ext4: make sure directory and symlink blocks are revoked
When an inode gets unlinked, the functions ext4_clear_blocks() and
ext4_remove_blocks() call ext4_forget() for all the buffer heads
corresponding to the deleted inode's data blocks. If the inode is a
directory or a symlink, the is_metadata parameter must be non-zero so
ext4_forget() will revoke them via jbd2_journal_revoke(). Otherwise,
if these blocks are reused for a data file, and the system crashes
before a journal checkpoint, the journal replay could end up
corrupting these data blocks.
Thanks to Curt Wohlgemuth for pointing out potential problems in this
area.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 13de1dd..c420aab 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4121,6 +4121,8 @@
__le32 *last)
{
__le32 *p;
+ int is_metadata = S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode);
+
if (try_to_extend_transaction(handle, inode)) {
if (bh) {
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
@@ -4151,11 +4153,11 @@
*p = 0;
tbh = sb_find_get_block(inode->i_sb, nr);
- ext4_forget(handle, 0, inode, tbh, nr);
+ ext4_forget(handle, is_metadata, inode, tbh, nr);
}
}
- ext4_free_blocks(handle, inode, block_to_free, count, 0);
+ ext4_free_blocks(handle, inode, block_to_free, count, is_metadata);
}
/**