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

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Date:	Fri, 22 Jan 2010 13:27:43 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	cmm@...ibm.com, tytso@....edu, sandeen@...hat.com
Cc:	linux-ext4@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
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 <aneesh.kumar@...ux.vnet.ibm.com>
---
 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

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