From 80641dc66a2d6dfb22af4413227a92b8ab84c7bb Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 19 Oct 2009 04:00:03 +0000 Subject: [PATCH] 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 Reported-by: Thomas Neumann Tested-by: Thomas Neumann Reviewed-by: Alex Elder Signed-off-by: Alex Elder --- fs/xfs/xfs_fsops.c | 2 +- fs/xfs/xfs_iomap.c | 9 ++++++++- fs/xfs/xfs_mount.c | 2 +- fs/xfs/xfs_trans.c | 7 ++++--- fs/xfs/xfs_trans.h | 2 +- 5 files changed, 15 insertions(+), 7 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index 2d0b3e1da9e6..6f83f58c099f 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -611,7 +611,7 @@ xfs_fs_log_dummy( xfs_inode_t *ip; int error; - tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1); + tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1, KM_SLEEP); error = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0); if (error) { xfs_trans_cancel(tp, 0); 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, diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 8b6c9e807efb..4d509f742bd2 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -1471,7 +1471,7 @@ xfs_log_sbcount( if (!xfs_sb_version_haslazysbcount(&mp->m_sb)) return 0; - tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT); + tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT, KM_SLEEP); error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0, XFS_DEFAULT_LOG_COUNT); if (error) { diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index 66b849358e62..237badcbac3b 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -236,19 +236,20 @@ xfs_trans_alloc( uint type) { xfs_wait_for_freeze(mp, SB_FREEZE_TRANS); - return _xfs_trans_alloc(mp, type); + return _xfs_trans_alloc(mp, type, KM_SLEEP); } xfs_trans_t * _xfs_trans_alloc( xfs_mount_t *mp, - uint type) + uint type, + uint memflags) { xfs_trans_t *tp; atomic_inc(&mp->m_active_trans); - tp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP); + tp = kmem_zone_zalloc(xfs_trans_zone, memflags); tp->t_magic = XFS_TRANS_MAGIC; tp->t_type = type; tp->t_mountp = mp; diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h index ed47fc77759c..a0574f593f52 100644 --- a/fs/xfs/xfs_trans.h +++ b/fs/xfs/xfs_trans.h @@ -924,7 +924,7 @@ typedef struct xfs_trans { * XFS transaction mechanism exported interfaces. */ xfs_trans_t *xfs_trans_alloc(struct xfs_mount *, uint); -xfs_trans_t *_xfs_trans_alloc(struct xfs_mount *, uint); +xfs_trans_t *_xfs_trans_alloc(struct xfs_mount *, uint, uint); xfs_trans_t *xfs_trans_dup(xfs_trans_t *); int xfs_trans_reserve(xfs_trans_t *, uint, uint, uint, uint, uint); -- 2.30.2