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-rw-r--r--src/shared/btrfs-util.c248
-rw-r--r--src/shared/btrfs-util.h1
-rw-r--r--src/shared/machine-image.c2
3 files changed, 182 insertions, 69 deletions
diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c
index 7fb92b22ee..5bf87a389e 100644
--- a/src/shared/btrfs-util.c
+++ b/src/shared/btrfs-util.c
@@ -101,74 +101,6 @@ int btrfs_is_snapshot(int fd) {
return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
}
-int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlags flags) {
- struct btrfs_ioctl_vol_args_v2 args = {
- .flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0,
- };
- _cleanup_close_ int new_fd = -1;
- const char *subvolume;
- int r;
-
- assert(new_path);
-
- r = btrfs_is_snapshot(old_fd);
- if (r < 0)
- return r;
- if (r == 0) {
- if (!(flags & BTRFS_SNAPSHOT_FALLBACK_COPY))
- return -EISDIR;
-
- r = btrfs_subvol_make(new_path);
- if (r < 0)
- return r;
-
- r = copy_directory_fd(old_fd, new_path, true);
- if (r < 0) {
- btrfs_subvol_remove(new_path, false);
- return r;
- }
-
- if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
- r = btrfs_subvol_set_read_only(new_path, true);
- if (r < 0) {
- btrfs_subvol_remove(new_path, false);
- return r;
- }
- }
-
- return 0;
- }
-
- r = extract_subvolume_name(new_path, &subvolume);
- if (r < 0)
- return r;
-
- new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (new_fd < 0)
- return new_fd;
-
- strncpy(args.name, subvolume, sizeof(args.name)-1);
- args.fd = old_fd;
-
- if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &args) < 0)
- return -errno;
-
- return 0;
-}
-
-int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnapshotFlags flags) {
- _cleanup_close_ int old_fd = -1;
-
- assert(old_path);
- assert(new_path);
-
- old_fd = open(old_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (old_fd < 0)
- return -errno;
-
- return btrfs_subvol_snapshot_fd(old_fd, new_path, flags);
-}
-
int btrfs_subvol_make(const char *path) {
struct btrfs_ioctl_vol_args args = {};
_cleanup_close_ int fd = -1;
@@ -909,3 +841,183 @@ int btrfs_subvol_remove(const char *path, bool recursive) {
int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive) {
return subvol_remove_children(fd, subvolume, 0, recursive);
}
+
+static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolume, uint64_t subvol_id, BtrfsSnapshotFlags flags) {
+
+ 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_v2 vol_args = {
+ .flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0,
+ .fd = old_fd,
+ };
+ int r;
+
+ assert(old_fd >= 0);
+ assert(new_fd >= 0);
+ assert(subvolume);
+
+ strncpy(vol_args.name, subvolume, sizeof(vol_args.name)-1);
+ vol_args.fd = old_fd;
+
+ if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &vol_args) < 0)
+ return -errno;
+
+ if (!(flags & BTRFS_SNAPSHOT_RECURSIVE))
+ return 0;
+
+ if (subvol_id == 0) {
+ r = btrfs_subvol_get_id_fd(old_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(old_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, *c = NULL, *np = NULL;
+ struct btrfs_ioctl_ino_lookup_args ino_args;
+ const struct btrfs_root_ref *ref;
+ _cleanup_close_ int old_child_fd = -1, new_child_fd = -1;
+
+ 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 = htole64(ref->dirid);
+
+ if (ioctl(old_fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0)
+ return -errno;
+
+ /* The kernel returns an empty name if the
+ * subvolume is in the top-level directory,
+ * and otherwise appends a slash, so that we
+ * can just concatenate easily here, without
+ * adding a slash. */
+ c = strappend(ino_args.name, p);
+ if (!c)
+ return -ENOMEM;
+
+ old_child_fd = openat(old_fd, c, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (old_child_fd < 0)
+ return -errno;
+
+ np = strjoin(subvolume, "/", ino_args.name, NULL);
+ if (!np)
+ return -ENOMEM;
+
+ new_child_fd = openat(new_fd, np, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (new_child_fd < 0)
+ return -errno;
+
+ /* When btrfs clones the subvolumes, child
+ * subvolumes appear as directories. Remove
+ * them, so that we can create a new snapshot
+ * in their place */
+ if (unlinkat(new_child_fd, p, AT_REMOVEDIR) < 0)
+ return -errno;
+
+ r = subvol_snapshot_children(old_child_fd, new_child_fd, p, sh->objectid, flags & ~BTRFS_SNAPSHOT_FALLBACK_COPY);
+ 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;
+ }
+
+ return 0;
+}
+
+int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlags flags) {
+ _cleanup_close_ int new_fd = -1;
+ const char *subvolume;
+ int r;
+
+ assert(old_fd >= 0);
+ assert(new_path);
+
+ r = btrfs_is_snapshot(old_fd);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ if (!(flags & BTRFS_SNAPSHOT_FALLBACK_COPY))
+ return -EISDIR;
+
+ r = btrfs_subvol_make(new_path);
+ if (r < 0)
+ return r;
+
+ r = copy_directory_fd(old_fd, new_path, true);
+ if (r < 0) {
+ btrfs_subvol_remove(new_path, false);
+ return r;
+ }
+
+ if (flags & BTRFS_SNAPSHOT_READ_ONLY) {
+ r = btrfs_subvol_set_read_only(new_path, true);
+ if (r < 0) {
+ btrfs_subvol_remove(new_path, false);
+ return r;
+ }
+ }
+
+ return 0;
+ }
+
+ r = extract_subvolume_name(new_path, &subvolume);
+ if (r < 0)
+ return r;
+
+ new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (new_fd < 0)
+ return new_fd;
+
+ return subvol_snapshot_children(old_fd, new_fd, subvolume, 0, flags);
+}
+
+int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnapshotFlags flags) {
+ _cleanup_close_ int old_fd = -1;
+
+ assert(old_path);
+ assert(new_path);
+
+ old_fd = open(old_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (old_fd < 0)
+ return -errno;
+
+ return btrfs_subvol_snapshot_fd(old_fd, new_path, flags);
+}
diff --git a/src/shared/btrfs-util.h b/src/shared/btrfs-util.h
index e3ad98750f..02e46e30ea 100644
--- a/src/shared/btrfs-util.h
+++ b/src/shared/btrfs-util.h
@@ -46,6 +46,7 @@ typedef struct BtrfsQuotaInfo {
typedef enum BtrfsSnapshotFlags {
BTRFS_SNAPSHOT_FALLBACK_COPY = 1,
BTRFS_SNAPSHOT_READ_ONLY = 2,
+ BTRFS_SNAPSHOT_RECURSIVE = 4,
} BtrfsSnapshotFlags;
int btrfs_is_snapshot(int fd);
diff --git a/src/shared/machine-image.c b/src/shared/machine-image.c
index ebe5a130f6..0b41860b5d 100644
--- a/src/shared/machine-image.c
+++ b/src/shared/machine-image.c
@@ -491,7 +491,7 @@ int image_clone(Image *i, const char *new_name, bool read_only) {
case IMAGE_DIRECTORY:
new_path = strjoina("/var/lib/machines/", new_name);
- r = btrfs_subvol_snapshot(i->path, new_path, (read_only ? BTRFS_SNAPSHOT_READ_ONLY : 0) | BTRFS_SNAPSHOT_FALLBACK_COPY);
+ r = btrfs_subvol_snapshot(i->path, new_path, (read_only ? BTRFS_SNAPSHOT_READ_ONLY : 0) | BTRFS_SNAPSHOT_FALLBACK_COPY | BTRFS_SNAPSHOT_RECURSIVE);
break;
case IMAGE_RAW:
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-18 11:27:33 +0000