X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fshared%2Fbtrfs-util.c;h=5a1ed60558be24e0eea6c3f52c4fd111bf231c24;hb=2c38d6cdf68973efb758ab546fb7553e3320bb84;hp=23a22db662528b50080e96a9c2d857305c1c9378;hpb=587fec427c80b6c34dcf1d7570f891fcb652a7c5;p=elogind.git diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c index 23a22db66..5a1ed6055 100644 --- a/src/shared/btrfs-util.c +++ b/src/shared/btrfs-util.c @@ -83,17 +83,10 @@ static int extract_subvolume_name(const char *path, const char **subvolume) { return 0; } -int btrfs_is_snapshot(int fd) { - struct stat st; +int btrfs_is_filesystem(int fd) { struct statfs sfs; - /* On btrfs subvolumes always have the inode 256 */ - - if (fstat(fd, &st) < 0) - return -errno; - - if (!S_ISDIR(st.st_mode) || st.st_ino != 256) - return 0; + assert(fd >= 0); if (fstatfs(fd, &sfs) < 0) return -errno; @@ -101,72 +94,20 @@ 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, bool read_only, bool fallback_copy) { - struct btrfs_ioctl_vol_args_v2 args = { - .flags = 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 (!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); - return r; - } - - if (read_only) { - r = btrfs_subvol_set_read_only(new_path, true); - if (r < 0) { - btrfs_subvol_remove(new_path); - return r; - } - } - - return 0; - } - - r = extract_subvolume_name(new_path, &subvolume); - if (r < 0) - return r; +int btrfs_is_subvol(int fd) { + struct stat st; - new_fd = open_parent(new_path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY); - if (new_fd < 0) - return new_fd; + assert(fd >= 0); - strncpy(args.name, subvolume, sizeof(args.name)-1); - args.fd = old_fd; + /* On btrfs subvolumes always have the inode 256 */ - if (ioctl(new_fd, BTRFS_IOC_SNAP_CREATE_V2, &args) < 0) + if (fstat(fd, &st) < 0) return -errno; - return 0; -} - -int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_only, bool fallback_copy) { - _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; + if (!S_ISDIR(st.st_mode) || st.st_ino != 256) + return 0; - return btrfs_subvol_snapshot_fd(old_fd, new_path, read_only, fallback_copy); + return btrfs_is_filesystem(fd); } int btrfs_subvol_make(const char *path) { @@ -211,30 +152,6 @@ 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; @@ -599,7 +516,7 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) { if (sh->type == BTRFS_QGROUP_INFO_KEY) { const struct btrfs_qgroup_info_item *qii = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh); - ret->referred = le64toh(qii->rfer); + ret->referenced = le64toh(qii->rfer); ret->exclusive = le64toh(qii->excl); found_info = true; @@ -607,11 +524,11 @@ int btrfs_subvol_get_quota_fd(int fd, BtrfsQuotaInfo *ret) { } else if (sh->type == BTRFS_QGROUP_LIMIT_KEY) { const struct btrfs_qgroup_limit_item *qli = BTRFS_IOCTL_SEARCH_HEADER_BODY(sh); - ret->referred_max = le64toh(qli->max_rfer); + ret->referenced_max = le64toh(qli->max_rfer); ret->exclusive_max = le64toh(qli->max_excl); - if (ret->referred_max == 0) - ret->referred_max = (uint64_t) -1; + if (ret->referenced_max == 0) + ret->referenced_max = (uint64_t) -1; if (ret->exclusive_max == 0) ret->exclusive_max = (uint64_t) -1; @@ -632,12 +549,12 @@ finish: return -ENODATA; if (!found_info) { - ret->referred = (uint64_t) -1; + ret->referenced = (uint64_t) -1; ret->exclusive = (uint64_t) -1; } if (!found_limit) { - ret->referred_max = (uint64_t) -1; + ret->referenced_max = (uint64_t) -1; ret->exclusive_max = (uint64_t) -1; } @@ -686,11 +603,11 @@ int btrfs_quota_enable(const char *path, bool b) { return btrfs_quota_enable_fd(fd, b); } -int btrfs_quota_limit_fd(int fd, uint64_t referred_max) { +int btrfs_quota_limit_fd(int fd, uint64_t referenced_max) { struct btrfs_ioctl_qgroup_limit_args args = { .lim.max_rfer = - referred_max == (uint64_t) -1 ? 0 : - referred_max == 0 ? 1 : referred_max, + referenced_max == (uint64_t) -1 ? 0 : + referenced_max == 0 ? 1 : referenced_max, .lim.flags = BTRFS_QGROUP_LIMIT_MAX_RFER, }; @@ -702,14 +619,14 @@ int btrfs_quota_limit_fd(int fd, uint64_t referred_max) { return 0; } -int btrfs_quota_limit(const char *path, uint64_t referred_max) { +int btrfs_quota_limit(const char *path, uint64_t referenced_max) { _cleanup_close_ int fd = -1; fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fd < 0) return -errno; - return btrfs_quota_limit_fd(fd, referred_max); + return btrfs_quota_limit_fd(fd, referenced_max); } int btrfs_resize_loopback_fd(int fd, uint64_t new_size, bool grow_only) { @@ -717,7 +634,7 @@ int btrfs_resize_loopback_fd(int fd, uint64_t new_size, bool grow_only) { _cleanup_free_ char *p = NULL, *loop = NULL, *backing = NULL; _cleanup_close_ int loop_fd = -1, backing_fd = -1; struct stat st; - dev_t dev; + dev_t dev = 0; int r; /* btrfs cannot handle file systems < 16M, hence use this as minimum */ @@ -798,3 +715,318 @@ 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 = htole64(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); +} + +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_subvol(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); +}