Currently quota is able to return real error code to caller.
Now it is possible to fix long standing bug with silent quota
corruption in dquot_transfer.
>From 5e529864261c7bffe32a8b3d45d7b51749b4512f Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
Date: Mon, 5 Apr 2010 13:02:18 +0400
Subject: [PATCH] quota: handle io errors in dquot_transfer
Currently if one of dquot structures absent due to some io errors
dquot_transfer will ignore corresponding quotatype. Which is very
bad because result in silent quota inconsistency.
Sane implementation must return corresponding error to caller.
Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
---
fs/quota/dquot.c | 35 +++++++++++++++++++----------------
1 files changed, 19 insertions(+), 16 deletions(-)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 88a8ef2..324a0fb 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1721,15 +1721,22 @@ static int __dquot_transfer(struct inode *inode, qid_t *chid, unsigned long mask
space = cur_space + rsv_space;
/* Build the transfer_from list and check the limits */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
- if (!transfer_to[cnt])
+ if (!(mask & (1 << cnt)))
continue;
transfer_from[cnt] = inode->i_dquot[cnt];
+ /*
+ * Due to IO error we might not have one of dquot structures.
+ * If so, cancel whole procedure */
+ if (!transfer_from[cnt] || !transfer_to[cnt]) {
+ ret = -EIO;
+ goto bad_quota;
+ }
ret = check_idq(transfer_to[cnt], 1, warntype_to + cnt);
if (ret)
- goto over_quota;
+ goto bad_quota;
ret = check_bdq(transfer_to[cnt], space, 0, warntype_to + cnt);
if (ret)
- goto over_quota;
+ goto bad_quota;
}
/*
@@ -1739,20 +1746,16 @@ static int __dquot_transfer(struct inode *inode, qid_t *chid, unsigned long mask
/*
* Skip changes for same uid or gid or for turned off quota-type.
*/
- if (!transfer_to[cnt])
+ if (!(mask & (1 << cnt)))
continue;
+ warntype_from_inodes[cnt] =
+ info_idq_free(transfer_from[cnt], 1);
+ warntype_from_space[cnt] =
+ info_bdq_free(transfer_from[cnt], space);
- /* Due to IO error we might not have transfer_from[] structure */
- if (transfer_from[cnt]) {
- warntype_from_inodes[cnt] =
- info_idq_free(transfer_from[cnt], 1);
- warntype_from_space[cnt] =
- info_bdq_free(transfer_from[cnt], space);
- dquot_decr_inodes(transfer_from[cnt], 1);
- dquot_decr_space(transfer_from[cnt], cur_space);
- dquot_free_reserved_space(transfer_from[cnt],
- rsv_space);
- }
+ dquot_decr_inodes(transfer_from[cnt], 1);
+ dquot_decr_space(transfer_from[cnt], cur_space);
+ dquot_free_reserved_space(transfer_from[cnt], rsv_space);
dquot_incr_inodes(transfer_to[cnt], 1);
dquot_incr_space(transfer_to[cnt], cur_space);
@@ -1776,7 +1779,7 @@ put_all:
dqput_all(transfer_from);
dqput_all(transfer_to);
return ret;
-over_quota:
+bad_quota:
spin_unlock(&dq_data_lock);
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Clear dquot pointers we don't want to dqput() */
--
1.6.6.1
