From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Date: Wed, 11 Mar 2009 17:03:23 +0000 (+0900)
Subject: Fix _fat_bmap() locking
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3a95ea1155c5d44aa58dde2f64f0ddafe27fd1fb;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

Fix _fat_bmap() locking

On swapon() path, it has already i_mutex. So, this uses i_alloc_sem
instead of it.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: Laurent GUERBY <laurent@guerby.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 6b74d09adbe5..de0004fe6e00 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -202,9 +202,9 @@ static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 	sector_t blocknr;
 
 	/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
-	mutex_lock(&mapping->host->i_mutex);
+	down_read(&mapping->host->i_alloc_sem);
 	blocknr = generic_block_bmap(mapping, block, fat_get_block);
-	mutex_unlock(&mapping->host->i_mutex);
+	up_read(&mapping->host->i_alloc_sem);
 
 	return blocknr;
 }