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gfs2: No quotas for meta inodes

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Inodes on the meta filesystem (mount -o meta) can never have quotas, so
skip them entirely in the quota code.  This avoids allocating
ip->i_qadata unnecessarily.

Without this fix, unlinking meta inodes like "statfs" on the meta
filesystem will result in a NULL pointer dereference at unmount time:

  gfs2_evict_inode() -> gfs2_dinode_dealloc() -> gfs2_quota_hold()
    -> qdsb_get() -> slot_get() -> find_first_zero_bit(sd_quota_bitmap)

Unlinking inodes on the meta filesystem isn't a useful operation, but it
still shouldn't cause the kernel to misbehave.

Reported-by: syzbot+cb79de2cc8b76fbf474f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cb79de2cc8b76fbf474f
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2026-08-26 12:41:28 +02:00
parent 59932d7f7e
commit 0008baad63
1 changed files with 3 additions and 1 deletions
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4
fs/gfs2/quota.c
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@ -562,6 +562,8 @@ int gfs2_qa_get(struct gfs2_inode *ip)
if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
return 0;
if (ip->i_diskflags & GFS2_DIF_SYSTEM)
return 0;
spin_lock(&inode->i_lock);
if (ip->i_qadata == NULL) {
@ -605,7 +607,7 @@ int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid)
return 0;
error = gfs2_qa_get(ip);
if (error)
if (error || !ip->i_qadata)
return error;
qd = ip->i_qadata->qa_qd;