if (!nbd_is_valid_blksize(arg))
return -EINVAL;
nbd_set_size(nbd, config->bytesize, arg);
return 0;
case NBD_SET_SIZE:
nbd_set_size(nbd, arg, config->blksize);
return 0;
case NBD_SET_SIZE_BLOCKS:
nbd_set_size(nbd, arg * config->blksize,
config->blksize);
return 0;
case NBD_SET_TIMEOUT:
nbd_set_cmd_timeout(nbd, arg);
return 0;
case NBD_SET_FLAGS:
config->flags = arg;
return 0;
case NBD_DO_IT:
return nbd_start_device_ioctl(nbd, bdev);
case NBD_CLEAR_QUE:
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 11:09:47 +03:00
/*
* This is for compatibility only. The queue is always cleared
* by NBD_DO_IT or NBD_CLEAR_SOCK.
*/
return 0;
case NBD_PRINT_DEBUG:
/*
* For compatibility only, we no longer keep a list of
* outstanding requests.
*/
return 0;
}
return -ENOTTY;
}
static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct nbd_device *nbd = bdev->bd_disk->private_data;
struct nbd_config *config = nbd->config;
int error = -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* The block layer will pass back some non-nbd ioctls in case we have
* special handling for them, but we don't so just return an error.
*/
if (_IOC_TYPE(cmd) != 0xab)
return -EINVAL;
mutex_lock(&nbd->config_lock);
/* Don't allow ioctl operations on a nbd device that was created with
* netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
*/
if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
(cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
error = __nbd_ioctl(bdev, nbd, cmd, arg);
else
dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
mutex_unlock(&nbd->config_lock);
return error;
}
static struct nbd_config *nbd_alloc_config(void)
{
struct nbd_config *config;
config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
if (!config)
return NULL;
atomic_set(&config->recv_threads, 0);
init_waitqueue_head(&config->recv_wq);
init_waitqueue_head(&config->conn_wait);
config->blksize = NBD_DEF_BLKSIZE;
atomic_set(&config->live_connections, 0);
try_module_get(THIS_MODULE);
return config;
}
static int nbd_open(struct block_device *bdev, fmode_t mode)
{
struct nbd_device *nbd;
int ret = 0;
mutex_lock(&nbd_index_mutex);
nbd = bdev->bd_disk->private_data;
if (!nbd) {
ret = -ENXIO;
goto out;
}
if (!refcount_inc_not_zero(&nbd->refs)) {
ret = -ENXIO;
goto out;
}
if (!refcount_inc_not_zero(&nbd->config_refs)) {
struct nbd_config *config;
mutex_lock(&nbd->config_lock);
if (refcount_inc_not_zero(&nbd->config_refs)) {
mutex_unlock(&nbd->config_lock);
goto out;
}
config = nbd->config = nbd_alloc_config();
if (!config) {
ret = -ENOMEM;
mutex_unlock(&nbd->config_lock);
goto out;
}
refcount_set(&nbd->config_refs, 1);
refcount_inc(&nbd->refs);
mutex_unlock(&nbd->config_lock);
set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
} else if (nbd_disconnected(nbd->config)) {
set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
}
out:
mutex_unlock(&nbd_index_mutex);
return ret;
}
static void nbd_release(struct gendisk *disk, fmode_t mode)
{
struct nbd_device *nbd = disk->private_data;
struct block_device *bdev = bdget_disk(disk, 0);
if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
bdev->bd_openers == 0)
nbd_disconnect_and_put(nbd);
bdput(bdev);
nbd_config_put(nbd);
nbd_put(nbd);
}
static const struct block_device_operations nbd_fops =
{
.owner = THIS_MODULE,
.open = nbd_open,
.release = nbd_release,
.ioctl = nbd_ioctl,
.compat_ioctl = nbd_ioctl,
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
{
struct nbd_device *nbd = s->private;
if (nbd->task_recv)
seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
return 0;
}
static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
{
return single_open(file, nbd_dbg_tasks_show, inode->i_private);
}
static const struct file_operations nbd_dbg_tasks_ops = {
.open = nbd_dbg_tasks_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
{
struct nbd_device *nbd = s->private;
u32 flags = nbd->config->flags;
seq_printf(s, "Hex: 0x%08x\n\n", flags);
seq_puts(s, "Known flags:\n");
if (flags & NBD_FLAG_HAS_FLAGS)
seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
if (flags & NBD_FLAG_READ_ONLY)
seq_puts(s, "NBD_FLAG_READ_ONLY\n");
if (flags & NBD_FLAG_SEND_FLUSH)
seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
if (flags & NBD_FLAG_SEND_FUA)
seq_puts(s, "NBD_FLAG_SEND_FUA\n");
if (flags & NBD_FLAG_SEND_TRIM)
seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
return 0;
}
static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
{
return single_open(file, nbd_dbg_flags_show, inode->i_private);
}
static const struct file_operations nbd_dbg_flags_ops = {
.open = nbd_dbg_flags_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int nbd_dev_dbg_init(struct nbd_device *nbd)
{
struct dentry *dir;
struct nbd_config *config = nbd->config;
if (!nbd_dbg_dir)
return -EIO;
dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
if (!dir) {
dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
nbd_name(nbd));
return -EIO;
}
config->dbg_dir = dir;
debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
return 0;
}
static void nbd_dev_dbg_close(struct nbd_device *nbd)
{
debugfs_remove_recursive(nbd->config->dbg_dir);
}
static int nbd_dbg_init(void)
{
struct dentry *dbg_dir;
dbg_dir = debugfs_create_dir("nbd", NULL);
if (!dbg_dir)
return -EIO;
nbd_dbg_dir = dbg_dir;
return 0;
}
static void nbd_dbg_close(void)
{
debugfs_remove_recursive(nbd_dbg_dir);
}
#else /* IS_ENABLED(CONFIG_DEBUG_FS) */
static int nbd_dev_dbg_init(struct nbd_device *nbd)
{
return 0;
}
static void nbd_dev_dbg_close(struct nbd_device *nbd)
{
}
static int nbd_dbg_init(void)
{
return 0;
}
static void nbd_dbg_close(void)
{
}
#endif
static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
unsigned int hctx_idx, unsigned int numa_node)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
cmd->nbd = set->driver_data;
cmd->flags = 0;
mutex_init(&cmd->lock);
return 0;
}
static const struct blk_mq_ops nbd_mq_ops = {
.queue_rq = nbd_queue_rq,
.complete = nbd_complete_rq,
.init_request = nbd_init_request,
.timeout = nbd_xmit_timeout,
};
static int nbd_dev_add(int index)
{
struct nbd_device *nbd;
struct gendisk *disk;
struct request_queue *q;
int err = -ENOMEM;
nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
if (!nbd)
goto out;
disk = alloc_disk(1 << part_shift);
if (!disk)
goto out_free_nbd;
if (index >= 0) {
err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
GFP_KERNEL);
if (err == -ENOSPC)
err = -EEXIST;
} else {
err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
if (err >= 0)
index = err;
}
if (err < 0)
goto out_free_disk;
nbd->index = index;
nbd->disk = disk;
nbd->tag_set.ops = &nbd_mq_ops;
nbd->tag_set.nr_hw_queues = 1;
nbd->tag_set.queue_depth = 128;
nbd->tag_set.numa_node = NUMA_NO_NODE;
nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
BLK_MQ_F_BLOCKING;
nbd->tag_set.driver_data = nbd;
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
nbd->destroy_complete = NULL;
err = blk_mq_alloc_tag_set(&nbd->tag_set);
if (err)
goto out_free_idr;
q = blk_mq_init_queue(&nbd->tag_set);
if (IS_ERR(q)) {
err = PTR_ERR(q);
goto out_free_tags;
}
disk->queue = q;
/*
* Tell the block layer that we are not a rotational device
*/
blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
disk->queue->limits.discard_granularity = 0;
disk->queue->limits.discard_alignment = 0;
blk_queue_max_discard_sectors(disk->queue, 0);
blk_queue_max_segment_size(disk->queue, UINT_MAX);
blk_queue_max_segments(disk->queue, USHRT_MAX);
blk_queue_max_hw_sectors(disk->queue, 65536);
disk->queue->limits.max_sectors = 256;
mutex_init(&nbd->config_lock);
refcount_set(&nbd->config_refs, 0);
refcount_set(&nbd->refs, 1);
INIT_LIST_HEAD(&nbd->list);
disk->major = NBD_MAJOR;
disk->first_minor = index << part_shift;
disk->fops = &nbd_fops;
disk->private_data = nbd;
sprintf(disk->disk_name, "nbd%d", index);
add_disk(disk);
nbd_total_devices++;
return index;
out_free_tags:
blk_mq_free_tag_set(&nbd->tag_set);
out_free_idr:
idr_remove(&nbd_index_idr, index);
out_free_disk:
put_disk(disk);
out_free_nbd:
kfree(nbd);
out:
return err;
}
static int find_free_cb(int id, void *ptr, void *data)
{
struct nbd_device *nbd = ptr;
struct nbd_device **found = data;
if (!refcount_read(&nbd->config_refs)) {
*found = nbd;
return 1;
}
return 0;
}
/* Netlink interface. */
static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
[NBD_ATTR_INDEX] = { .type = NLA_U32 },
[NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
[NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
[NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
[NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
[NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
[NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
[NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
[NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
};
static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
[NBD_SOCK_FD] = { .type = NLA_U32 },
};
/* We don't use this right now since we don't parse the incoming list, but we
* still want it here so userspace knows what to expect.
*/
static const struct nla_policy __attribute__((unused))
nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
[NBD_DEVICE_INDEX] = { .type = NLA_U32 },
[NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
};
static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
{
struct nbd_config *config = nbd->config;
u64 bsize = config->blksize;
u64 bytes = config->bytesize;
if (info->attrs[NBD_ATTR_SIZE_BYTES])
bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
if (!bsize)
bsize = NBD_DEF_BLKSIZE;
if (!nbd_is_valid_blksize(bsize)) {
printk(KERN_ERR "Invalid block size %llu\n", bsize);
return -EINVAL;
}
}
if (bytes != config->bytesize || bsize != config->blksize)
nbd_set_size(nbd, bytes, bsize);
return 0;
}
static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
{
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
DECLARE_COMPLETION_ONSTACK(destroy_complete);
struct nbd_device *nbd = NULL;
struct nbd_config *config;
int index = -1;
int ret;
bool put_dev = false;
if (!netlink_capable(skb, CAP_SYS_ADMIN))
return -EPERM;
if (info->attrs[NBD_ATTR_INDEX])
index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
if (!info->attrs[NBD_ATTR_SOCKETS]) {
printk(KERN_ERR "nbd: must specify at least one socket\n");
return -EINVAL;
}
if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
return -EINVAL;
}
again:
mutex_lock(&nbd_index_mutex);
if (index == -1) {
ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
if (ret == 0) {
int new_index;
new_index = nbd_dev_add(-1);
if (new_index < 0) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: failed to add new device\n");
return new_index;
}
nbd = idr_find(&nbd_index_idr, new_index);
}
} else {
nbd = idr_find(&nbd_index_idr, index);
if (!nbd) {
ret = nbd_dev_add(index);
if (ret < 0) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: failed to add new device\n");
return ret;
}
nbd = idr_find(&nbd_index_idr, index);
}
}
if (!nbd) {
printk(KERN_ERR "nbd: couldn't find device at index %d\n",
index);
mutex_unlock(&nbd_index_mutex);
return -EINVAL;
}
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {
nbd->destroy_complete = &destroy_complete;
mutex_unlock(&nbd_index_mutex);
/* Wait untill the the nbd stuff is totally destroyed */
wait_for_completion(&destroy_complete);
goto again;
}
if (!refcount_inc_not_zero(&nbd->refs)) {
mutex_unlock(&nbd_index_mutex);
if (index == -1)
goto again;
printk(KERN_ERR "nbd: device at index %d is going down\n",
index);
return -EINVAL;
}
mutex_unlock(&nbd_index_mutex);
mutex_lock(&nbd->config_lock);
if (refcount_read(&nbd->config_refs)) {
mutex_unlock(&nbd->config_lock);
nbd_put(nbd);
if (index == -1)
goto again;
printk(KERN_ERR "nbd: nbd%d already in use\n", index);
return -EBUSY;
}
if (WARN_ON(nbd->config)) {
mutex_unlock(&nbd->config_lock);
nbd_put(nbd);
return -EINVAL;
}
config = nbd->config = nbd_alloc_config();
if (!nbd->config) {
mutex_unlock(&nbd->config_lock);
nbd_put(nbd);
printk(KERN_ERR "nbd: couldn't allocate config\n");
return -ENOMEM;
}
refcount_set(&nbd->config_refs, 1);
set_bit(NBD_RT_BOUND, &config->runtime_flags);
ret = nbd_genl_size_set(info, nbd);
if (ret)
goto out;
if (info->attrs[NBD_ATTR_TIMEOUT])
nbd_set_cmd_timeout(nbd,
nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
config->dead_conn_timeout =
nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
config->dead_conn_timeout *= HZ;
}
if (info->attrs[NBD_ATTR_SERVER_FLAGS])
config->flags =
nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
&config->runtime_flags);
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
put_dev = true;
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
} else {
clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
}
if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
&config->runtime_flags);
}
}
if (info->attrs[NBD_ATTR_SOCKETS]) {
struct nlattr *attr;
int rem, fd;
nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
rem) {
struct nlattr *socks[NBD_SOCK_MAX+1];
if (nla_type(attr) != NBD_SOCK_ITEM) {
printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
ret = -EINVAL;
goto out;
}
netlink: make validation more configurable for future strictness We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-26 15:07:28 +03:00
ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
attr,
nbd_sock_policy,
info->extack);
if (ret != 0) {
printk(KERN_ERR "nbd: error processing sock list\n");
ret = -EINVAL;
goto out;
}
if (!socks[NBD_SOCK_FD])
continue;
fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
ret = nbd_add_socket(nbd, fd, true);
if (ret)
goto out;
}
}
ret = nbd_start_device(nbd);
out:
mutex_unlock(&nbd->config_lock);
if (!ret) {
set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
refcount_inc(&nbd->config_refs);
nbd_connect_reply(info, nbd->index);
}
nbd_config_put(nbd);
if (put_dev)
nbd_put(nbd);
return ret;
}
static void nbd_disconnect_and_put(struct nbd_device *nbd)
{
mutex_lock(&nbd->config_lock);
nbd_disconnect(nbd);
nbd_clear_sock(nbd);
mutex_unlock(&nbd->config_lock);
/*
* Make sure recv thread has finished, so it does not drop the last
* config ref and try to destroy the workqueue from inside the work
* queue.
*/
flush_workqueue(nbd->recv_workq);
if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
&nbd->config->runtime_flags))
nbd_config_put(nbd);
}
static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
{
struct nbd_device *nbd;
int index;
if (!netlink_capable(skb, CAP_SYS_ADMIN))
return -EPERM;
if (!info->attrs[NBD_ATTR_INDEX]) {
printk(KERN_ERR "nbd: must specify an index to disconnect\n");
return -EINVAL;
}
index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
mutex_lock(&nbd_index_mutex);
nbd = idr_find(&nbd_index_idr, index);
if (!nbd) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: couldn't find device at index %d\n",
index);
return -EINVAL;
}
if (!refcount_inc_not_zero(&nbd->refs)) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: device at index %d is going down\n",
index);
return -EINVAL;
}
mutex_unlock(&nbd_index_mutex);
if (!refcount_inc_not_zero(&nbd->config_refs)) {
nbd_put(nbd);
return 0;
}
nbd_disconnect_and_put(nbd);
nbd_config_put(nbd);
nbd_put(nbd);
return 0;
}
static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
{
struct nbd_device *nbd = NULL;
struct nbd_config *config;
int index;
int ret = 0;
bool put_dev = false;
if (!netlink_capable(skb, CAP_SYS_ADMIN))
return -EPERM;
if (!info->attrs[NBD_ATTR_INDEX]) {
printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
return -EINVAL;
}
index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
mutex_lock(&nbd_index_mutex);
nbd = idr_find(&nbd_index_idr, index);
if (!nbd) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
index);
return -EINVAL;
}
if (!refcount_inc_not_zero(&nbd->refs)) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: device at index %d is going down\n",
index);
return -EINVAL;
}
mutex_unlock(&nbd_index_mutex);
if (!refcount_inc_not_zero(&nbd->config_refs)) {
dev_err(nbd_to_dev(nbd),
"not configured, cannot reconfigure\n");
nbd_put(nbd);
return -EINVAL;
}
mutex_lock(&nbd->config_lock);
config = nbd->config;
if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
!nbd->task_recv) {
dev_err(nbd_to_dev(nbd),
"not configured, cannot reconfigure\n");
ret = -EINVAL;
goto out;
}
ret = nbd_genl_size_set(info, nbd);
if (ret)
goto out;
if (info->attrs[NBD_ATTR_TIMEOUT])
nbd_set_cmd_timeout(nbd,
nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
config->dead_conn_timeout =
nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
config->dead_conn_timeout *= HZ;
}
if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
&config->runtime_flags))
put_dev = true;
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
} else {
if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT,
&config->runtime_flags))
refcount_inc(&nbd->refs);
nbd: fix possible page fault for nbd disk When the NBD_CFLAG_DESTROY_ON_DISCONNECT flag is set and at the same time when the socket is closed due to the server daemon is restarted, just before the last DISCONNET is totally done if we start a new connection by using the old nbd_index, there will be crashing randomly, like: <3>[ 110.151949] block nbd1: Receive control failed (result -32) <1>[ 110.152024] BUG: unable to handle page fault for address: 0000058000000840 <1>[ 110.152063] #PF: supervisor read access in kernel mode <1>[ 110.152083] #PF: error_code(0x0000) - not-present page <6>[ 110.152094] PGD 0 P4D 0 <4>[ 110.152106] Oops: 0000 [#1] SMP PTI <4>[ 110.152120] CPU: 0 PID: 6698 Comm: kworker/u5:1 Kdump: loaded Not tainted 5.3.0-rc4+ #2 <4>[ 110.152136] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 <4>[ 110.152166] Workqueue: knbd-recv recv_work [nbd] <4>[ 110.152187] RIP: 0010:__dev_printk+0xd/0x67 <4>[ 110.152206] Code: 10 e8 c5 fd ff ff 48 8b 4c 24 18 65 48 33 0c 25 28 00 [...] <4>[ 110.152244] RSP: 0018:ffffa41581f13d18 EFLAGS: 00010206 <4>[ 110.152256] RAX: ffffa41581f13d30 RBX: ffff96dd7374e900 RCX: 0000000000000000 <4>[ 110.152271] RDX: ffffa41581f13d20 RSI: 00000580000007f0 RDI: ffffffff970ec24f <4>[ 110.152285] RBP: ffffa41581f13d80 R08: ffff96dd7fc17908 R09: 0000000000002e56 <4>[ 110.152299] R10: ffffffff970ec24f R11: 0000000000000003 R12: ffff96dd7374e900 <4>[ 110.152313] R13: 0000000000000000 R14: ffff96dd7374e9d8 R15: ffff96dd6e3b02c8 <4>[ 110.152329] FS: 0000000000000000(0000) GS:ffff96dd7fc00000(0000) knlGS:0000000000000000 <4>[ 110.152362] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 110.152383] CR2: 0000058000000840 CR3: 0000000067cc6002 CR4: 00000000001606f0 <4>[ 110.152401] Call Trace: <4>[ 110.152422] _dev_err+0x6c/0x83 <4>[ 110.152435] nbd_read_stat.cold+0xda/0x578 [nbd] <4>[ 110.152448] ? __switch_to_asm+0x34/0x70 <4>[ 110.152468] ? __switch_to_asm+0x40/0x70 <4>[ 110.152478] ? __switch_to_asm+0x34/0x70 <4>[ 110.152491] ? __switch_to_asm+0x40/0x70 <4>[ 110.152501] ? __switch_to_asm+0x34/0x70 <4>[ 110.152511] ? __switch_to_asm+0x40/0x70 <4>[ 110.152522] ? __switch_to_asm+0x34/0x70 <4>[ 110.152533] recv_work+0x35/0x9e [nbd] <4>[ 110.152547] process_one_work+0x19d/0x340 <4>[ 110.152558] worker_thread+0x50/0x3b0 <4>[ 110.152568] kthread+0xfb/0x130 <4>[ 110.152577] ? process_one_work+0x340/0x340 <4>[ 110.152609] ? kthread_park+0x80/0x80 <4>[ 110.152637] ret_from_fork+0x35/0x40 This is very easy to reproduce by running the nbd-runner. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17 14:56:06 +03:00
clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
}
if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
&config->runtime_flags);
} else {
clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
&config->runtime_flags);
}
}
if (info->attrs[NBD_ATTR_SOCKETS]) {
struct nlattr *attr;
int rem, fd;
nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
rem) {
struct nlattr *socks[NBD_SOCK_MAX+1];
if (nla_type(attr) != NBD_SOCK_ITEM) {
printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
ret = -EINVAL;
goto out;
}
netlink: make validation more configurable for future strictness We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-26 15:07:28 +03:00
ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
attr,
nbd_sock_policy,
info->extack);
if (ret != 0) {
printk(KERN_ERR "nbd: error processing sock list\n");
ret = -EINVAL;
goto out;
}
if (!socks[NBD_SOCK_FD])
continue;
fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
ret = nbd_reconnect_socket(nbd, fd);
if (ret) {
if (ret == -ENOSPC)
ret = 0;
goto out;
}
dev_info(nbd_to_dev(nbd), "reconnected socket\n");
}
}
out:
mutex_unlock(&nbd->config_lock);
nbd_config_put(nbd);
nbd_put(nbd);
if (put_dev)
nbd_put(nbd);
return ret;
}
static const struct genl_small_ops nbd_connect_genl_ops[] = {
{
.cmd = NBD_CMD_CONNECT,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = nbd_genl_connect,
},
{
.cmd = NBD_CMD_DISCONNECT,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = nbd_genl_disconnect,
},
{
.cmd = NBD_CMD_RECONFIGURE,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = nbd_genl_reconfigure,
},
{
.cmd = NBD_CMD_STATUS,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = nbd_genl_status,
},
};
static const struct genl_multicast_group nbd_mcast_grps[] = {
{ .name = NBD_GENL_MCAST_GROUP_NAME, },
};
static struct genl_family nbd_genl_family __ro_after_init = {
.hdrsize = 0,
.name = NBD_GENL_FAMILY_NAME,
.version = NBD_GENL_VERSION,
.module = THIS_MODULE,
.small_ops = nbd_connect_genl_ops,
.n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
.maxattr = NBD_ATTR_MAX,
.policy = nbd_attr_policy,
.mcgrps = nbd_mcast_grps,
.n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
};
static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
{
struct nlattr *dev_opt;
u8 connected = 0;
int ret;
/* This is a little racey, but for status it's ok. The
* reason we don't take a ref here is because we can't
* take a ref in the index == -1 case as we would need
* to put under the nbd_index_mutex, which could
* deadlock if we are configured to remove ourselves
* once we're disconnected.
*/
if (refcount_read(&nbd->config_refs))
connected = 1;
dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
if (!dev_opt)
return -EMSGSIZE;
ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
if (ret)
return -EMSGSIZE;
ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
connected);
if (ret)
return -EMSGSIZE;
nla_nest_end(reply, dev_opt);
return 0;
}
static int status_cb(int id, void *ptr, void *data)
{
struct nbd_device *nbd = ptr;
return populate_nbd_status(nbd, (struct sk_buff *)data);
}
static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
{
struct nlattr *dev_list;
struct sk_buff *reply;
void *reply_head;
size_t msg_size;
int index = -1;
int ret = -ENOMEM;
if (info->attrs[NBD_ATTR_INDEX])
index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
mutex_lock(&nbd_index_mutex);
msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
nla_attr_size(sizeof(u8)));
msg_size *= (index == -1) ? nbd_total_devices : 1;
reply = genlmsg_new(msg_size, GFP_KERNEL);
if (!reply)
goto out;
reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
NBD_CMD_STATUS);
if (!reply_head) {
nlmsg_free(reply);
goto out;
}
dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
if (index == -1) {
ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
if (ret) {
nlmsg_free(reply);
goto out;
}
} else {
struct nbd_device *nbd;
nbd = idr_find(&nbd_index_idr, index);
if (nbd) {
ret = populate_nbd_status(nbd, reply);
if (ret) {
nlmsg_free(reply);
goto out;
}
}
}
nla_nest_end(reply, dev_list);
genlmsg_end(reply, reply_head);
ret = genlmsg_reply(reply, info);
out:
mutex_unlock(&nbd_index_mutex);
return ret;
}
static void nbd_connect_reply(struct genl_info *info, int index)
{
struct sk_buff *skb;
void *msg_head;
int ret;
skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
if (!skb)
return;
msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
NBD_CMD_CONNECT);
if (!msg_head) {
nlmsg_free(skb);
return;
}
ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
if (ret) {
nlmsg_free(skb);
return;
}
genlmsg_end(skb, msg_head);
genlmsg_reply(skb, info);
}
static void nbd_mcast_index(int index)
{
struct sk_buff *skb;
void *msg_head;
int ret;
skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
if (!skb)
return;
msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
NBD_CMD_LINK_DEAD);
if (!msg_head) {
nlmsg_free(skb);
return;
}
ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
if (ret) {
nlmsg_free(skb);
return;
}
genlmsg_end(skb, msg_head);
genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
}
static void nbd_dead_link_work(struct work_struct *work)
{
struct link_dead_args *args = container_of(work, struct link_dead_args,
work);
nbd_mcast_index(args->index);
kfree(args);
}
static int __init nbd_init(void)
{
int i;
BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
NBD: add partition support Permit the use of partitions with network block devices (NBD). A new parameter is introduced to define how many partition we want to be able to manage per network block device. This parameter is "max_part". For instance, to manage 63 partitions / loop device, we will do: [on the server side] # nbd-server 1234 /dev/sdb [on the client side] # modprobe nbd max_part=63 # ls -l /dev/nbd* brw-rw---- 1 root disk 43, 0 2008-03-25 11:14 /dev/nbd0 brw-rw---- 1 root disk 43, 64 2008-03-25 11:11 /dev/nbd1 brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10 brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11 brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12 brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13 brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14 brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15 brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2 brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3 brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4 brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5 brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6 brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7 brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8 brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9 # nbd-client localhost 1234 /dev/nbd0 Negotiation: ..size = 80418240KB bs=1024, sz=80418240 -------NOTE, RFC: partition table is not automatically read. The driver sets bdev->bd_invalidated to 1 to force the read of the partition table of the device, but this is done only on an open of the device. So we have to do a "touch /dev/nbdX" or something like that. It can't be done from the nbd-client or nbd driver because at this level we can't ask to read the partition table and to serve the request at the same time (-> deadlock) If someone has a better idea, I'm open to any suggestion. -------NOTE, RFC # fdisk -l /dev/nbd0 Disk /dev/nbd0: 82.3 GB, 82348277760 bytes 255 heads, 63 sectors/track, 10011 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/nbd0p1 * 1 9965 80043831 83 Linux /dev/nbd0p2 9966 10011 369495 5 Extended /dev/nbd0p5 9966 10011 369463+ 82 Linux swap / Solaris # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 brw-rw---- 1 root disk 43, 1 2008-03-25 11:16 /dev/nbd0p1 brw-rw---- 1 root disk 43, 2 2008-03-25 11:16 /dev/nbd0p2 brw-rw---- 1 root disk 43, 5 2008-03-25 11:16 /dev/nbd0p5 # mount /dev/nbd0p1 /mnt # ls /mnt bin dev initrd lost+found opt sbin sys var boot etc initrd.img media proc selinux tmp vmlinuz cdrom home lib mnt root srv usr # umount /mnt # nbd-client -d /dev/nbd0 # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 -------NOTE On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table: as the size of the device is 0, we don't have to serve the partition manager request (-> no deadlock). -------NOTE Signed-off-by: Paul Clements <paul.clements@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:02:51 +04:00
if (max_part < 0) {
printk(KERN_ERR "nbd: max_part must be >= 0\n");
NBD: add partition support Permit the use of partitions with network block devices (NBD). A new parameter is introduced to define how many partition we want to be able to manage per network block device. This parameter is "max_part". For instance, to manage 63 partitions / loop device, we will do: [on the server side] # nbd-server 1234 /dev/sdb [on the client side] # modprobe nbd max_part=63 # ls -l /dev/nbd* brw-rw---- 1 root disk 43, 0 2008-03-25 11:14 /dev/nbd0 brw-rw---- 1 root disk 43, 64 2008-03-25 11:11 /dev/nbd1 brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10 brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11 brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12 brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13 brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14 brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15 brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2 brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3 brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4 brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5 brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6 brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7 brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8 brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9 # nbd-client localhost 1234 /dev/nbd0 Negotiation: ..size = 80418240KB bs=1024, sz=80418240 -------NOTE, RFC: partition table is not automatically read. The driver sets bdev->bd_invalidated to 1 to force the read of the partition table of the device, but this is done only on an open of the device. So we have to do a "touch /dev/nbdX" or something like that. It can't be done from the nbd-client or nbd driver because at this level we can't ask to read the partition table and to serve the request at the same time (-> deadlock) If someone has a better idea, I'm open to any suggestion. -------NOTE, RFC # fdisk -l /dev/nbd0 Disk /dev/nbd0: 82.3 GB, 82348277760 bytes 255 heads, 63 sectors/track, 10011 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/nbd0p1 * 1 9965 80043831 83 Linux /dev/nbd0p2 9966 10011 369495 5 Extended /dev/nbd0p5 9966 10011 369463+ 82 Linux swap / Solaris # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 brw-rw---- 1 root disk 43, 1 2008-03-25 11:16 /dev/nbd0p1 brw-rw---- 1 root disk 43, 2 2008-03-25 11:16 /dev/nbd0p2 brw-rw---- 1 root disk 43, 5 2008-03-25 11:16 /dev/nbd0p5 # mount /dev/nbd0p1 /mnt # ls /mnt bin dev initrd lost+found opt sbin sys var boot etc initrd.img media proc selinux tmp vmlinuz cdrom home lib mnt root srv usr # umount /mnt # nbd-client -d /dev/nbd0 # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 -------NOTE On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table: as the size of the device is 0, we don't have to serve the partition manager request (-> no deadlock). -------NOTE Signed-off-by: Paul Clements <paul.clements@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:02:51 +04:00
return -EINVAL;
}
part_shift = 0;
if (max_part > 0) {
NBD: add partition support Permit the use of partitions with network block devices (NBD). A new parameter is introduced to define how many partition we want to be able to manage per network block device. This parameter is "max_part". For instance, to manage 63 partitions / loop device, we will do: [on the server side] # nbd-server 1234 /dev/sdb [on the client side] # modprobe nbd max_part=63 # ls -l /dev/nbd* brw-rw---- 1 root disk 43, 0 2008-03-25 11:14 /dev/nbd0 brw-rw---- 1 root disk 43, 64 2008-03-25 11:11 /dev/nbd1 brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10 brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11 brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12 brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13 brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14 brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15 brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2 brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3 brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4 brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5 brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6 brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7 brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8 brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9 # nbd-client localhost 1234 /dev/nbd0 Negotiation: ..size = 80418240KB bs=1024, sz=80418240 -------NOTE, RFC: partition table is not automatically read. The driver sets bdev->bd_invalidated to 1 to force the read of the partition table of the device, but this is done only on an open of the device. So we have to do a "touch /dev/nbdX" or something like that. It can't be done from the nbd-client or nbd driver because at this level we can't ask to read the partition table and to serve the request at the same time (-> deadlock) If someone has a better idea, I'm open to any suggestion. -------NOTE, RFC # fdisk -l /dev/nbd0 Disk /dev/nbd0: 82.3 GB, 82348277760 bytes 255 heads, 63 sectors/track, 10011 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/nbd0p1 * 1 9965 80043831 83 Linux /dev/nbd0p2 9966 10011 369495 5 Extended /dev/nbd0p5 9966 10011 369463+ 82 Linux swap / Solaris # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 brw-rw---- 1 root disk 43, 1 2008-03-25 11:16 /dev/nbd0p1 brw-rw---- 1 root disk 43, 2 2008-03-25 11:16 /dev/nbd0p2 brw-rw---- 1 root disk 43, 5 2008-03-25 11:16 /dev/nbd0p5 # mount /dev/nbd0p1 /mnt # ls /mnt bin dev initrd lost+found opt sbin sys var boot etc initrd.img media proc selinux tmp vmlinuz cdrom home lib mnt root srv usr # umount /mnt # nbd-client -d /dev/nbd0 # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 -------NOTE On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table: as the size of the device is 0, we don't have to serve the partition manager request (-> no deadlock). -------NOTE Signed-off-by: Paul Clements <paul.clements@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:02:51 +04:00
part_shift = fls(max_part);
/*
* Adjust max_part according to part_shift as it is exported
* to user space so that user can know the max number of
* partition kernel should be able to manage.
*
* Note that -1 is required because partition 0 is reserved
* for the whole disk.
*/
max_part = (1UL << part_shift) - 1;
}
nbd: limit module parameters to a sane value The 'max_part' parameter controls the number of maximum partition a nbd device can have. However if a user specifies very large value it would exceed the limitation of device minor number and can cause a kernel oops (or, at least, produce invalid device nodes in some cases). In addition, specifying large 'nbds_max' value causes same problem for the same reason. On my desktop, following command results to the kernel bug: $ sudo modprobe nbd max_part=100000 kernel BUG at /media/Linux_Data/project/linux/fs/sysfs/group.c:65! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/devices/virtual/block/nbd4/range CPU 1 Modules linked in: nbd(+) bridge stp llc kvm_intel kvm asus_atk0110 sg sr_mod cdrom Pid: 2522, comm: modprobe Tainted: G W 2.6.39-leonard+ #159 System manufacturer System Product Name/P5G41TD-M PRO RIP: 0010:[<ffffffff8115aa08>] [<ffffffff8115aa08>] internal_create_group+0x2f/0x166 RSP: 0018:ffff8801009f1de8 EFLAGS: 00010246 RAX: 00000000ffffffef RBX: ffff880103920478 RCX: 00000000000a7bd3 RDX: ffffffff81a2dbe0 RSI: 0000000000000000 RDI: ffff880103920478 RBP: ffff8801009f1e38 R08: ffff880103920468 R09: ffff880103920478 R10: ffff8801009f1de8 R11: ffff88011eccbb68 R12: ffffffff81a2dbe0 R13: ffff880103920468 R14: 0000000000000000 R15: ffff880103920400 FS: 00007f3c49de9700(0000) GS:ffff88011f800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f3b7fe7c000 CR3: 00000000cd58d000 CR4: 00000000000406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process modprobe (pid: 2522, threadinfo ffff8801009f0000, task ffff8801009a93a0) Stack: ffff8801009f1e58 ffffffff812e8f6e ffff8801009f1e58 ffffffff812e7a80 ffff880000000010 ffff880103920400 ffff8801002fd0c0 ffff880103920468 0000000000000011 ffff880103920400 ffff8801009f1e48 ffffffff8115ab6a Call Trace: [<ffffffff812e8f6e>] ? device_add+0x4f1/0x5e4 [<ffffffff812e7a80>] ? dev_set_name+0x41/0x43 [<ffffffff8115ab6a>] sysfs_create_group+0x13/0x15 [<ffffffff810b857e>] blk_trace_init_sysfs+0x14/0x16 [<ffffffff811ee58b>] blk_register_queue+0x4c/0xfd [<ffffffff811f3bdf>] add_disk+0xe4/0x29c [<ffffffffa007e2ab>] nbd_init+0x2ab/0x30d [nbd] [<ffffffffa007e000>] ? 0xffffffffa007dfff [<ffffffff8100020f>] do_one_initcall+0x7f/0x13e [<ffffffff8107ab0a>] sys_init_module+0xa1/0x1e3 [<ffffffff814f3542>] system_call_fastpath+0x16/0x1b Code: 41 57 41 56 41 55 41 54 53 48 83 ec 28 0f 1f 44 00 00 48 89 fb 41 89 f6 49 89 d4 48 85 ff 74 0b 85 f6 75 0b 48 83 7f 30 00 75 14 <0f> 0b eb fe b9 ea ff ff ff 48 83 7f 30 00 0f 84 09 01 00 00 49 RIP [<ffffffff8115aa08>] internal_create_group+0x2f/0x166 RSP <ffff8801009f1de8> ---[ end trace 753285ffbf72c57c ]--- Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Laurent Vivier <Laurent.Vivier@bull.net> Cc: Paul Clements <Paul.Clements@steeleye.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-28 16:44:46 +04:00
if ((1UL << part_shift) > DISK_MAX_PARTS)
return -EINVAL;
if (nbds_max > 1UL << (MINORBITS - part_shift))
return -EINVAL;
if (register_blkdev(NBD_MAJOR, "nbd"))
return -EIO;
if (genl_register_family(&nbd_genl_family)) {
unregister_blkdev(NBD_MAJOR, "nbd");
return -EINVAL;
}
nbd_dbg_init();
mutex_lock(&nbd_index_mutex);
for (i = 0; i < nbds_max; i++)
nbd_dev_add(i);
mutex_unlock(&nbd_index_mutex);
return 0;
}
static int nbd_exit_cb(int id, void *ptr, void *data)
{
struct list_head *list = (struct list_head *)data;
struct nbd_device *nbd = ptr;
list_add_tail(&nbd->list, list);
return 0;
}
static void __exit nbd_cleanup(void)
{
struct nbd_device *nbd;
LIST_HEAD(del_list);
nbd_dbg_close();
mutex_lock(&nbd_index_mutex);
idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
mutex_unlock(&nbd_index_mutex);
while (!list_empty(&del_list)) {
nbd = list_first_entry(&del_list, struct nbd_device, list);
list_del_init(&nbd->list);
if (refcount_read(&nbd->refs) != 1)
printk(KERN_ERR "nbd: possibly leaking a device\n");
nbd_put(nbd);
}
idr_destroy(&nbd_index_idr);
genl_unregister_family(&nbd_genl_family);
unregister_blkdev(NBD_MAJOR, "nbd");
}
module_init(nbd_init);
module_exit(nbd_cleanup);
MODULE_DESCRIPTION("Network Block Device");
MODULE_LICENSE("GPL");
module_param(nbds_max, int, 0444);
NBD: add partition support Permit the use of partitions with network block devices (NBD). A new parameter is introduced to define how many partition we want to be able to manage per network block device. This parameter is "max_part". For instance, to manage 63 partitions / loop device, we will do: [on the server side] # nbd-server 1234 /dev/sdb [on the client side] # modprobe nbd max_part=63 # ls -l /dev/nbd* brw-rw---- 1 root disk 43, 0 2008-03-25 11:14 /dev/nbd0 brw-rw---- 1 root disk 43, 64 2008-03-25 11:11 /dev/nbd1 brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10 brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11 brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12 brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13 brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14 brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15 brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2 brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3 brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4 brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5 brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6 brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7 brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8 brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9 # nbd-client localhost 1234 /dev/nbd0 Negotiation: ..size = 80418240KB bs=1024, sz=80418240 -------NOTE, RFC: partition table is not automatically read. The driver sets bdev->bd_invalidated to 1 to force the read of the partition table of the device, but this is done only on an open of the device. So we have to do a "touch /dev/nbdX" or something like that. It can't be done from the nbd-client or nbd driver because at this level we can't ask to read the partition table and to serve the request at the same time (-> deadlock) If someone has a better idea, I'm open to any suggestion. -------NOTE, RFC # fdisk -l /dev/nbd0 Disk /dev/nbd0: 82.3 GB, 82348277760 bytes 255 heads, 63 sectors/track, 10011 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/nbd0p1 * 1 9965 80043831 83 Linux /dev/nbd0p2 9966 10011 369495 5 Extended /dev/nbd0p5 9966 10011 369463+ 82 Linux swap / Solaris # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 brw-rw---- 1 root disk 43, 1 2008-03-25 11:16 /dev/nbd0p1 brw-rw---- 1 root disk 43, 2 2008-03-25 11:16 /dev/nbd0p2 brw-rw---- 1 root disk 43, 5 2008-03-25 11:16 /dev/nbd0p5 # mount /dev/nbd0p1 /mnt # ls /mnt bin dev initrd lost+found opt sbin sys var boot etc initrd.img media proc selinux tmp vmlinuz cdrom home lib mnt root srv usr # umount /mnt # nbd-client -d /dev/nbd0 # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 -------NOTE On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table: as the size of the device is 0, we don't have to serve the partition manager request (-> no deadlock). -------NOTE Signed-off-by: Paul Clements <paul.clements@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 12:02:51 +04:00
MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
module_param(max_part, int, 0444);
MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");