[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: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/xfs_vfsops.c b/fs/xfs/xfs_vfsops.c
index 65c5612..92c1425 100644
--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -1128,58 +1128,41 @@
* 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.
- */
+ /*
+ * 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);
- 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);
- }
-
- 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) &&