linux-kernel - [39/39] ext4: fix sleep inside spinlock issue with quota and dealloc (#14739)

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Message-Id: <20100105200304.069136093@mini.kroah.org>
Date:	Tue, 05 Jan 2010 12:02:35 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org,
	akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
	stable-review@...nel.org
Cc:	Theodore Tso <tytso@....edu>,
	Dmitry Monakhov <dmonakhov@...nvz.org>, Jan Kara <jack@...e.cz>
Subject: [39/39] ext4: fix sleep inside spinlock issue with quota and dealloc (#14739)

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Dmitry Monakhov <dmonakhov@...nvz.org>

commit 39bc680a8160bb9d6743f7873b535d553ff61058 upstream.

Unlock i_block_reservation_lock before vfs_dq_reserve_block().
This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=14739

Cc: Theodore Ts'o <tytso@....edu>
Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 fs/ext4/inode.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1859,19 +1859,17 @@ repeat:
 
 	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
 	total = md_needed + nrblocks;
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
 	/*
 	 * Make quota reservation here to prevent quota overflow
 	 * later. Real quota accounting is done at pages writeout
 	 * time.
 	 */
-	if (vfs_dq_reserve_block(inode, total)) {
-		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+	if (vfs_dq_reserve_block(inode, total))
 		return -EDQUOT;
-	}
 
 	if (ext4_claim_free_blocks(sbi, total)) {
-		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 		vfs_dq_release_reservation_block(inode, total);
 		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
 			yield();
@@ -1879,10 +1877,11 @@ repeat:
 		}
 		return -ENOSPC;
 	}
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
 	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
-	EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
-
+	EXT4_I(inode)->i_reserved_meta_blocks += md_needed;
 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
 	return 0;       /* success */
 }
 


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