tree a4cf50f078a0c94d76e363bedc7be91bde7125f6
parent 7b506b1035326543b7cd2d768449ccbd1ef3f368
author Jan Kara <jack@suse.cz> 1434851057 -0400
committer Theodore Ts'o <tytso@mit.edu> 1434851057 -0400

jbd2: speedup jbd2_journal_dirty_metadata()

It is often the case that we mark buffer as having dirty metadata when
the buffer is already in that state (frequent for bitmaps, inode table
blocks, superblock). Thus it is unnecessary to contend on grabbing
journal head reference and bh_state lock. Avoid that by checking whether
any modification to the buffer is needed before grabbing any locks or
references.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>