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ceph: Fix i_size update race

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ceph_aio_write() has an optimization that marks cap EPH_CAP_FILE_WR
dirty before data is copied to page cache and inode size is updated.
If ceph_check_caps() flushes the dirty cap before the inode size is
updated, MDS can miss the new inode size. The fix is move
ceph_{get,put}_cap_refs() into ceph_write_{begin,end}() and call
__ceph_mark_dirty_caps() after inode size is updated.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Sage Weil <sage@inktank.com>
This commit is contained in:
Sage Weil
2012-11-05 11:07:23 -08:00
parent 4d1d0534f5
commit 22cddde104
2 changed files with 78 additions and 48 deletions
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75
fs/ceph/file.c
View File

@@ -712,63 +712,53 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
struct ceph_osd_client *osdc =
&ceph_sb_to_client(inode->i_sb)->client->osdc;
loff_t endoff = pos + iov->iov_len;
int want, got = 0;
int ret, err;
int got = 0;
int ret, err, written;
if (ceph_snap(inode) != CEPH_NOSNAP)
return -EROFS;
retry_snap:
written = 0;
if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
return -ENOSPC;
__ceph_do_pending_vmtruncate(inode);
dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
inode->i_size);
if (fi->fmode & CEPH_FILE_MODE_LAZY)
want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
else
want = CEPH_CAP_FILE_BUFFER;
ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
if (ret < 0)
goto out_put;
dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
ceph_cap_string(got));
if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
(iocb->ki_filp->f_flags & O_DIRECT) ||
(inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
(fi->flags & CEPH_F_SYNC)) {
ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
&iocb->ki_pos);
} else {
/*
* buffered write; drop Fw early to avoid slow
* revocation if we get stuck on balance_dirty_pages
*/
int dirty;
spin_lock(&ci->i_ceph_lock);
dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
spin_unlock(&ci->i_ceph_lock);
ceph_put_cap_refs(ci, got);
/*
* try to do a buffered write. if we don't have sufficient
* caps, we'll get -EAGAIN from generic_file_aio_write, or a
* short write if we only get caps for some pages.
*/
if (!(iocb->ki_filp->f_flags & O_DIRECT) &&
!(inode->i_sb->s_flags & MS_SYNCHRONOUS) &&
!(fi->flags & CEPH_F_SYNC)) {
ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
if (ret >= 0)
written = ret;
if ((ret >= 0 || ret == -EIOCBQUEUED) &&
((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
|| ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
err = vfs_fsync_range(file, pos, pos + written - 1, 1);
if (err < 0)
ret = err;
}
if (dirty)
__mark_inode_dirty(inode, dirty);
goto out;
if ((ret < 0 && ret != -EAGAIN) || pos + written >= endoff)
goto out;
}
dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
inode, ceph_vinop(inode), pos + written,
(unsigned)iov->iov_len - written, inode->i_size);
ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, 0, &got, endoff);
if (ret < 0)
goto out;
dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n",
inode, ceph_vinop(inode), pos + written,
(unsigned)iov->iov_len - written, ceph_cap_string(got));
ret = ceph_sync_write(file, iov->iov_base + written,
iov->iov_len - written, &iocb->ki_pos);
if (ret >= 0) {
int dirty;
spin_lock(&ci->i_ceph_lock);
@@ -777,13 +767,10 @@ retry_snap:
if (dirty)
__mark_inode_dirty(inode, dirty);
}
out_put:
dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
ceph_cap_string(got));
inode, ceph_vinop(inode), pos + written,
(unsigned)iov->iov_len - written, ceph_cap_string(got));
ceph_put_cap_refs(ci, got);
out:
if (ret == -EOLDSNAPC) {
dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",