* [PATCH] Btrfs: do not backup tree roots when fsync @ 2017-09-13 18:25 Liu Bo 2017-09-14 1:55 ` Qu Wenruo 2017-09-22 23:36 ` [PATCH] Btrfs: use self-explaining variable Liu Bo 0 siblings, 2 replies; 9+ messages in thread From: Liu Bo @ 2017-09-13 18:25 UTC (permalink / raw) To: linux-btrfs It doens't make sense to backup tree roots when doing fsync, since during fsync those tree roots have not been consistent on disk. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/disk-io.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 79ac228..a145a88 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3668,7 +3668,14 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) u64 flags; do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); - backup_super_roots(fs_info); + + /* + * max_mirrors == 0 indicates we're from commit_transaction, + * not from fsync where the tree roots in fs_info have not + * been consistent on disk. + */ + if (max_mirrors == 0) + backup_super_roots(fs_info); sb = fs_info->super_for_commit; dev_item = &sb->dev_item; -- 2.9.4 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: do not backup tree roots when fsync 2017-09-13 18:25 [PATCH] Btrfs: do not backup tree roots when fsync Liu Bo @ 2017-09-14 1:55 ` Qu Wenruo 2017-09-14 12:49 ` David Sterba 2017-09-22 23:36 ` [PATCH] Btrfs: use self-explaining variable Liu Bo 1 sibling, 1 reply; 9+ messages in thread From: Qu Wenruo @ 2017-09-14 1:55 UTC (permalink / raw) To: Liu Bo, linux-btrfs On 2017年09月14日 02:25, Liu Bo wrote: > It doens't make sense to backup tree roots when doing fsync, since > during fsync those tree roots have not been consistent on disk. > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com> With a pit can be improved. > --- > fs/btrfs/disk-io.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 79ac228..a145a88 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -3668,7 +3668,14 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > u64 flags; > > do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); > - backup_super_roots(fs_info); > + > + /* > + * max_mirrors == 0 indicates we're from commit_transaction, > + * not from fsync where the tree roots in fs_info have not > + * been consistent on disk. > + */ > + if (max_mirrors == 0) > + backup_super_roots(fs_info); BTW, the @max_mirrors naming here is really confusing. Normally I would expect max_mirrors == 0 means we don't need to backup super roots... And since there are only two callers it won't be a big thing to change. Thanks, Qu > > sb = fs_info->super_for_commit; > dev_item = &sb->dev_item; > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: do not backup tree roots when fsync 2017-09-14 1:55 ` Qu Wenruo @ 2017-09-14 12:49 ` David Sterba 2017-09-15 21:09 ` Liu Bo 0 siblings, 1 reply; 9+ messages in thread From: David Sterba @ 2017-09-14 12:49 UTC (permalink / raw) To: Qu Wenruo; +Cc: Liu Bo, linux-btrfs On Thu, Sep 14, 2017 at 09:55:48AM +0800, Qu Wenruo wrote: > > > On 2017年09月14日 02:25, Liu Bo wrote: > > It doens't make sense to backup tree roots when doing fsync, since > > during fsync those tree roots have not been consistent on disk. > > > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com> > > With a pit can be improved. > > --- > > fs/btrfs/disk-io.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > > index 79ac228..a145a88 100644 > > --- a/fs/btrfs/disk-io.c > > +++ b/fs/btrfs/disk-io.c > > @@ -3668,7 +3668,14 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > > u64 flags; > > > > do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); > > - backup_super_roots(fs_info); > > + > > + /* > > + * max_mirrors == 0 indicates we're from commit_transaction, > > + * not from fsync where the tree roots in fs_info have not > > + * been consistent on disk. > > + */ > > + if (max_mirrors == 0) > > + backup_super_roots(fs_info); > > BTW, the @max_mirrors naming here is really confusing. > Normally I would expect max_mirrors == 0 means we don't need to backup > super roots... Agreed it's confusing, could be something like "bool write_backups" (in a separate patch). ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: do not backup tree roots when fsync 2017-09-14 12:49 ` David Sterba @ 2017-09-15 21:09 ` Liu Bo 0 siblings, 0 replies; 9+ messages in thread From: Liu Bo @ 2017-09-15 21:09 UTC (permalink / raw) To: dsterba, Qu Wenruo, linux-btrfs On Thu, Sep 14, 2017 at 02:49:03PM +0200, David Sterba wrote: > On Thu, Sep 14, 2017 at 09:55:48AM +0800, Qu Wenruo wrote: > > > > > > On 2017年09月14日 02:25, Liu Bo wrote: > > > It doens't make sense to backup tree roots when doing fsync, since > > > during fsync those tree roots have not been consistent on disk. > > > > > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > > > Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com> > > > > With a pit can be improved. > > > --- > > > fs/btrfs/disk-io.c | 9 ++++++++- > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > > > index 79ac228..a145a88 100644 > > > --- a/fs/btrfs/disk-io.c > > > +++ b/fs/btrfs/disk-io.c > > > @@ -3668,7 +3668,14 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > > > u64 flags; > > > > > > do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); > > > - backup_super_roots(fs_info); > > > + > > > + /* > > > + * max_mirrors == 0 indicates we're from commit_transaction, > > > + * not from fsync where the tree roots in fs_info have not > > > + * been consistent on disk. > > > + */ > > > + if (max_mirrors == 0) > > > + backup_super_roots(fs_info); > > > > BTW, the @max_mirrors naming here is really confusing. > > Normally I would expect max_mirrors == 0 means we don't need to backup > > super roots... > > Agreed it's confusing, could be something like "bool write_backups" (in a > separate patch). Good point, will do in a separate one, thanks to both for the comments. Thanks, -liubo ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH] Btrfs: use self-explaining variable 2017-09-13 18:25 [PATCH] Btrfs: do not backup tree roots when fsync Liu Bo 2017-09-14 1:55 ` Qu Wenruo @ 2017-09-22 23:36 ` Liu Bo 2017-09-23 0:46 ` Qu Wenruo 1 sibling, 1 reply; 9+ messages in thread From: Liu Bo @ 2017-09-22 23:36 UTC (permalink / raw) To: linux-btrfs This uses a bool 'do_backup' to help understand this piece of code. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- This is based on a patch "Btrfs: do not backup tree roots when fsync". fs/btrfs/disk-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index cdb7043..9811b9d 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3691,6 +3691,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) int max_errors; int total_errors = 0; u64 flags; + bool do_backup = (max_mirrors == 0); do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); @@ -3699,7 +3700,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) * not from fsync where the tree roots in fs_info have not * been consistent on disk. */ - if (max_mirrors == 0) + if (do_backup) backup_super_roots(fs_info); sb = fs_info->super_for_commit; -- 2.9.4 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: use self-explaining variable 2017-09-22 23:36 ` [PATCH] Btrfs: use self-explaining variable Liu Bo @ 2017-09-23 0:46 ` Qu Wenruo 2017-09-23 0:48 ` Liu Bo 0 siblings, 1 reply; 9+ messages in thread From: Qu Wenruo @ 2017-09-23 0:46 UTC (permalink / raw) To: Liu Bo, linux-btrfs On 2017年09月23日 07:36, Liu Bo wrote: > This uses a bool 'do_backup' to help understand this piece of code. > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > --- > This is based on a patch "Btrfs: do not backup tree roots when fsync". > > fs/btrfs/disk-io.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index cdb7043..9811b9d 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -3691,6 +3691,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > int max_errors; > int total_errors = 0; > u64 flags; > + bool do_backup = (max_mirrors == 0); Why not replacing @max_mirrors with @do_backup as parameter? Thanks, Qu > > do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); > > @@ -3699,7 +3700,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > * not from fsync where the tree roots in fs_info have not > * been consistent on disk. > */ > - if (max_mirrors == 0) > + if (do_backup) > backup_super_roots(fs_info); > > sb = fs_info->super_for_commit; > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: use self-explaining variable 2017-09-23 0:46 ` Qu Wenruo @ 2017-09-23 0:48 ` Liu Bo 2017-09-23 1:09 ` Qu Wenruo 0 siblings, 1 reply; 9+ messages in thread From: Liu Bo @ 2017-09-23 0:48 UTC (permalink / raw) To: Qu Wenruo; +Cc: linux-btrfs On Sat, Sep 23, 2017 at 08:46:55AM +0800, Qu Wenruo wrote: > > > On 2017年09月23日 07:36, Liu Bo wrote: > > This uses a bool 'do_backup' to help understand this piece of code. > > > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > --- > > This is based on a patch "Btrfs: do not backup tree roots when fsync". > > > > fs/btrfs/disk-io.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > > index cdb7043..9811b9d 100644 > > --- a/fs/btrfs/disk-io.c > > +++ b/fs/btrfs/disk-io.c > > @@ -3691,6 +3691,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > > int max_errors; > > int total_errors = 0; > > u64 flags; > > + bool do_backup = (max_mirrors == 0); > > Why not replacing @max_mirrors with @do_backup as parameter? If I read the code correctly, max_mirrors is not just for deciding backup. thanks, -liubo > > Thanks, > Qu > > do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); > > @@ -3699,7 +3700,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > > * not from fsync where the tree roots in fs_info have not > > * been consistent on disk. > > */ > > - if (max_mirrors == 0) > > + if (do_backup) > > backup_super_roots(fs_info); > > sb = fs_info->super_for_commit; > > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: use self-explaining variable 2017-09-23 0:48 ` Liu Bo @ 2017-09-23 1:09 ` Qu Wenruo 2017-09-24 13:24 ` David Sterba 0 siblings, 1 reply; 9+ messages in thread From: Qu Wenruo @ 2017-09-23 1:09 UTC (permalink / raw) To: bo.li.liu; +Cc: linux-btrfs On 2017年09月23日 08:48, Liu Bo wrote: > On Sat, Sep 23, 2017 at 08:46:55AM +0800, Qu Wenruo wrote: >> >> >> On 2017年09月23日 07:36, Liu Bo wrote: >>> This uses a bool 'do_backup' to help understand this piece of code. >>> >>> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> >>> --- >>> This is based on a patch "Btrfs: do not backup tree roots when fsync". >>> >>> fs/btrfs/disk-io.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >>> index cdb7043..9811b9d 100644 >>> --- a/fs/btrfs/disk-io.c >>> +++ b/fs/btrfs/disk-io.c >>> @@ -3691,6 +3691,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) >>> int max_errors; >>> int total_errors = 0; >>> u64 flags; >>> + bool do_backup = (max_mirrors == 0); >> >> Why not replacing @max_mirrors with @do_backup as parameter? > > If I read the code correctly, max_mirrors is not just for deciding > backup. That's strange. write_all_supers() only uses @max_mirrors by passing it to write_dev_supers() and wait_dev_supers(). Both of the write/wait_dev_supers() will replace @max_mirrors to BTRFS_SUPER_MIRROR_MAX if it's zero. Further more, all write_all_supers() callers just pass @max_mirrors as bool (either 0 or 1). So I don't see any point not replacing the parameter as bool. Thanks, Qu > > thanks, > > -liubo > >> >> Thanks, >> Qu >>> do_barriers = !btrfs_test_opt(fs_info, NOBARRIER); >>> @@ -3699,7 +3700,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) >>> * not from fsync where the tree roots in fs_info have not >>> * been consistent on disk. >>> */ >>> - if (max_mirrors == 0) >>> + if (do_backup) >>> backup_super_roots(fs_info); >>> sb = fs_info->super_for_commit; >>> > -- > 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 > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Btrfs: use self-explaining variable 2017-09-23 1:09 ` Qu Wenruo @ 2017-09-24 13:24 ` David Sterba 0 siblings, 0 replies; 9+ messages in thread From: David Sterba @ 2017-09-24 13:24 UTC (permalink / raw) To: Qu Wenruo; +Cc: bo.li.liu, linux-btrfs On Sat, Sep 23, 2017 at 09:09:24AM +0800, Qu Wenruo wrote: > > > On 2017年09月23日 08:48, Liu Bo wrote: > > On Sat, Sep 23, 2017 at 08:46:55AM +0800, Qu Wenruo wrote: > >> > >> > >> On 2017年09月23日 07:36, Liu Bo wrote: > >>> This uses a bool 'do_backup' to help understand this piece of code. > >>> > >>> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > >>> --- > >>> This is based on a patch "Btrfs: do not backup tree roots when fsync". > >>> > >>> fs/btrfs/disk-io.c | 3 ++- > >>> 1 file changed, 2 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > >>> index cdb7043..9811b9d 100644 > >>> --- a/fs/btrfs/disk-io.c > >>> +++ b/fs/btrfs/disk-io.c > >>> @@ -3691,6 +3691,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) > >>> int max_errors; > >>> int total_errors = 0; > >>> u64 flags; > >>> + bool do_backup = (max_mirrors == 0); > >> > >> Why not replacing @max_mirrors with @do_backup as parameter? > > > > If I read the code correctly, max_mirrors is not just for deciding > > backup. > > That's strange. > > write_all_supers() only uses @max_mirrors by passing it to > write_dev_supers() and wait_dev_supers(). > > Both of the write/wait_dev_supers() will replace @max_mirrors to > BTRFS_SUPER_MIRROR_MAX if it's zero. > > Further more, all write_all_supers() callers just pass @max_mirrors as > bool (either 0 or 1). > > So I don't see any point not replacing the parameter as bool. Agreed, the idea was to replace the parameter by the bool. ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-09-24 13:26 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-09-13 18:25 [PATCH] Btrfs: do not backup tree roots when fsync Liu Bo 2017-09-14 1:55 ` Qu Wenruo 2017-09-14 12:49 ` David Sterba 2017-09-15 21:09 ` Liu Bo 2017-09-22 23:36 ` [PATCH] Btrfs: use self-explaining variable Liu Bo 2017-09-23 0:46 ` Qu Wenruo 2017-09-23 0:48 ` Liu Bo 2017-09-23 1:09 ` Qu Wenruo 2017-09-24 13:24 ` David Sterba
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