diff options
| author | Ian Bridges <icb@fastmail.org> | 2026-07-23 23:57:03 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-05 11:20:13 -0700 |
| commit | 0cdc7dde00ec63ac714271fa8b2918d630b8da1a (patch) | |
| tree | 4d1071cd83091868502d5188364c3d285aa76e67 | |
| parent | 2c5a2a6afe8fb59722c427d208085e088012999d (diff) | |
ocfs2: fix missing metadata reservation for large xattrs
[BUG]
lsetxattr() panics the kernel when setting a large xattr value on a
fragmented filesystem where the file already has an external xattr
block.
[CAUSE]
ocfs2_calc_xattr_set_need() never reserves metadata blocks for a new
xattr value's extent tree when the file already has an external xattr
block. The not_found path leaves meta_add at zero, so meta_ac is NULL
when ocfs2_xattr_extend_allocation() runs.
A new value root has room for a single extent record. On a fragmented
filesystem, the allocator cannot satisfy the xattr value in one
contiguous run, so each non-contiguous run requires its own extent
record. When the value root's extent list is full and meta_ac is NULL,
ocfs2_add_clusters_in_btree() returns RESTART_META, and
ocfs2_xattr_extend_allocation() hits BUG_ON(why == RESTART_META).
[FIX]
The case where no xattr block exists yet already calls
ocfs2_extend_meta_needed(&def_xv.xv.xr_list) to reserve value tree
metadata. Add the same reservation to the case where an xattr block
already exists, making the two cases consistent.
Replace the BUG_ON with a -ENOSPC return so that if RESTART_META is
returned despite the reservation, the error propagates to userspace
instead of panicking the kernel.
Link: https://lore.kernel.org/amLwn3i9tET8yhG7@dev
Fixes: a78f9f466894 ("ocfs2: make xattr extension work with new local alloc reservation.")
Signed-off-by: Ian Bridges <icb@fastmail.org>
Reported-by: syzbot+e538032956b1157914a3@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e538032956b1157914a3
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>
| -rw-r--r-- | fs/ocfs2/xattr.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index ed774bded974..94ae1fb83cf1 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -764,12 +764,10 @@ static int ocfs2_xattr_extend_allocation(struct inode *inode, prev_clusters; if (why != RESTART_NONE && clusters_to_add) { - /* - * We can only fail in case the alloc file doesn't give - * up enough clusters. - */ - BUG_ON(why == RESTART_META); - + if (why == RESTART_META) { + status = -ENOSPC; + break; + } credits = ocfs2_calc_extend_credits(inode->i_sb, &vb->vb_xv->xr_list); status = ocfs2_extend_trans(handle, credits); @@ -3444,6 +3442,14 @@ meta_guess: credits += OCFS2_SUBALLOC_ALLOC + 1; /* + * Reserve metadata for the new xattr's value extent tree. + * The not_found path above adds credits for this tree but + * omits meta_add, leaving meta_ac NULL for large values. + */ + if (xi->xi_value_len > OCFS2_XATTR_INLINE_SIZE) + meta_add += ocfs2_extend_meta_needed(&def_xv.xv.xr_list); + + /* * This cluster will be used either for new bucket or for * new xattr block. * If the cluster size is the same as the bucket size, one |