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[ Upstream commit 93cdf49f6eca5e23f6546b8f28457b2e6a6961d9 ]
When the length of best extent found is less than the length of goal extent
we need to make sure that the best extent atleast covers the start of the
original request. This is done by adjusting the ac_b_ex.fe_logical (logical
start) of the extent.
While doing so, the current logic sometimes results in the best extent's
logical range overflowing the goal extent. Since this best extent is later
added to the inode preallocation list, we have a possibility of introducing
overlapping preallocations. This is discussed in detail here [1].
As per Jan's suggestion, to fix this, replace the existing logic with the
below logic for adjusting best extent as it keeps fragmentation in check
while ensuring logical range of best extent doesn't overflow out of goal
extent:
1. Check if best extent can be kept at end of goal range and still cover
original start.
2. Else, check if best extent can be kept at start of goal range and still
cover original start.
3. Else, keep the best extent at start of original request.
Also, add a few extra BUG_ONs that might help catch errors faster.
[1] https://lore.kernel.org/r/Y+OGkVvzPN0RMv0O@li-bb2b2a4c-3307-11b2-a85c-8fa5c3a69313.ibm.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/f96aca6d415b36d1f90db86c1a8cd7e2e9d7ab0e.1679731817.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b07ffe6927c75d99af534d685282ea188d9f71a6 ]
We need to set ac_g_ex to notify the goal start used in
ext4_mb_find_by_goal. Set ac_g_ex instead of ac_f_ex in
ext4_mb_normalize_request.
Besides we should assure goal start is in range [first_data_block,
blocks_count) as ext4_mb_initialize_context does.
[ Added a check to make sure size is less than ar->pright; otherwise
we could end up passing an underflowed value of ar->pright - size to
ext4_get_group_no_and_offset(), which will trigger a BUG_ON later on.
- TYT ]
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230303172120.3800725-2-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5354b2af34064a4579be8bc0e2f15a7b70f14b5f ]
Previously, ext4_get_group_info() would treat an invalid group number
as BUG(), since in theory it should never happen. However, if a
malicious attaker (or fuzzer) modifies the superblock via the block
device while it is the file system is mounted, it is possible for
s_first_data_block to get set to a very large number. In that case,
when calculating the block group of some block number (such as the
starting block of a preallocation region), could result in an
underflow and very large block group number. Then the BUG_ON check in
ext4_get_group_info() would fire, resutling in a denial of service
attack that can be triggered by root or someone with write access to
the block device.
For a quality of implementation perspective, it's best that even if
the system administrator does something that they shouldn't, that it
will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info()
will call ext4_error and return NULL. We also add fallback code in
all of the callers of ext4_get_group_info() that it might NULL.
Also, since ext4_get_group_info() was already borderline to be an
inline function, un-inline it. The results in a next reduction of the
compiled text size of ext4 by roughly 2k.
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230430154311.579720-2-tytso@mit.edu
Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 01e4ca29451760b9ac10b4cdc231c52150842643 ]
If EXT4_MB_HINT_GOAL_ONLY is set, ext4_mb_regular_allocator will only
allocate blocks from ext4_mb_find_by_goal. Allow to find by goal in
ext4_mb_find_by_goal if EXT4_MB_HINT_GOAL_ONLY is set or allocation
with EXT4_MB_HINT_GOAL_ONLY set will always fail.
EXT4_MB_HINT_GOAL_ONLY is not used at all, so the problem is not
found for now.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20230303172120.3800725-3-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stable-dep-of: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6 upstream.
Block range to free is validated in ext4_free_blocks() using
ext4_inode_block_valid() and then it's passed to ext4_mb_clear_bb().
However in some situations on bigalloc file system the range might be
adjusted after the validation in ext4_free_blocks() which can lead to
troubles on corrupted file systems such as one found by syzkaller that
resulted in the following BUG
kernel BUG at fs/ext4/ext4.h:3319!
PREEMPT SMP NOPTI
CPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014
RIP: 0010:ext4_free_blocks+0x95e/0xa90
Call Trace:
<TASK>
? lock_timer_base+0x61/0x80
? __es_remove_extent+0x5a/0x760
? __mod_timer+0x256/0x380
? ext4_ind_truncate_ensure_credits+0x90/0x220
ext4_clear_blocks+0x107/0x1b0
ext4_free_data+0x15b/0x170
ext4_ind_truncate+0x214/0x2c0
? _raw_spin_unlock+0x15/0x30
? ext4_discard_preallocations+0x15a/0x410
? ext4_journal_check_start+0xe/0x90
? __ext4_journal_start_sb+0x2f/0x110
ext4_truncate+0x1b5/0x460
? __ext4_journal_start_sb+0x2f/0x110
ext4_evict_inode+0x2b4/0x6f0
evict+0xd0/0x1d0
ext4_enable_quotas+0x11f/0x1f0
ext4_orphan_cleanup+0x3de/0x430
? proc_create_seq_private+0x43/0x50
ext4_fill_super+0x295f/0x3ae0
? snprintf+0x39/0x40
? sget_fc+0x19c/0x330
? ext4_reconfigure+0x850/0x850
get_tree_bdev+0x16d/0x260
vfs_get_tree+0x25/0xb0
path_mount+0x431/0xa70
__x64_sys_mount+0xe2/0x120
do_syscall_64+0x5b/0x80
? do_user_addr_fault+0x1e2/0x670
? exc_page_fault+0x70/0x170
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fdf4e512ace
Fix it by making sure that the block range is properly validated before
used every time it changes in ext4_free_blocks() or ext4_mb_clear_bb().
Link: https://syzkaller.appspot.com/bug?id=5266d464285a03cee9dbfda7d2452a72c3c2ae7c
Reported-by: syzbot+15cd994e273307bf5cfa@syzkaller.appspotmail.com
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: Tadeusz Struk <tadeusz.struk@linaro.org>
Tested-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Link: https://lore.kernel.org/r/20220714165903.58260-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a00b482b82fb098956a5bed22bd7873e56f152f1 upstream.
Currently ext4_mb_clear_bb() & ext4_group_add_blocks() only checks
whether the given block ranges (which is to be freed) belongs to any FS
metadata blocks or not, of the block's respective block group.
But to detect any FS error early, it is better to add more strict
checkings in those functions which checks whether the given blocks
belongs to any critical FS metadata or not within system-zone.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/ddd9143d064774e32d6364a99667817c6e8bfdc0.1644992610.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ac3939db99f99667b8eb670cf4baf292896e72d upstream.
ext4_free_blocks() function became too long and confusing, this patch
just pulls out the ext4_mb_clear_bb() function logic from it
which clears the block bitmap and frees it.
No functionality change in this patch
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/22c30fbb26ba409cf8aa5f0c7912970272c459e8.1644992610.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a9f2a2931d0e197ab28c6007966053fdababd53f upstream.
Curently we don't use any preallocation when a file is already closed
when allocating blocks (from writeback code when converting delayed
allocation). However for small files, using locality group preallocation
is actually desirable as that is not specific to a particular file.
Rather it is a method to pack small files together to reduce
fragmentation and for that the fact the file is closed is actually even
stronger hint the file would benefit from packing. So change the logic
to allow locality group preallocation in this case.
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@kernel.org
Reported-and-tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com/
Link: https://lore.kernel.org/r/20220908092136.11770-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1940265ede6683f6317cba0d428ce6505eaca944 upstream.
mb_set_largest_free_order() updates lists containing groups with largest
chunk of free space of given order. The way it updates it leads to
always moving the group to the tail of the list. Thus allocations
looking for free space of given order effectively end up cycling through
all groups (and due to initialization in last to first order). This
spreads allocations among block groups which reduces performance for
rotating disks or low-end flash media. Change
mb_set_largest_free_order() to only update lists if the order of the
largest free chunk in the group changed.
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@kernel.org
Reported-and-tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com/
Link: https://lore.kernel.org/r/20220908092136.11770-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4fca50d440cc5d4dc570ad5484cc0b70b381bc2a upstream.
One of the side-effects of mb_optimize_scan was that the optimized
functions to select next group to try were called even before we tried
the goal group. As a result we no longer allocate files close to
corresponding inodes as well as we don't try to expand currently
allocated extent in the same group. This results in reaim regression
with workfile.disk workload of upto 8% with many clients on my test
machine:
baseline mb_optimize_scan
Hmean disk-1 2114.16 ( 0.00%) 2099.37 ( -0.70%)
Hmean disk-41 87794.43 ( 0.00%) 83787.47 * -4.56%*
Hmean disk-81 148170.73 ( 0.00%) 135527.05 * -8.53%*
Hmean disk-121 177506.11 ( 0.00%) 166284.93 * -6.32%*
Hmean disk-161 220951.51 ( 0.00%) 207563.39 * -6.06%*
Hmean disk-201 208722.74 ( 0.00%) 203235.59 ( -2.63%)
Hmean disk-241 222051.60 ( 0.00%) 217705.51 ( -1.96%)
Hmean disk-281 252244.17 ( 0.00%) 241132.72 * -4.41%*
Hmean disk-321 255844.84 ( 0.00%) 245412.84 * -4.08%*
Also this is causing huge regression (time increased by a factor of 5 or
so) when untarring archive with lots of small files on some eMMC storage
cards.
Fix the problem by making sure we try goal group first.
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@kernel.org
Reported-and-tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/all/20220727105123.ckwrhbilzrxqpt24@quack3/
Link: https://lore.kernel.org/all/0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com/
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220908092136.11770-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 80fa46d6b9e7b1527bfd2197d75431fd9c382161 upstream.
This patch avoids threads live-locking for hours when a large number
threads are competing over the last few free extents as they blocks
getting added and removed from preallocation pools. From our bug
reporter:
A reliable way for triggering this has multiple writers
continuously write() to files when the filesystem is full, while
small amounts of space are freed (e.g. by truncating a large file
-1MiB at a time). In the local filesystem, this can be done by
simply not checking the return code of write (0) and/or the error
(ENOSPACE) that is set. Over NFS with an async mount, even clients
with proper error checking will behave this way since the linux NFS
client implementation will not propagate the server errors [the
write syscalls immediately return success] until the file handle is
closed. This leads to a situation where NFS clients send a
continuous stream of WRITE rpcs which result in ERRNOSPACE -- but
since the client isn't seeing this, the stream of writes continues
at maximum network speed.
When some space does appear, multiple writers will all attempt to
claim it for their current write. For NFS, we may see dozens to
hundreds of threads that do this.
The real-world scenario of this is database backup tooling (in
particular, github.com/mdkent/percona-xtrabackup) which may write
large files (>1TiB) to NFS for safe keeping. Some temporary files
are written, rewound, and read back -- all before closing the file
handle (the temp file is actually unlinked, to trigger automatic
deletion on close/crash.) An application like this operating on an
async NFS mount will not see an error code until TiB have been
written/read.
The lockup was observed when running this database backup on large
filesystems (64 TiB in this case) with a high number of block
groups and no free space. Fragmentation is generally not a factor
in this filesystem (~thousands of large files, mostly contiguous
except for the parts written while the filesystem is at capacity.)
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a08f789d2ab5242c07e716baf9a835725046be89 upstream.
Hulk Robot reported a BUG_ON:
==================================================================
kernel BUG at fs/ext4/mballoc.c:3211!
[...]
RIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f
[...]
Call Trace:
ext4_mb_new_blocks+0x9df/0x5d30
ext4_ext_map_blocks+0x1803/0x4d80
ext4_map_blocks+0x3a4/0x1a10
ext4_writepages+0x126d/0x2c30
do_writepages+0x7f/0x1b0
__filemap_fdatawrite_range+0x285/0x3b0
file_write_and_wait_range+0xb1/0x140
ext4_sync_file+0x1aa/0xca0
vfs_fsync_range+0xfb/0x260
do_fsync+0x48/0xa0
[...]
==================================================================
Above issue may happen as follows:
-------------------------------------
do_fsync
vfs_fsync_range
ext4_sync_file
file_write_and_wait_range
__filemap_fdatawrite_range
do_writepages
ext4_writepages
mpage_map_and_submit_extent
mpage_map_one_extent
ext4_map_blocks
ext4_mb_new_blocks
ext4_mb_normalize_request
>>> start + size <= ac->ac_o_ex.fe_logical
ext4_mb_regular_allocator
ext4_mb_simple_scan_group
ext4_mb_use_best_found
ext4_mb_new_preallocation
ext4_mb_new_inode_pa
ext4_mb_use_inode_pa
>>> set ac->ac_b_ex.fe_len <= 0
ext4_mb_mark_diskspace_used
>>> BUG_ON(ac->ac_b_ex.fe_len <= 0);
we can easily reproduce this problem with the following commands:
`fallocate -l100M disk`
`mkfs.ext4 -b 1024 -g 256 disk`
`mount disk /mnt`
`fsstress -d /mnt -l 0 -n 1000 -p 1`
The size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP.
Therefore, "start + size <= ac->ac_o_ex.fe_logical" may occur
when the size is truncated. So start should be the start position of
the group where ac_o_ex.fe_logical is located after alignment.
In addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP
is very large, the value calculated by start_off is more accurate.
Cc: stable@kernel.org
Fixes: cd648b8a8fd5 ("ext4: trim allocation requests to group size")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220528110017.354175-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d63c00ea435a5352f486c259665a4ced60399421 upstream.
Otherwise nonaligned fstrim calls will works inconveniently for iterative
scanners, for example:
// trim [0,16MB] for group-1, but mark full group as trimmed
fstrim -o $((1024*1024*128)) -l $((1024*1024*16)) ./m
// handle [16MB,16MB] for group-1, do nothing because group already has the flag.
fstrim -o $((1024*1024*144)) -l $((1024*1024*16)) ./m
[ Update function documentation for ext4_trim_all_free -- TYT ]
Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Link: https://lore.kernel.org/r/1650214995-860245-1-git-send-email-dmtrmonakhov@yandex-team.ru
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit bfdc502a4a4c058bf4cbb1df0c297761d528f54d ]
In case of flex_bg feature (which is by default enabled), extents for
any given inode might span across blocks from two different block group.
ext4_mb_mark_bb() only reads the buffer_head of block bitmap once for the
starting block group, but it fails to read it again when the extent length
boundary overflows to another block group. Then in this below loop it
accesses memory beyond the block group bitmap buffer_head and results
into a data abort.
for (i = 0; i < clen; i++)
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state)
already++;
This patch adds this functionality for checking block group boundary in
ext4_mb_mark_bb() and update the buffer_head(bitmap_bh) for every different
block group.
w/o this patch, I was easily able to hit a data access abort using Power platform.
<...>
[ 74.327662] EXT4-fs error (device loop3): ext4_mb_generate_buddy:1141: group 11, block bitmap and bg descriptor inconsistent: 21248 vs 23294 free clusters
[ 74.533214] EXT4-fs (loop3): shut down requested (2)
[ 74.536705] Aborting journal on device loop3-8.
[ 74.702705] BUG: Unable to handle kernel data access on read at 0xc00000005e980000
[ 74.703727] Faulting instruction address: 0xc0000000007bffb8
cpu 0xd: Vector: 300 (Data Access) at [c000000015db7060]
pc: c0000000007bffb8: ext4_mb_mark_bb+0x198/0x5a0
lr: c0000000007bfeec: ext4_mb_mark_bb+0xcc/0x5a0
sp: c000000015db7300
msr: 800000000280b033
dar: c00000005e980000
dsisr: 40000000
current = 0xc000000027af6880
paca = 0xc00000003ffd5200 irqmask: 0x03 irq_happened: 0x01
pid = 5167, comm = mount
<...>
enter ? for help
[c000000015db7380] c000000000782708 ext4_ext_clear_bb+0x378/0x410
[c000000015db7400] c000000000813f14 ext4_fc_replay+0x1794/0x2000
[c000000015db7580] c000000000833f7c do_one_pass+0xe9c/0x12a0
[c000000015db7710] c000000000834504 jbd2_journal_recover+0x184/0x2d0
[c000000015db77c0] c000000000841398 jbd2_journal_load+0x188/0x4a0
[c000000015db7880] c000000000804de8 ext4_fill_super+0x2638/0x3e10
[c000000015db7a40] c0000000005f8404 get_tree_bdev+0x2b4/0x350
[c000000015db7ae0] c0000000007ef058 ext4_get_tree+0x28/0x40
[c000000015db7b00] c0000000005f6344 vfs_get_tree+0x44/0x100
[c000000015db7b70] c00000000063c408 path_mount+0xdd8/0xe70
[c000000015db7c40] c00000000063c8f0 sys_mount+0x450/0x550
[c000000015db7d50] c000000000035770 system_call_exception+0x4a0/0x4e0
[c000000015db7e10] c00000000000c74c system_call_common+0xec/0x250
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/2609bc8f66fc15870616ee416a18a3d392a209c4.1644992609.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a5c0e2fdf7cea535ba03259894dc184e5a4c2800 ]
ext4_mb_mark_bb() currently wrongly calculates cluster len (clen) and
flex_group->free_clusters. This patch fixes that.
Identified based on code review of ext4_mb_mark_bb() function.
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/a0b035d536bafa88110b74456853774b64c8ac40.1644992609.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 31a074a0c62dc0d2bfb9b543142db4fe27f9e5eb upstream.
For now in ext4_mb_new_blocks_simple, if we found a block which
should be excluded then will switch to next group, this may
probably cause 'group' run out of range.
Change to check next block in the same group when get a block should
be excluded. Also change the search range to EXT4_CLUSTERS_PER_GROUP
and add error checking.
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20220110035141.1980-3-yinxin.x@bytedance.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8c80fb312d7abf8bcd66cca1d843a80318a2c522 upstream.
We found on older kernel (3.10) that in the scenario of insufficient
disk space, system may trigger an ABBA deadlock problem, it seems that
this problem still exists in latest kernel, try to fix it here. The
main process triggered by this problem is that task A occupies the PA
and waits for the jbd2 transaction finish, the jbd2 transaction waits
for the completion of task B's IO (plug_list), but task B waits for
the release of PA by task A to finish discard, which indirectly forms
an ABBA deadlock. The related calltrace is as follows:
Task A
vfs_write
ext4_mb_new_blocks()
ext4_mb_mark_diskspace_used() JBD2
jbd2_journal_get_write_access() -> jbd2_journal_commit_transaction()
->schedule() filemap_fdatawait()
| |
| Task B |
| do_unlinkat() |
| ext4_evict_inode() |
| jbd2_journal_begin_ordered_truncate() |
| filemap_fdatawrite_range() |
| ext4_mb_new_blocks() |
-ext4_mb_discard_group_preallocations() <-----
Here, try to cancel ext4_mb_discard_group_preallocations() internal
retry due to PA busy, and do a limited number of retries inside
ext4_mb_discard_preallocations(), which can circumvent the above
problems, but also has some advantages:
1. Since the PA is in a busy state, if other groups have free PAs,
keeping the current PA may help to reduce fragmentation.
2. Continue to traverse forward instead of waiting for the current
group PA to be released. In most scenarios, the PA discard time
can be reduced.
However, in the case of smaller free space, if only a few groups have
space, then due to multiple traversals of the group, it may increase
CPU overhead. But in contrast, I feel that the overall benefit is
better than the cost.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1637630277-23496-1-git-send-email-brookxu.cn@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 173b6e383d2a204c9921ffc1eca3b87aa2106c33 ]
A user reported FITRIM ioctl failing for him on ext4 on some devices
without apparent reason. After some debugging we've found out that
these devices (being LVM volumes) report rather large discard
granularity of 42MB and the filesystem had 1k blocksize and thus group
size of 8MB. Because ext4 FITRIM implementation puts discard
granularity into minlen, ext4_trim_fs() declared the trim request as
invalid. However just silently doing nothing seems to be a more
appropriate reaction to such combination of parameters since user did
not specify anything wrong.
CC: Lukas Czerner <lczerner@redhat.com>
Fixes: 5c2ed62fd447 ("ext4: Adjust minlen with discard_granularity in the FITRIM ioctl")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211112152202.26614-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
JBD2 layer support triggers which are called when journaling layer moves
buffer to a certain state. We can use the frozen trigger, which gets
called when buffer data is frozen and about to be written out to the
journal, to compute block checksums for some buffer types (similarly as
does ocfs2). This avoids unnecessary repeated recomputation of the
checksum (at the cost of larger window where memory corruption won't be
caught by checksumming) and is even necessary when there are
unsynchronized updaters of the checksummed data.
So add superblock and journal trigger type arguments to
ext4_journal_get_write_access() and ext4_journal_get_create_access() so
that frozen triggers can be set accordingly. Also add inode argument to
ext4_walk_page_buffers() and all the callbacks used with that function
for the same purpose. This patch is mostly only a change of prototype of
the above mentioned functions and a few small helpers. Real checksumming
will come later.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Add sparse annotations to suppress false positive context imbalance
warnings, and use NULL instead of 0 in EXT_MAX_{EXTENT,INDEX}.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The background discard kwork tries to mark blocks used and issue
discard. This can make filesystem suffer from NOSPC error, xfstest
generic/371 can fail due to it. Fix it by flushing discard kwork
in ext4_should_retry_alloc. At the same time, give up discard at
the moment.
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Link: https://lore.kernel.org/r/20210830075246.12516-6-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Right now, discard is issued and waited to be completed in jbd2
commit kthread context after the logs are committed. When large
amount of files are deleted and discard is flooding, jbd2 commit
kthread can be blocked for long time. Then all of the metadata
operations can be blocked to wait the log space.
One case is the page fault path with read mm->mmap_sem held, which
wants to update the file time but has to wait for the log space.
When other threads in the task wants to do mmap, then write mmap_sem
is blocked. Finally all of the following read mmap_sem requirements
are blocked, even the ps command which need to read the /proc/pid/
-cmdline. Our monitor service which needs to read /proc/pid/cmdline
used to be blocked for 5 mins.
This patch frees the blocks back to buddy after commit and then do
discard in a async kworker context in fstrim fashion, namely,
- mark blocks to be discarded as used if they have not been allocated
- do discard
- mark them free
After this, jbd2 commit kthread won't be blocked any more by discard
and we won't get NOSPC even if the discard is slow or throttled.
Link: https://marc.info/?l=linux-kernel&m=162143690731901&w=2
Suggested-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Link: https://lore.kernel.org/r/20210830075246.12516-5-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
There is no functional change in this patch but just split the
codes, which serachs free block and does trim, into a new function
ext4_try_to_trim_range. This is preparing for the following async
backgroup discard.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210724074124.25731-3-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Get rid of the 'group' parameter of ext4_trim_extent as we can get
it from the 'e4b'.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210724074124.25731-2-jianchao.wan9@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit 5d1b1b3f492f ("ext4: fix BUG when calling ext4_error with locked
block group") introduces ext4_grp_locked_error to handle unlocking a
group in error cases. Otherwise, there is a possibility of a sleep while
atomic. However, since 43c73221b3b1 ("ext4: replace BUG_ON with WARN_ON
in mb_find_extent()"), mb_find_extent() has contained a ext4_error()
call while a group spinlock is held. Replace this with
ext4_grp_locked_error.
Fixes: 43c73221b3b1 ("ext4: replace BUG_ON with WARN_ON in mb_find_extent()")
Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Link: https://lore.kernel.org/r/20210623232114.34457-1-stephen.s.brennan@oracle.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Made suggested modifications from checkpatch in reference to ERROR:
trailing whitespace
Signed-off-by: Jack Qiu <jack.qiu@huawei.com>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20210409042035.15516-1-jack.qiu@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Instead of traversing through groups linearly, scan groups in specific
orders at cr 0 and cr 1. At cr 0, we want to find groups that have the
largest free order >= the order of the request. So, with this patch,
we maintain lists for each possible order and insert each group into a
list based on the largest free order in its buddy bitmap. During cr 0
allocation, we traverse these lists in the increasing order of largest
free orders. This allows us to find a group with the best available cr
0 match in constant time. If nothing can be found, we fallback to cr 1
immediately.
At CR1, the story is slightly different. We want to traverse in the
order of increasing average fragment size. For CR1, we maintain a rb
tree of groupinfos which is sorted by average fragment size. Instead
of traversing linearly, at CR1, we traverse in the order of increasing
average fragment size, starting at the most optimal group. This brings
down cr 1 search complexity to log(num groups).
For cr >= 2, we just perform the linear search as before. Also, in
case of lock contention, we intermittently fallback to linear search
even in CR 0 and CR 1 cases. This allows us to proceed during the
allocation path even in case of high contention.
There is an opportunity to do optimization at CR2 too. That's because
at CR2 we only consider groups where bb_free counter (number of free
blocks) is greater than the request extent size. That's left as future
work.
All the changes introduced in this patch are protected under a new
mount option "mb_optimize_scan".
With this patchset, following experiment was performed:
Created a highly fragmented disk of size 65TB. The disk had no
contiguous 2M regions. Following command was run consecutively for 3
times:
time dd if=/dev/urandom of=file bs=2M count=10
Here are the results with and without cr 0/1 optimizations introduced
in this patch:
|---------+------------------------------+---------------------------|
| | Without CR 0/1 Optimizations | With CR 0/1 Optimizations |
|---------+------------------------------+---------------------------|
| 1st run | 5m1.871s | 2m47.642s |
| 2nd run | 2m28.390s | 0m0.611s |
| 3rd run | 2m26.530s | 0m1.255s |
|---------+------------------------------+---------------------------|
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20210401172129.189766-6-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
A few arrays in mballoc.c use the total number of valid orders as
their size. Currently, this value is set as "sb->s_blocksize_bits +
2". This makes code harder to read. So, instead add a new macro
MB_NUM_ORDERS(sb) to make the code more readable.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-5-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
s_mb_buddies_generated gets used later in this patch series to
determine if the cr 0 and cr 1 optimziations should be performed or
not. Currently, s_mb_buddies_generated is protected under a
spin_lock. In the allocation path, it is better if we don't depend on
the lock and instead read the value atomically. In order to do that,
we drop s_bal_lock altogether and we convert the only two protected
fields by it s_mb_buddies_generated and s_mb_generation_time to atomic
type.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20210401172129.189766-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
syzbot found UBSAN: shift-out-of-bounds in ext4_mb_init [1], when
1 << sbi->s_es->s_log_groups_per_flex is bigger than UINT_MAX,
where sbi->s_mb_prefetch is unsigned integer type.
32 is the maximum allowed power of s_log_groups_per_flex. Following if
check will also trigger UBSAN shift-out-of-bound:
if (1 << sbi->s_es->s_log_groups_per_flex >= UINT_MAX) {
So I'm checking it against the raw number, perhaps there is another way
to calculate UINT_MAX max power. Also use min_t as to make sure it's
uint type.
[1] UBSAN: shift-out-of-bounds in fs/ext4/mballoc.c:2713:24
shift exponent 60 is too large for 32-bit type 'int'
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x137/0x1be lib/dump_stack.c:120
ubsan_epilogue lib/ubsan.c:148 [inline]
__ubsan_handle_shift_out_of_bounds+0x432/0x4d0 lib/ubsan.c:395
ext4_mb_init_backend fs/ext4/mballoc.c:2713 [inline]
ext4_mb_init+0x19bc/0x19f0 fs/ext4/mballoc.c:2898
ext4_fill_super+0xc2ec/0xfbe0 fs/ext4/super.c:4983
Reported-by: syzbot+a8b4b0c60155e87e9484@syzkaller.appspotmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210224095800.3350002-1-snovitoll@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit cfd732377221 ("ext4: add prefetching for block allocation
bitmaps") introduced block bitmap prefetch, and expects to read block
bitmaps of flex_bg through an IO. However, it seems to ignore the
value range of s_log_groups_per_flex. In the scenario where the value
of s_log_groups_per_flex is greater than 27, s_mb_prefetch or
s_mb_prefetch_limit will overflow, cause a divide zero exception.
In addition, the logic of calculating nr is also flawed, because the
size of flexbg is fixed during a single mount, but s_mb_prefetch can
be modified, which causes nr to fail to meet the value condition of
[1, flexbg_size].
To solve this problem, we need to set the upper limit of
s_mb_prefetch. Since we expect to load block bitmaps of a flex_bg
through an IO, we can consider determining a reasonable upper limit
among the IO limit parameters. After consideration, we chose
BLK_MAX_SEGMENT_SIZE. This is a good choice to solve divide zero
problem and avoiding performance degradation.
[ Some minor code simplifications to make the changes easy to follow -- TYT ]
Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Samuel Liao <samuelliao@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/1607051143-24508-1-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When freeing metadata, we will create an ext4_free_data and
insert it into the pending free list. After the current
transaction is committed, the object will be freed.
ext4_mb_free_metadata() will check whether the area to be freed
overlaps with the pending free list. If true, return directly. At this
time, ext4_free_data is leaked. Fortunately, the probability of this
problem is small, since it only occurs if the file system is corrupted
such that a block is claimed by more one inode and those inodes are
deleted within a single jbd2 transaction.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Link: https://lore.kernel.org/r/1604764698-4269-8-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
The code of mb_find_order_for_block is a bit obscure, but we can
simplify it with mb_find_buddy(), make the code more concise.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/1604764698-4269-3-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After this patch (163a203), if an abnormal bitmap is detected, we
will mark the group as corrupt, and we will not use this group in
the future. Therefore, it should be meaningless to regenerate the
buddy bitmap of this group, It might be better to delete it.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/1604764698-4269-2-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fast commit file system states are recorded in
sbi->s_mount_flags. Fast commit expects these bit manipulations to be
atomic. This patch adds helpers to make those modifications atomic.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-21-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Smatch complains that "i" can be uninitialized if we don't enter the
loop. I don't know if it's possible but we may as well silence this
warning.
[ Initialize i to sb->s_blocksize instead of 0. The only way the for
loop could be skipped entirely is the in-memory data structures, in
particular the bh->b_data for the on-disk superblock has gotten
corrupted enough that calculated value of group is >= to
ext4_get_groups_count(sb). In that case, we want to exit
immediately without allocating a block. -- TYT ]
Fixes: 8016e29f4362 ("ext4: fast commit recovery path")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201030114620.GB3251003@mwanda
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
This patch adds fast commit recovery path support for Ext4 file
system. We add several helper functions that are similar in spirit to
e2fsprogs journal recovery path handlers. Example of such functions
include - a simple block allocator, idempotent block bitmap update
function etc. Using these routines and the fast commit log in the fast
commit area, the recovery path (ext4_fc_replay()) performs fast commit
log recovery.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-8-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Delete repeated words in fs/ext4/.
{the, this, of, we, after}
Also change spelling of "xttr" in inline.c to "xattr" in 2 places.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200805024850.12129-1-rdunlap@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_mb_discard_group_preallocations() can be releasing group lock with
preallocations accumulated on its local list. Thus although
discard_pa_seq was incremented and concurrent allocating processes will
be retrying allocations, it can happen that premature ENOSPC error is
returned because blocks used for preallocations are not available for
reuse yet. Make sure we always free locally accumulated preallocations
before releasing group lock.
Fixes: 07b5b8e1ac40 ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924150959.4335-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
