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btrfs-progs: optionally restore symlinks. 

Restore symlinks, optionally with owner/times.

Signed-off-by: Dan Merillat <dan.merillat@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
This commit is contained in:
Dan Merillat 2015-04-29 18:06:27 +02:00 committed by David Sterba
parent 829950844e
commit bd91f80725
2 changed files with 141 additions and 3 deletions
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3
Documentation/btrfs-restore.asciidoc
View File

@ -32,6 +32,9 @@ get extended attributes.
-m|--metadata::
restore owner, mode and times.
-S|--symlinks::
restore symbolic links as well as normal files.
-v::
verbose.

141
cmds-restore.c
View File

@ -45,9 +45,11 @@
static char fs_name[PATH_MAX];
static char path_name[PATH_MAX];
static char symlink_target[PATH_MAX];
static int get_snaps = 0;
static int verbose = 0;
static int restore_metadata = 0;
static int restore_symlinks = 0;
static int ignore_errors = 0;
static int overwrite = 0;
static int get_xattrs = 0;
@ -811,6 +813,126 @@ static int overwrite_ok(const char * path)
return 1;
}
static int copy_symlink(struct btrfs_root *root, struct btrfs_key *key,
const char *file)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *extent_item;
struct btrfs_inode_item *inode_item;
u32 len;
u32 name_offset;
int ret;
struct btrfs_timespec *bts;
struct timespec times[2];
ret = overwrite_ok(path_name);
if (ret == 0)
return 0; /* skip this file */
/* symlink() can't overwrite, so unlink first */
if (ret == 2) {
ret = unlink(path_name);
if (ret) {
fprintf(stderr, "failed to unlink '%s' for overwrite\n",
path_name);
return ret;
}
}
key->type = BTRFS_EXTENT_DATA_KEY;
key->offset = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret < 0)
goto out;
leaf = path->nodes[0];
if (!leaf) {
fprintf(stderr, "Error getting leaf for symlink '%s'\n", file);
ret = -1;
goto out;
}
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
len = btrfs_file_extent_inline_item_len(leaf,
btrfs_item_nr(path->slots[0]));
if (len > PATH_MAX) {
fprintf(stderr, "Symlink '%s' target length %d is longer than PATH_MAX\n",
fs_name, len);
ret = -1;
goto out;
}
name_offset = (unsigned long) extent_item
+ offsetof(struct btrfs_file_extent_item, disk_bytenr);
read_extent_buffer(leaf, symlink_target, name_offset, len);
symlink_target[len] = 0;
if (!dry_run) {
ret = symlink(symlink_target, path_name);
if (ret < 0) {
fprintf(stderr, "Failed to restore symlink '%s': %s\n",
path_name, strerror(errno));
goto out;
}
}
printf("SYMLINK: '%s' => '%s'\n", path_name, symlink_target);
ret = 0;
if (!restore_metadata)
goto out;
/*
* Symlink metadata operates differently than files/directories, so do
* our own work here.
*/
key->type = BTRFS_INODE_ITEM_KEY;
key->offset = 0;
btrfs_release_path(path);
ret = btrfs_lookup_inode(NULL, root, path, key, 0);
if (ret) {
fprintf(stderr, "Failed to lookup inode for '%s'\n", file);
goto out;
}
inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_item);
ret = fchownat(-1, file, btrfs_inode_uid(path->nodes[0], inode_item),
btrfs_inode_gid(path->nodes[0], inode_item),
AT_SYMLINK_NOFOLLOW);
if (ret) {
fprintf(stderr, "Failed to change owner: %s\n",
strerror(errno));
goto out;
}
bts = btrfs_inode_atime(inode_item);
times[0].tv_sec = btrfs_timespec_sec(path->nodes[0], bts);
times[0].tv_nsec = btrfs_timespec_nsec(path->nodes[0], bts);
bts = btrfs_inode_mtime(inode_item);
times[1].tv_sec = btrfs_timespec_sec(path->nodes[0], bts);
times[1].tv_nsec = btrfs_timespec_nsec(path->nodes[0], bts);
ret = utimensat(-1, file, times, AT_SYMLINK_NOFOLLOW);
if (ret)
fprintf(stderr, "Failed to set times: %s\n", strerror(errno));
out:
btrfs_free_path(path);
return ret;
}
static int search_dir(struct btrfs_root *root, struct btrfs_key *key,
const char *output_rootdir, const char *in_dir,
const regex_t *mreg)
@ -925,8 +1047,7 @@ static int search_dir(struct btrfs_root *root, struct btrfs_key *key,
snprintf(path_name, PATH_MAX, "%s%s", output_rootdir, fs_name);
/*
* At this point we're only going to restore directories and
* files, no symlinks or anything else.
* Restore directories, files, symlinks and metadata.
*/
if (type == BTRFS_FT_REG_FILE) {
if (!overwrite_ok(path_name))
@ -1033,6 +1154,15 @@ static int search_dir(struct btrfs_root *root, struct btrfs_key *key,
goto next;
goto out;
}
} else if (type == BTRFS_FT_SYMLINK) {
if (restore_symlinks)
ret = copy_symlink(root, &location, path_name);
if (ret < 0) {
if (ignore_errors)
goto next;
btrfs_free_path(path);
return ret;
}
}
next:
path->slots[0]++;
@ -1259,6 +1389,7 @@ const char * const cmd_restore_usage[] = {
"-s get snapshots",
"-x get extended attributes",
"-m|--metadata restore owner, mode and times",
"-S|--symlinks restore symbolic links"
"-v verbose",
"-i ignore errors",
"-o overwrite",
@ -1301,10 +1432,11 @@ int cmd_restore(int argc, char **argv)
{ "path-regex", required_argument, NULL, 256},
{ "dry-run", no_argument, NULL, 'D'},
{ "metadata", no_argument, NULL, 'm'},
{ "symlinks", no_argument, NULL, 'S'},
{ NULL, 0, NULL, 0}
};
opt = getopt_long(argc, argv, "sxviot:u:dmf:r:lDc", long_options,
opt = getopt_long(argc, argv, "sSxviot:u:dmf:r:lDc", long_options,
NULL);
if (opt < 0)
break;
@ -1353,6 +1485,9 @@ int cmd_restore(int argc, char **argv)
case 'm':
restore_metadata = 1;
break;
case 'S':
restore_symlinks = 1;
break;
case 'D':
dry_run = 1;
break;