• Nikolay Borisov's avatar
    btrfs: Remove unnecessary check from join_running_log_trans · e678934c
    Nikolay Borisov authored
    join_running_log_trans checks btrfs_root::log_root outside of
    btrfs_root::log_mutex to avoid contention on the mutex. Turns out this
    check is not necessary because the two callers of join_running_log_trans
    (both of which deal with removing entries from the tree-log during
    unlink) explicitly check whether the respective inode has been logged in
    the current transaction.
    
    If it hasn't then it won't have any items in the tree-log and call path
    will return before calling join_running_log_trans. If the check passes,
    however, then it's guaranteed that btrfs_root::log_root is set because
    the inode is logged.
    
    Those guarantees allows us to remove the speculative as well as the
    implicity and tricky memory barrier.
    Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
    Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
    Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
    e678934c
tree-log.c 173 KB