ext4_ext_migrate() records the failure of the migration in retval, but ext4_journal_ensure_credits() overwrites it: it returns 0 when the handle has enough credits or the transaction could be extended, and 1 when the transaction had to be restarted. A failed migration is therefore reported as success, and a restart leaks the internal value 1 to userspace through EXT4_IOC_MIGRATE and FS_IOC_SETFLAGS. Fixes: a413036791d0 ("ext4: Provide function to handle transaction restarts") Signed-off-by: Yichong Chen --- fs/ext4/migrate.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index 2aa6572088cf..e06d847033a1 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -410,7 +410,7 @@ static int free_ext_block(handle_t *handle, struct inode *inode) int ext4_ext_migrate(struct inode *inode) { handle_t *handle; - int retval = 0, i; + int retval = 0, err, i; __le32 *i_data; struct ext4_inode_info *ei; struct inode *tmp_inode = NULL; @@ -567,9 +567,12 @@ int ext4_ext_migrate(struct inode *inode) } /* We mark the tmp_inode dirty via ext4_ext_tree_init. */ - retval = ext4_journal_ensure_credits(handle, 1, 0); - if (retval < 0) + err = ext4_journal_ensure_credits(handle, 1, 0); + if (err < 0) { + if (!retval) + retval = err; goto out_stop; + } /* * Mark the tmp_inode as of size zero */ -- 2.51.0