This is a note to let you know that I've just added the patch titled
xfs: clean up cow fork reservation and tag inodes correctly
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfs-clean-up-cow-fork-reservation-and-tag-inodes-correctly.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From hch@xxxxxx Tue Jan 10 11:25:29 2017
From: Christoph Hellwig <hch@xxxxxx>
Date: Mon, 9 Jan 2017 16:38:45 +0100
Subject: xfs: clean up cow fork reservation and tag inodes correctly
To: stable@xxxxxxxxxxxxxxx
Cc: linux-xfs@xxxxxxxxxxxxxxx, Brian Foster <bfoster@xxxxxxxxxx>, Dave Chinner <david@xxxxxxxxxxxxx>
Message-ID: <1483976343-661-15-git-send-email-hch@xxxxxx>
From: Brian Foster <bfoster@xxxxxxxxxx>
commit 0260d8ff5f76617e3a55a1c471383ecb4404c3ad upstream.
COW fork reservation is implemented via delayed allocation. The code is
modeled after the traditional delalloc allocation code, but is slightly
different in terms of how preallocation occurs. Rather than post-eof
speculative preallocation, COW fork preallocation is implemented via a
COW extent size hint that is designed to minimize fragmentation as a
reflinked file is split over time.
xfs_reflink_reserve_cow() still uses logic that is oriented towards
dealing with post-eof speculative preallocation, however, and is stale
or not necessarily correct. First, the EOF alignment to the COW extent
size hint is implemented in xfs_bmapi_reserve_delalloc() (which does so
correctly by aligning the start and end offsets) and so is not necessary
in xfs_reflink_reserve_cow(). The backoff and retry logic on ENOSPC is
also ineffective for the same reason, as xfs_bmapi_reserve_delalloc()
will simply perform the same allocation request on the retry. Finally,
since the COW extent size hint aligns the start and end offset of the
range to allocate, the end_fsb != orig_end_fsb logic is not sufficient.
Indeed, if a write request happens to end on an aligned offset, it is
possible that we do not tag the inode for COW preallocation even though
xfs_bmapi_reserve_delalloc() may have preallocated at the start offset.
Kill the unnecessary, duplicate code in xfs_reflink_reserve_cow().
Remove the inode tag logic as well since xfs_bmapi_reserve_delalloc()
has been updated to tag the inode correctly.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/xfs_reflink.c | 29 +++--------------------------
1 file changed, 3 insertions(+), 26 deletions(-)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -245,11 +245,9 @@ xfs_reflink_reserve_cow(
{
struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
struct xfs_bmbt_irec got;
- xfs_fileoff_t end_fsb, orig_end_fsb;
int error = 0;
bool eof = false, trimmed;
xfs_extnum_t idx;
- xfs_extlen_t align;
/*
* Search the COW fork extent list first. This serves two purposes:
@@ -287,33 +285,12 @@ xfs_reflink_reserve_cow(
if (error)
return error;
- end_fsb = orig_end_fsb = imap->br_startoff + imap->br_blockcount;
-
- align = xfs_eof_alignment(ip, xfs_get_cowextsz_hint(ip));
- if (align)
- end_fsb = roundup_64(end_fsb, align);
-
-retry:
error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, imap->br_startoff,
- end_fsb - imap->br_startoff, 0, &got, &idx, eof);
- switch (error) {
- case 0:
- break;
- case -ENOSPC:
- case -EDQUOT:
- /* retry without any preallocation */
+ imap->br_blockcount, 0, &got, &idx, eof);
+ if (error == -ENOSPC || error == -EDQUOT)
trace_xfs_reflink_cow_enospc(ip, imap);
- if (end_fsb != orig_end_fsb) {
- end_fsb = orig_end_fsb;
- goto retry;
- }
- /*FALLTHRU*/
- default:
+ if (error)
return error;
- }
-
- if (end_fsb != orig_end_fsb)
- xfs_inode_set_cowblocks_tag(ip);
trace_xfs_reflink_cow_alloc(ip, &got);
return 0;
Patches currently in stable-queue which might be from hch@xxxxxx are
queue-4.9/xfs-always-succeed-when-deduping-zero-bytes.patch
queue-4.9/xfs-fix-crash-and-data-corruption-due-to-removal-of-busy-cow-extents.patch
queue-4.9/xfs-don-t-allow-di_size-with-high-bit-set.patch
queue-4.9/xfs-new-inode-extent-list-lookup-helpers.patch
queue-4.9/xfs-don-t-call-xfs_sb_quota_from_disk-twice.patch
queue-4.9/xfs-factor-rmap-btree-size-into-the-indlen-calculations.patch
queue-4.9/xfs-check-return-value-of-_trans_reserve_quota_nblks.patch
queue-4.9/xfs-complain-if-we-don-t-get-nextents-bmap-records.patch
queue-4.9/xfs-check-for-bogus-values-in-btree-block-headers.patch
queue-4.9/xfs-use-gpf_nofs-when-allocating-btree-cursors.patch
queue-4.9/xfs-fix-max_retries-_show-and-_store-functions.patch
queue-4.9/xfs-fix-double-cleanup-when-cui-recovery-fails.patch
queue-4.9/xfs-don-t-skip-cow-forks-w-delalloc-blocks-in-cowblocks-scan.patch
queue-4.9/xfs-track-preallocation-separately-in-xfs_bmapi_reserve_delalloc.patch
queue-4.9/xfs-use-the-actual-ag-length-when-reserving-blocks.patch
queue-4.9/xfs-ignore-leaf-attr-ichdr.count-in-verifier-during-log-replay.patch
queue-4.9/xfs-pass-post-eof-speculative-prealloc-blocks-to-bmapi.patch
queue-4.9/xfs-don-t-cap-maximum-dedupe-request-length.patch
queue-4.9/xfs-pass-state-not-whichfork-to-trace_xfs_extlist.patch
queue-4.9/xfs-move-agi-buffer-type-setting-to-xfs_read_agi.patch
queue-4.9/xfs-check-minimum-block-size-for-crc-filesystems.patch
queue-4.9/xfs-handle-cow-fork-in-xfs_bmap_trace_exlist.patch
queue-4.9/pci-msi-check-for-null-affinity-mask-in-pci_irq_get_affinity.patch
queue-4.9/xfs-error-out-if-trying-to-add-attrs-and-anextents-0.patch
queue-4.9/xfs-don-t-bug-on-mixed-direct-and-mapped-i-o.patch
queue-4.9/xfs-use-new-extent-lookup-helpers-xfs_file_iomap_begin_delay.patch
queue-4.9/xfs-fix-unbalanced-inode-reclaim-flush-locking.patch
queue-4.9/genirq-affinity-fix-node-generation-from-cpumask.patch
queue-4.9/xfs-use-new-extent-lookup-helpers-in-__xfs_reflink_reserve_cow.patch
queue-4.9/xfs-don-t-crash-if-reading-a-directory-results-in-an-unexpected-hole.patch
queue-4.9/xfs-remove-prev-argument-to-xfs_bmapi_reserve_delalloc.patch
queue-4.9/xfs-clean-up-cow-fork-reservation-and-tag-inodes-correctly.patch
queue-4.9/xfs-forbid-ag-btrees-with-level-0.patch
queue-4.9/xfs-provide-helper-for-counting-extents-from-if_bytes.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html