diff options
| -rw-r--r-- | src/basic/btrfs-util.c | 43 | ||||
| -rw-r--r-- | src/basic/btrfs-util.h | 1 |
2 files changed, 35 insertions, 9 deletions
diff --git a/src/basic/btrfs-util.c b/src/basic/btrfs-util.c index 49528dbf01..074deeccda 100644 --- a/src/basic/btrfs-util.c +++ b/src/basic/btrfs-util.c @@ -352,6 +352,19 @@ int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) { return 0; } +int btrfs_subvol_get_id(int fd, const char *subvol, uint64_t *ret) { + _cleanup_close_ int subvol_fd = -1; + + assert(fd >= 0); + assert(ret); + + subvol_fd = openat(fd, subvol, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); + if (subvol_fd < 0) + return -errno; + + return btrfs_subvol_get_id_fd(subvol_fd, ret); +} + static bool btrfs_ioctl_search_args_inc(struct btrfs_ioctl_search_args *args) { assert(args); @@ -937,7 +950,7 @@ 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) { +static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolume, uint64_t old_subvol_id, BtrfsSnapshotFlags flags) { struct btrfs_ioctl_search_args args = { .key.tree_id = BTRFS_ROOT_TREE_OBJECTID, @@ -956,8 +969,9 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum .flags = flags & BTRFS_SNAPSHOT_READ_ONLY ? BTRFS_SUBVOL_RDONLY : 0, .fd = old_fd, }; - int r; _cleanup_close_ int subvolume_fd = -1; + uint64_t new_subvol_id; + int r; assert(old_fd >= 0); assert(new_fd >= 0); @@ -972,13 +986,17 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum if (!(flags & BTRFS_SNAPSHOT_RECURSIVE)) return 0; - if (subvol_id == 0) { - r = btrfs_subvol_get_id_fd(old_fd, &subvol_id); + if (old_subvol_id == 0) { + r = btrfs_subvol_get_id_fd(old_fd, &old_subvol_id); if (r < 0) return r; } - args.key.min_offset = args.key.max_offset = subvol_id; + r = btrfs_subvol_get_id(new_fd, vol_args.name, &new_subvol_id); + if (r < 0) + return r; + + args.key.min_offset = args.key.max_offset = old_subvol_id; while (btrfs_ioctl_search_args_compare(&args) <= 0) { const struct btrfs_ioctl_search_header *sh; @@ -1001,17 +1019,24 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum if (sh->type != BTRFS_ROOT_BACKREF_KEY) continue; - if (sh->offset != subvol_id) + + /* Avoid finding the source subvolume a second + * time */ + if (sh->offset != old_subvol_id) continue; - ref = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh); + /* Avoid running into loops if the new + * subvolume is below the old one. */ + if (sh->objectid == new_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.treeid = old_subvol_id; ino_args.objectid = htole64(ref->dirid); if (ioctl(old_fd, BTRFS_IOC_INO_LOOKUP, &ino_args) < 0) @@ -1056,7 +1081,7 @@ static int subvol_snapshot_children(int old_fd, int new_fd, const char *subvolum } /* When btrfs clones the subvolumes, child - * subvolumes appear as directories. Remove + * subvolumes appear as empty directories. Remove * them, so that we can create a new snapshot * in their place */ if (unlinkat(new_child_fd, p, AT_REMOVEDIR) < 0) { diff --git a/src/basic/btrfs-util.h b/src/basic/btrfs-util.h index a7eb895c93..8632c3638c 100644 --- a/src/basic/btrfs-util.h +++ b/src/basic/btrfs-util.h @@ -61,6 +61,7 @@ int btrfs_subvol_snapshot(const char *old_path, const char *new_path, BtrfsSnaps int btrfs_subvol_set_read_only_fd(int fd, bool b); int btrfs_subvol_set_read_only(const char *path, bool b); int btrfs_subvol_get_read_only_fd(int fd); +int btrfs_subvol_get_id(int fd, const char *subvolume, uint64_t *ret); int btrfs_subvol_get_id_fd(int fd, uint64_t *ret); int btrfs_subvol_get_info_fd(int fd, BtrfsSubvolInfo *info); int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *quota); |