Wang Shilong
2014-Jan-18 04:58 UTC
[PATCH v3 1/4] Btrfs: fix wrong send_in_progress accounting
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.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
---
changelog
v2->v3:
add comments as david addressed.
v1->v2:
use right root to check
---
fs/btrfs/send.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index bff0b1a..83b6bdb 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4752,6 +4752,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user
*arg_)
u32 i;
u64 *clone_sources_tmp = NULL;
int clone_sources_to_rollback = 0;
+ int sort_clone_roots = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -4942,6 +4943,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user
*arg_)
sort(sctx->clone_roots, sctx->clone_roots_cnt,
sizeof(*sctx->clone_roots), __clone_root_cmp_sort,
NULL);
+ sort_clone_roots = 1;
ret = send_subvol(sctx);
if (ret < 0)
@@ -4957,11 +4959,22 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user
*arg_)
}
out:
- for (i = 0; sctx && i < clone_sources_to_rollback; i++)
- btrfs_root_dec_send_in_progress(sctx->clone_roots[i].root);
+ if (sort_clone_roots) {
+ for (i = 0; i < sctx->clone_roots_cnt; i++)
+ btrfs_root_dec_send_in_progress(
+ sctx->clone_roots[i].root);
+ } else {
+ for (i = 0; sctx && i < clone_sources_to_rollback; i++)
+ btrfs_root_dec_send_in_progress(
+ sctx->clone_roots[i].root);
+ /*
+ * if we fail to add @send_root in clone roots, we still
+ * need to decrease @send_in_progress count here.
+ */
+ btrfs_root_dec_send_in_progress(send_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);
--
1.8.3.1
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