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authorYan, Zheng <zheng.z.yan@intel.com>2013-05-31 16:48:29 +0800
committerSage Weil <sage@inktank.com>2013-07-03 15:32:47 -0700
commitfc2744aa12da7182509b1059aa3ab53754d0c83a (patch)
tree3a601a5e8a6bb5fe60141c21e07d99ebb8472d6a /fs/ceph
parent3803da4963db01da6a983ab589ebe2e6ccb97ba9 (diff)
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ceph: fix race between page writeback and truncate
The client can receive truncate request from MDS at any time. So the page writeback code need to get i_size, truncate_seq and truncate_size atomically Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Reviewed-by: Sage Weil <sage@inktank.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/addr.c84
1 files changed, 40 insertions, 44 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 3e68ac1..3500b74 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -438,13 +438,12 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
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;
+ loff_t page_off = page_offset(page);
long writeback_stat;
+ u64 truncate_size, snap_size = 0;
+ u32 truncate_seq;
+ int err = 0, len = PAGE_CACHE_SIZE;
dout("writepage %p idx %lu\n", page, page->index);
@@ -474,13 +473,20 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
}
ceph_put_snap_context(oldest);
+ spin_lock(&ci->i_ceph_lock);
+ truncate_seq = ci->i_truncate_seq;
+ truncate_size = ci->i_truncate_size;
+ if (!snap_size)
+ snap_size = i_size_read(inode);
+ spin_unlock(&ci->i_ceph_lock);
+
/* 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;
+ if (page_off >= snap_size) {
+ dout("%p page eof %llu\n", page, snap_size);
+ goto out;
+ }
+ if (snap_size < page_off + len)
+ len = snap_size - page_off;
dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
inode, page, page->index, page_off, len, snapc);
@@ -494,7 +500,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
err = ceph_osdc_writepages(osdc, ceph_vino(inode),
&ci->i_layout, snapc,
page_off, len,
- ci->i_truncate_seq, ci->i_truncate_size,
+ truncate_seq, truncate_size,
&inode->i_mtime, &page, 1);
if (err < 0) {
dout("writepage setting page/mapping error %d %p\n", err, page);
@@ -631,25 +637,6 @@ static void writepages_finish(struct ceph_osd_request *req,
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
*/
@@ -658,7 +645,8 @@ static int ceph_writepages_start(struct address_space *mapping,
{
struct inode *inode = mapping->host;
struct ceph_inode_info *ci = ceph_inode(inode);
- struct ceph_fs_client *fsc;
+ struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+ struct ceph_vino vino = ceph_vino(inode);
pgoff_t index, start, end;
int range_whole = 0;
int should_loop = 1;
@@ -670,7 +658,8 @@ static int ceph_writepages_start(struct address_space *mapping,
unsigned wsize = 1 << inode->i_blkbits;
struct ceph_osd_request *req = NULL;
int do_sync;
- u64 snap_size;
+ u64 truncate_size, snap_size;
+ u32 truncate_seq;
/*
* Include a 'sync' in the OSD request if this is a data
@@ -685,7 +674,6 @@ static int ceph_writepages_start(struct address_space *mapping,
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! */
@@ -728,6 +716,14 @@ retry:
snap_size = i_size_read(inode);
dout(" oldest snapc is %p seq %lld (%d snaps)\n",
snapc, snapc->seq, snapc->num_snaps);
+
+ spin_lock(&ci->i_ceph_lock);
+ truncate_seq = ci->i_truncate_seq;
+ truncate_size = ci->i_truncate_size;
+ if (!snap_size)
+ snap_size = i_size_read(inode);
+ spin_unlock(&ci->i_ceph_lock);
+
if (last_snapc && snapc != last_snapc) {
/* if we switched to a newer snapc, restart our scan at the
* start of the original file range. */
@@ -739,7 +735,6 @@ retry:
while (!done && index <= end) {
int num_ops = do_sync ? 2 : 1;
- struct ceph_vino vino;
unsigned i;
int first;
pgoff_t next;
@@ -833,17 +828,18 @@ get_more_pages:
* 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);
-
+ req = 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, truncate_seq,
+ truncate_size, true);
if (IS_ERR(req)) {
rc = PTR_ERR(req);
unlock_page(page);
@@ -854,8 +850,8 @@ get_more_pages:
req->r_inode = inode;
max_pages = calc_pages_for(0, (u64)len);
- size = max_pages * sizeof (*pages);
- pages = kmalloc(size, GFP_NOFS);
+ pages = kmalloc(max_pages * sizeof (*pages),
+ GFP_NOFS);
if (!pages) {
pool = fsc->wb_pagevec_pool;
pages = mempool_alloc(pool, GFP_NOFS);