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b9d59846f7
linux/fs/xfs
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Dave Chinner b9d59846f7 xfs: DIO write completion size updates race 
xfs_end_io_direct_write() can race with other IO completions when
updating the in-core inode size. The IO completion processing is not
serialised for direct IO - they are done either under the
IOLOCK_SHARED for non-AIO DIO, and without any IOLOCK held at all
during AIO DIO completion. Hence the non-atomic test-and-set update
of the in-core inode size is racy and can result in the in-core
inode size going backwards if the race if hit just right.

If the inode size goes backwards, this can trigger the EOF zeroing
code to run incorrectly on the next IO, which then will zero data
that has successfully been written to disk by a previous DIO.

To fix this bug, we need to serialise the test/set updates of the
in-core inode size. This first patch introduces locking around the
relevant updates and checks in the DIO path. Because we now have an
ioend in xfs_end_io_direct_write(), we know exactly then we are
doing an IO that requires an in-core EOF update, and we know that
they are not running in interrupt context. As such, we do not need to
use irqsave() spinlock variants to protect against interrupts while
the lock is held.

Hence we can use an existing spinlock in the inode to do this
serialisation and so not need to grow the struct xfs_inode just to
work around this problem.

This patch does not address the test/set EOF update in
generic_file_write_direct() for various reasons - that will be done
as a followup with separate explanation.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-04-16 22:03:07 +10:00
..
libxfs Merge branch 'xfs-buf-type-fixes' into for-next 2015-01-22 09:51:30 +11:00
Kconfig xfs: require 64-bit sector_t 2014-07-30 09:12:05 +10:00
kmem.c xfs: change kmem_free to use generic kvfree() 2015-02-02 09:54:18 +11:00
kmem.h xfs: change kmem_free to use generic kvfree() 2015-02-02 09:54:18 +11:00
Makefile xfs: implement pNFS export operations 2015-02-16 11:49:23 +11:00
mrlock.h xfs: introduce CONFIG_XFS_WARN 2013-05-07 18:45:36 -05:00
uuid.c
uuid.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_acl.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_acl.h xfs: move acl structures to xfs_format.h 2014-11-28 14:24:37 +11:00
xfs_aops.c xfs: DIO write completion size updates race 2015-04-16 22:03:07 +10:00
xfs_aops.h xfs: don't allocate an ioend for direct I/O completions 2015-02-02 10:02:09 +11:00
xfs_attr_inactive.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_attr_list.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_attr.h xfs: kill xfs_vnodeops.[ch] 2013-08-12 16:53:39 -05:00
xfs_bit.c xfs: fix static and extern sparse warnings 2013-10-30 13:59:56 -05:00
xfs_bmap_util.c Merge branch 'xfs-consolidate-format-defs' into for-next 2014-11-28 14:52:16 +11:00
xfs_bmap_util.h xfs: move xfs_bmap_finish prototype 2015-01-09 10:47:14 +11:00
xfs_buf_item.c Merge branch 'xfs-buf-type-fixes' into for-next 2015-01-22 09:51:30 +11:00
xfs_buf_item.h xfs: decouple inode and bmap btree header files 2013-10-23 16:28:49 -05:00
xfs_buf.c list_lru: add helpers to isolate items 2015-02-12 18:54:10 -08:00
xfs_buf.h xfs: split metadata and log buffer completion to separate workqueues 2014-12-04 09:43:17 +11:00
xfs_dir2_readdir.c Merge branch 'xfs-misc-fixes-for-3.19-2' into for-next 2014-12-04 09:46:17 +11:00
xfs_discard.c xfs: merge xfs_ag.h into xfs_format.h 2014-11-28 14:25:04 +11:00
xfs_discard.h
xfs_dquot_item.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_dquot_item.h xfs: remove the quotaoff log format from the quotaoff log item 2013-12-13 11:34:08 +11:00
xfs_dquot.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_dquot.h xfs: fix implicit bool to int conversion 2015-01-09 10:48:58 +11:00
xfs_error.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_error.h xfs: global error sign conversion 2014-06-25 14:58:08 +10:00
xfs_export.c xfs: implement pNFS export operations 2015-02-16 11:49:23 +11:00
xfs_export.h
xfs_extent_busy.c xfs: merge xfs_ag.h into xfs_format.h 2014-11-28 14:25:04 +11:00
xfs_extent_busy.h xfs: decouple inode and bmap btree header files 2013-10-23 16:28:49 -05:00
xfs_extfree_item.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_extfree_item.h xfs: split out EFI/EFD log item format definition 2013-08-12 16:07:13 -05:00
xfs_file.c xfs: DIO write completion size updates race 2015-04-16 22:03:07 +10:00
xfs_filestream.c xfs: merge xfs_inum.h into xfs_format.h 2014-11-28 14:27:10 +11:00
xfs_filestream.h xfs: add filestream allocator tracepoints 2014-04-23 07:11:52 +10:00
xfs_fsops.c xfs: implement pNFS export operations 2015-02-16 11:49:23 +11:00
xfs_fsops.h
xfs_globals.c xfs: export log_recovery_delay to delay mount time log recovery 2014-09-09 11:56:13 +10:00
xfs_icache.c Merge branch 'xfs-misc-fixes-for-3.19-2' into for-next 2014-12-04 09:46:17 +11:00
xfs_icache.h xfs: merge xfs_ag.h into xfs_format.h 2014-11-28 14:25:04 +11:00
xfs_icreate_item.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_icreate_item.h xfs: separate icreate log format definitions from xfs_icreate_item.h 2013-08-12 16:10:35 -05:00
xfs_inode_item.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_inode_item.h xfs: remove the inode log format from the inode log item 2013-12-13 11:34:05 +11:00
xfs_inode.c Merge branch 'xfs-buf-type-fixes' into for-next 2015-01-22 09:51:30 +11:00
xfs_inode.h Merge branch 'xfs-misc-fixes-for-3.20-3' into for-next 2015-02-02 10:03:18 +11:00
xfs_ioctl32.c xfs: remove incorrect error negation in attr_multi ioctl 2015-01-22 10:04:24 +11:00
xfs_ioctl32.h xfs: compat_xfs_bstat does not have forkoff 2014-10-02 09:17:58 +10:00
xfs_ioctl.c Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-02-22 17:42:14 -08:00
xfs_ioctl.h xfs: consolidate extent swap code 2013-08-12 16:56:06 -05:00
xfs_iomap.c xfs: pass a 64-bit count argument to xfs_iomap_write_unwritten 2015-01-09 10:48:12 +11:00
xfs_iomap.h xfs: pass a 64-bit count argument to xfs_iomap_write_unwritten 2015-01-09 10:48:12 +11:00
xfs_iops.c xfs: recall pNFS layouts on conflicting access 2015-02-16 11:59:50 +11:00
xfs_iops.h xfs: implement pNFS export operations 2015-02-16 11:49:23 +11:00
xfs_itable.c Merge branch 'xfs-misc-fixes-for-3.19-2' into for-next 2014-12-04 09:46:17 +11:00
xfs_itable.h xfs: bulkstat chunk formatting cursor is broken 2014-11-07 08:30:30 +11:00
xfs_linux.h xfs: merge xfs_dinode.h into xfs_format.h 2014-11-28 14:24:06 +11:00
xfs_log_cil.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_log_priv.h xfs: add xlog sysfs kobject and attribute handlers 2014-07-15 08:07:29 +10:00
xfs_log_recover.c Merge branch 'xfs-misc-fixes-for-3.19-2' into for-next 2014-12-04 09:46:17 +11:00
xfs_log.c Merge branch 'xfs-sb-logging-rework' into for-next 2015-01-22 09:20:53 +11:00
xfs_log.h xfs: log vector rounding leaks log space 2014-05-20 08:18:09 +10:00
xfs_message.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_message.h xfs: introduce CONFIG_XFS_WARN 2013-05-07 18:45:36 -05:00
xfs_mount.c xfs: sanitise sb_bad_features2 handling 2015-01-22 09:10:33 +11:00
xfs_mount.h xfs: implement pNFS export operations 2015-02-16 11:49:23 +11:00
xfs_mru_cache.c xfs: mark all internal workqueues as freezable 2014-09-09 11:44:46 +10:00
xfs_mru_cache.h xfs: embedd mru_elem into parent structure 2014-04-23 07:11:51 +10:00
xfs_pnfs.c xfs: recall pNFS layouts on conflicting access 2015-02-16 11:59:50 +11:00
xfs_pnfs.h xfs: recall pNFS layouts on conflicting access 2015-02-16 11:59:50 +11:00
xfs_qm_bhv.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_qm_syscalls.c xfs: update for 3.20-rc1 2015-02-10 16:15:17 -08:00
xfs_qm.c list_lru: add helpers to isolate items 2015-02-12 18:54:10 -08:00
xfs_qm.h xfs: update for 3.20-rc1 2015-02-10 16:15:17 -08:00
xfs_quota.h xfs: split dquot buffer operations out 2013-10-23 14:28:35 -05:00
xfs_quotaops.c quota: Split ->set_xstate callback into two 2015-01-30 12:49:40 +01:00
xfs_rtalloc.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_rtalloc.h xfs: combine xfs_rtmodify_summary and xfs_rtget_summary 2014-09-09 11:58:42 +10:00
xfs_stats.c xfs: support the XFS_BTNUM_FINOBT free inode btree type 2014-04-24 16:00:52 +10:00
xfs_stats.h xfs: support the XFS_BTNUM_FINOBT free inode btree type 2014-04-24 16:00:52 +10:00
xfs_super.c fs: consolidate {nr,free}_cached_objects args in shrink_control 2015-02-12 18:54:08 -08:00
xfs_super.h xfs: require 64-bit sector_t 2014-07-30 09:12:05 +10:00
xfs_symlink.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_symlink.h xfs: push down inactive transaction mgmt for remote symlinks 2013-10-08 14:53:02 -05:00
xfs_sysctl.c xfs: remove deprecated sysctls 2015-01-09 10:47:43 +11:00
xfs_sysctl.h xfs: export log_recovery_delay to delay mount time log recovery 2014-09-09 11:56:13 +10:00
xfs_sysfs.c xfs: export log_recovery_delay to delay mount time log recovery 2014-09-09 11:56:13 +10:00
xfs_sysfs.h xfs: add debug sysfs attribute set 2014-09-09 11:52:42 +10:00
xfs_trace.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_trace.h xfs: DIO writes within EOF don't need an ioend 2015-04-16 22:00:00 +10:00
xfs_trans_ail.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_trans_buf.c xfs: only trace buffer items if they exist 2015-02-10 09:23:40 +11:00
xfs_trans_dquot.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_trans_extfree.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_trans_inode.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs_trans_priv.h xfs: remove unused ail pointer arg from xfs_trans_ail_cursor_done() 2014-04-14 19:06:05 +10:00
xfs_trans.c xfs: set superblock buffer type correctly 2015-01-22 09:30:23 +11:00
xfs_trans.h xfs: format log items write directly into the linear CIL buffer 2013-12-13 11:34:02 +11:00
xfs_xattr.c xfs: move most of xfs_sb.h to xfs_format.h 2014-11-28 14:27:09 +11:00
xfs.h xfs: introduce CONFIG_XFS_WARN 2013-05-07 18:45:36 -05:00