Hi, Jan Kara wrote: > > On Fri 16-05-08 19:26:57, Hidehiro Kawai wrote: > >>Jan Kara wrote: >> >> >>>On Wed 14-05-08 13:49:51, Hidehiro Kawai wrote: >>> >>> >>>>Subject: [PATCH 3/4] jbd: abort when failed to log metadata buffers >>>> >>>>If we failed to write metadata buffers to the journal space and >>>>succeeded to write the commit record, stale data can be written >>>>back to the filesystem as metadata in the recovery phase. >>>> >>>>To avoid this, when we failed to write out metadata buffers, >>>>abort the journal before writing the commit record. >>>> >>>>Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@xxxxxxxxxxx> >>>>--- >>>>fs/jbd/commit.c | 3 +++ >>>>1 file changed, 3 insertions(+) >>>> >>>>Index: linux-2.6.26-rc2/fs/jbd/commit.c >>>>=================================================================== >>>>--- linux-2.6.26-rc2.orig/fs/jbd/commit.c >>>>+++ linux-2.6.26-rc2/fs/jbd/commit.c >>>>@@ -703,6 +703,9 @@ wait_for_iobuf: >>>> __brelse(bh); >>>> } >>>> >>>>+ if (err) >>>>+ journal_abort(journal, err); >>>>+ >>>> J_ASSERT (commit_transaction->t_shadow_list == NULL); >>> >>> Shouldn't this rather be further just before >>>journal_write_commit_record()? We should abort also if writing revoke >>>records etc. failed, shouldn't we? >> >>Unlike metadata blocks, each revoke block has a descriptor with the >>sequence number of the commiting transaction. If we failed to write >>a revoke block, there should be an old control block, metadata block, >>or zero-filled block where we tried to write the revoke block. >>In the recovery process, this old invalid block is detected by >>checking its magic number and sequence number, then the transaction >>is ignored even if we have succeeded to write the commit record. >>So I think we don't need to check for errors just after writing >>revoke records. > > Yes, I agree that not doing such check will not cause data corruption but > still I think that in case we fail to properly commit a transaction, we > should detect the error and abort the journal... I see. I'll move the aborting point to just before journal_write_commit_record() in the next version. Thanks, -- Hidehiro Kawai Hitachi, Systems Development Laboratory Linux Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
