2.6.12 quotaoff loop on a read-only ext3 filesystem

From: xb
Date: Fri Jul 06 2007 - 05:41:34 EST


Hi all,

Running on a 2.6.12.6 kernel, we found a problem with running quotaoff on an ext3 read-only filesystem:

quotaoff loops in dqput() because DQ_ACTIVE_B is set and ext3_release_dquot() returns because of ext3_journal_start() returning EROFS without calling dquot_release() that should have removed DQ_ACTIVE_B.
Then if we try to run the mount command to remount rw the file system, it deadlocks on the down_write(&s->s_umount) owned by quotaoff.
Has this problem been already identified and fixed in recent versions ?
Thanks in advance.

traces -------------------------------------------------------
/static int ext3_release_dquot(struct dquot *dquot)
{
...
handle = ext3_journal_start(dquot_to_inode(dquot),
EXT3_QUOTA_INIT_BLOCKS);
if (IS_ERR(handle))
return PTR_ERR(handle); <------ returns here
ret = dquot_release(dquot); <------- not executed
...
}/

/ <4>Backtrace of current task (pid 20974, quotaoff)
<4>
<4>Call Trace:
<4> [<a00000010019ca10>] dqput+0x210/0x4e0
<4> sp=e00000062a21fbe0 bsp=e00000062a211198
<4> [<a0000001001a15f0>] vfs_quota_off+0x590/0xca0
<4> sp=e00000062a21fbe0 bsp=e00000062a2110f8
<4> [<a0000001001a5660>] sys_quotactl+0x1540/0x15e0
<4> [<a00000010000b040>] ia64_ret_from_syscall+0x0/0x20
/
/ <4>mount D a000000100547520 0 24222 21243 (NOTLB)
<4>
<4>Call Trace:
<4> [<a000000100543ab0>] schedule+0xc10/0x23a0
<4> sp=e00000055a5efaf0 bsp=e00000055a5e1248
<4> [<a000000100547520>] rwsem_down_write_failed+0x1c0/0x4e0
<4> sp=e00000055a5efb30 bsp=e00000055a5e1200
<4> [<a000000100139930>] sget+0x6d0/0xb60
<4> sp=e00000055a5efb50 bsp=e00000055a5e1198
<4> [<a00000010013b6d0>] get_sb_bdev+0xd0/0x400
<4> sp=e00000055a5efb70 bsp=e00000055a5e1148
<4> [<a000000205508980>] ext3_get_sb+0x40/0x60 [ext3]
<4> sp=e00000055a5efb90 bsp=e00000055a5e1110
<4> [<a00000010013bfe0>] do_kern_mount+0x140/0x480
<4> [<a0000001001759f0>] do_mount+0x370/0x1060
<4> sp=e00000055a5efb90 bsp=e00000055a5e1060
<4> [<a000000100177000>] sys_mount+0x100/0x1c0
/

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