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8c042b0df9
linux/fs/ceph/addr.c
Alex Elder 8c042b0df9 libceph: add data pointers in osd op structures 
An extent type osd operation currently implies that there will
be corresponding data supplied in the data portion of the request
(for write) or response (for read) message.  Similarly, an osd class
method operation implies a data item will be supplied to receive
the response data from the operation.

Add a ceph_osd_data pointer to each of those structures, and assign
it to point to eithre the incoming or the outgoing data structure in
the osd message.  The data is not always available when an op is
initially set up, so add two new functions to allow setting them
after the op has been initialized.

Begin to make use of the data item pointer available in the osd
operation rather than the request data in or out structure in
places where it's convenient.  Add some assertions to verify
pointers are always set the way they're expected to be.

This is a sort of stepping stone toward really moving the data
into the osd request ops, to allow for some validation before
making that jump.

This is the first in a series of patches that resolve:
    http://tracker.ceph.com/issues/4657

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:18:14 -07:00

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#include <linux/ceph/ceph_debug.h>
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h> /* generic_writepages */
#include <linux/slab.h>
#include <linux/pagevec.h>
#include <linux/task_io_accounting_ops.h>
#include "super.h"
#include "mds_client.h"
#include <linux/ceph/osd_client.h>
/*
* Ceph address space ops.
*
* There are a few funny things going on here.
*
* The page->private field is used to reference a struct
* ceph_snap_context for _every_ dirty page. This indicates which
* snapshot the page was logically dirtied in, and thus which snap
* context needs to be associated with the osd write during writeback.
*
* Similarly, struct ceph_inode_info maintains a set of counters to
* count dirty pages on the inode. In the absence of snapshots,
* i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
*
* When a snapshot is taken (that is, when the client receives
* notification that a snapshot was taken), each inode with caps and
* with dirty pages (dirty pages implies there is a cap) gets a new
* ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
* order, new snaps go to the tail). The i_wrbuffer_ref_head count is
* moved to capsnap->dirty. (Unless a sync write is currently in
* progress. In that case, the capsnap is said to be "pending", new
* writes cannot start, and the capsnap isn't "finalized" until the
* write completes (or fails) and a final size/mtime for the inode for
* that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
*
* On writeback, we must submit writes to the osd IN SNAP ORDER. So,
* we look for the first capsnap in i_cap_snaps and write out pages in
* that snap context _only_. Then we move on to the next capsnap,
* eventually reaching the "live" or "head" context (i.e., pages that
* are not yet snapped) and are writing the most recently dirtied
* pages.
*
* Invalidate and so forth must take care to ensure the dirty page
* accounting is preserved.
*/
#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
#define CONGESTION_OFF_THRESH(congestion_kb) \
(CONGESTION_ON_THRESH(congestion_kb) - \
(CONGESTION_ON_THRESH(congestion_kb) >> 2))
static inline struct ceph_snap_context *page_snap_context(struct page *page)
{
if (PagePrivate(page))
return (void *)page->private;
return NULL;
}
/*
* Dirty a page. Optimistically adjust accounting, on the assumption
* that we won't race with invalidate. If we do, readjust.
*/
static int ceph_set_page_dirty(struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode;
struct ceph_inode_info *ci;
int undo = 0;
struct ceph_snap_context *snapc;
if (unlikely(!mapping))
return !TestSetPageDirty(page);
if (TestSetPageDirty(page)) {
dout("%p set_page_dirty %p idx %lu -- already dirty\n",
mapping->host, page, page->index);
return 0;
}
inode = mapping->host;
ci = ceph_inode(inode);
/*
* Note that we're grabbing a snapc ref here without holding
* any locks!
*/
snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
/* dirty the head */
spin_lock(&ci->i_ceph_lock);
if (ci->i_head_snapc == NULL)
ci->i_head_snapc = ceph_get_snap_context(snapc);
++ci->i_wrbuffer_ref_head;
if (ci->i_wrbuffer_ref == 0)
ihold(inode);
++ci->i_wrbuffer_ref;
dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
"snapc %p seq %lld (%d snaps)\n",
mapping->host, page, page->index,
ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
snapc, snapc->seq, snapc->num_snaps);
spin_unlock(&ci->i_ceph_lock);
/* now adjust page */
spin_lock_irq(&mapping->tree_lock);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(!PageUptodate(page));
account_page_dirtied(page, page->mapping);
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
/*
* Reference snap context in page->private. Also set
* PagePrivate so that we get invalidatepage callback.
*/
page->private = (unsigned long)snapc;
SetPagePrivate(page);
} else {
dout("ANON set_page_dirty %p (raced truncate?)\n", page);
undo = 1;
}
spin_unlock_irq(&mapping->tree_lock);
if (undo)
/* whoops, we failed to dirty the page */
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
BUG_ON(!PageDirty(page));
return 1;
}
/*
* If we are truncating the full page (i.e. offset == 0), adjust the
* dirty page counters appropriately. Only called if there is private
* data on the page.
*/
static void ceph_invalidatepage(struct page *page, unsigned long offset)
{
struct inode *inode;
struct ceph_inode_info *ci;
struct ceph_snap_context *snapc = page_snap_context(page);
BUG_ON(!PageLocked(page));
BUG_ON(!PagePrivate(page));
BUG_ON(!page->mapping);
inode = page->mapping->host;
/*
* We can get non-dirty pages here due to races between
* set_page_dirty and truncate_complete_page; just spit out a
* warning, in case we end up with accounting problems later.
*/
if (!PageDirty(page))
pr_err("%p invalidatepage %p page not dirty\n", inode, page);
if (offset == 0)
ClearPageChecked(page);
ci = ceph_inode(inode);
if (offset == 0) {
dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
inode, page, page->index, offset);
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
ceph_put_snap_context(snapc);
page->private = 0;
ClearPagePrivate(page);
} else {
dout("%p invalidatepage %p idx %lu partial dirty page\n",
inode, page, page->index);
}
}
/* just a sanity check */
static int ceph_releasepage(struct page *page, gfp_t g)
{
struct inode *inode = page->mapping ? page->mapping->host : NULL;
dout("%p releasepage %p idx %lu\n", inode, page, page->index);
WARN_ON(PageDirty(page));
WARN_ON(PagePrivate(page));
return 0;
}
/*
* read a single page, without unlocking it.
*/
static int readpage_nounlock(struct file *filp, struct page *page)
{
struct inode *inode = file_inode(filp);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
int err = 0;
u64 len = PAGE_CACHE_SIZE;
dout("readpage inode %p file %p page %p index %lu\n",
inode, filp, page, page->index);
err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
(u64) page_offset(page), &len,
ci->i_truncate_seq, ci->i_truncate_size,
&page, 1, 0);
if (err == -ENOENT)
err = 0;
if (err < 0) {
SetPageError(page);
goto out;
} else if (err < PAGE_CACHE_SIZE) {
/* zero fill remainder of page */
zero_user_segment(page, err, PAGE_CACHE_SIZE);
}
SetPageUptodate(page);
out:
return err < 0 ? err : 0;
}
static int ceph_readpage(struct file *filp, struct page *page)
{
int r = readpage_nounlock(filp, page);
unlock_page(page);
return r;
}
/*
* Finish an async read(ahead) op.
*/
static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
{
struct inode *inode = req->r_inode;
struct ceph_osd_data *osd_data;
int rc = req->r_result;
int bytes = le32_to_cpu(msg->hdr.data_len);
int num_pages;
int i;
dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
/* unlock all pages, zeroing any data we didn't read */
osd_data = &req->r_data_in;
BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
num_pages = calc_pages_for((u64)osd_data->alignment,
(u64)osd_data->length);
for (i = 0; i < num_pages; i++) {
struct page *page = osd_data->pages[i];
if (bytes < (int)PAGE_CACHE_SIZE) {
/* zero (remainder of) page */
int s = bytes < 0 ? 0 : bytes;
zero_user_segment(page, s, PAGE_CACHE_SIZE);
}
dout("finish_read %p uptodate %p idx %lu\n", inode, page,
page->index);
flush_dcache_page(page);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
bytes -= PAGE_CACHE_SIZE;
}
kfree(osd_data->pages);
}
static void ceph_unlock_page_vector(struct page **pages, int num_pages)
{
int i;
for (i = 0; i < num_pages; i++)
unlock_page(pages[i]);
}
/*
* start an async read(ahead) operation. return nr_pages we submitted
* a read for on success, or negative error code.
*/
static int start_read(struct inode *inode, struct list_head *page_list, int max)
{
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
struct ceph_inode_info *ci = ceph_inode(inode);
struct page *page = list_entry(page_list->prev, struct page, lru);
struct ceph_vino vino;
struct ceph_osd_request *req;
u64 off;
u64 len;
int i;
struct page **pages;
pgoff_t next_index;
int nr_pages = 0;
int ret;
off = (u64) page_offset(page);
/* count pages */
next_index = page->index;
list_for_each_entry_reverse(page, page_list, lru) {
if (page->index != next_index)
break;
nr_pages++;
next_index++;
if (max && nr_pages == max)
break;
}
len = nr_pages << PAGE_CACHE_SHIFT;
dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
off, len);
vino = ceph_vino(inode);
req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
1, CEPH_OSD_OP_READ,
CEPH_OSD_FLAG_READ, NULL,
ci->i_truncate_seq, ci->i_truncate_size,
false);
if (IS_ERR(req))
return PTR_ERR(req);
/* build page vector */
nr_pages = calc_pages_for(0, len);
pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
ret = -ENOMEM;
if (!pages)
goto out;
for (i = 0; i < nr_pages; ++i) {
page = list_entry(page_list->prev, struct page, lru);
BUG_ON(PageLocked(page));
list_del(&page->lru);
dout("start_read %p adding %p idx %lu\n", inode, page,
page->index);
if (add_to_page_cache_lru(page, &inode->i_data, page->index,
GFP_NOFS)) {
page_cache_release(page);
dout("start_read %p add_to_page_cache failed %p\n",
inode, page);
nr_pages = i;
goto out_pages;
}
pages[i] = page;
}
BUG_ON(req->r_ops[0].extent.osd_data != &req->r_data_in);
ceph_osd_data_pages_init(req->r_ops[0].extent.osd_data, pages, len, 0,
false, false);
req->r_callback = finish_read;
req->r_inode = inode;
ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
ret = ceph_osdc_start_request(osdc, req, false);
if (ret < 0)
goto out_pages;
ceph_osdc_put_request(req);
return nr_pages;
out_pages:
ceph_unlock_page_vector(pages, nr_pages);
ceph_release_page_vector(pages, nr_pages);
out:
ceph_osdc_put_request(req);
return ret;
}
/*
* Read multiple pages. Leave pages we don't read + unlock in page_list;
* the caller (VM) cleans them up.
*/
static int ceph_readpages(struct file *file, struct address_space *mapping,
struct list_head *page_list, unsigned nr_pages)
{
struct inode *inode = file_inode(file);
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
int rc = 0;
int max = 0;
if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
>> PAGE_SHIFT;
dout("readpages %p file %p nr_pages %d max %d\n", inode,
file, nr_pages,
max);
while (!list_empty(page_list)) {
rc = start_read(inode, page_list, max);
if (rc < 0)
goto out;
BUG_ON(rc == 0);
}
out:
dout("readpages %p file %p ret %d\n", inode, file, rc);
return rc;
}
/*
* Get ref for the oldest snapc for an inode with dirty data... that is, the
* only snap context we are allowed to write back.
*/
static struct ceph_snap_context *get_oldest_context(struct inode *inode,
u64 *snap_size)
{
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_snap_context *snapc = NULL;
struct ceph_cap_snap *capsnap = NULL;
spin_lock(&ci->i_ceph_lock);
list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
capsnap->context, capsnap->dirty_pages);
if (capsnap->dirty_pages) {
snapc = ceph_get_snap_context(capsnap->context);
if (snap_size)
*snap_size = capsnap->size;
break;
}
}
if (!snapc && ci->i_wrbuffer_ref_head) {
snapc = ceph_get_snap_context(ci->i_head_snapc);
dout(" head snapc %p has %d dirty pages\n",
snapc, ci->i_wrbuffer_ref_head);
}
spin_unlock(&ci->i_ceph_lock);
return snapc;
}
/*
* Write a single page, but leave the page locked.
*
* If we get a write error, set the page error bit, but still adjust the
* dirty page accounting (i.e., page is no longer dirty).
*/
static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
{
struct inode *inode;
struct ceph_inode_info *ci;
struct ceph_fs_client *fsc;
struct ceph_osd_client *osdc;
loff_t page_off = page_offset(page);
int len = PAGE_CACHE_SIZE;
loff_t i_size;
int err = 0;
struct ceph_snap_context *snapc, *oldest;
u64 snap_size = 0;
long writeback_stat;
dout("writepage %p idx %lu\n", page, page->index);
if (!page->mapping || !page->mapping->host) {
dout("writepage %p - no mapping\n", page);
return -EFAULT;
}
inode = page->mapping->host;
ci = ceph_inode(inode);
fsc = ceph_inode_to_client(inode);
osdc = &fsc->client->osdc;
/* verify this is a writeable snap context */
snapc = page_snap_context(page);
if (snapc == NULL) {
dout("writepage %p page %p not dirty?\n", inode, page);
goto out;
}
oldest = get_oldest_context(inode, &snap_size);
if (snapc->seq > oldest->seq) {
dout("writepage %p page %p snapc %p not writeable - noop\n",
inode, page, snapc);
/* we should only noop if called by kswapd */
WARN_ON((current->flags & PF_MEMALLOC) == 0);
ceph_put_snap_context(oldest);
goto out;
}
ceph_put_snap_context(oldest);
/* is this a partial page at end of file? */
if (snap_size)
i_size = snap_size;
else
i_size = i_size_read(inode);
if (i_size < page_off + len)
len = i_size - page_off;
dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
inode, page, page->index, page_off, len, snapc);
writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
if (writeback_stat >
CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
set_page_writeback(page);
err = ceph_osdc_writepages(osdc, ceph_vino(inode),
&ci->i_layout, snapc,
page_off, len,
ci->i_truncate_seq, ci->i_truncate_size,
&inode->i_mtime, &page, 1);
if (err < 0) {
dout("writepage setting page/mapping error %d %p\n", err, page);
SetPageError(page);
mapping_set_error(&inode->i_data, err);
if (wbc)
wbc->pages_skipped++;
} else {
dout("writepage cleaned page %p\n", page);
err = 0; /* vfs expects us to return 0 */
}
page->private = 0;
ClearPagePrivate(page);
end_page_writeback(page);
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
ceph_put_snap_context(snapc); /* page's reference */
out:
return err;
}
static int ceph_writepage(struct page *page, struct writeback_control *wbc)
{
int err;
struct inode *inode = page->mapping->host;
BUG_ON(!inode);
ihold(inode);
err = writepage_nounlock(page, wbc);
unlock_page(page);
iput(inode);
return err;
}
/*
* lame release_pages helper. release_pages() isn't exported to
* modules.
*/
static void ceph_release_pages(struct page **pages, int num)
{
struct pagevec pvec;
int i;
pagevec_init(&pvec, 0);
for (i = 0; i < num; i++) {
if (pagevec_add(&pvec, pages[i]) == 0)
pagevec_release(&pvec);
}
pagevec_release(&pvec);
}
/*
* async writeback completion handler.
*
* If we get an error, set the mapping error bit, but not the individual
* page error bits.
*/
static void writepages_finish(struct ceph_osd_request *req,
struct ceph_msg *msg)
{
struct inode *inode = req->r_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_osd_data *osd_data;
unsigned wrote;
struct page *page;
int num_pages;
int i;
struct ceph_snap_context *snapc = req->r_snapc;
struct address_space *mapping = inode->i_mapping;
int rc = req->r_result;
u64 bytes = req->r_ops[0].extent.length;
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
long writeback_stat;
unsigned issued = ceph_caps_issued(ci);
osd_data = &req->r_data_out;
BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
num_pages = calc_pages_for((u64)osd_data->alignment,
(u64)osd_data->length);
if (rc >= 0) {
/*
* Assume we wrote the pages we originally sent. The
* osd might reply with fewer pages if our writeback
* raced with a truncation and was adjusted at the osd,
* so don't believe the reply.
*/
wrote = num_pages;
} else {
wrote = 0;
mapping_set_error(mapping, rc);
}
dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
inode, rc, bytes, wrote);
/* clean all pages */
for (i = 0; i < num_pages; i++) {
page = osd_data->pages[i];
BUG_ON(!page);
WARN_ON(!PageUptodate(page));
writeback_stat =
atomic_long_dec_return(&fsc->writeback_count);
if (writeback_stat <
CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
clear_bdi_congested(&fsc->backing_dev_info,
BLK_RW_ASYNC);
ceph_put_snap_context(page_snap_context(page));
page->private = 0;
ClearPagePrivate(page);
dout("unlocking %d %p\n", i, page);
end_page_writeback(page);
/*
* We lost the cache cap, need to truncate the page before
* it is unlocked, otherwise we'd truncate it later in the
* page truncation thread, possibly losing some data that
* raced its way in
*/
if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
generic_error_remove_page(inode->i_mapping, page);
unlock_page(page);
}
dout("%p wrote+cleaned %d pages\n", inode, wrote);
ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
ceph_release_pages(osd_data->pages, num_pages);
if (osd_data->pages_from_pool)
mempool_free(osd_data->pages,
ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
else
kfree(osd_data->pages);
ceph_osdc_put_request(req);
}
static struct ceph_osd_request *
ceph_writepages_osd_request(struct inode *inode, u64 offset, u64 *len,
struct ceph_snap_context *snapc, int num_ops)
{
struct ceph_fs_client *fsc;
struct ceph_inode_info *ci;
struct ceph_vino vino;
fsc = ceph_inode_to_client(inode);
ci = ceph_inode(inode);
vino = ceph_vino(inode);
/* BUG_ON(vino.snap != CEPH_NOSNAP); */
return ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
vino, offset, len, num_ops, CEPH_OSD_OP_WRITE,
CEPH_OSD_FLAG_WRITE|CEPH_OSD_FLAG_ONDISK,
snapc, ci->i_truncate_seq, ci->i_truncate_size, true);
}
/*
* initiate async writeback
*/
static int ceph_writepages_start(struct address_space *mapping,
struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_fs_client *fsc;
pgoff_t index, start, end;
int range_whole = 0;
int should_loop = 1;
pgoff_t max_pages = 0, max_pages_ever = 0;
struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
struct pagevec pvec;
int done = 0;
int rc = 0;
unsigned wsize = 1 << inode->i_blkbits;
struct ceph_osd_request *req = NULL;
int do_sync;
u64 snap_size = 0;
/*
* Include a 'sync' in the OSD request if this is a data
* integrity write (e.g., O_SYNC write or fsync()), or if our
* cap is being revoked.
*/
do_sync = wbc->sync_mode == WB_SYNC_ALL;
if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
do_sync = 1;
dout("writepages_start %p dosync=%d (mode=%s)\n",
inode, do_sync,
wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
(wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
fsc = ceph_inode_to_client(inode);
if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
pr_warning("writepage_start %p on forced umount\n", inode);
return -EIO; /* we're in a forced umount, don't write! */
}
if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
wsize = fsc->mount_options->wsize;
if (wsize < PAGE_CACHE_SIZE)
wsize = PAGE_CACHE_SIZE;
max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
pagevec_init(&pvec, 0);
/* where to start/end? */
if (wbc->range_cyclic) {
start = mapping->writeback_index; /* Start from prev offset */
end = -1;
dout(" cyclic, start at %lu\n", start);
} else {
start = wbc->range_start >> PAGE_CACHE_SHIFT;
end = wbc->range_end >> PAGE_CACHE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
should_loop = 0;
dout(" not cyclic, %lu to %lu\n", start, end);
}
index = start;
retry:
/* find oldest snap context with dirty data */
ceph_put_snap_context(snapc);
snapc = get_oldest_context(inode, &snap_size);
if (!snapc) {
/* hmm, why does writepages get called when there
is no dirty data? */
dout(" no snap context with dirty data?\n");
goto out;
}
dout(" oldest snapc is %p seq %lld (%d snaps)\n",
snapc, snapc->seq, snapc->num_snaps);
if (last_snapc && snapc != last_snapc) {
/* if we switched to a newer snapc, restart our scan at the
* start of the original file range. */
dout(" snapc differs from last pass, restarting at %lu\n",
index);
index = start;
}
last_snapc = snapc;
while (!done && index <= end) {
int num_ops = do_sync ? 2 : 1;
struct ceph_vino vino;
unsigned i;
int first;
pgoff_t next;
int pvec_pages, locked_pages;
struct page **pages = NULL;
mempool_t *pool = NULL; /* Becomes non-null if mempool used */
struct page *page;
int want;
u64 offset, len;
long writeback_stat;
next = 0;
locked_pages = 0;
max_pages = max_pages_ever;
get_more_pages:
first = -1;
want = min(end - index,
min((pgoff_t)PAGEVEC_SIZE,
max_pages - (pgoff_t)locked_pages) - 1)
+ 1;
pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
PAGECACHE_TAG_DIRTY,
want);
dout("pagevec_lookup_tag got %d\n", pvec_pages);
if (!pvec_pages && !locked_pages)
break;
for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
page = pvec.pages[i];
dout("? %p idx %lu\n", page, page->index);
if (locked_pages == 0)
lock_page(page); /* first page */
else if (!trylock_page(page))
break;
/* only dirty pages, or our accounting breaks */
if (unlikely(!PageDirty(page)) ||
unlikely(page->mapping != mapping)) {
dout("!dirty or !mapping %p\n", page);
unlock_page(page);
break;
}
if (!wbc->range_cyclic && page->index > end) {
dout("end of range %p\n", page);
done = 1;
unlock_page(page);
break;
}
if (next && (page->index != next)) {
dout("not consecutive %p\n", page);
unlock_page(page);
break;
}
if (wbc->sync_mode != WB_SYNC_NONE) {
dout("waiting on writeback %p\n", page);
wait_on_page_writeback(page);
}
if ((snap_size && page_offset(page) > snap_size) ||
(!snap_size &&
page_offset(page) > i_size_read(inode))) {
dout("%p page eof %llu\n", page, snap_size ?
snap_size : i_size_read(inode));
done = 1;
unlock_page(page);
break;
}
if (PageWriteback(page)) {
dout("%p under writeback\n", page);
unlock_page(page);
break;
}
/* only if matching snap context */
pgsnapc = page_snap_context(page);
if (pgsnapc->seq > snapc->seq) {
dout("page snapc %p %lld > oldest %p %lld\n",
pgsnapc, pgsnapc->seq, snapc, snapc->seq);
unlock_page(page);
if (!locked_pages)
continue; /* keep looking for snap */
break;
}
if (!clear_page_dirty_for_io(page)) {
dout("%p !clear_page_dirty_for_io\n", page);
unlock_page(page);
break;
}
/*
* We have something to write. If this is
* the first locked page this time through,
* allocate an osd request and a page array
* that it will use.
*/
if (locked_pages == 0) {
size_t size;
BUG_ON(pages);
/* prepare async write request */
offset = (u64)page_offset(page);
len = wsize;
req = ceph_writepages_osd_request(inode,
offset, &len, snapc,
num_ops);
if (IS_ERR(req)) {
rc = PTR_ERR(req);
unlock_page(page);
break;
}
req->r_callback = writepages_finish;
req->r_inode = inode;
max_pages = calc_pages_for(0, (u64)len);
size = max_pages * sizeof (*pages);
pages = kmalloc(size, GFP_NOFS);
if (!pages) {
pool = fsc->wb_pagevec_pool;
pages = mempool_alloc(pool, GFP_NOFS);
BUG_ON(!pages);
}
}
/* note position of first page in pvec */
if (first < 0)
first = i;
dout("%p will write page %p idx %lu\n",
inode, page, page->index);
writeback_stat =
atomic_long_inc_return(&fsc->writeback_count);
if (writeback_stat > CONGESTION_ON_THRESH(
fsc->mount_options->congestion_kb)) {
set_bdi_congested(&fsc->backing_dev_info,
BLK_RW_ASYNC);
}
set_page_writeback(page);
pages[locked_pages] = page;
locked_pages++;
next = page->index + 1;
}
/* did we get anything? */
if (!locked_pages)
goto release_pvec_pages;
if (i) {
int j;
BUG_ON(!locked_pages || first < 0);
if (pvec_pages && i == pvec_pages &&
locked_pages < max_pages) {
dout("reached end pvec, trying for more\n");
pagevec_reinit(&pvec);
goto get_more_pages;
}
/* shift unused pages over in the pvec... we
* will need to release them below. */
for (j = i; j < pvec_pages; j++) {
dout(" pvec leftover page %p\n",
pvec.pages[j]);
pvec.pages[j-i+first] = pvec.pages[j];
}
pvec.nr -= i-first;
}
/* Format the osd request message and submit the write */
offset = page_offset(pages[0]);
len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
(u64)locked_pages << PAGE_CACHE_SHIFT);
dout("writepages got %d pages at %llu~%llu\n",
locked_pages, offset, len);
BUG_ON(req->r_ops[0].extent.osd_data != &req->r_data_out);
ceph_osd_data_pages_init(req->r_ops[0].extent.osd_data, pages,
len, 0, !!pool, false);
pages = NULL; /* request message now owns the pages array */
pool = NULL;
/* Update the write op length in case we changed it */
osd_req_op_extent_update(&req->r_ops[0], len);
vino = ceph_vino(inode);
ceph_osdc_build_request(req, offset, snapc, vino.snap,
&inode->i_mtime);
rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
BUG_ON(rc);
req = NULL;
/* continue? */
index = next;
wbc->nr_to_write -= locked_pages;
if (wbc->nr_to_write <= 0)
done = 1;
release_pvec_pages:
dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
pvec.nr ? pvec.pages[0] : NULL);
pagevec_release(&pvec);
if (locked_pages && !done)
goto retry;
}
if (should_loop && !done) {
/* more to do; loop back to beginning of file */
dout("writepages looping back to beginning of file\n");
should_loop = 0;
index = 0;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
mapping->writeback_index = index;
out:
if (req)
ceph_osdc_put_request(req);
ceph_put_snap_context(snapc);
dout("writepages done, rc = %d\n", rc);
return rc;
}
/*
* See if a given @snapc is either writeable, or already written.
*/
static int context_is_writeable_or_written(struct inode *inode,
struct ceph_snap_context *snapc)
{
struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
int ret = !oldest || snapc->seq <= oldest->seq;
ceph_put_snap_context(oldest);
return ret;
}
/*
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
*
* called with page locked.
* return success with page locked,
* or any failure (incl -EAGAIN) with page unlocked.
*/
static int ceph_update_writeable_page(struct file *file,
loff_t pos, unsigned len,
struct page *page)
{
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
loff_t page_off = pos & PAGE_CACHE_MASK;
int pos_in_page = pos & ~PAGE_CACHE_MASK;
int end_in_page = pos_in_page + len;
loff_t i_size;
int r;
struct ceph_snap_context *snapc, *oldest;
retry_locked:
/* writepages currently holds page lock, but if we change that later, */
wait_on_page_writeback(page);
/* check snap context */
BUG_ON(!ci->i_snap_realm);
down_read(&mdsc->snap_rwsem);
BUG_ON(!ci->i_snap_realm->cached_context);
snapc = page_snap_context(page);
if (snapc && snapc != ci->i_head_snapc) {
/*
* this page is already dirty in another (older) snap
* context! is it writeable now?
*/
oldest = get_oldest_context(inode, NULL);
up_read(&mdsc->snap_rwsem);
if (snapc->seq > oldest->seq) {
ceph_put_snap_context(oldest);
dout(" page %p snapc %p not current or oldest\n",
page, snapc);
/*
* queue for writeback, and wait for snapc to
* be writeable or written
*/
snapc = ceph_get_snap_context(snapc);
unlock_page(page);
ceph_queue_writeback(inode);
r = wait_event_interruptible(ci->i_cap_wq,
context_is_writeable_or_written(inode, snapc));
ceph_put_snap_context(snapc);
if (r == -ERESTARTSYS)
return r;
return -EAGAIN;
}
ceph_put_snap_context(oldest);
/* yay, writeable, do it now (without dropping page lock) */
dout(" page %p snapc %p not current, but oldest\n",
page, snapc);
if (!clear_page_dirty_for_io(page))
goto retry_locked;
r = writepage_nounlock(page, NULL);
if (r < 0)
goto fail_nosnap;
goto retry_locked;
}
if (PageUptodate(page)) {
dout(" page %p already uptodate\n", page);
return 0;
}
/* full page? */
if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
return 0;
/* past end of file? */
i_size = inode->i_size; /* caller holds i_mutex */
if (i_size + len > inode->i_sb->s_maxbytes) {
/* file is too big */
r = -EINVAL;
goto fail;
}
if (page_off >= i_size ||
(pos_in_page == 0 && (pos+len) >= i_size &&
end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
dout(" zeroing %p 0 - %d and %d - %d\n",
page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
zero_user_segments(page,
0, pos_in_page,
end_in_page, PAGE_CACHE_SIZE);
return 0;
}
/* we need to read it. */
up_read(&mdsc->snap_rwsem);
r = readpage_nounlock(file, page);
if (r < 0)
goto fail_nosnap;
goto retry_locked;
fail:
up_read(&mdsc->snap_rwsem);
fail_nosnap:
unlock_page(page);
return r;
}
/*
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
*/
static int ceph_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = file_inode(file);
struct page *page;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
int r;
do {
/* get a page */
page = grab_cache_page_write_begin(mapping, index, 0);
if (!page)
return -ENOMEM;
*pagep = page;
dout("write_begin file %p inode %p page %p %d~%d\n", file,
inode, page, (int)pos, (int)len);
r = ceph_update_writeable_page(file, pos, len, page);
} while (r == -EAGAIN);
return r;
}
/*
* we don't do anything in here that simple_write_end doesn't do
* except adjust dirty page accounting and drop read lock on
* mdsc->snap_rwsem.
*/
static int ceph_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = file_inode(file);
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
struct ceph_mds_client *mdsc = fsc->mdsc;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
int check_cap = 0;
dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
inode, page, (int)pos, (int)copied, (int)len);
/* zero the stale part of the page if we did a short copy */
if (copied < len)
zero_user_segment(page, from+copied, len);
/* did file size increase? */
/* (no need for i_size_read(); we caller holds i_mutex */
if (pos+copied > inode->i_size)
check_cap = ceph_inode_set_size(inode, pos+copied);
if (!PageUptodate(page))
SetPageUptodate(page);
set_page_dirty(page);
unlock_page(page);
up_read(&mdsc->snap_rwsem);
page_cache_release(page);
if (check_cap)
ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
return copied;
}
/*
* we set .direct_IO to indicate direct io is supported, but since we
* intercept O_DIRECT reads and writes early, this function should
* never get called.
*/
static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
const struct iovec *iov,
loff_t pos, unsigned long nr_segs)
{
WARN_ON(1);
return -EINVAL;
}
const struct address_space_operations ceph_aops = {
.readpage = ceph_readpage,
.readpages = ceph_readpages,
.writepage = ceph_writepage,
.writepages = ceph_writepages_start,
.write_begin = ceph_write_begin,
.write_end = ceph_write_end,
.set_page_dirty = ceph_set_page_dirty,
.invalidatepage = ceph_invalidatepage,
.releasepage = ceph_releasepage,
.direct_IO = ceph_direct_io,
};
/*
* vm ops
*/
/*
* Reuse write_begin here for simplicity.
*/
static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct inode *inode = file_inode(vma->vm_file);
struct page *page = vmf->page;
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
loff_t off = page_offset(page);
loff_t size, len;
int ret;
/* Update time before taking page lock */
file_update_time(vma->vm_file);
size = i_size_read(inode);
if (off + PAGE_CACHE_SIZE <= size)
len = PAGE_CACHE_SIZE;
else
len = size & ~PAGE_CACHE_MASK;
dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
off, len, page, page->index);
lock_page(page);
ret = VM_FAULT_NOPAGE;
if ((off > size) ||
(page->mapping != inode->i_mapping))
goto out;
ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
if (ret == 0) {
/* success. we'll keep the page locked. */
set_page_dirty(page);
up_read(&mdsc->snap_rwsem);
ret = VM_FAULT_LOCKED;
} else {
if (ret == -ENOMEM)
ret = VM_FAULT_OOM;
else
ret = VM_FAULT_SIGBUS;
}
out:
dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
if (ret != VM_FAULT_LOCKED)
unlock_page(page);
return ret;
}
static struct vm_operations_struct ceph_vmops = {
.fault = filemap_fault,
.page_mkwrite = ceph_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
int ceph_mmap(struct file *file, struct vm_area_struct *vma)
{
struct address_space *mapping = file->f_mapping;
if (!mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &ceph_vmops;
return 0;
}
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