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author | Jan Kara <jack@suse.cz> | 2013-06-04 20:08:56 +0400 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2013-06-04 20:08:56 +0400 |
commit | b34090e5e22a02fba0e4473056cce9420ad9dd0b (patch) | |
tree | 7ffb9ecd10ada2aefe9079c2df91405592132e47 /include/linux/jbd.h | |
parent | e5a120aeb57f40ae568a5ca1dd6ace53d0213582 (diff) | |
download | linux-b34090e5e22a02fba0e4473056cce9420ad9dd0b.tar.xz |
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>
Diffstat (limited to 'include/linux/jbd.h')
-rw-r--r-- | include/linux/jbd.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/jbd.h b/include/linux/jbd.h index 9c505f1aa1fd..2439054a6c9a 100644 --- a/include/linux/jbd.h +++ b/include/linux/jbd.h @@ -244,6 +244,31 @@ typedef struct journal_superblock_s #include <linux/fs.h> #include <linux/sched.h> + +enum jbd_state_bits { + BH_JBD /* Has an attached ext3 journal_head */ + = BH_PrivateStart, + BH_JWrite, /* Being written to log (@@@ DEBUGGING) */ + BH_Freed, /* Has been freed (truncated) */ + BH_Revoked, /* Has been revoked from the log */ + BH_RevokeValid, /* Revoked flag is valid */ + BH_JBDDirty, /* Is dirty but journaled */ + BH_State, /* Pins most journal_head state */ + BH_JournalHead, /* Pins bh->b_private and jh->b_bh */ + BH_Unshadow, /* Dummy bit, for BJ_Shadow wakeup filtering */ + BH_JBDPrivateStart, /* First bit available for private use by FS */ +}; + +BUFFER_FNS(JBD, jbd) +BUFFER_FNS(JWrite, jwrite) +BUFFER_FNS(JBDDirty, jbddirty) +TAS_BUFFER_FNS(JBDDirty, jbddirty) +BUFFER_FNS(Revoked, revoked) +TAS_BUFFER_FNS(Revoked, revoked) +BUFFER_FNS(RevokeValid, revokevalid) +TAS_BUFFER_FNS(RevokeValid, revokevalid) +BUFFER_FNS(Freed, freed) + #include <linux/jbd_common.h> #define J_ASSERT(assert) BUG_ON(!(assert)) |