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95808459b1
linux/fs/xfs
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Brian Foster 95808459b1 xfs: refactor xfs_buf_log_item reference count handling 
The xfs_buf_log_item structure has a reference counter with slightly
tricky semantics. In the common case, a buffer is logged and
committed in a transaction, committed to the on-disk log (added to
the AIL) and then finally written back and removed from the AIL. The
bli refcount covers two potentially overlapping timeframes:

 1. the bli is held in an active transaction
 2. the bli is pinned by the log

The caveat to this approach is that the reference counter does not
purely dictate the lifetime of the bli. IOW, when a dirty buffer is
physically logged and unpinned, the bli refcount may go to zero as
the log item is inserted into the AIL. Only once the buffer is
written back can the bli finally be freed.

The above semantics means that it is not enough for the various
refcount decrementing contexts to release the bli on decrement to
zero. xfs_trans_brelse(), transaction commit (->iop_unlock()) and
unpin (->iop_unpin()) must all drop the associated reference and
make additional checks to determine if the current context is
responsible for freeing the item.

For example, if a transaction holds but does not dirty a particular
bli, the commit may drop the refcount to zero. If the bli itself is
clean, it is also not AIL resident and must be freed at this time.
The same is true for xfs_trans_brelse(). If the transaction dirties
a bli and then aborts or an unpin results in an abort due to a log
I/O error, the last reference count holder is expected to explicitly
remove the item from the AIL and release it (since an abort means
filesystem shutdown and metadata writeback will never occur).

This leads to fairly complex checks being replicated in a few
different places. Since ->iop_unlock() and xfs_trans_brelse() are
nearly identical, refactor the logic into a common helper that
implements and documents the semantics in one place. This patch does
not change behavior.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-09-29 13:45:26 +10:00
..
libxfs xfs: remove last of unnecessary xfs_defer_cancel() callers 2018-09-29 13:41:58 +10:00
scrub xfs: sanity check ag header values in xrep_calc_ag_resblks 2018-08-14 08:17:02 -07:00
Kconfig xfs: implement the metadata repair ioctl flag 2018-05-15 18:12:50 -07:00
kmem.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
kmem.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
Makefile xfs: move the repair extent list into its own file 2018-07-29 22:37:09 -07:00
mrlock.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_aops.c xfs: use WRITE_ONCE to update if_seq 2018-08-07 10:57:12 -07:00
xfs_aops.h xfs: remove xfs_map_cow 2018-07-11 22:25:59 -07:00
xfs_attr_inactive.c xfs: remove all boilerplate defer init/finish code 2018-07-26 10:15:15 -07:00
xfs_attr_list.c xfs: substitute spaces with tabs 2018-08-02 23:05:14 -07:00
xfs_attr.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_bmap_item.c xfs: pass transaction to xfs_defer_add() 2018-08-02 23:05:14 -07:00
xfs_bmap_item.h xfs: use transaction for intent recovery instead of raw dfops 2018-08-02 23:05:13 -07:00
xfs_bmap_util.c xfs: remove last of unnecessary xfs_defer_cancel() callers 2018-09-29 13:41:58 +10:00
xfs_bmap_util.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_buf_item.c xfs: refactor xfs_buf_log_item reference count handling 2018-09-29 13:45:26 +10:00
xfs_buf_item.h xfs: refactor xfs_buf_log_item reference count handling 2018-09-29 13:45:26 +10:00
xfs_buf.c xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00
xfs_buf.h xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00
xfs_dir2_readdir.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_discard.c xfs: trivial xfs_btree_del_cursor cleanups 2018-07-23 09:08:00 -07:00
xfs_discard.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_dquot_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_dquot_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_dquot.c xfs: remove dead error handling code in xfs_dquot_disk_alloc() 2018-08-07 10:57:13 -07:00
xfs_dquot.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_error.c xfs: force summary counter recalc at next mount 2018-07-23 09:08:01 -07:00
xfs_error.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_export.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_export.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extfree_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extfree_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_file.c overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
xfs_filestream.c xfs: replace dop_low with transaction flag 2018-08-02 23:05:13 -07:00
xfs_filestream.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsmap.c xfs: trivial xfs_btree_del_cursor cleanups 2018-07-23 09:08:00 -07:00
xfs_fsmap.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsops.c xfs: pass transaction lock while setting up agresv on cyclic metadata 2018-07-29 22:37:08 -07:00
xfs_fsops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_globals.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_icache.c xfs: introduce a new xfs_inode_has_cow_data helper 2018-07-30 07:57:48 -07:00
xfs_icache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_icreate_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_icreate_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode_item.c xfs: remove if_real_bytes 2018-07-30 07:57:48 -07:00
xfs_inode_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode.c xfs: remove last of unnecessary xfs_defer_cancel() callers 2018-09-29 13:41:58 +10:00
xfs_inode.h xfs: fold dfops into the transaction 2018-08-02 23:05:14 -07:00
xfs_ioctl32.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ioctl32.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ioctl.c Changes since last update: 2018-06-12 15:49:00 -07:00
xfs_ioctl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_iomap.c Merge branch 'iomap-4.19-merge' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux 2018-08-13 22:29:03 -07:00
xfs_iomap.h xfs: avoid COW fork extent lookups in writeback if the fork didn't change 2018-07-31 13:18:09 -07:00
xfs_iops.c xfs: don't crash the vfs on a garbage inline symlink 2018-09-29 13:40:40 +10:00
xfs_iops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_itable.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_itable.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_linux.h xfs: replace do_mod with native operations 2018-06-08 10:07:52 -07:00
xfs_log_cil.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_log_priv.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_log_recover.c xfs: pass transaction to dfops reset/move helpers 2018-08-02 23:05:13 -07:00
xfs_log.c xfs: fix a comment in xfs_log_reserve 2018-08-03 08:17:54 -07:00
xfs_log.h xfs: refactor log recovery check 2018-08-01 07:40:48 -07:00
xfs_message.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_message.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_mount.c xfs: recalculate summary counters at mount time if icount is bad 2018-08-13 07:58:27 -07:00
xfs_mount.h xfs: remove deprecated barrier/nobarrier mount 2018-07-26 10:15:17 -07:00
xfs_mru_cache.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_mru_cache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ondisk.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_pnfs.c xfs: prepare xfs_break_layouts() for another layout type 2018-05-22 07:19:08 -07:00
xfs_pnfs.h xfs: prepare xfs_break_layouts() for another layout type 2018-05-22 07:19:08 -07:00
xfs_qm_bhv.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_qm_syscalls.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_qm.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_qm.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_quota.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_quotaops.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_refcount_item.c xfs: pass transaction to xfs_defer_add() 2018-08-02 23:05:14 -07:00
xfs_refcount_item.h xfs: use transaction for intent recovery instead of raw dfops 2018-08-02 23:05:13 -07:00
xfs_reflink.c xfs: fold dfops into the transaction 2018-08-02 23:05:14 -07:00
xfs_reflink.h xfs: remove xfs_reflink_find_cow_mapping 2018-07-11 22:26:01 -07:00
xfs_rmap_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_rmap_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_rtalloc.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_rtalloc.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_stats.c Changes since last update: 2018-06-12 15:49:00 -07:00
xfs_stats.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_super.c xfs: remove the xfs_ifork_t typedef 2018-07-30 07:57:48 -07:00
xfs_super.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_symlink.c xfs: automatic dfops inode relogging 2018-08-02 23:05:14 -07:00
xfs_symlink.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysctl.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysctl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysfs.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysfs.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.h xfs: don't unlock invalidated buf on aborted tx commit 2018-09-29 13:44:40 +10:00
xfs_trans_ail.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trans_bmap.c xfs: drop dop param from xfs_defer_op_type ->finish_item() callback 2018-08-02 23:05:14 -07:00
xfs_trans_buf.c xfs: refactor xfs_buf_log_item reference count handling 2018-09-29 13:45:26 +10:00
xfs_trans_dquot.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trans_extfree.c xfs: drop dop param from xfs_defer_op_type ->finish_item() callback 2018-08-02 23:05:14 -07:00
xfs_trans_inode.c vfs/y2038: inode timestamps conversion to timespec64 2018-06-15 07:31:07 +09:00
xfs_trans_priv.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trans_refcount.c xfs: drop dop param from xfs_defer_op_type ->finish_item() callback 2018-08-02 23:05:14 -07:00
xfs_trans_rmap.c xfs: drop dop param from xfs_defer_op_type ->finish_item() callback 2018-08-02 23:05:14 -07:00
xfs_trans.c xfs: fold dfops into the transaction 2018-08-02 23:05:14 -07:00
xfs_trans.h xfs: fold dfops into the transaction 2018-08-02 23:05:14 -07:00
xfs_xattr.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs.h xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00