From 705912ca95f4bbdbb3be753e46bf30d6be15a5e8 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 1 Sep 2014 14:34:09 -0400 Subject: ext4: teach ext4_ext_find_extent() to free path on error Right now, there are a places where it is all to easy to leak memory on an error path, via a usage like this: struct ext4_ext_path *path = NULL while (...) { ... path = ext4_ext_find_extent(inode, block, path, 0); if (IS_ERR(path)) { /* oops, if path was non-NULL before the call to ext4_ext_find_extent, we've leaked it! :-( */ ... return PTR_ERR(path); } ... } Unfortunately, there some code paths where we are doing the following instead: path = ext4_ext_find_extent(inode, block, orig_path, 0); and where it's important that we _not_ free orig_path in the case where ext4_ext_find_extent() returns an error. So change the function signature of ext4_ext_find_extent() so that it takes a struct ext4_ext_path ** for its third argument, and by default, on an error, it will free the struct ext4_ext_path, and then zero out the struct ext4_ext_path * pointer. In order to avoid causing problems, we add a flag EXT4_EX_NOFREE_ON_ERR which causes ext4_ext_find_extent() to use the original behavior of forcing the caller to deal with freeing the original path pointer on the error case. The goal is to get rid of EXT4_EX_NOFREE_ON_ERR entirely, but this allows for a gentle transition and makes the patches easier to verify. Signed-off-by: Theodore Ts'o --- fs/ext4/move_extent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4/move_extent.c') diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index c8f895b410f6..5e2465a8e4ce 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -37,7 +37,7 @@ get_ext_path(struct inode *inode, ext4_lblk_t lblock, int ret = 0; struct ext4_ext_path *path; - path = ext4_ext_find_extent(inode, lblock, *orig_path, EXT4_EX_NOCACHE); + path = ext4_ext_find_extent(inode, lblock, orig_path, EXT4_EX_NOCACHE); if (IS_ERR(path)) ret = PTR_ERR(path); else if (path[ext_depth(inode)].p_ext == NULL) -- cgit v1.2.2