kernel-ark/fs/jbd2
Jan Kara b34090e5e2 jbd2: refine waiting for shadow buffers
Currently when we add a buffer to a transaction, we wait until the
buffer is removed from BJ_Shadow list (so that we prevent any changes
to the buffer that is just written to the journal).  This can take
unnecessarily long as a lot happens between the time the buffer is
submitted to the journal and the time when we remove the buffer from
BJ_Shadow list.  (e.g.  We wait for all data buffers in the
transaction, we issue a cache flush, etc.)  Also this creates a
dependency of do_get_write_access() on transaction commit (namely
waiting for data IO to complete) which we want to avoid when
implementing transaction reservation.

So we modify commit code to set new BH_Shadow flag when temporary
shadowing buffer is created and we clear that flag once IO on that
buffer is complete.  This allows do_get_write_access() to wait only
for BH_Shadow bit and thus removes the dependency on data IO
completion.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:08:56 -04:00
..
checkpoint.c jbd2: remove journal_head from descriptor buffers 2013-06-04 12:06:01 -04:00
commit.c jbd2: refine waiting for shadow buffers 2013-06-04 12:08:56 -04:00
journal.c jbd2: refine waiting for shadow buffers 2013-06-04 12:08:56 -04:00
Kconfig jbd2: Grab a reference to the crc32c driver if necessary 2012-05-27 07:50:56 -04:00
Makefile
recovery.c jbd2: fix block tag checksum verification brokenness 2013-05-28 07:31:59 -04:00
revoke.c jbd2: remove journal_head from descriptor buffers 2013-06-04 12:06:01 -04:00
transaction.c jbd2: refine waiting for shadow buffers 2013-06-04 12:08:56 -04:00