Commit 40095b64 authored by David Chinner's avatar David Chinner Committed by Tim Shimmin

[XFS] Sleeping with the ilock waiting for I/O completion is Bad.

Recent fixes to the filesystem freezing code introduced a vn_iowait call
in the middle of the sync code. Unfortunately, at the point where this
call was added we are holding the ilock. The ilock is needed by I/O
completion for unwritten extent conversion and now updating the file size.
Hence I/o cannot complete if we hold the ilock while waiting for I/O
completion.

Fix up the bug and clean the code up around it.

SGI-PV: 963674
SGI-Modid: xfs-linux-melb:xfs-kern:28566a
Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
parent 4cc929ee
......@@ -1128,58 +1128,41 @@ xfs_sync_inodes(
* in the inode list.
*/
if ((flags & SYNC_CLOSE) && (vp != NULL)) {
/*
* This is the shutdown case. We just need to
* flush and invalidate all the pages associated
* with the inode. Drop the inode lock since
* we can't hold it across calls to the buffer
* cache.
*
* We don't set the VREMAPPING bit in the vnode
* here, because we don't hold the vnode lock
* exclusively. It doesn't really matter, though,
* because we only come here when we're shutting
* down anyway.
*/
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (XFS_FORCED_SHUTDOWN(mp)) {
bhv_vop_toss_pages(vp, 0, -1, FI_REMAPF);
} else {
error = bhv_vop_flushinval_pages(vp, 0, -1, FI_REMAPF);
/*
* If we have to flush data or wait for I/O completion
* we need to drop the ilock that we currently hold.
* If we need to drop the lock, insert a marker if we
* have not already done so.
*/
if ((flags & (SYNC_CLOSE|SYNC_IOWAIT)) ||
((flags & SYNC_DELWRI) && VN_DIRTY(vp))) {
if (mount_locked) {
IPOINTER_INSERT(ip, mp);
}
xfs_iunlock(ip, XFS_ILOCK_SHARED);
xfs_ilock(ip, XFS_ILOCK_SHARED);
} else if ((flags & SYNC_DELWRI) && (vp != NULL)) {
if (VN_DIRTY(vp)) {
/* We need to have dropped the lock here,
* so insert a marker if we have not already
* done so.
*/
if (mount_locked) {
IPOINTER_INSERT(ip, mp);
}
/*
* Drop the inode lock since we can't hold it
* across calls to the buffer cache.
*/
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (flags & SYNC_CLOSE) {
/* Shutdown case. Flush and invalidate. */
if (XFS_FORCED_SHUTDOWN(mp))
bhv_vop_toss_pages(vp, 0, -1, FI_REMAPF);
else
error = bhv_vop_flushinval_pages(vp, 0,
-1, FI_REMAPF);
} else if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
error = bhv_vop_flush_pages(vp, (xfs_off_t)0,
-1, fflag, FI_NONE);
xfs_ilock(ip, XFS_ILOCK_SHARED);
}
/*
* When freezing, we need to wait ensure all I/O (including direct
* I/O) is complete to ensure no further data modification can take
* place after this point
*/
if (flags & SYNC_IOWAIT)
vn_iowait(vp);
xfs_ilock(ip, XFS_ILOCK_SHARED);
}
/*
* When freezing, we need to wait ensure all I/O (including direct
* I/O) is complete to ensure no further data modification can take
* place after this point
*/
if (flags & SYNC_IOWAIT)
vn_iowait(vp);
if (flags & SYNC_BDFLUSH) {
if ((flags & SYNC_ATTR) &&
......
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