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authorJan Kara <jack@suse.cz>2013-11-05 01:15:38 +0100
committerZefan Li <lizefan@huawei.com>2014-09-25 11:49:19 +0800
commit3a8f61352a884762e6485ab21af08054b76cff69 (patch)
parentf79bb94b5ae6581d81f7b65cfc8f11e86bc2c8de (diff)
ext2: Fix fs corruption in ext2_get_xip_mem()
commit 7ba3ec5749ddb61f79f7be17b5fd7720eebc52de upstream. Commit 8e3dffc651cb "Ext2: mark inode dirty after the function dquot_free_block_nodirty is called" unveiled a bug in __ext2_get_block() called from ext2_get_xip_mem(). That function called ext2_get_block() mistakenly asking it to map 0 blocks while 1 was intended. Before the above mentioned commit things worked out fine by luck but after that commit we started returning that we allocated 0 blocks while we in fact allocated 1 block and thus allocation was looping until all blocks in the filesystem were exhausted. Fix the problem by properly asking for one block and also add assertion in ext2_get_blocks() to catch similar problems. Reported-and-tested-by: Andiry Xu <andiry.xu@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Cc: Wang Nan <wangnan0@huawei.com> Signed-off-by: Zefan Li <lizefan@huawei.com>
2 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 740cad8dcd8d..6a7c4837cc7c 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -614,6 +614,8 @@ static int ext2_get_blocks(struct inode *inode,
int count = 0;
ext2_fsblk_t first_block = 0;
+ BUG_ON(maxblocks == 0);
depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
if (depth == 0)
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
index 1c3312858fcf..e98171a11cfe 100644
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -35,6 +35,7 @@ __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
int rc;
memset(&tmp, 0, sizeof(struct buffer_head));
+ tmp.b_size = 1 << inode->i_blkbits;
rc = ext2_get_block(inode, pgoff, &tmp, create);
*result = tmp.b_blocknr;