diff options
| -rw-r--r-- | man/tmpfiles.d.xml | 16 | ||||
| -rw-r--r-- | src/basic/btrfs-util.c | 18 | ||||
| -rw-r--r-- | src/basic/btrfs-util.h | 4 | ||||
| -rw-r--r-- | src/tmpfiles/tmpfiles.c | 24 |
4 files changed, 49 insertions, 13 deletions
diff --git a/man/tmpfiles.d.xml b/man/tmpfiles.d.xml index 3f6128cb5b..5bf1f2956b 100644 --- a/man/tmpfiles.d.xml +++ b/man/tmpfiles.d.xml @@ -169,13 +169,15 @@ <varlistentry> <term><varname>v</varname></term> <listitem><para>Create a subvolume if the path does not - exist yet and the file system supports this - (btrfs). Otherwise, create a normal directory, in the same - way as <varname>d</varname>. A subvolume created with this - line type is not assigned to any higher-level quota - group. For that, use <varname>q</varname> or - <varname>Q</varname>, which allow creating simple quota group - hierarchies, see below.</para></listitem> + exist yet, the file system supports subvolumes (btrfs), and + the system itself is installed into a subvolume + (specifically: the root directory <filename>/</filename> is + itself a subvolume). Otherwise, create a normal directory, in + the same way as <varname>d</varname>. A subvolume created + with this line type is not assigned to any higher-level + quota group. For that, use <varname>q</varname> or + <varname>Q</varname>, which allow creating simple quota + group hierarchies, see below.</para></listitem> </varlistentry> <varlistentry> diff --git a/src/basic/btrfs-util.c b/src/basic/btrfs-util.c index 8c2d76b8aa..be40dc5702 100644 --- a/src/basic/btrfs-util.c +++ b/src/basic/btrfs-util.c @@ -105,7 +105,7 @@ int btrfs_is_filesystem(int fd) { return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC); } -int btrfs_is_subvol(int fd) { +int btrfs_is_subvol_fd(int fd) { struct stat st; assert(fd >= 0); @@ -121,6 +121,18 @@ int btrfs_is_subvol(int fd) { return btrfs_is_filesystem(fd); } +int btrfs_is_subvol(const char *path) { + _cleanup_close_ int fd = -1; + + assert(path); + + fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY); + if (fd < 0) + return -errno; + + return btrfs_is_subvol_fd(fd); +} + int btrfs_subvol_make(const char *path) { struct btrfs_ioctl_vol_args args = {}; _cleanup_close_ int fd = -1; @@ -1686,7 +1698,7 @@ int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, BtrfsSnapshotFlag assert(old_fd >= 0); assert(new_path); - r = btrfs_is_subvol(old_fd); + r = btrfs_is_subvol_fd(old_fd); if (r < 0) return r; if (r == 0) { @@ -1872,7 +1884,7 @@ int btrfs_subvol_auto_qgroup_fd(int fd, uint64_t subvol_id, bool insert_intermed */ if (subvol_id == 0) { - r = btrfs_is_subvol(fd); + r = btrfs_is_subvol_fd(fd); if (r < 0) return r; if (!r) diff --git a/src/basic/btrfs-util.h b/src/basic/btrfs-util.h index fc9efd72d5..8c11ce35d2 100644 --- a/src/basic/btrfs-util.h +++ b/src/basic/btrfs-util.h @@ -56,7 +56,9 @@ typedef enum BtrfsRemoveFlags { } BtrfsRemoveFlags; int btrfs_is_filesystem(int fd); -int btrfs_is_subvol(int fd); + +int btrfs_is_subvol_fd(int fd); +int btrfs_is_subvol(const char *path); int btrfs_reflink(int infd, int outfd); int btrfs_clone_range(int infd, uint64_t in_offset, int ofd, uint64_t out_offset, uint64_t sz); diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c index 74b6b91593..f9a759e223 100644 --- a/src/tmpfiles/tmpfiles.c +++ b/src/tmpfiles/tmpfiles.c @@ -1226,8 +1226,28 @@ static int create_item(Item *i) { mkdir_parents_label(i->path, 0755); if (IN_SET(i->type, CREATE_SUBVOLUME, CREATE_SUBVOLUME_INHERIT_QUOTA, CREATE_SUBVOLUME_NEW_QUOTA)) { - RUN_WITH_UMASK((~i->mode) & 0777) - r = btrfs_subvol_make(i->path); + + if (btrfs_is_subvol(isempty(arg_root) ? "/" : arg_root) <= 0) + + /* Don't create a subvolume unless the + * root directory is one, too. We do + * this under the assumption that if + * the root directory is just a plain + * directory (i.e. very light-weight), + * we shouldn't try to split it up + * into subvolumes (i.e. more + * heavy-weight). Thus, chroot() + * environments and suchlike will get + * a full brtfs subvolume set up below + * their tree only if they + * specifically set up a btrfs + * subvolume for the root dir too. */ + + r = -ENOTTY; + else { + RUN_WITH_UMASK((~i->mode) & 0777) + r = btrfs_subvol_make(i->path); + } } else r = 0; |