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btrfs: support recursively removing btrfs snapshots

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This commit is contained in:
Lennart Poettering
2015-04-06 11:28:16 +02:00
parent 41d1ed059b
commit d9e2daaf3d
17 changed files with 239 additions and 70 deletions
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src/shared/btrfs-ctree.h
+6
View File
@@ -90,3 +90,9 @@ struct btrfs_qgroup_limit_item {
le64_t rsv_rfer;
le64_t rsv_excl;
} _packed_;
struct btrfs_root_ref {
le64_t dirid;
le64_t sequence;
le16_t name_len;
} _packed_;
src/shared/btrfs-util.c
+137 -26
View File
@@ -124,14 +124,14 @@ int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, bool read_only, b
r = copy_directory_fd(old_fd, new_path, true);
if (r < 0) {
btrfs_subvol_remove(new_path);
btrfs_subvol_remove(new_path, false);
return r;
}
if (read_only) {
r = btrfs_subvol_set_read_only(new_path, true);
if (r < 0) {
btrfs_subvol_remove(new_path);
btrfs_subvol_remove(new_path, false);
return r;
}
}
@@ -211,30 +211,6 @@ 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;
@@ -798,3 +774,138 @@ 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 = 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);
}
src/shared/btrfs-util.h
+3 -1
View File
@@ -47,7 +47,6 @@ int btrfs_is_snapshot(int fd);
int btrfs_subvol_make(const char *path);
int btrfs_subvol_make_label(const char *path);
int btrfs_subvol_remove(const char *path);
int btrfs_subvol_snapshot_fd(int old_fd, const char *new_path, bool read_only, bool fallback_copy);
int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_only, bool fallback_copy);
@@ -76,3 +75,6 @@ int btrfs_quota_limit(const char *path, uint64_t referenced_max);
int btrfs_resize_loopback_fd(int fd, uint64_t size, bool grow_only);
int btrfs_resize_loopback(const char *path, uint64_t size, bool grow_only);
int btrfs_subvol_remove(const char *path, bool recursive);
int btrfs_subvol_remove_fd(int fd, const char *subvolume, bool recursive);
src/shared/machine-image.c
+1 -1
View File
@@ -358,7 +358,7 @@ int image_remove(Image *i) {
switch (i->type) {
case IMAGE_SUBVOLUME:
return btrfs_subvol_remove(i->path);
return btrfs_subvol_remove(i->path, true);
case IMAGE_DIRECTORY:
/* Allow deletion of read-only directories */
src/shared/missing.h
+8
View File
@@ -428,6 +428,10 @@ struct btrfs_ioctl_clone_range_args {
#define BTRFS_FIRST_FREE_OBJECTID 256
#endif
#ifndef BTRFS_LAST_FREE_OBJECTID
#define BTRFS_LAST_FREE_OBJECTID -256ULL
#endif
#ifndef BTRFS_ROOT_TREE_OBJECTID
#define BTRFS_ROOT_TREE_OBJECTID 1
#endif
@@ -452,6 +456,10 @@ struct btrfs_ioctl_clone_range_args {
#define BTRFS_QGROUP_LIMIT_KEY 244
#endif
#ifndef BTRFS_ROOT_BACKREF_KEY
#define BTRFS_ROOT_BACKREF_KEY 144
#endif
#ifndef BTRFS_SUPER_MAGIC
#define BTRFS_SUPER_MAGIC 0x9123683E
#endif
src/shared/rm-rf.c
+22 -9
View File
@@ -21,6 +21,7 @@
#include "util.h"
#include "path-util.h"
#include "btrfs-util.h"
#include "rm-rf.h"
int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
@@ -116,22 +117,22 @@ int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
}
if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
struct btrfs_ioctl_vol_args args = {};
/* This could be a subvolume, try to remove it */
strncpy(args.name, de->d_name, sizeof(args.name)-1);
if (ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args) < 0) {
if (errno != ENOTTY && errno != EINVAL) {
r = btrfs_subvol_remove_fd(fd, de->d_name, true);
if (r < 0) {
if (r != -ENOTTY && r != -EINVAL) {
if (ret == 0)
ret = -errno;
ret = r;
safe_close(subdir_fd);
continue;
}
/* ENOTTY, then it wasn't a btrfs subvolume */
/* ENOTTY, then it wasn't a
* btrfs subvolume, continue
* below. */
} else {
/* It was a subvolume, continue. */
safe_close(subdir_fd);
@@ -175,6 +176,18 @@ int rm_rf(const char *path, RemoveFlags flags) {
return -EPERM;
}
if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
/* Try to remove as subvolume first */
r = btrfs_subvol_remove(path, true);
if (r >= 0)
return r;
if (r != -ENOTTY && r != -EINVAL)
return r;
/* Not btrfs or not a subvolume */
}
fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (fd < 0) {
@@ -201,8 +214,8 @@ int rm_rf(const char *path, RemoveFlags flags) {
r = rm_rf_children(fd, flags, NULL);
if (flags & REMOVE_ROOT) {
if (rmdir(path) < 0 && errno != ENOENT) {
if (r == 0)
if (rmdir(path) < 0) {
if (r == 0 && errno != ENOENT)
r = -errno;
}
}