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Message-ID: <20241030045617.2920173-1-alexjlzheng@tencent.com>
Date: Wed, 30 Oct 2024 12:56:17 +0800
From: Jinliang Zheng <alexjlzheng@...il.com>
To: dchinner@...hat.com,
cem@...nel.org
Cc: chandanbabu@...nel.org,
djwong@...nel.org,
zhangjiachen.jaycee@...edance.com,
linux-xfs@...r.kernel.org,
linux-kernel@...r.kernel.org,
Jinliang Zheng <alexjlzheng@...cent.com>
Subject: [PATCH v2] xfs: fix the entry condition of exact EOF block allocation optimization
When we call create(), lseek() and write() sequentially, offset != 0
cannot be used as a judgment condition for whether the file already
has extents.
Furthermore, when xfs_bmap_adjacent() has not given a better blkno,
it is not necessary to use exact EOF block allocation.
Signed-off-by: Jinliang Zheng <alexjlzheng@...cent.com>
---
Changelog:
- V2: Fix the entry condition
- V1: https://lore.kernel.org/linux-xfs/ZyFJm7xg7Msd6eVr@dread.disaster.area/T/#t
---
fs/xfs/libxfs/xfs_bmap.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 36dd08d13293..c1e5372b6b2e 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3531,12 +3531,14 @@ xfs_bmap_btalloc_at_eof(
int error;
/*
- * If there are already extents in the file, try an exact EOF block
- * allocation to extend the file as a contiguous extent. If that fails,
- * or it's the first allocation in a file, just try for a stripe aligned
- * allocation.
+ * If there are already extents in the file, and xfs_bmap_adjacent() has
+ * given a better blkno, try an exact EOF block allocation to extend the
+ * file as a contiguous extent. If that fails, or it's the first
+ * allocation in a file, just try for a stripe aligned allocation.
*/
- if (ap->offset) {
+ if (ap->prev.br_startoff != NULLFILEOFF &&
+ !isnullstartblock(ap->prev.br_startblock) &&
+ xfs_bmap_adjacent_valid(ap, ap->blkno, ap->prev.br_startblock)) {
xfs_extlen_t nextminlen = 0;
/*
--
2.41.1
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