[PATCH] vfs_btrfs: add qgroup-aware disk free support

Justin Maggard jmaggard10 at gmail.com
Thu Jan 14 00:27:48 UTC 2016


Add support for qgroup-aware representation of disk free statistics to
vfs_btrfs.  If max_rfer has been defined on the subvolume, use metrics
from qgroups to represent disk free.

This can be disabled by setting "btrfs:qgroup dfree" to false in smb.conf.

Signed-off-by: Justin Maggard <jmaggard at netgear.com>
---
 source3/modules/vfs_btrfs.c | 170 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)

diff --git a/source3/modules/vfs_btrfs.c b/source3/modules/vfs_btrfs.c
index bd95637..435f08f 100644
--- a/source3/modules/vfs_btrfs.c
+++ b/source3/modules/vfs_btrfs.c
@@ -50,7 +50,13 @@ static uint32_t btrfs_fs_capabilities(struct vfs_handle_struct *handle,
 
 #define BTRFS_SUBVOL_RDONLY		(1ULL << 1)
 #define BTRFS_SUBVOL_NAME_MAX		4039
+#define BTRFS_INO_LOOKUP_PATH_MAX	4080
 #define BTRFS_PATH_NAME_MAX		4087
+#define BTRFS_FIRST_FREE_OBJECTID	256ULL
+#define BTRFS_QUOTA_TREE_OBJECTID	8ULL
+#define BTRFS_QGROUP_INFO_KEY		242
+#define BTRFS_QGROUP_LIMIT_KEY		244
+#define BTRFS_SEARCH_ARGS_BUFSIZE	(4096 - sizeof(struct btrfs_ioctl_search_key))
 struct btrfs_ioctl_vol_args_v2 {
 	int64_t fd;
 	uint64_t transid;
@@ -70,11 +76,65 @@ struct btrfs_ioctl_clone_range_args {
 	uint64_t dest_offset;
 };
 
+struct btrfs_ioctl_search_key {
+	uint64_t tree_id;
+	uint64_t min_objectid;
+	uint64_t max_objectid;
+	uint64_t min_offset;
+	uint64_t max_offset;
+	uint64_t min_transid;
+	uint64_t max_transid;
+	uint32_t min_type;
+	uint32_t max_type;
+	uint32_t nr_items;
+	uint32_t unused;
+	uint64_t unused1[4];
+};
+
+struct btrfs_ioctl_search_header {
+	uint64_t transid;
+	uint64_t objectid;
+	uint64_t offset;
+	uint32_t type;
+	uint32_t len;
+} __attribute__((may_alias));
+
+struct btrfs_ioctl_search_args {
+	struct btrfs_ioctl_search_key key;
+	char buf[BTRFS_SEARCH_ARGS_BUFSIZE];
+};
+
+struct btrfs_ioctl_ino_lookup_args {
+	uint64_t treeid;
+	uint64_t objectid;
+	char name[BTRFS_INO_LOOKUP_PATH_MAX];
+};
+
+struct btrfs_qgroup_info_item {
+	uint64_t generation;
+	uint64_t referenced;
+	uint64_t referenced_compressed;
+	uint64_t exclusive;
+	uint64_t exclusive_compressed;
+} __attribute__ ((__packed__, may_alias));
+
+struct btrfs_qgroup_limit_item {
+	uint64_t flags;
+	uint64_t max_referenced;
+	uint64_t max_exclusive;
+	uint64_t rsv_referenced;
+	uint64_t rsv_exclusive;
+} __attribute__ ((__packed__, may_alias));
+
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_IOC_CLONE_RANGE _IOW(BTRFS_IOCTL_MAGIC, 13, \
 				   struct btrfs_ioctl_clone_range_args)
 #define BTRFS_IOC_SNAP_DESTROY _IOW(BTRFS_IOCTL_MAGIC, 15, \
 				    struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_TREE_SEARCH _IOWR(BTRFS_IOCTL_MAGIC, 17, \
+				    struct btrfs_ioctl_search_args)
+#define BTRFS_IOC_INO_LOOKUP _IOWR(BTRFS_IOCTL_MAGIC, 18, \
+				   struct btrfs_ioctl_ino_lookup_args)
 #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
 				      struct btrfs_ioctl_vol_args_v2)
 
@@ -665,6 +725,115 @@ static NTSTATUS btrfs_snap_delete(struct vfs_handle_struct *handle,
 	return NT_STATUS_OK;
 }
 
+static uint64_t btrfs_get_path_rootid(int fd)
+{
+	int ret;
+	struct btrfs_ioctl_ino_lookup_args args;
+
+	memset(&args, 0, sizeof(args));
+	args.objectid = BTRFS_FIRST_FREE_OBJECTID;
+
+	ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
+	if (ret < 0) {
+		return (uint64_t)ret;
+	}
+	return args.treeid;
+}
+
+static int qgroup_search(int fd, uint64_t *used, uint64_t *quota, uint64_t qgroupid)
+{
+	struct btrfs_ioctl_search_args args;
+	struct btrfs_ioctl_search_key *sk = &args.key;
+	struct btrfs_ioctl_search_header *sh;
+	struct btrfs_qgroup_info_item *info;
+	struct btrfs_qgroup_limit_item *limit;
+	unsigned long off = 0;
+	unsigned int i;
+	int ret;
+
+	memset(&args, 0, sizeof(args));
+	sk->tree_id = BTRFS_QUOTA_TREE_OBJECTID;
+	sk->min_type = BTRFS_QGROUP_INFO_KEY;
+	sk->max_type = BTRFS_QGROUP_LIMIT_KEY;
+	sk->max_objectid = (uint64_t)-1;
+	sk->max_offset = (uint64_t)-1;
+	sk->max_transid = (uint64_t)-1;
+	sk->nr_items = 4096;
+
+	while (true) {
+		ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+		if (ret < 0) {
+			return ret;
+		}
+		if (sk->nr_items == 0) {
+			break;
+		}
+		off = 0;
+		for (i = 0; i < sk->nr_items; i++) {
+			sh = (struct btrfs_ioctl_search_header *)(args.buf +
+								  off);
+			off += sizeof(*sh);
+
+			if (sh->type == BTRFS_QGROUP_INFO_KEY) {
+				info = (struct btrfs_qgroup_info_item *)
+				       (args.buf + off);
+				if (sh->offset == qgroupid) {
+					*used = BVAL(&info->referenced, 0);
+				}
+			} else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) {
+				limit = (struct btrfs_qgroup_limit_item *)
+				    (args.buf + off);
+				if (sh->offset == qgroupid) {
+					*quota = BVAL(&limit->max_referenced, 0);
+				}
+			} else {
+				return 0;
+			}
+
+			off += sh->len;
+			sk->min_type = sh->type;
+			sk->min_offset = sh->offset;
+			sk->min_objectid = sh->objectid;
+		}
+		sk->nr_items = 4096;
+		if (sk->min_offset < (uint64_t)-1) {
+			sk->min_offset++;
+		} else {
+			break;
+		}
+	}
+	return 0;
+}
+
+static uint64_t btrfs_disk_free(vfs_handle_struct *handle,
+				const char *path, uint64_t *bsize,
+				uint64_t *dfree, uint64_t *dsize)
+{
+	int ret = -1, fd;
+	uint64_t used = UINT64_MAX, quota = 0, id;
+
+	if (lp_parm_bool(-1, "btrfs", "qgroup dfree", true)) {
+		become_root();
+		if ((fd = open(path, 0)) >= 0) {
+			id = btrfs_get_path_rootid(fd);
+			if (id != (uint64_t)-1) {
+				ret = qgroup_search(fd, &used, &quota, id);
+			}
+			close(fd);
+		}
+		unbecome_root();
+	}
+	if (ret || used == UINT64_MAX || !quota) {
+		return SMB_VFS_NEXT_DISK_FREE(handle, path,
+					      bsize, dfree, dsize);
+	}
+	*bsize = 4096;
+	*dfree = (quota - used)/4096;
+	*dsize = quota/4096;
+	return (quota - used)/1024;
+}
+
+
 static struct vfs_fn_pointers btrfs_fns = {
 	.fs_capabilities_fn = btrfs_fs_capabilities,
 	.copy_chunk_send_fn = btrfs_copy_chunk_send,
@@ -674,6 +843,7 @@ static struct vfs_fn_pointers btrfs_fns = {
 	.snap_check_path_fn = btrfs_snap_check_path,
 	.snap_create_fn = btrfs_snap_create,
 	.snap_delete_fn = btrfs_snap_delete,
+	.disk_free_fn = btrfs_disk_free,
 };
 
 NTSTATUS vfs_btrfs_init(void);
-- 
2.7.0




More information about the samba-technical mailing list