Hello, some time ago we discussed on #btrfs that the nocow attribute for files wasn''t working (around 3.3 or 3.4 kernels). That was evident by files fragmenting even with the attribute set. Chris mentioned to find a fix quickly for that, and posted some lines of change into irc. But recently someone mentioned that 3.6-rc looks like still not respecting nocow for files. Is there really a fix upstream for that? Do nocow attribute on files work for anyone already? Regards, Lluís. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 15, 2012 at 08:05:11AM -0500, Kyle Gates wrote:> > Is there really a fix upstream for that? Do nocow attribute on files work for > > anyone already? > > IIRC the nocow attribute seems to work if the volume is mounted with "nodatasum"Shouldn''t nocow mean also nodatasum *only for that file*? I find it a bit useless, to require whole fs nodatasum for per-file nocow to work. Thank you, Lluís. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/15/2012 06:12 PM, Lluís Batlle i Rossell wrote:> Hello, > > some time ago we discussed on #btrfs that the nocow attribute for files wasn''t > working (around 3.3 or 3.4 kernels). That was evident by files fragmenting even > with the attribute set. > > Chris mentioned to find a fix quickly for that, and posted some lines of change > into irc. But recently someone mentioned that 3.6-rc looks like still not > respecting nocow for files. > > Is there really a fix upstream for that? Do nocow attribute on files work for > anyone already? >Hi Lluís, Dave had post a patch to fix it but only enabling NOCOW with zero sized file. FYI, the patch is http://article.gmane.org/gmane.comp.file-systems.btrfs/17351 With the patch, you don''t need to mount with nodatacow any more :) And why it is only for only zero sized file: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18046 thanks, liubo> Regards, > Lluís. > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Aug 17, 2012 at 09:45:20AM +0800, Liu Bo wrote:> On 08/15/2012 06:12 PM, Lluís Batlle i Rossell wrote: > > some time ago we discussed on #btrfs that the nocow attribute for files wasn''t > > working (around 3.3 or 3.4 kernels). That was evident by files fragmenting even > > with the attribute set. > > > > Chris mentioned to find a fix quickly for that, and posted some lines of change > > into irc. But recently someone mentioned that 3.6-rc looks like still not > > respecting nocow for files. > > > > Is there really a fix upstream for that? Do nocow attribute on files work for > > anyone already? > > > > Dave had post a patch to fix it but only enabling NOCOW with zero sized file. > > FYI, the patch is http://article.gmane.org/gmane.comp.file-systems.btrfs/17351 > > With the patch, you don''t need to mount with nodatacow any more :) > > And why it is only for only zero sized file: > http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18046the original patch http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18031 did two things, the reasoning why it is not allowed to set nodatasum in general applies only to the second hunk but this @@ -139,7 +139,7 @@ void btrfs_inherit_iflags(struct inode *inode, struct inode *dir) } if (flags & BTRFS_INODE_NODATACOW) - BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW | BTRFS_INODE_NODATASUM; btrfs_update_iflags(inode); } --- is sufficient to create nocow files via a directory with NOCOW attribute set, and all new files will inherit it (they are automatically zero-sized so it''s safe). This usecase is similar to setting the COMPRESS attribute on a directory and all new files will inherit the flag. If Andrei wants to resend just this particular hunk, I''m giving it my ACK. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/17/2012 10:59 PM, David Sterba wrote:> On Fri, Aug 17, 2012 at 09:45:20AM +0800, Liu Bo wrote: >> On 08/15/2012 06:12 PM, Lluís Batlle i Rossell wrote: >>> some time ago we discussed on #btrfs that the nocow attribute for files wasn''t >>> working (around 3.3 or 3.4 kernels). That was evident by files fragmenting even >>> with the attribute set. >>> >>> Chris mentioned to find a fix quickly for that, and posted some lines of change >>> into irc. But recently someone mentioned that 3.6-rc looks like still not >>> respecting nocow for files. >>> >>> Is there really a fix upstream for that? Do nocow attribute on files work for >>> anyone already? >>> >> >> Dave had post a patch to fix it but only enabling NOCOW with zero sized file. >> >> FYI, the patch is http://article.gmane.org/gmane.comp.file-systems.btrfs/17351 >> >> With the patch, you don''t need to mount with nodatacow any more :) >> >> And why it is only for only zero sized file: >> http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18046 > > the original patch http://permalink.gmane.org/gmane.comp.file-systems.btrfs/18031 > did two things, the reasoning why it is not allowed to set nodatasum in > general applies only to the second hunk but this > > @@ -139,7 +139,7 @@ void btrfs_inherit_iflags(struct inode *inode, struct inode *dir) > } > > if (flags & BTRFS_INODE_NODATACOW) > - BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; > + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW | BTRFS_INODE_NODATASUM; > > btrfs_update_iflags(inode); > } > --- > > is sufficient to create nocow files via a directory with NOCOW attribute > set, and all new files will inherit it (they are automatically > zero-sized so it''s safe). This usecase is similar to setting the > COMPRESS attribute on a directory and all new files will inherit the > flag. > > If Andrei wants to resend just this particular hunk, I''m giving it my ACK. >IMO the following is better, just make use of the original check. If you agree with this, I''ll send it as a patch :) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 6e8f416..d4e58df 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4721,8 +4721,10 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, if (btrfs_test_opt(root, NODATASUM)) BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; if (btrfs_test_opt(root, NODATACOW) || - (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) + (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) { BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; + } } insert_inode_hash(inode);> > david > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Aug 17, 2012 at 11:30:14PM +0800, Liu Bo wrote:> IMO the following is better, just make use of the original check. If you agree with this, > I''ll send it as a patch :)I think it''s cleaner to keep all flags that get inherited from the directory -> new file at one place, ie btrfs_inherit_iflags(), than having them scattered over the code.> > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 6e8f416..d4e58df 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -4721,8 +4721,10 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, > if (btrfs_test_opt(root, NODATASUM)) > BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; > if (btrfs_test_opt(root, NODATACOW) || > - (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) > + (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) { > BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; > + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; > + } > }And even better, this particular check of dir->flags should be removed entirely, because it duplicates the equivalent in btrfs_inherit_iflags().> > insert_inode_hash(inode);david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/21/2012 10:33 PM, David Sterba wrote:> On Fri, Aug 17, 2012 at 11:30:14PM +0800, Liu Bo wrote: >> IMO the following is better, just make use of the original check. If you agree with this, >> I''ll send it as a patch :) > > I think it''s cleaner to keep all flags that get inherited from the > directory -> new file at one place, ie btrfs_inherit_iflags(), than > having them scattered over the code. > >> >> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c >> index 6e8f416..d4e58df 100644 >> --- a/fs/btrfs/inode.c >> +++ b/fs/btrfs/inode.c >> @@ -4721,8 +4721,10 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, >> if (btrfs_test_opt(root, NODATASUM)) >> BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; >> if (btrfs_test_opt(root, NODATACOW) || >> - (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) >> + (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) { >> BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; >> + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; >> + } >> } > > And even better, this particular check of dir->flags should be removed > entirely, because it duplicates the equivalent in > btrfs_inherit_iflags(). >Fine, it''s cleaner now. thanks, liubo>> >> insert_inode_hash(inode); > > > david > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html