| Message ID | 20140108121609.GF6498@suse.cz (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
Hello David, > On Tue, Jan 07, 2014 at 05:25:18PM +0800, Wang Shilong wrote: >> Steps to reproduce: >> # mkfs.btrfs -f /dev/sda8 >> # mount /dev/sda8 /mnt >> # btrfs sub snapshot -r /mnt /mnt/snap1 >> # btrfs sub snapshot -r /mnt /mnt/snap2 >> # btrfs send /mnt/snap1 -p /mnt/snap2 -f /mnt/1 >> # dmesg >> >> The problem is that we will sort clone roots(include @send_root), it >> might push @send_root before thus @send_root's @send_in_progress will >> be decreased twice. > > Of course, the sort(). I think your fix adds some complexity that's not > necessary. Whether the clone_roots array is sorted is not important, we > just have to process each root once. > > send_root becomes a clone_root member, so the missing part is to account > in the rollback counter: > > --- a/fs/btrfs/send.c > +++ b/fs/btrfs/send.c > @@ -4937,6 +4937,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) > * for possible clone sources. > */ > sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root; > + clone_sources_to_rollback++; Not really, If we fail to come here, we still need decrease @send_root. Please correct me if i miss something here.^_^ Thanks, Wang > > /* We do a bsearch later */ > sort(sctx->clone_roots, sctx->clone_roots_cnt, > @@ -4961,7 +4962,6 @@ out: > btrfs_root_dec_send_in_progress(sctx->clone_roots[i].root); > if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) > btrfs_root_dec_send_in_progress(sctx->parent_root); > - btrfs_root_dec_send_in_progress(send_root); > > kfree(arg); > vfree(clone_sources_tmp); > --- > -- > 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 Wed, Jan 08, 2014 at 11:09:02PM +0800, Wang Shilong wrote: > > Hello David, > > > On Tue, Jan 07, 2014 at 05:25:18PM +0800, Wang Shilong wrote: > >> Steps to reproduce: > >> # mkfs.btrfs -f /dev/sda8 > >> # mount /dev/sda8 /mnt > >> # btrfs sub snapshot -r /mnt /mnt/snap1 > >> # btrfs sub snapshot -r /mnt /mnt/snap2 > >> # btrfs send /mnt/snap1 -p /mnt/snap2 -f /mnt/1 > >> # dmesg > >> > >> The problem is that we will sort clone roots(include @send_root), it > >> might push @send_root before thus @send_root's @send_in_progress will > >> be decreased twice. > > > > Of course, the sort(). I think your fix adds some complexity that's not > > necessary. Whether the clone_roots array is sorted is not important, we > > just have to process each root once. > > > > send_root becomes a clone_root member, so the missing part is to account > > in the rollback counter: > > > > --- a/fs/btrfs/send.c > > +++ b/fs/btrfs/send.c > > @@ -4937,6 +4937,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) > > * for possible clone sources. > > */ > > sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root; > > + clone_sources_to_rollback++; > > Not really, If we fail to come here, we still need decrease @send_root. Right. I was thinking if the code can be simplified somehow, but don't have anything vastly better. Can you please add a comment to the first branch that send_root is processed in the loop and not missed? It looks unabalanced when it's handled just a few lines below and not in the 1st loop. thanks, 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 01/14/2014 02:40 AM, David Sterba wrote: > On Wed, Jan 08, 2014 at 11:09:02PM +0800, Wang Shilong wrote: >> Hello David, >> >>> On Tue, Jan 07, 2014 at 05:25:18PM +0800, Wang Shilong wrote: >>>> Steps to reproduce: >>>> # mkfs.btrfs -f /dev/sda8 >>>> # mount /dev/sda8 /mnt >>>> # btrfs sub snapshot -r /mnt /mnt/snap1 >>>> # btrfs sub snapshot -r /mnt /mnt/snap2 >>>> # btrfs send /mnt/snap1 -p /mnt/snap2 -f /mnt/1 >>>> # dmesg >>>> >>>> The problem is that we will sort clone roots(include @send_root), it >>>> might push @send_root before thus @send_root's @send_in_progress will >>>> be decreased twice. >>> Of course, the sort(). I think your fix adds some complexity that's not >>> necessary. Whether the clone_roots array is sorted is not important, we >>> just have to process each root once. >>> >>> send_root becomes a clone_root member, so the missing part is to account >>> in the rollback counter: >>> >>> --- a/fs/btrfs/send.c >>> +++ b/fs/btrfs/send.c >>> @@ -4937,6 +4937,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) >>> * for possible clone sources. >>> */ >>> sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root; >>> + clone_sources_to_rollback++; >> Not really, If we fail to come here, we still need decrease @send_root. > Right. I was thinking if the code can be simplified somehow, but don't > have anything vastly better. Can you please add a comment to the first > branch that send_root is processed in the loop and not missed? It looks > unabalanced when it's handled just a few lines below and not in the 1st > loop. Reasonable, i will send v3 for this patch and add some comments. David, really thanks for you costing time to review and correct me.^_^ Thanks, Wang > > thanks, > 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
--- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -4937,6 +4937,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) * for possible clone sources. */ sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root; + clone_sources_to_rollback++; /* We do a bsearch later */ sort(sctx->clone_roots, sctx->clone_roots_cnt, @@ -4961,7 +4962,6 @@ out: btrfs_root_dec_send_in_progress(sctx->clone_roots[i].root); if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) btrfs_root_dec_send_in_progress(sctx->parent_root); - btrfs_root_dec_send_in_progress(send_root); kfree(arg); vfree(clone_sources_tmp);