Hi Chao, On Wed, Jan 14, 2015 at 01:01:13PM +0800, Chao Yu wrote: > Hi Jaegeuk, > > > -----Original Message----- > > From: Jaegeuk Kim [mailto:[email protected]] > > Sent: Wednesday, January 14, 2015 8:22 AM > > To: Chao Yu > > Cc: 'Changman Lee'; [email protected]; > > [email protected] > > Subject: Re: [f2fs-dev][PATCH 2/2] f2fs: enable recover_xattr_data to avoid > > cp when fsync after > > operating xattr > > > > On Mon, Jan 12, 2015 at 05:40:28PM +0800, Chao Yu wrote: > > > Hi Jaegeuk, > > > > > > > -----Original Message----- > > > > From: Jaegeuk Kim [mailto:[email protected]] > > > > Sent: Sunday, January 11, 2015 1:32 PM > > > > To: Chao Yu > > > > Cc: 'Changman Lee'; [email protected]; > > > > [email protected] > > > > Subject: Re: [f2fs-dev][PATCH 2/2] f2fs: enable recover_xattr_data to > > > > avoid cp when fsync > > after > > > > operating xattr > > > > > > > > On Sat, Jan 10, 2015 at 08:08:33PM +0800, Chao Yu wrote: > > > > > Hi Jaegeuk, > > > > > > > > > > > -----Original Message----- > > > > > > From: Jaegeuk Kim [mailto:[email protected]] > > > > > > Sent: Wednesday, January 07, 2015 3:44 AM > > > > > > To: Chao Yu > > > > > > Cc: Changman Lee; [email protected]; > > > > > > [email protected] > > > > > > Subject: Re: [f2fs-dev][PATCH 2/2] f2fs: enable recover_xattr_data > > > > > > to avoid cp when > > fsync > > > > after > > > > > > operating xattr > > > > > > > > > > > > Hi Chao, > > > > > > > > > > > > On Tue, Jan 06, 2015 at 02:29:40PM +0800, Chao Yu wrote: > > > > > > > Now if we call fsync() after we update the xattr date belongs to > > > > > > > the file, f2fs > > > > > > > will do checkpoint to keep data. > > > > > > > This can cause low performance because checkpoint block most > > > > > > > operation and write > > > > > > > lots of blocks. So we'd better to avoid doing checkpoint by > > > > > > > writing modified > > > > > > > xattr node page to warm node segment, and then it can be > > > > > > > recovered when we mount > > > > > > > this device later on. > > > > > > > > > > > > You're trying to change the writing policy as xattr blocks are > > > > > > written into > > > > > > WARM_NODE area instead of COLD_NODE area. > > > > > > I don't think xattrs are frequently changed between each fsync > > > > > > calls. > > > > > > > > > > > > How do you think? > > > > > > > > > > I'm not sure whether there is a scenario that setxattr and fsync are > > > > > invoked > > > > > alternately, but if there is, our performance will decrease obviously. > > > > > > > > > > If you don't want to change writing policy, how about writing xattr > > > > > node with > > > > > fsync flag into cold node segment when fsync() is called, then try to > > > > > recover > > > > > it from cold node chain when recovery after abnormally pow-cut, this > > > > > way can > > > > > avoid cp frequently in above scenario. > > > > > > > > Firt of all, I don't think this scenario is frequent enough that we > > > > have to > > > > break the exisiting writing and recovery procedures. > > > > Moreover, if xattr entries are covered by inline_xattr, it doesn't > > > > trigger > > > > checkpoint. > > > > > > Agree, that's a good solution. > > > > > > > > > > > Let me know, if I'm missing something. > > > > > > > > If you try to change the recovery procedure, it needs to think about the > > > > disk full condition. (i.e., space_for_roll_forward()) > > > > And, I don't want to search cold node chain. > > > > > > OK, if we keep writing policy and recovery procedure as it is, then, > > > shouldn't our > > > recover_xattr_data be dropped because it will be not used from any call > > > path? > > > How do you think of below patch? > > > > Hi Chao, > > > > Nice catch. > > But, IIRC, this code was remained for backward compatibility, since long > > time > > ago, xattr blocks were written into the warm node chain. > > Ah, I got it, thanks for your explanation! :) > How do you think of adding some comments on these codes, because this can help > developers understand it well and not to submit the wrong fix patch like me > again.
Something like this? >From 6b609421e4f9f52de26554300aae62de33e0703a Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim <[email protected]> Date: Thu, 22 Jan 2015 14:48:28 -0800 Subject: [PATCH] f2fs: leave comment for code readability During the recovery, any xattr blocks should not be found, since they are written into cold log, not the warm node chain. Signed-off-by: Jaegeuk Kim <[email protected]> --- fs/f2fs/recovery.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index c4211a5..57603a7 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -346,6 +346,10 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode, if (IS_INODE(page)) { recover_inline_xattr(inode, page); } else if (f2fs_has_xattr_block(ofs_of_node(page))) { + /* + * Deprecated; xattr blocks should be found from cold log. + * But, we should remain this for backward compatibility. + */ recover_xattr_data(inode, page, blkaddr); goto out; } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
