summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_iomap.c
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@infradead.org>2009-10-19 04:00:03 +0000
committerAlex Elder <aelder@sgi.com>2009-12-11 15:11:20 -0600
commit80641dc66a2d6dfb22af4413227a92b8ab84c7bb (patch)
treef7353e4ca2bd4629b41c9ec79306d042d64f90f7 /fs/xfs/xfs_iomap.c
parentc56c9631cbe88f08854a56ff9776c1f310916830 (diff)
xfs: I/O completion handlers must use NOFS allocations
When completing I/O requests we must not allow the memory allocator to recurse into the filesystem, as we might deadlock on waiting for the I/O completion otherwise. The only thing currently allocating normal GFP_KERNEL memory is the allocation of the transaction structure for the unwritten extent conversion. Add a memflags argument to _xfs_trans_alloc to allow controlling the allocator behaviour. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Thomas Neumann <tneumann@users.sourceforge.net> Tested-by: Thomas Neumann <tneumann@users.sourceforge.net> Reviewed-by: Alex Elder <aelder@sgi.com> Signed-off-by: Alex Elder <aelder@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_iomap.c')
-rw-r--r--fs/xfs/xfs_iomap.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 67ae5555a30a..7294abce6ef2 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -860,8 +860,15 @@ xfs_iomap_write_unwritten(
* set up a transaction to convert the range of extents
* from unwritten to real. Do allocations in a loop until
* we have covered the range passed in.
+ *
+ * Note that we open code the transaction allocation here
+ * to pass KM_NOFS--we can't risk to recursing back into
+ * the filesystem here as we might be asked to write out
+ * the same inode that we complete here and might deadlock
+ * on the iolock.
*/
- tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
+ xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);
+ tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS);
tp->t_flags |= XFS_TRANS_RESERVE;
error = xfs_trans_reserve(tp, resblks,
XFS_WRITE_LOG_RES(mp), 0,