Commit 7ba3ec57 authored by Jan Kara's avatar Jan Kara

ext2: Fix fs corruption in ext2_get_xip_mem()

Commit 8e3dffc6 "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: default avatarAndiry Xu <andiry.xu@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 18da65e7
...@@ -632,6 +632,8 @@ static int ext2_get_blocks(struct inode *inode, ...@@ -632,6 +632,8 @@ static int ext2_get_blocks(struct inode *inode,
int count = 0; int count = 0;
ext2_fsblk_t first_block = 0; ext2_fsblk_t first_block = 0;
BUG_ON(maxblocks == 0);
depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary); depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
if (depth == 0) if (depth == 0)
......
...@@ -35,6 +35,7 @@ __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create, ...@@ -35,6 +35,7 @@ __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
int rc; int rc;
memset(&tmp, 0, sizeof(struct buffer_head)); memset(&tmp, 0, sizeof(struct buffer_head));
tmp.b_size = 1 << inode->i_blkbits;
rc = ext2_get_block(inode, pgoff, &tmp, create); rc = ext2_get_block(inode, pgoff, &tmp, create);
*result = tmp.b_blocknr; *result = tmp.b_blocknr;
......
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