Btrfs: qgroup: Introduce a may_use to account space_info->bytes_may_use.
Currently, for pre_alloc or delay_alloc, the bytes will be accounted
in space_info by the three guys.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
But on the other hand, in qgroup, there are only two counters to account the
bytes, qgroup->reserved and qgroup->excl. And qg->reserved accounts
bytes in space_info->bytes_may_use and qg->excl accounts bytes in
space_info->used. So the bytes in space_info->reserved is not accounted
in qgroup. If so, there is a window we can exceed the quota limit when
bytes is in space_info->reserved.
Example:
# btrfs quota enable /mnt
# btrfs qgroup limit -e 10M /mnt
# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
# sync
# btrfs qgroup show -pcre /mnt
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 20987904 20987904 0 10485760 --- ---
qg->excl is 20987904 larger than max_excl 10485760.
This patch introduce a new counter named may_use to qgroup, then
there are three counters in qgroup to account bytes in space_info
as below.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
qgroup->may_use --- qgroup->reserved --- qgroup->excl
With this patch applied:
# btrfs quota enable /mnt
# btrfs qgroup limit -e 10M /mnt
# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
fallocate: /mnt/data9: fallocate failed: Disk quota exceeded
fallocate: /mnt/data10: fallocate failed: Disk quota exceeded
fallocate: /mnt/data11: fallocate failed: Disk quota exceeded
fallocate: /mnt/data12: fallocate failed: Disk quota exceeded
fallocate: /mnt/data13: fallocate failed: Disk quota exceeded
fallocate: /mnt/data14: fallocate failed: Disk quota exceeded
fallocate: /mnt/data15: fallocate failed: Disk quota exceeded
fallocate: /mnt/data16: fallocate failed: Disk quota exceeded
fallocate: /mnt/data17: fallocate failed: Disk quota exceeded
fallocate: /mnt/data18: fallocate failed: Disk quota exceeded
fallocate: /mnt/data19: fallocate failed: Disk quota exceeded
# sync
# btrfs qgroup show -pcre /mnt
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 9453568 9453568 0 10485760 --- ---
Reported-by: Cyril SCETBON <cyril.scetbon@free.fr>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 695d511..3113e0b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5725,8 +5725,12 @@
set_extent_dirty(root->fs_info->pinned_extents, bytenr,
bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
- if (reserved)
+ if (reserved) {
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ num_bytes, -1);
trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
+ }
return 0;
}
@@ -6464,6 +6468,9 @@
btrfs_put_block_group(cache);
trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
pin = 0;
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ buf->len, -1);
}
out:
if (pin)
@@ -7196,7 +7203,11 @@
ret = btrfs_discard_extent(root, start, len, NULL);
btrfs_add_free_space(cache, start, len);
btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ len, -1);
}
+
btrfs_put_block_group(cache);
trace_btrfs_reserved_extent_free(root, start, len);
@@ -7433,6 +7444,9 @@
BUG_ON(ret); /* logic error */
ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
0, owner, offset, ins, 1);
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ ins->offset, 1);
btrfs_put_block_group(block_group);
return ret;
}
@@ -7579,6 +7593,10 @@
return ERR_PTR(ret);
}
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root_objectid,
+ ins.offset, 1);
+
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
BUG_ON(IS_ERR(buf)); /* -ENOMEM */