linux/fs/xfs
Brian Foster 9c7504aa72 xfs: track and serialize in-flight async buffers against unmount
Newly allocated XFS metadata buffers are added to the LRU once the hold
count is released, which typically occurs after I/O completion. There is
no other mechanism at current that tracks the existence or I/O state of
a new buffer. Further, readahead I/O tends to be submitted
asynchronously by nature, which means the I/O can remain in flight and
actually complete long after the calling context is gone. This means
that file descriptors or any other holds on the filesystem can be
released, allowing the filesystem to be unmounted while I/O is still in
flight. When I/O completion occurs, core data structures may have been
freed, causing completion to run into invalid memory accesses and likely
to panic.

This problem is reproduced on XFS via directory readahead. A filesystem
is mounted, a directory is opened/closed and the filesystem immediately
unmounted. The open/close cycle triggers a directory readahead that if
delayed long enough, runs buffer I/O completion after the unmount has
completed.

To address this problem, add a mechanism to track all in-flight,
asynchronous buffers using per-cpu counters in the buftarg. The buffer
is accounted on the first I/O submission after the current reference is
acquired and unaccounted once the buffer is returned to the LRU or
freed. Update xfs_wait_buftarg() to wait on all in-flight I/O before
walking the LRU list. Once in-flight I/O has completed and the workqueue
has drained, all new buffers should have been released onto the LRU.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-20 11:15:28 +10:00
..
libxfs xfs: update for 4.7-rc1 2016-05-26 10:13:40 -07:00
Kconfig
kmem.c xfs: improve kmem_realloc 2016-04-06 09:47:01 +10:00
kmem.h xfs: improve kmem_realloc 2016-04-06 09:47:01 +10:00
Makefile nfsd: add SCSI layout support 2016-03-18 11:42:53 -04:00
mrlock.h
uuid.c
uuid.h
xfs_acl.c posix_acl: Inode acl caching fixes 2016-03-31 00:30:15 -04:00
xfs_acl.h xfs: Change how listxattr generates synthetic attributes 2015-12-06 21:34:16 -05:00
xfs_aops.c xfs: update for 4.7-rc1 2016-05-26 10:13:40 -07:00
xfs_aops.h xfs: optimize bio handling in the buffer writeback path 2016-04-06 08:34:30 +10:00
xfs_attr_inactive.c xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_attr_list.c xfs: collapse cases in xfs_attr3_leaf_list_int 2016-04-06 07:57:47 +10:00
xfs_attr.h xfs: remove put_value from attr ->put_listent context 2016-04-06 07:57:45 +10:00
xfs_bmap_util.c DAX error handling for 4.7 2016-05-26 19:34:26 -07:00
xfs_bmap_util.h
xfs_buf_item.c xfs: don't reset b_retries to 0 on every failure 2016-07-20 10:54:09 +10:00
xfs_buf_item.h xfs: fix non-debug build warnings 2015-08-25 10:05:13 +10:00
xfs_buf.c xfs: track and serialize in-flight async buffers against unmount 2016-07-20 11:15:28 +10:00
xfs_buf.h xfs: track and serialize in-flight async buffers against unmount 2016-07-20 11:15:28 +10:00
xfs_dir2_readdir.c xfs: concurrent readdir hangs on data buffer locks 2016-05-18 13:20:21 -04:00
xfs_discard.c xfs: fix format specifier , should be %llx and not %llu 2016-03-02 09:57:04 +11:00
xfs_discard.h
xfs_dquot_item.c
xfs_dquot_item.h
xfs_dquot.c Merge branch 'xfs-4.7-misc-fixes' into for-next 2016-05-20 10:33:17 +10:00
xfs_dquot.h
xfs_error.c xfs: print name of verifier if it fails 2016-01-04 16:10:19 +11:00
xfs_error.h
xfs_export.c Various bugfixes, a RDMA update from Chuck Lever, and support for a new 2016-03-24 19:50:32 -07:00
xfs_export.h
xfs_extent_busy.c
xfs_extent_busy.h
xfs_extfree_item.c xfs: add helper to conditionally remove items from the AIL 2015-08-19 10:01:08 +10:00
xfs_extfree_item.h xfs: fix efi/efd error handling to avoid fs shutdown hangs 2015-08-19 09:51:16 +10:00
xfs_file.c DAX error handling for 4.7 2016-05-26 19:34:26 -07:00
xfs_filestream.c xfs: mode di_mode to vfs inode 2016-02-09 16:54:58 +11:00
xfs_filestream.h
xfs_fsops.c Merge branch 'xfs-4.7-trans-type-cleanup' into for-next 2016-05-20 10:31:52 +10:00
xfs_fsops.h xfs: remove unused function definitions 2016-02-08 14:58:07 +11:00
xfs_globals.c
xfs_icache.c xfs: move reclaim tagging functions 2016-05-18 14:20:08 +10:00
xfs_icache.h
xfs_icreate_item.c
xfs_icreate_item.h
xfs_inode_item.c Merge branch 'xfs-4.7-misc-fixes' into for-next 2016-05-20 10:33:17 +10:00
xfs_inode_item.h xfs: remove timestamps from incore inode 2016-02-09 16:54:58 +11:00
xfs_inode.c Merge branch 'xfs-4.7-inode-reclaim' into for-next 2016-05-20 10:34:00 +10:00
xfs_inode.h xfs: set up inode operation vectors later 2016-04-06 07:48:27 +10:00
xfs_ioctl32.c xfs: prefix XATTR_LIST_MAX with XFS_ 2015-10-12 16:02:56 +11:00
xfs_ioctl32.h
xfs_ioctl.c Merge branch 'xfs-4.7-optimise-inline-symlinks' into for-next 2016-05-20 10:32:10 +10:00
xfs_ioctl.h
xfs_iomap.c xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_iomap.h
xfs_iops.c Merge branch 'xfs-4.7-optimise-inline-symlinks' into for-next 2016-05-20 10:32:10 +10:00
xfs_iops.h
xfs_itable.c xfs: mode di_mode to vfs inode 2016-02-09 16:54:58 +11:00
xfs_itable.h
xfs_linux.h mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
xfs_log_cil.c xfs: remove transaction types 2016-04-06 09:20:36 +10:00
xfs_log_priv.h xfs: remove transaction types 2016-04-06 09:20:36 +10:00
xfs_log_recover.c Merge branch 'xfs-4.7-misc-fixes' into for-next 2016-05-20 10:33:17 +10:00
xfs_log.c xfs: exclude never-released buffers from buftarg I/O accounting 2016-07-20 11:13:43 +10:00
xfs_log.h xfs: remove transaction types 2016-04-06 09:20:36 +10:00
xfs_message.c xfs: more info from kmem deadlocks and high-level error msgs 2015-10-12 16:04:45 +11:00
xfs_message.h
xfs_mount.c xfs: exclude never-released buffers from buftarg I/O accounting 2016-07-20 11:13:43 +10:00
xfs_mount.h xfs: update for 4.7-rc1 2016-05-26 10:13:40 -07:00
xfs_mru_cache.c
xfs_mru_cache.h
xfs_ondisk.h xfs: check sizes of XFS on-disk structures at compile time 2016-03-09 08:15:14 +11:00
xfs_pnfs.c xfs: update for 4.7-rc1 2016-05-26 10:13:40 -07:00
xfs_pnfs.h nfsd: add SCSI layout support 2016-03-18 11:42:53 -04:00
xfs_qm_bhv.c
xfs_qm_syscalls.c xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_qm.c xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_qm.h xfs: Split default quota limits by quota type 2016-02-08 11:27:55 +11:00
xfs_quota.h
xfs_quotaops.c xfs: wire up Q_XGETNEXTQUOTA / get_nextdqblk 2016-02-08 11:27:38 +11:00
xfs_rtalloc.c xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_rtalloc.h
xfs_stats.c xfs: stats are no longer dependent on CONFIG_PROC_FS 2015-10-19 08:42:46 +11:00
xfs_stats.h xfs: per-filesystem stats counter implementation 2015-10-12 18:21:22 +11:00
xfs_super.c DAX error handling for 4.7 2016-05-26 19:34:26 -07:00
xfs_super.h xfs: fix up inode32/64 (re)mount handling 2016-03-02 09:58:09 +11:00
xfs_symlink.c Merge branch 'xfs-4.7-optimise-inline-symlinks' into for-next 2016-05-20 10:32:10 +10:00
xfs_symlink.h
xfs_sysctl.c xfs: pass xfsstats structures to handlers and macros 2015-10-12 05:19:45 +11:00
xfs_sysctl.h
xfs_sysfs.c xfs: fix xfs_error_get_cfg for negative errnos 2016-07-20 10:48:51 +10:00
xfs_sysfs.h xfs: configurable error behavior via sysfs 2016-05-18 10:58:51 +10:00
xfs_trace.c
xfs_trace.h Merge branch 'xfs-4.7-error-cfg' into for-next 2016-05-20 10:33:38 +10:00
xfs_trans_ail.c xfs: Make xfsaild freezeable again 2016-02-08 14:59:07 +11:00
xfs_trans_buf.c xfs: remove XBF_STALE flag wrapper macros 2016-02-10 15:01:11 +11:00
xfs_trans_dquot.c xfs: Split default quota limits by quota type 2016-02-08 11:27:55 +11:00
xfs_trans_extfree.c xfs: ensure EFD trans aborts on log recovery extent free failure 2015-08-19 09:51:43 +10:00
xfs_trans_inode.c xfs: move di_changecount to VFS inode 2016-02-09 16:54:58 +11:00
xfs_trans_priv.h xfs: add helper to conditionally remove items from the AIL 2015-08-19 10:01:08 +10:00
xfs_trans.c xfs: remove transaction types 2016-04-06 09:20:36 +10:00
xfs_trans.h xfs: better xfs_trans_alloc interface 2016-04-06 09:19:55 +10:00
xfs_xattr.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-05-27 17:14:05 -07:00
xfs.h