Thanks, done in V3. On Fri, Aug 9, 2019 at 12:48 PM Andreas Dilger <adilger@xxxxxxxxx> wrote: > > On Aug 8, 2019, at 9:45 PM, Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx> wrote: > > > > For fast commits, JBD2 as of now allocates a default of 128 blocks at > > the end of the journalling area. Although JBD2 owns these blocks, it > > doesn't control what exactly should be written in these blocks. It > > just provides the right abstraction for making these blocks usable by > > file systems. This patch adds necessary fields to manage these fast > > commit blocks. > > > > Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx> > > Contrary to the description, this patch doesn't really do anything beyond > adding unused fields and constants to the header, and as such isn't really > useful to land on its own since there is no way to see what the fields > are used for. In particular, I was going to say that JBD2_FAST_COMMIT_BLOCKS > should only be reserved if the FAST_COMMIT feature is enabled (unlike what > is written above, which implies that they are always reserved), otherwise > it can impact filesystem performance even when the feature is not active. > > I'd recommend to merge these changes with the patch where the fields/constants > are actually used. > > Cheers, Andreas > > > --- > > > > Changelog: > > > > V2: Added struct transaction_run_stats_s * argument to > > j_fc_commit_callback to collect stats > > --- > > include/linux/jbd2.h | 79 ++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 79 insertions(+) > > > > diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h > > index b7eed49b8ecd..9a750b732241 100644 > > --- a/include/linux/jbd2.h > > +++ b/include/linux/jbd2.h > > @@ -66,6 +66,7 @@ void __jbd2_debug(int level, const char *file, const char *func, > > extern void *jbd2_alloc(size_t size, gfp_t flags); > > extern void jbd2_free(void *ptr, size_t size); > > > > +#define JBD2_FAST_COMMIT_BLOCKS 128 > > #define JBD2_MIN_JOURNAL_BLOCKS 1024 > > > > #ifdef __KERNEL__ > > @@ -918,6 +919,34 @@ struct journal_s > > */ > > unsigned long j_last; > > > > + /** > > + * @j_first_fc: > > + * > > + * The block number of the first fast commit block in the journal > > + */ > > + unsigned long j_first_fc; > > + > > + /** > > + * @j_current_fc: > > + * > > + * Journal fc block iterator > > + */ > > + unsigned long j_fc_off; > > + > > + /** > > + * @j_last_fc: > > + * > > + * The block number of the last fast commit block in the journal > > + */ > > + unsigned long j_last_fc; > > + > > + /** > > + * @j_do_full_commit: > > + * > > + * Force a full commit. If this flag is set JBD2 won't try fast commits > > + */ > > + bool j_do_full_commit; > > + > > /** > > * @j_dev: Device where we store the journal. > > */ > > @@ -987,6 +1016,15 @@ struct journal_s > > */ > > tid_t j_transaction_sequence; > > > > + /** > > + * @j_subtid: > > + * > > + * One plus the sequence number of the most recently committed fast > > + * commit. This represents the sub transaction ID for the next fast > > + * commit. > > + */ > > + tid_t j_subtid; > > + > > /** > > * @j_commit_sequence: > > * > > @@ -1068,6 +1106,20 @@ struct journal_s > > */ > > int j_wbufsize; > > > > + /** > > + * @j_fc_wbuf: > > + * > > + * Array of bhs for fast commit transactions > > + */ > > + struct buffer_head **j_fc_wbuf; > > + > > + /** > > + * @j_fc_wbufsize: > > + * > > + * Size of @j_fc_wbufsize array. > > + */ > > + int j_fc_wbufsize; > > + > > /** > > * @j_last_sync_writer: > > * > > @@ -1167,6 +1219,33 @@ struct journal_s > > */ > > struct lockdep_map j_trans_commit_map; > > #endif > > + /** > > + * @j_fc_commit_callback: > > + * > > + * File-system specific function that performs actual fast commit > > + * operation. Should return 0 if the fast commit was successful, in that > > + * case, JBD2 will just increment journal->j_subtid and move on. If it > > + * returns < 0, JBD2 will fall-back to full commit. > > + */ > > + int (*j_fc_commit_callback)(struct journal_s *journal, tid_t tid, > > + tid_t subtid, > > + struct transaction_run_stats_s *stats); > > + /** > > + * @j_fc_replay_callback: > > + * > > + * File-system specific function that performs replay of a fast > > + * commit. JBD2 calls this function for each fast commit block found in > > + * the journal. > > + */ > > + int (*j_fc_replay_callback)(struct journal_s *journal, > > + struct buffer_head *bh); > > + /** > > + * @j_fc_cleanup_callback: > > + * > > + * Clean-up after fast commit or full commit. JBD2 calls this function > > + * after every commit operation. > > + */ > > + void (*j_fc_cleanup_callback)(struct journal_s *journal); > > }; > > > > #define jbd2_might_wait_for_commit(j) \ > > -- > > 2.23.0.rc1.153.gdeed80330f-goog > > > > > Cheers, Andreas > > > > >
