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authorLennart Poettering <lennart@poettering.net>2015-04-06 10:57:17 +0200
committerLennart Poettering <lennart@poettering.net>2015-04-06 11:28:16 +0200
commitd9e2daaf3d8649650cf9784b4fe9d9de4507da0c (patch)
treea6f5960da742e676f249036e59656dac040ecaed /src/shared/btrfs-util.c
parent41d1ed059bbc863c73161f39594de2eb7b338886 (diff)
btrfs: support recursively removing btrfs snapshots
Diffstat (limited to 'src/shared/btrfs-util.c')
-rw-r--r--src/shared/btrfs-util.c163
1 files changed, 137 insertions, 26 deletions
diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c
index a95cb8394f..fc795cb189 100644
--- a/src/shared/btrfs-util.c
+++ b/src/shared/btrfs-util.c
@@ -124,14 +124,14 @@ int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, bool read_only, b
r = copy_directory_fd(old_fd, new_path, true);
if (r < 0) {
- btrfs_subvol_remove(new_path);
+ btrfs_subvol_remove(new_path, false);
return r;
}
if (read_only) {
r = btrfs_subvol_set_read_only(new_path, true);
if (r < 0) {
- btrfs_subvol_remove(new_path);
+ btrfs_subvol_remove(new_path, false);
return r;
}
}
@@ -211,30 +211,6 @@ int btrfs_subvol_make_label(const char *path) {
return mac_smack_fix(path, false, false);
}
-int btrfs_subvol_remove(const char *path) {
- struct btrfs_ioctl_vol_args args = {};
- _cleanup_close_ int fd = -1;
- const char *subvolume;
- int r;
-
- assert(path);
-
- r = extract_subvolume_name(path, &subvolume);
- if (r < 0)
- return r;
-
- fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (fd < 0)
- return fd;
-
- strncpy(args.name, subvolume, sizeof(args.name)-1);
-
- if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args) < 0)
- return -errno;
-
- return 0;
-}
-
int btrfs_subvol_set_read_only_fd(int fd, bool b) {
uint64_t flags, nflags;
struct stat st;
@@ -798,3 +774,138 @@ int btrfs_resize_loopback(const char *p, uint64_t new_size, bool grow_only) {
return btrfs_resize_loopback_fd(fd, new_size, grow_only);
}
+
+static int subvol_remove_children(int fd, const char *subvolume, uint64_t subvol_id, bool recursive) {
+ struct btrfs_ioctl_search_args args = {
+ .key.tree_id = BTRFS_ROOT_TREE_OBJECTID,
+
+ .key.min_objectid = BTRFS_FIRST_FREE_OBJECTID,
+ .key.max_objectid = BTRFS_LAST_FREE_OBJECTID,
+
+ .key.min_type = BTRFS_ROOT_BACKREF_KEY,
+ .key.max_type = BTRFS_ROOT_BACKREF_KEY,
+
+ .key.min_transid = 0,
+ .key.max_transid = (uint64_t) -1,
+ };
+
+ struct btrfs_ioctl_vol_args vol_args = {};
+ _cleanup_close_ int subvol_fd = -1;
+ int r;
+
+ assert(fd >= 0);
+ assert(subvolume);
+
+ /* First, try to remove the subvolume. If it happens to be
+ * already empty, this will just work. */
+ strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
+ if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) >= 0)
+ return 0;
+ if (!recursive || errno != ENOTEMPTY)
+ return -errno;
+
+ /* OK, the subvolume is not empty, let's look for child
+ * subvolumes, and remove them, first */
+ subvol_fd = openat(fd, subvolume, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (subvol_fd < 0)
+ return -errno;
+
+ if (subvol_id == 0) {
+ r = btrfs_subvol_get_id_fd(subvol_fd, &subvol_id);
+ if (r < 0)
+ return r;
+ }
+
+ args.key.min_offset = args.key.max_offset = subvol_id;
+
+ while (btrfs_ioctl_search_args_compare(&args) <= 0) {
+ const struct btrfs_ioctl_search_header *sh;
+ unsigned i;
+
+ args.key.nr_items = 256;
+ if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args) < 0)
+ return -errno;
+
+ if (args.key.nr_items <= 0)
+ break;
+
+ FOREACH_BTRFS_IOCTL_SEARCH_HEADER(i, sh, args) {
+ _cleanup_free_ char *p = NULL;
+ const struct btrfs_root_ref *ref;
+ struct btrfs_ioctl_ino_lookup_args ino_args;
+
+ btrfs_ioctl_search_args_set(&args, sh);
+
+ if (sh->type != BTRFS_ROOT_BACKREF_KEY)
+ continue;
+ if (sh->offset != subvol_id)
+ continue;
+
+ ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh);
+
+ p = strndup((char*) ref + sizeof(struct btrfs_root_ref), le64toh(ref->name_len));
+ if (!p)
+ return -ENOMEM;
+
+ zero(ino_args);
+ ino_args.treeid = subvol_id;
+ ino_args.objectid = ref->dirid;
+
+ if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
+ return -errno;
+
+ if (isempty(ino_args.name))
+ /* Subvolume is in the top-level
+ * directory of the subvolume. */
+ r = subvol_remove_children(subvol_fd, p, sh->objectid, recursive);
+ else {
+ _cleanup_close_ int child_fd = -1;
+
+ /* Subvolume is somewhere further down,
+ * hence we need to open the
+ * containing directory first */
+
+ child_fd = openat(subvol_fd, ino_args.name, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (child_fd < 0)
+ return -errno;
+
+ r = subvol_remove_children(child_fd, p, sh->objectid, recursive);
+ }
+ if (r < 0)
+ return r;
+ }
+
+ /* Increase search key by one, to read the next item, if we can. */
+ if (!btrfs_ioctl_search_args_inc(&args))
+ break;
+ }
+
+ /* OK, the child subvolumes should all be gone now, let's try
+ * again to remove the subvolume */
+ if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &vol_args) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int btrfs_subvol_remove(const char *path, bool recursive) {
+ _cleanup_close_ int fd = -1;
+ const char *subvolume;
+ int r;
+
+ assert(path);
+
+ r = extract_subvolume_name(path, &subvolume);
+ if (r < 0)
+ return r;
+
+ fd = open_parent(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (fd < 0)
+ return fd;
+
+ return subvol_remove_children(fd, subvolume, 0, recursive);
+}
+
+int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive) {
+ return subvol_remove_children(fd, subvolume, 0, recursive);
+}