ext2: fix a block leak

open file, unlink it, then use ioctl(2) to make it immutable or
append only.  Now close it and watch the blocks *not* freed...

Immutable/append-only checks belong in ->setattr().
Note: the bug is old and backport to anything prior to 737f2e93b972
("ext2: convert to use the new truncate convention") will need
these checks lifted into ext2_setattr().

Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 1e01fab..7163590 100644 (file)
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1264,21 +1264,11 @@ do_indirects:
 
 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
 {
-       /*
-        * XXX: it seems like a bug here that we don't allow
-        * IS_APPEND inode to have blocks-past-i_size trimmed off.
-        * review and fix this.
-        *
-        * Also would be nice to be able to handle IO errors and such,
-        * but that's probably too much to ask.
-        */
        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
            S_ISLNK(inode->i_mode)))
                return;
        if (ext2_inode_is_fast_symlink(inode))
                return;
-       if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
-               return;
 
        dax_sem_down_write(EXT2_I(inode));
        __ext2_truncate_blocks(inode, offset);