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| author | Christoph Hellwig <hch@infradead.org> | 2009-10-19 04:00:03 +0000 |
|---|---|---|
| committer | Alex Elder <aelder@sgi.com> | 2009-12-11 15:11:20 -0600 |
| commit | 80641dc66a2d6dfb22af4413227a92b8ab84c7bb (patch) | |
| tree | f7353e4ca2bd4629b41c9ec79306d042d64f90f7 /fs/xfs/xfs_iomap.c | |
| parent | c56c9631cbe88f08854a56ff9776c1f310916830 (diff) | |
| download | lwn-80641dc66a2d6dfb22af4413227a92b8ab84c7bb.tar.gz lwn-80641dc66a2d6dfb22af4413227a92b8ab84c7bb.zip | |
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.c | 9 |
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, |