ext4: More buffer head reference leaks

After the patch I posted last week regarding buffer head ref leaks in
no-journal mode, I looked at all the code that uses buffer heads and
searched for more potential leaks.

The patch below fixes the issues I found; these can occur even when a
journal is present.

The change to inode.c fixes a double release if
ext4_journal_get_create_access() fails.

The changes to namei.c are more complicated.  add_dirent_to_buf() will
release the input buffer head EXCEPT when it returns -ENOSPC.  There are
some callers of this routine that don't always do the brelse() in the event
that -ENOSPC is returned.  Unfortunately, to put this fix into ext4_add_entry()
required capturing the return value of make_indexed_dir() and
add_dirent_to_buf().

Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f9c642b22efa..deb14a728791 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -762,8 +762,9 @@ static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
                 BUFFER_TRACE(bh, "call get_create_access");
                 err = ext4_journal_get_create_access(handle, bh);
                 if (err) {
+                        /* Don't brelse(bh) here; it's done in
+                         * ext4_journal_forget() below */
                         unlock_buffer(bh);
-                        brelse(bh);
                         goto failed;
                 }