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Btrfs: qgroup: Introduce a may_use to account space_info->bytes_may_use.

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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>
This commit is contained in:
Dongsheng Yang 2014-12-12 16:44:35 +08:00 committed by Chris Mason
parent 804ca127fb
commit 31193213f1
4 changed files with 104 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fs/btrfs/extent-tree.c
View File

@ -5725,8 +5725,12 @@ static int pin_down_extent(struct btrfs_root *root,
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 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
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 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root,
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 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
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 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
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 */

18
fs/btrfs/inode.c
View File

@ -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 @@ retry:
}
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 @@ static noinline int cow_file_range(struct inode *inode,
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 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
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 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
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);

68
fs/btrfs/qgroup.c
View File

@ -72,6 +72,7 @@ struct btrfs_qgroup {
/*
* reservation tracking
*/
u64 may_use;
u64 reserved;
/*
@ -1417,6 +1418,8 @@ static int qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
WARN_ON(sign < 0 && qgroup->excl < oper->num_bytes);
qgroup->excl += sign * oper->num_bytes;
qgroup->excl_cmpr += sign * oper->num_bytes;
if (sign > 0)
qgroup->reserved -= oper->num_bytes;
qgroup_dirty(fs_info, qgroup);
@ -1436,6 +1439,8 @@ static int qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
qgroup->rfer_cmpr += sign * oper->num_bytes;
WARN_ON(sign < 0 && qgroup->excl < oper->num_bytes);
qgroup->excl += sign * oper->num_bytes;
if (sign > 0)
qgroup->reserved -= oper->num_bytes;
qgroup->excl_cmpr += sign * oper->num_bytes;
qgroup_dirty(fs_info, qgroup);
@ -2378,6 +2383,61 @@ out:
return ret;
}
int btrfs_qgroup_update_reserved_bytes(struct btrfs_fs_info *fs_info,
u64 ref_root,
u64 num_bytes,
int sign)
{
struct btrfs_root *quota_root;
struct btrfs_qgroup *qgroup;
int ret = 0;
struct ulist_node *unode;
struct ulist_iterator uiter;
if (!is_fstree(ref_root) || !fs_info->quota_enabled)
return 0;
if (num_bytes == 0)
return 0;
spin_lock(&fs_info->qgroup_lock);
quota_root = fs_info->quota_root;
if (!quota_root)
goto out;
qgroup = find_qgroup_rb(fs_info, ref_root);
if (!qgroup)
goto out;
ulist_reinit(fs_info->qgroup_ulist);
ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
(uintptr_t)qgroup, GFP_ATOMIC);
if (ret < 0)
goto out;
ULIST_ITER_INIT(&uiter);
while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
struct btrfs_qgroup *qg;
struct btrfs_qgroup_list *glist;
qg = u64_to_ptr(unode->aux);
qg->reserved += sign * num_bytes;
list_for_each_entry(glist, &qg->groups, next_group) {
ret = ulist_add(fs_info->qgroup_ulist,
glist->group->qgroupid,
(uintptr_t)glist->group, GFP_ATOMIC);
if (ret < 0)
goto out;
}
}
out:
spin_unlock(&fs_info->qgroup_lock);
return ret;
}
/*
* reserve some space for a qgroup and all its parents. The reservation takes
* place with start_transaction or dealloc_reserve, similar to ENOSPC
@ -2426,14 +2486,14 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
qg = u64_to_ptr(unode->aux);
if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
qg->reserved + (s64)qg->rfer + num_bytes >
qg->reserved + qg->may_use + (s64)qg->rfer + num_bytes >
qg->max_rfer) {
ret = -EDQUOT;
goto out;
}
if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
qg->reserved + (s64)qg->excl + num_bytes >
qg->reserved + qg->may_use + (s64)qg->excl + num_bytes >
qg->max_excl) {
ret = -EDQUOT;
goto out;
@ -2457,7 +2517,7 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
qg = u64_to_ptr(unode->aux);
qg->reserved += num_bytes;
qg->may_use += num_bytes;
}
out:
@ -2503,7 +2563,7 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes)
qg = u64_to_ptr(unode->aux);
qg->reserved -= num_bytes;
qg->may_use -= num_bytes;
list_for_each_entry(glist, &qg->groups, next_group) {
ret = ulist_add(fs_info->qgroup_ulist,

4
fs/btrfs/qgroup.h
View File

@ -94,6 +94,10 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid,
struct btrfs_qgroup_inherit *inherit);
int btrfs_qgroup_update_reserved_bytes(struct btrfs_fs_info *fs_info,
u64 ref_root,
u64 num_bytes,
int sign);
int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes);
void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes);