From: Brian Foster <bfoster@redhat.com>
To: linux-xfs@vger.kernel.org
Subject: [PATCH v2 2/5] xfs: logically separate iomap range from allocation range
Date: Wed, 11 Jan 2017 12:54:06 -0500 [thread overview]
Message-ID: <1484157249-464-3-git-send-email-bfoster@redhat.com> (raw)
In-Reply-To: <1484157249-464-1-git-send-email-bfoster@redhat.com>
xfs_file_iomap_begin_delay() uses the got variable for the extent
returned by the in-core extent list lookup, the allocated extent
returned by xfs_bmapi_reserve_delalloc() and the extent mapped to the
iomap data structure for the caller.
This is fine for current usage, but doesn't work for COW fork
reservation. In that case, the extent returned by
xfs_bmapi_reserve_delalloc() is the COW reservation and not the extent
to be mapped to the iomap. Instead, the shared data fork extent should
be trimmed appropriately and mapped to the iomap.
To prepare *_begin_delay() to support COW fork reservation, add a new
imap variable to separately track the data fork extent (for iomap) from
the extent returned from the lookup. The latter extent may refer to
either the data or COW fork in the future.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_iomap.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index ec86262..8791ed5 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -536,6 +536,7 @@ xfs_iomap_search_extents(
struct xfs_inode *ip,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb,
+ struct xfs_bmbt_irec *imap, /* for iomap mapping */
int *eof,
int *idx,
struct xfs_bmbt_irec *got,
@@ -546,15 +547,21 @@ xfs_iomap_search_extents(
*found = false;
- *eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, idx, got);
- if (*eof || got->br_startoff > offset_fsb)
+ /*
+ * Look up a preexisting extent directly into imap. Set got for the
+ * bmapi delalloc call if nothing is found.
+ */
+ *eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, idx, imap);
+ if (*eof || imap->br_startoff > offset_fsb) {
+ *got = *imap;
return 0;
+ }
if (xfs_is_reflink_inode(ip)) {
bool shared;
- xfs_trim_extent(got, offset_fsb, end_fsb - offset_fsb);
- error = xfs_reflink_reserve_cow(ip, got, &shared);
+ xfs_trim_extent(imap, offset_fsb, end_fsb - offset_fsb);
+ error = xfs_reflink_reserve_cow(ip, imap, &shared);
if (error)
return error;
}
@@ -580,6 +587,7 @@ xfs_file_iomap_begin_delay(
xfs_fileoff_t maxbytes_fsb =
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
int error = 0, eof = 0;
+ struct xfs_bmbt_irec imap;
struct xfs_bmbt_irec got;
xfs_extnum_t idx;
xfs_fsblock_t prealloc_blocks = 0;
@@ -614,12 +622,12 @@ xfs_file_iomap_begin_delay(
* Search for preexisting extents. If an existing data extent is shared,
* this will perform COW fork reservation.
*/
- error = xfs_iomap_search_extents(ip, offset_fsb, end_fsb, &eof, &idx,
- &got, &found);
+ error = xfs_iomap_search_extents(ip, offset_fsb, end_fsb, &imap, &eof,
+ &idx, &got, &found);
if (error)
goto out_unlock;
if (found) {
- trace_xfs_iomap_found(ip, offset, count, 0, &got);
+ trace_xfs_iomap_found(ip, offset, count, 0, &imap);
goto done;
}
@@ -680,17 +688,18 @@ xfs_file_iomap_begin_delay(
}
trace_xfs_iomap_alloc(ip, offset, count, 0, &got);
+ imap = got;
done:
- if (isnullstartblock(got.br_startblock))
- got.br_startblock = DELAYSTARTBLOCK;
+ if (isnullstartblock(imap.br_startblock))
+ imap.br_startblock = DELAYSTARTBLOCK;
- if (!got.br_startblock) {
- error = xfs_alert_fsblock_zero(ip, &got);
+ if (!imap.br_startblock) {
+ error = xfs_alert_fsblock_zero(ip, &imap);
if (error)
goto out_unlock;
}
- xfs_bmbt_to_iomap(ip, iomap, &got);
+ xfs_bmbt_to_iomap(ip, iomap, &imap);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
--
2.7.4
next prev parent reply other threads:[~2017-01-11 17:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-11 17:54 [PATCH v2 0/5] xfs: basic cow fork speculative preallocation Brian Foster
2017-01-11 17:54 ` [PATCH v2 1/5] xfs: refactor iomap delalloc existing extent search into helper Brian Foster
2017-01-11 17:54 ` Brian Foster [this message]
2017-01-11 17:54 ` [PATCH v2 3/5] xfs: reuse iomap delalloc code for COW fork reservation Brian Foster
2017-01-13 17:13 ` Christoph Hellwig
2017-01-16 16:26 ` Brian Foster
2017-01-16 17:37 ` Christoph Hellwig
2017-01-16 19:04 ` Brian Foster
2017-01-11 17:54 ` [PATCH v2 4/5] xfs: free cowblocks and retry on buffered write ENOSPC Brian Foster
2017-01-13 17:12 ` Christoph Hellwig
2017-01-11 17:54 ` [PATCH v2 5/5] xfs: implement basic COW fork speculative preallocation Brian Foster
2017-01-13 17:13 ` [PATCH v2 0/5] xfs: basic cow " Christoph Hellwig
2017-01-16 16:26 ` Brian Foster
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