btrfs in v4.3-rc1 failed many xfstests items with '-o nospace_cache'
mount option.
Failed cases are:
btrfs/008,016,019,020,026,027,028,029,031,041,046,048,050,051,053,054,
077,083,084,087,092,094
generic/004,010,014,023,024,074,075,080,086,087,089,091,092,100,112,123,
124,125,126,127,131,133,192,193,198,207,208,209,213,214,215,228,239,240,
246,247,248,255,263,285,306,313,316,323
We can reproduce this bug with following simple command:
TEST_DEV=/dev/vdh
TEST_DIR=/mnt/tmp
umount "$TEST_DEV" >/dev/null
mkfs.btrfs -f "$TEST_DEV"
mount "$TEST_DEV" "$TEST_DIR"
umount "$TEST_DEV"
mount "$TEST_DEV" "$TEST_DIR"
cp /bin/bash $TEST_DIR
Result is:
(omit previous commands)
# cp /bin/bash $TEST_DIR
cp: writing `/mnt/tmp/bash': No space left on device
By bisect, we can see it is triggered by patch titled:
commit e44163e17796
("btrfs: explictly delete unused block groups in close_ctree and ro-remount")
But the wrong code is not in above patch, btrfs delete all chunks
if no data in filesystem, and above patch just make it obviously.
Detail reason:
1: mkfs a blank filesystem, or delete everything in filesystem
2: umount fs
(current code will delete all data chunks)
3: mount fs
Because no any data chunks, data's space_cache have no chance
to init, it means: space_info->total_bytes == 0, and
space_info->full == 1.
4: do some write
Current code will ignore chunk allocate because space_info->full,
and return -ENOSPC.
Fix:
Don't auto-delete last blockgroup for a raid type.
If we delete all blockgroup for a raidtype, it not only cause above bug,
but also may change filesystem to all-single in some case.
Test:
Test by above script, and confirmed the logic by debug output.
Signed-off-by: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>
---
fs/btrfs/extent-tree.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5411f0a..35cf7eb 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -10012,7 +10012,8 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
bg_list);
space_info = block_group->space_info;
list_del_init(&block_group->bg_list);
- if (ret || btrfs_mixed_space_info(space_info)) {
+ if (ret || btrfs_mixed_space_info(space_info) ||
+ block_group->list.next == block_group->list.prev) {
btrfs_put_block_group(block_group);
continue;
}
--
1.8.5.1
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