It needs a lot more information about the snapshots if
snapshot's life cycle has to be all auto managed by
scripts _some day_. this patch is a step towards that.
This patch provides the size which would be freed
if the subvol/snapshot is deleted.
preview:
---------------------
btrfs su show /btrfs/sv1
::
Unshared space: 89.09MiB
---------------------
v2: rename to 'unshared space' and edit commit text
worked on review comments
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
cmds-subvolume.c | 2 +
utils.c | 154 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
utils.h | 1 +
3 files changed, 157 insertions(+)
diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index de246ab..d801e00 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -915,6 +915,8 @@ static int cmd_subvol_show(int argc, char **argv)
else
printf("\tFlags: \t\t\t-\n");
+ printf("\tUnshared space: \t%s\n",
+ pretty_size(get_subvol_freeable_bytes(fd)));
/* print the snapshots of the given subvol if any*/
printf("\tSnapshot(s):\n");
filter_set = btrfs_list_alloc_filter_set();
diff --git a/utils.c b/utils.c
index ccb5199..ca30485 100644
--- a/utils.c
+++ b/utils.c
@@ -2062,3 +2062,157 @@ int lookup_ino_rootid(int fd, u64 *rootid)
return 0;
}
+
+/* gets the ref count for given extent
+ * 0 = didn't find the item
+ * n = number of references
+*/
+u64 get_extent_refcnt(int fd, u64 disk_blk)
+{
+ int ret = 0, i, e;
+ struct btrfs_ioctl_search_args args;
+ struct btrfs_ioctl_search_key *sk = &args.key;
+ struct btrfs_ioctl_search_header sh;
+ unsigned long off = 0;
+
+ memset(&args, 0, sizeof(args));
+
+ sk->tree_id = BTRFS_EXTENT_TREE_OBJECTID;
+
+ sk->min_type = BTRFS_EXTENT_ITEM_KEY;
+ sk->max_type = BTRFS_EXTENT_ITEM_KEY;
+
+ sk->min_objectid = disk_blk;
+ sk->max_objectid = disk_blk;
+
+ sk->max_offset = (u64)-1;
+ sk->max_transid = (u64)-1;
+
+ while (1) {
+ sk->nr_items = 4096;
+
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+ e = errno;
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: search failed - %s\n",
+ strerror(e));
+ return 0;
+ }
+ if (sk->nr_items == 0)
+ break;
+
+ off = 0;
+ for (i = 0; i < sk->nr_items; i++) {
+ struct btrfs_extent_item *ei;
+ u64 ref;
+
+ memcpy(&sh, args.buf + off, sizeof(sh));
+ off += sizeof(sh);
+
+ if (sh.type != BTRFS_EXTENT_ITEM_KEY) {
+ off += sh.len;
+ continue;
+ }
+
+ ei = (struct btrfs_extent_item *)(args.buf + off);
+ ref = btrfs_stack_extent_refs(ei);
+ return ref;
+ }
+ sk->min_objectid = sh.objectid;
+ sk->min_offset = sh.offset;
+ sk->min_type = sh.type;
+ if (sk->min_offset < (u64)-1)
+ sk->min_offset++;
+ else if (sk->min_objectid < (u64)-1) {
+ sk->min_objectid++;
+ sk->min_offset = 0;
+ sk->min_type = 0;
+ } else
+ break;
+ }
+ return 0;
+}
+
+u64 get_subvol_freeable_bytes(int fd)
+{
+ int ret = 0, i, e;
+ struct btrfs_ioctl_search_args args;
+ struct btrfs_ioctl_search_key *sk = &args.key;
+ struct btrfs_ioctl_search_header sh;
+ unsigned long off = 0;
+ u64 size_bytes = 0;
+
+ memset(&args, 0, sizeof(args));
+
+ sk->tree_id = 0;
+
+ sk->min_type = BTRFS_EXTENT_DATA_KEY;
+ sk->max_type = BTRFS_EXTENT_DATA_KEY;
+
+ sk->max_objectid = (u64) -1;
+ sk->max_offset = (u64)-1;
+ sk->max_transid = (u64)-1;
+
+ while (1) {
+ sk->nr_items = 4096;
+
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+ e = errno;
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: search failed - %s\n",
+ strerror(e));
+ return 0;
+ }
+ if (sk->nr_items == 0)
+ break;
+
+ off = 0;
+ for (i = 0; i < sk->nr_items; i++) {
+ struct btrfs_file_extent_item *efi;
+ u64 disk_bytenr = 0;
+ u64 num_bytes = 0;
+ u64 refcnt;
+ u8 type;
+
+ memcpy(&sh, args.buf + off, sizeof(sh));
+ off += sizeof(sh);
+
+ if (sh.type != BTRFS_EXTENT_DATA_KEY) {
+ off += sh.len;
+ continue;
+ }
+
+ efi = (struct btrfs_file_extent_item *)(args.buf + off);
+ type = btrfs_stack_file_extent_type(efi);
+
+ if (type == BTRFS_FILE_EXTENT_INLINE) {
+ size_bytes +=
+ btrfs_stack_file_extent_ram_bytes(efi);
+ goto skip_extent_data;
+ }
+ disk_bytenr = btrfs_stack_file_extent_disk_bytenr(efi);
+ num_bytes = btrfs_stack_file_extent_num_bytes(efi);
+
+ if (disk_bytenr) {
+ refcnt = get_extent_refcnt(fd, disk_bytenr);
+ if (refcnt == 1)
+ size_bytes += num_bytes;
+ }
+skip_extent_data:
+ off += sh.len;
+ }
+ sk->min_objectid = sh.objectid;
+ sk->min_offset = sh.offset;
+ sk->min_type = sh.type;
+
+ if (sk->min_offset < (u64)-1)
+ sk->min_offset++;
+ else if (sk->min_objectid < (u64)-1) {
+ sk->min_objectid++;
+ sk->min_offset = 0;
+ sk->min_type = 0;
+ } else
+ break;
+ }
+ return size_bytes;
+}
diff --git a/utils.h b/utils.h
index 0f31db7..4ddcf09 100644
--- a/utils.h
+++ b/utils.h
@@ -91,5 +91,6 @@ int csum_tree_block(struct btrfs_root *root, struct
extent_buffer *buf,
int ask_user(char *question);
int lookup_ino_rootid(int fd, u64 *rootid);
int btrfs_scan_lblkid(int update_kernel);
+u64 get_subvol_freeable_bytes(int fd);
#endif
--
1.8.4.rc4.1.g0d8beaa
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