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.

Boris Burkov committed 3 years ago

Commit bd7c1ea1 parent 5343cd96 files · +40 −6Browse files

Unified · Split

6 files

fs/btrfs/accessors.h +2 −0
fs/btrfs/extent-tree.c +4 −0
fs/btrfs/fs.h +1 −0
fs/btrfs/qgroup.c +22 −6
fs/btrfs/qgroup.h +2 −0
include/uapi/linux/btrfs_tree.h +9 −0

fs/btrfs/accessors.h+2−0

@@ -980,6 +980,8 @@ BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item, · 979 unmodified lines
980	980	flags, 64);
981	981	BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
982	982	rescan, 64);
	983	+BTRFS_SETGET_FUNCS(qgroup_status_enable_gen, struct btrfs_qgroup_status_item,
	984	+ enable_gen, 64);
983	985
984	986	/* btrfs_qgroup_info_item */
985	987	BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,

fs/btrfs/extent-tree.c+4−0

@@ -1566,6 +1566,7 @@ static int run_delayed_data_ref(struct btrfs_trans_handle *trans, · 1565 unmodified lines
1566	1566	.rsv_bytes = href->reserved_bytes,
1567	1567	.is_data = true,
1568	1568	.is_inc = true,
	1569	+ .generation = trans->transid,
1569	1570	};
1570	1571
1571	1572	if (extent_op)
@@ -1738,6 +1739,7 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans, · 166 unmodified lines
1738	1739	.rsv_bytes = 0,
1739	1740	.is_data = false,
1740	1741	.is_inc = true,
	1742	+ .generation = trans->transid,
1741	1743	};
1742	1744
1743	1745	BUG_ON(!extent_op \|\| !extent_op->update_flags);
@@ -3287,6 +3289,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, · 1543 unmodified lines
3287	3289	.rsv_bytes = 0,
3288	3290	.is_data = is_data,
3289	3291	.is_inc = false,
	3292	+ .generation = btrfs_extent_generation(leaf, ei),
3290	3293	};
3291	3294
3292	3295	/* In this branch refs == 1 */
@@ -4924,6 +4927,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, · 1631 unmodified lines
4924	4927	struct btrfs_squota_delta delta = {
4925	4928	.root = root_objectid,
4926	4929	.num_bytes = ins->offset,
	4930	+ .generation = trans->transid,
4927	4931	.rsv_bytes = 0,
4928	4932	.is_data = true,
4929	4933	.is_inc = true,

fs/btrfs/fs.h+1−0

@@ -687,6 +687,7 @@ struct btrfs_fs_info { · 686 unmodified lines
687	687	/* Protected by qgroup_rescan_lock */
688	688	bool qgroup_rescan_running;
689	689	u8 qgroup_drop_subtree_thres;
	690	+ u64 qgroup_enable_gen;
690	691
691	692	/*
692	693	* If this is not 0, then it indicates a serious filesystem error has

fs/btrfs/qgroup.c+22−6

@@ -369,6 +369,15 @@ static void qgroup_mark_inconsistent(struct btrfs_fs_info *fs_info) · 368 unmodified lines
369	369	BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING);
370	370	}
371	371
	372	+static void qgroup_read_enable_gen(struct btrfs_fs_info *fs_info,
	373	+ struct extent_buffer *leaf, int slot,
	374	+ struct btrfs_qgroup_status_item *ptr)
	375	+{
	376	+ ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
	377	+ ASSERT(btrfs_item_size(leaf, slot) >= sizeof(*ptr));
	378	+ fs_info->qgroup_enable_gen = btrfs_qgroup_status_enable_gen(leaf, ptr);
	379	+}
	380	+
372	381	/*
373	382	* The full config is read in one go, only called from open_ctree()
374	383	* 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) · 9 unmodified lines
384	393	int ret = 0;
385	394	u64 flags = 0;
386	395	u64 rescan_progress = 0;
387		− bool simple;
388	396
389	397	if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED)
390	398	return 0;
@@ -437,9 +445,9 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info) · 46 unmodified lines
437	445	goto out;
438	446	}
439	447	fs_info->qgroup_flags = btrfs_qgroup_status_flags(l, ptr);
440		− simple = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE);
441		− if (btrfs_qgroup_status_generation(l, ptr) !=
442		− fs_info->generation && !simple) {
	448	+ if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE) {
	449	+ qgroup_read_enable_gen(fs_info, l, slot, ptr);
	450	+ } else if (btrfs_qgroup_status_generation(l, ptr) != fs_info->generation) {
443	451	qgroup_mark_inconsistent(fs_info);
444	452	btrfs_err(fs_info,
445	453	"qgroup generation mismatch, marked as inconsistent");
@@ -1103,10 +1111,12 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info, · 657 unmodified lines
1103	1111	btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
1104	1112	btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
1105	1113	fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON;
1106		− if (simple)
	1114	+ if (simple) {
1107	1115	fs_info->qgroup_flags \|= BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE;
1108		− else
	1116	+ btrfs_set_qgroup_status_enable_gen(leaf, ptr, trans->transid);
	1117	+ } else {
1109	1118	fs_info->qgroup_flags \|= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
	1119	+ }
1110	1120	btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags &
1111	1121	BTRFS_QGROUP_STATUS_FLAGS_MASK);
1112	1122	btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
@@ -1210,6 +1220,8 @@ out_add_root: · 97 unmodified lines
1210	1220	goto out_free_path;
1211	1221	}
1212	1222
	1223	+ fs_info->qgroup_enable_gen = trans->transid;
	1224	+
1213	1225	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1214	1226	/*
1215	1227	* 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, · 3439 unmodified lines
4655	4667	if (!is_fstree(root))
4656	4668	return 0;
4657	4669
	4670	+ /* If the extent predates enabling quotas, don't count it. */
	4671	+ if (delta->generation < fs_info->qgroup_enable_gen)
	4672	+ return 0;
	4673	+
4658	4674	spin_lock(&fs_info->qgroup_lock);
4659	4675	qgroup = find_qgroup_rb(fs_info, root);
4660	4676	if (!qgroup) {

fs/btrfs/qgroup.h+2−0

@@ -276,6 +276,8 @@ struct btrfs_squota_delta { · 275 unmodified lines
276	276	u64 num_bytes;
277	277	/* The number of bytes reserved for this extent. */
278	278	u64 rsv_bytes;
	279	+ /* The generation the extent was created in. */
	280	+ u64 generation;
279	281	/* Whether we are using or freeing the extent. */
280	282	bool is_inc;
281	283	/* Whether the extent is data or metadata. */

include/uapi/linux/btrfs_tree.h+9−0

@@ -1277,6 +1277,15 @@ struct btrfs_qgroup_status_item { · 1276 unmodified lines
1277	1277	* of the scan. It contains a logical address
1278	1278	*/
1279	1279	__le64 rescan;
	1280	+
	1281	+ /*
	1282	+ * The generation when quotas were last enabled. Used by simple quotas to
	1283	+ * avoid decrementing when freeing an extent that was written before
	1284	+ * enable.
	1285	+ *
	1286	+ * Set only if flags contain BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE.
	1287	+ */
	1288	+ __le64 enable_gen;
1280	1289	} __attribute__ ((__packed__));
1281	1290
1282	1291	struct btrfs_qgroup_info_item {

btrfs: qgroup: check generation when recording simple quota delta

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