linux/fs/xfs/linux-2.6
Lachlan McIlroy 364f358a73 [XFS] Prevent direct I/O from mapping extents beyond eof
With the help from some tracing I found that we try to map extents beyond
eof when doing a direct I/O read. It appears that the way to inform the
generic direct I/O path (ie do_direct_IO()) that we have breached eof is
to return an unmapped buffer from xfs_get_blocks_direct(). This will cause
do_direct_IO() to jump to the hole handling code where is will check for
eof and then abort.

This problem was found because a direct I/O read was trying to map beyond
eof and was encountering delayed allocations. The delayed allocations
beyond eof are speculative allocations and they didn't get converted when
the direct I/O flushed the file because there was only enough space in the
current AG to convert and write out the dirty pages within eof. Note that
xfs_iomap_write_allocate() wont necessarily convert all the delayed
allocation passed to it - it will return after allocating the first extent
- so if the delayed allocation extends beyond eof then it will stay that
way.

SGI-PV: 983683

SGI-Modid: xfs-linux-melb:xfs-kern:31929a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
2008-09-17 16:50:14 +10:00
..
kmem.c
kmem.h
mrlock.h
mutex.h
sv.h
time.h
xfs_aops.c [XFS] Prevent direct I/O from mapping extents beyond eof 2008-09-17 16:50:14 +10:00
xfs_aops.h
xfs_buf.c [XFS] Use KM_NOFS for debug trace buffers 2008-08-13 16:51:57 +10:00
xfs_buf.h [XFS] replace the XFS buf iodone semaphore with a completion 2008-08-13 16:36:11 +10:00
xfs_cred.h
xfs_dmapi_priv.h
xfs_export.c [XFS] convert xfs to use ERR_CAST 2008-08-13 16:09:25 +10:00
xfs_export.h
xfs_file.c [PATCH] fix ->llseek() for a bunch of directories 2008-08-25 01:18:09 -04:00
xfs_fs_subr.c
xfs_fs_subr.h
xfs_globals.c
xfs_globals.h
xfs_ioctl.c
xfs_ioctl32.c
xfs_ioctl32.h
xfs_iops.c [PATCH] change d_add_ci argument ordering 2008-08-25 01:18:05 -04:00
xfs_iops.h [XFS] stop using file_update_time 2008-08-13 16:48:12 +10:00
xfs_linux.h CRED: Introduce credential access wrappers 2008-08-14 09:35:23 +10:00
xfs_lrw.c [XFS] stop using file_update_time 2008-08-13 16:48:12 +10:00
xfs_lrw.h
xfs_stats.c
xfs_stats.h
xfs_super.c [XFS] Fix regression introduced by remount fixup 2008-09-17 16:49:33 +10:00
xfs_super.h [XFS] sanitize xfs_initialize_vnode 2008-08-13 16:23:13 +10:00
xfs_sysctl.c
xfs_sysctl.h
xfs_version.h
xfs_vfs.h
xfs_vnode.c [XFS] clean up stale references to semaphores 2008-08-13 16:34:31 +10:00
xfs_vnode.h [XFS] kill bhv_vnode_t 2008-08-13 16:22:40 +10:00
xfs_xattr.c