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/inode.c b/fs/btrfs/inode.c
index 6ef97c1..a9f69a0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -60,6 +60,7 @@
#include "backref.h"
#include "hash.h"
#include "props.h"
+#include "qgroup.h"
struct btrfs_iget_args {
struct btrfs_key *location;
@@ -753,7 +754,9 @@
}
goto out_free;
}
-
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ ins.offset, 1);
/*
* here we're doing allocation and writeback of the
* compressed pages
@@ -978,6 +981,10 @@
if (ret < 0)
goto out_unlock;
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ ins.offset, 1);
+
em = alloc_extent_map();
if (!em) {
ret = -ENOMEM;
@@ -7030,6 +7037,10 @@
return ERR_PTR(ret);
}
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ ins.offset, 1);
+
return em;
}
@@ -9583,6 +9594,11 @@
btrfs_end_transaction(trans, root);
break;
}
+
+ btrfs_qgroup_update_reserved_bytes(root->fs_info,
+ root->root_key.objectid,
+ ins.offset, 1);
+
btrfs_drop_extent_cache(inode, cur_offset,
cur_offset + ins.offset -1, 0);