2010-01-22 07:57:50

by Aneesh Kumar K.V

Subject: [PATCH] ext4: Handle -EDQUOT error on write

We need to release the journal before we do a write_inode. Otherwise
we could deadlock.

Signed-off-by: Aneesh Kumar K.V <[email protected]>
---
fs/ext4/inode.c | 31 +++++++++++++++++--------------
1 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c818972..5af483a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1835,24 +1835,12 @@ repeat:
* later. Real quota accounting is done at pages writeout
* time.
*/
- if (vfs_dq_reserve_block(inode, md_needed + 1)) {
- /*
- * We tend to badly over-estimate the amount of
- * metadata blocks which are needed, so if we have
- * reserved any metadata blocks, try to force out the
- * inode and see if we have any better luck.
- */
- if (md_reserved && retries++ <= 3)
- goto retry;
+ if (vfs_dq_reserve_block(inode, md_needed + 1))
return -EDQUOT;
- }

if (ext4_claim_free_blocks(sbi, md_needed + 1)) {
vfs_dq_release_reservation_block(inode, md_needed + 1);
if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
- retry:
- if (md_reserved)
- write_inode_now(inode, (retries == 3));
yield();
goto repeat;
}
@@ -3032,7 +3020,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
- int ret, retries = 0;
+ int ret, retries = 0, quota_retries = 0;
struct page *page;
pgoff_t index;
unsigned from, to;
@@ -3091,6 +3079,21 @@ retry:

if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
+
+ if ((ret == -EDQUOT) && (quota_retries <= 3)) {
+ /*
+ * Since we do aggressive quota reservation may get no quota error
+ * even though we may be having quota. Forcing the inode write will
+ * free up the extra quota reserved. We do it only if we have
+ * meta data blocks reserved because we do aggressive reservation only
+ * for meta data blocks.
+ */
+ if (EXT4_I(inode)->i_reserved_meta_blocks) {
+ write_inode_now(inode, (quota_retries == 3));
+ quota_retries++;
+ goto retry;
+ }
+ }
out:
return ret;
}
--
1.6.6.1.383.g5a9f

2010-01-22 22:24:51

by Theodore Ts'o

Subject: Re: [PATCH] ext4: Handle -EDQUOT error on write

On Fri, Jan 22, 2010 at 01:27:43PM +0530, Aneesh Kumar K.V wrote:
> We need to release the journal before we do a write_inode. Otherwise
> we could deadlock.
>
> Signed-off-by: Aneesh Kumar K.V <[email protected]>

Thanks, applied with some minor adjustments (mostly comment
reformatting/rewording).

- Ted