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| author | Kyle Zeng <kylebot@openai.com> | 2026-06-11 14:35:10 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-06-17 15:37:47 -0700 |
| commit | 22920541c35a9f23f219038ba5874c843a7c4419 (patch) | |
| tree | c8844ca8dbff4e88e2435806c59dd3b91e96a7d6 /fs | |
| parent | 07669b0abe4ce76c716e8437e198e1337cf43d1f (diff) | |
| download | ath-22920541c35a9f23f219038ba5874c843a7c4419.tar.gz | |
ocfs2: avoid moving extents to occupied clusters
For non-auto OCFS2_IOC_MOVE_EXT operations, userspace supplies a physical
me_goal. ocfs2_move_extent() initializes new_phys_cpos from that goal and
expects ocfs2_probe_alloc_group() to replace it with a free run in the
target block group.
The probe currently leaves *phys_cpos unchanged if the scan reaches the
end of the group without finding a free run. An occupied goal at the last
bit can therefore survive the probe and be passed to
__ocfs2_move_extent(), which copies file data into a cluster still owned
by another inode before the bitmap is updated.
When the probe does find a free run, it also subtracts move_len from the
ending bit. The start of an N-bit run ending at i is i - N + 1, so the
current calculation can report the bit immediately before the free run.
Clear *phys_cpos before scanning and use the correct free-run start.
Callers already treat a zero result as -ENOSPC, so failed probes no longer
continue with an occupied caller-controlled goal.
Link: https://lore.kernel.org/20260611213510.16956-1-kylebot@openai.com
Fixes: e6b5859cccfa ("Ocfs2/move_extents: helper to probe a proper region to move in an alloc group.")
Fixes: 236b9254f8d1 ("ocfs2: fix non-auto defrag path not working issue")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ocfs2/move_extents.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c index c53de4439d933..ad1678ee7cc46 100644 --- a/fs/ocfs2/move_extents.c +++ b/fs/ocfs2/move_extents.c @@ -534,6 +534,8 @@ static void ocfs2_probe_alloc_group(struct inode *inode, struct buffer_head *bh, u32 base_cpos = ocfs2_blocks_to_clusters(inode->i_sb, le64_to_cpu(gd->bg_blkno)); + *phys_cpos = 0; + for (i = base_bit; i < le16_to_cpu(gd->bg_bits); i++) { used = ocfs2_test_bit(i, (unsigned long *)gd->bg_bitmap); @@ -555,7 +557,7 @@ static void ocfs2_probe_alloc_group(struct inode *inode, struct buffer_head *bh, last_free_bits++; if (last_free_bits == move_len) { - i -= move_len; + i = i - move_len + 1; *goal_bit = i; *phys_cpos = base_cpos + i; break; |