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authorLennart Poettering <lennart@poettering.net>2015-02-26 00:40:43 +0100
committerLennart Poettering <lennart@poettering.net>2015-02-26 00:43:16 +0100
commitefe0286285a7432f738fafae840fa4eda51c2986 (patch)
tree8e1871cedf8f4f23bace08ae42b1d4a901a706f1 /src/shared/btrfs-util.c
parent3a4efbff2e729194d286f483bd8e122c52ff1129 (diff)
machined: if /var/lib/machines is backed by a loop file, resize it on "machinectl set-limit"
When the pool size limit is altered with "machinectl set-limit", then not only set the subvolume quota of the /var/lib/machine subvolume, but also resize the backing loop file and the btrfs file system on it dynamically.
Diffstat (limited to 'src/shared/btrfs-util.c')
-rw-r--r--src/shared/btrfs-util.c101
1 files changed, 94 insertions, 7 deletions
diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c
index 6761501da2..52fc5f4a17 100644
--- a/src/shared/btrfs-util.c
+++ b/src/shared/btrfs-util.c
@@ -34,6 +34,7 @@
#include "copy.h"
#include "selinux-util.h"
#include "smack-util.h"
+#include "fileio.h"
#include "btrfs-ctree.h"
#include "btrfs-util.h"
@@ -308,18 +309,13 @@ int btrfs_clone_range(int infd, uint64_t in_offset, int outfd, uint64_t out_offs
return 0;
}
-int btrfs_get_block_device(const char *path, dev_t *dev) {
+int btrfs_get_block_device_fd(int fd, dev_t *dev) {
struct btrfs_ioctl_fs_info_args fsi = {};
- _cleanup_close_ int fd = -1;
uint64_t id;
- assert(path);
+ assert(fd >= 0);
assert(dev);
- fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
- if (fd < 0)
- return -errno;
-
if (ioctl(fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
return -errno;
@@ -356,6 +352,19 @@ int btrfs_get_block_device(const char *path, dev_t *dev) {
return -ENODEV;
}
+int btrfs_get_block_device(const char *path, dev_t *dev) {
+ _cleanup_close_ int fd = -1;
+
+ assert(path);
+ assert(dev);
+
+ fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ return btrfs_get_block_device_fd(fd, dev);
+}
+
int btrfs_subvol_get_id_fd(int fd, uint64_t *ret) {
struct btrfs_ioctl_ino_lookup_args args = {
.objectid = BTRFS_FIRST_FREE_OBJECTID
@@ -695,3 +704,81 @@ int btrfs_quota_limit(const char *path, uint64_t referred_max) {
return btrfs_quota_limit_fd(fd, referred_max);
}
+
+int btrfs_resize_loopback_fd(int fd, uint64_t new_size) {
+ struct btrfs_ioctl_vol_args args = {};
+ _cleanup_free_ char *p = NULL, *loop = NULL, *backing = NULL;
+ _cleanup_close_ int loop_fd = -1, backing_fd = -1;
+ struct stat st;
+ dev_t dev;
+ int r;
+
+ /* btrfs cannot handle file systems < 16M, hence use this as minimum */
+ if (new_size < 16*1024*1024)
+ new_size = 16*1024*1024;
+
+ r = btrfs_get_block_device_fd(fd, &dev);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -ENODEV;
+
+ if (asprintf(&p, "/sys/dev/block/%u:%u/loop/backing_file", major(dev), minor(dev)) < 0)
+ return -ENOMEM;
+ r = read_one_line_file(p, &backing);
+ if (r < 0)
+ return r;
+ if (isempty(backing) || !path_is_absolute(backing))
+ return -ENODEV;
+
+ backing_fd = open(backing, O_RDWR|O_CLOEXEC|O_NOCTTY);
+ if (backing_fd < 0)
+ return -errno;
+
+ if (fstat(backing_fd, &st) < 0)
+ return -errno;
+ if (!S_ISREG(st.st_mode))
+ return -ENODEV;
+
+ if (new_size == (uint64_t) st.st_size)
+ return 0;
+
+ if (asprintf(&loop, "/dev/block/%u:%u", major(dev), minor(dev)) < 0)
+ return -ENOMEM;
+ loop_fd = open(loop, O_RDWR|O_CLOEXEC|O_NOCTTY);
+ if (loop_fd < 0)
+ return -errno;
+
+ if (snprintf(args.name, sizeof(args.name), "%" PRIu64, new_size) >= (int) sizeof(args.name))
+ return -EINVAL;
+
+ if (new_size < (uint64_t) st.st_size) {
+ /* Decrease size: first decrease btrfs size, then shorten loopback */
+ if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
+ return -errno;
+ }
+
+ if (ftruncate(backing_fd, new_size) < 0)
+ return -errno;
+
+ if (ioctl(loop_fd, LOOP_SET_CAPACITY, 0) < 0)
+ return -errno;
+
+ if (new_size > (uint64_t) st.st_size) {
+ /* Increase size: first enlarge loopback, then increase btrfs size */
+ if (ioctl(fd, BTRFS_IOC_RESIZE, &args) < 0)
+ return -errno;
+ }
+
+ return 0;
+}
+
+int btrfs_resize_loopback(const char *p, uint64_t new_size) {
+ _cleanup_close_ int fd = -1;
+
+ fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ return btrfs_resize_loopback_fd(fd, new_size);
+}