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authorZhaolei <zhaolei@cn.fujitsu.com>2015-11-17 18:46:17 +0800
committerChris Mason <clm@fb.com>2015-11-25 05:19:51 -0800
commit76a8efa171bf6cf37ffb83d3f62fed2e47e2abc8 (patch)
tree4039ddb49bef2996add0327a8d63d6df1338d826 /fs
parentbtrfs: fix clashing number of the enhanced balance usage filter (diff)
downloadlinux-dev-76a8efa171bf6cf37ffb83d3f62fed2e47e2abc8.tar.xz
linux-dev-76a8efa171bf6cf37ffb83d3f62fed2e47e2abc8.zip
btrfs: Continue replace when set_block_ro failed
xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/scrub.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 2907a77fb1f6..6b3fd51d9a99 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3483,6 +3483,7 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
u64 length;
u64 chunk_offset;
int ret = 0;
+ int ro_set;
int slot;
struct extent_buffer *l;
struct btrfs_key key;
@@ -3568,7 +3569,21 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
scrub_pause_on(fs_info);
ret = btrfs_inc_block_group_ro(root, cache);
scrub_pause_off(fs_info);
- if (ret) {
+
+ if (ret == 0) {
+ ro_set = 1;
+ } else if (ret == -ENOSPC) {
+ /*
+ * btrfs_inc_block_group_ro return -ENOSPC when it
+ * failed in creating new chunk for metadata.
+ * It is not a problem for scrub/replace, because
+ * metadata are always cowed, and our scrub paused
+ * commit_transactions.
+ */
+ ro_set = 0;
+ } else {
+ btrfs_warn(fs_info, "failed setting block group ro, ret=%d\n",
+ ret);
btrfs_put_block_group(cache);
break;
}
@@ -3611,7 +3626,8 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
scrub_pause_off(fs_info);
- btrfs_dec_block_group_ro(root, cache);
+ if (ro_set)
+ btrfs_dec_block_group_ro(root, cache);
btrfs_put_block_group(cache);
if (ret)