| Message ID | 1433416690-19177-4-git-send-email-robbieko@synology.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jun 4, 2015 at 12:18 PM, Robbie Ko <robbieko@synology.com> wrote: > There's one case where we not clear orphan_dir_info issue. You mean where we leak a orphan_dir_info structure. > > Example: > > Parent snapshot: > |---- a/ (ino 279) > |---- c (ino 282) > |---- del/ (ino 281) > |---- tmp/ (ino 280) > |---- long/ (ino 283) > |---- longlong/ (ino 284) > > Send snapshot: > |---- a/ (ino 279) > |---- long (ino 283) > |---- longlong (ino 284) > |---- c/ (ino 282) > |---- tmp/ (ino 280) > > Here we process 281 use can_rmdir check, but 280 is waiting, so create orphan_dir_info > and when 282 is move to dest, so 280 can move to c/tmp, and now run can_rmdir check again. > Return is false, because 283 and 284 is unprocess, but now not release orphan_dir_info. > When 283 and 284 is processd, 281 be delete, but not delete orphan_dir_info. > So fix this by release orphan_dir_info for this case. Could be described more generically as freeing an existing orphan_dir_info for a directory, when we realize we can't rmdir the directory because it has a descendant that wasn't yet processed, and the orphan_dir_info was created because it had a descendant that had its rename operation delayed. > > Signed-off-by: Robbie Ko <robbieko@synology.com> > --- > fs/btrfs/send.c | 19 ++++++++++++------- > 1 file changed, 12 insertions(+), 7 deletions(-) > > diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c > index 596b9dc..ff9d052 100644 > --- a/fs/btrfs/send.c > +++ b/fs/btrfs/send.c > @@ -2785,12 +2785,6 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) > struct rb_node *parent = NULL; > struct orphan_dir_info *entry, *odi; > > - odi = kmalloc(sizeof(*odi), GFP_NOFS); > - if (!odi) > - return ERR_PTR(-ENOMEM); > - odi->ino = dir_ino; > - odi->gen = 0; > - > while (*p) { > parent = *p; > entry = rb_entry(parent, struct orphan_dir_info, node); > @@ -2799,11 +2793,16 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) > } else if (dir_ino > entry->ino) { > p = &(*p)->rb_right; > } else { > - kfree(odi); > return entry; > } > } > > + odi = kmalloc(sizeof(*odi), GFP_NOFS); > + if (!odi) > + return ERR_PTR(-ENOMEM); > + odi->ino = dir_ino; > + odi->gen = 0; > + All the above changes don't fix the issue described in this change - the memory leak - they just avoid the overhead of allocating an orphan_dir_info object unnecessarily. The change is ok, but should be a separate patch in the series that does only that. > rb_link_node(&odi->node, parent, p); > rb_insert_color(&odi->node, &sctx->orphan_dirs); > return odi; > @@ -2913,6 +2912,12 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, > } > > if (loc.objectid > send_progress) { > + struct orphan_dir_info *odi; > + > + odi = get_orphan_dir_info(sctx, dir); > + if (odi) { > + free_orphan_dir_info(sctx, odi); > + } Looks correct, great catch. Thanks. > ret = 0; > goto out; > } > -- > 1.9.1 > > -- > 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 Thu, Jun 04, 2015 at 07:18:08PM +0800, Robbie Ko wrote: > @@ -2913,6 +2912,12 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, > } > > if (loc.objectid > send_progress) { > + struct orphan_dir_info *odi; > + > + odi = get_orphan_dir_info(sctx, dir); > + if (odi) { > + free_orphan_dir_info(sctx, odi); > + } As you're going to resend, please drop the { .. } around the call. -- 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
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 596b9dc..ff9d052 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -2785,12 +2785,6 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) struct rb_node *parent = NULL; struct orphan_dir_info *entry, *odi; - odi = kmalloc(sizeof(*odi), GFP_NOFS); - if (!odi) - return ERR_PTR(-ENOMEM); - odi->ino = dir_ino; - odi->gen = 0; - while (*p) { parent = *p; entry = rb_entry(parent, struct orphan_dir_info, node); @@ -2799,11 +2793,16 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) } else if (dir_ino > entry->ino) { p = &(*p)->rb_right; } else { - kfree(odi); return entry; } } + odi = kmalloc(sizeof(*odi), GFP_NOFS); + if (!odi) + return ERR_PTR(-ENOMEM); + odi->ino = dir_ino; + odi->gen = 0; + rb_link_node(&odi->node, parent, p); rb_insert_color(&odi->node, &sctx->orphan_dirs); return odi; @@ -2913,6 +2912,12 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, } if (loc.objectid > send_progress) { + struct orphan_dir_info *odi; + + odi = get_orphan_dir_info(sctx, dir); + if (odi) { + free_orphan_dir_info(sctx, odi); + } ret = 0; goto out; }
There's one case where we not clear orphan_dir_info issue. Example: Parent snapshot: |---- a/ (ino 279) |---- c (ino 282) |---- del/ (ino 281) |---- tmp/ (ino 280) |---- long/ (ino 283) |---- longlong/ (ino 284) Send snapshot: |---- a/ (ino 279) |---- long (ino 283) |---- longlong (ino 284) |---- c/ (ino 282) |---- tmp/ (ino 280) Here we process 281 use can_rmdir check, but 280 is waiting, so create orphan_dir_info and when 282 is move to dest, so 280 can move to c/tmp, and now run can_rmdir check again. Return is false, because 283 and 284 is unprocess, but now not release orphan_dir_info. When 283 and 284 is processd, 281 be delete, but not delete orphan_dir_info. So fix this by release orphan_dir_info for this case. Signed-off-by: Robbie Ko <robbieko@synology.com> --- fs/btrfs/send.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)