btrfs: qgroup: check generation when recording simple quota delta

Simple quotas count extents only from the moment the feature is enabled.
Therefore, if we do something like:

1. create subvol S
2. write F in S
3. enable quotas
4. remove F
5. write G in S

then after 3. and 4. we would expect the simple quota usage of S to be 0
(putting aside some metadata extents that might be written) and after
5., it should be the size of G plus metadata. Therefore, we need to be
able to determine whether a particular quota delta we are processing
predates simple quota enablement.

To do this, store the transaction id when quotas were enabled. In
fs_info for immediate use and in the quota status item to make it
recoverable on mount. When we see a delta, check if the generation of
the extent item is less than that of quota enablement. If so, we should
ignore the delta from this extent.

Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Boris Burkov 2023-03-28 15:45:20 -07:00 committed by David Sterba
parent 5343cd9364
commit bd7c1ea3a3
6 changed files with 40 additions and 6 deletions

View File

@ -980,6 +980,8 @@ BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item,
flags, 64);
BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
rescan, 64);
BTRFS_SETGET_FUNCS(qgroup_status_enable_gen, struct btrfs_qgroup_status_item,
enable_gen, 64);
/* btrfs_qgroup_info_item */
BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,

View File

@ -1566,6 +1566,7 @@ static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
.rsv_bytes = href->reserved_bytes,
.is_data = true,
.is_inc = true,
.generation = trans->transid,
};
if (extent_op)
@ -1738,6 +1739,7 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
.rsv_bytes = 0,
.is_data = false,
.is_inc = true,
.generation = trans->transid,
};
BUG_ON(!extent_op || !extent_op->update_flags);
@ -3287,6 +3289,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
.rsv_bytes = 0,
.is_data = is_data,
.is_inc = false,
.generation = btrfs_extent_generation(leaf, ei),
};
/* In this branch refs == 1 */
@ -4924,6 +4927,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_squota_delta delta = {
.root = root_objectid,
.num_bytes = ins->offset,
.generation = trans->transid,
.rsv_bytes = 0,
.is_data = true,
.is_inc = true,

View File

@ -687,6 +687,7 @@ struct btrfs_fs_info {
/* Protected by qgroup_rescan_lock */
bool qgroup_rescan_running;
u8 qgroup_drop_subtree_thres;
u64 qgroup_enable_gen;
/*
* If this is not 0, then it indicates a serious filesystem error has

View File

@ -369,6 +369,15 @@ static void qgroup_mark_inconsistent(struct btrfs_fs_info *fs_info)
BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING);
}
static void qgroup_read_enable_gen(struct btrfs_fs_info *fs_info,
struct extent_buffer *leaf, int slot,
struct btrfs_qgroup_status_item *ptr)
{
ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
ASSERT(btrfs_item_size(leaf, slot) >= sizeof(*ptr));
fs_info->qgroup_enable_gen = btrfs_qgroup_status_enable_gen(leaf, ptr);
}
/*
* The full config is read in one go, only called from open_ctree()
* It doesn't use any locking, as at this point we're still single-threaded
@ -384,7 +393,6 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
int ret = 0;
u64 flags = 0;
u64 rescan_progress = 0;
bool simple;
if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED)
return 0;
@ -437,9 +445,9 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
goto out;
}
fs_info->qgroup_flags = btrfs_qgroup_status_flags(l, ptr);
simple = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE);
if (btrfs_qgroup_status_generation(l, ptr) !=
fs_info->generation && !simple) {
if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE) {
qgroup_read_enable_gen(fs_info, l, slot, ptr);
} else if (btrfs_qgroup_status_generation(l, ptr) != fs_info->generation) {
qgroup_mark_inconsistent(fs_info);
btrfs_err(fs_info,
"qgroup generation mismatch, marked as inconsistent");
@ -1103,10 +1111,12 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info,
btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON;
if (simple)
if (simple) {
fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE;
else
btrfs_set_qgroup_status_enable_gen(leaf, ptr, trans->transid);
} else {
fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
}
btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags &
BTRFS_QGROUP_STATUS_FLAGS_MASK);
btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
@ -1210,6 +1220,8 @@ out_add_root:
goto out_free_path;
}
fs_info->qgroup_enable_gen = trans->transid;
mutex_unlock(&fs_info->qgroup_ioctl_lock);
/*
* Commit the transaction while not holding qgroup_ioctl_lock, to avoid
@ -4655,6 +4667,10 @@ int btrfs_record_squota_delta(struct btrfs_fs_info *fs_info,
if (!is_fstree(root))
return 0;
/* If the extent predates enabling quotas, don't count it. */
if (delta->generation < fs_info->qgroup_enable_gen)
return 0;
spin_lock(&fs_info->qgroup_lock);
qgroup = find_qgroup_rb(fs_info, root);
if (!qgroup) {

View File

@ -276,6 +276,8 @@ struct btrfs_squota_delta {
u64 num_bytes;
/* The number of bytes reserved for this extent. */
u64 rsv_bytes;
/* The generation the extent was created in. */
u64 generation;
/* Whether we are using or freeing the extent. */
bool is_inc;
/* Whether the extent is data or metadata. */

View File

@ -1277,6 +1277,15 @@ struct btrfs_qgroup_status_item {
* of the scan. It contains a logical address
*/
__le64 rescan;
/*
* The generation when quotas were last enabled. Used by simple quotas to
* avoid decrementing when freeing an extent that was written before
* enable.
*
* Set only if flags contain BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE.
*/
__le64 enable_gen;
} __attribute__ ((__packed__));
struct btrfs_qgroup_info_item {