btrfs-progs: rework get_fs_info to remove side effects

[platform/upstream/btrfs-progs.git] / utils.c

diff --git a/utils.c b/utils.c
index 9c48de4..cfb6116 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -719,7 +719,7 @@ int open_path_or_dev_mnt(const char *path)
                        errno = EINVAL;
                        return -1;
                }
-               fdmnt = open(mp, O_RDWR);
+               fdmnt = open_file_or_dir(mp);
        } else {
                fdmnt = open_file_or_dir(path);
        }
@@ -1547,9 +1547,20 @@ int get_device_info(int fd, u64 devid,
        return ret ? -errno : 0;
 }
 
-int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
+/*
+ * For a given path, fill in the ioctl fs_ and info_ args.
+ * If the path is a btrfs mountpoint, fill info for all devices.
+ * If the path is a btrfs device, fill in only that device.
+ *
+ * The path provided must be either on a mounted btrfs fs,
+ * or be a mounted btrfs device.
+ *
+ * Returns 0 on success, or a negative errno.
+ */
+int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                struct btrfs_ioctl_dev_info_args **di_ret)
 {
+       int fd = -1;
        int ret = 0;
        int ndevs = 0;
        int i = 1;
@@ -1559,33 +1570,56 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
 
        memset(fi_args, 0, sizeof(*fi_args));
 
-       ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
-       if (ret && (errno == EINVAL || errno == ENOTTY)) {
-               /* path is not a mounted btrfs. Try if it's a device */
+       if (is_block_device(path)) {
+               /* Ensure it's mounted, then set path to the mountpoint */
+               fd = open(path, O_RDONLY);
+               if (fd < 0) {
+                       ret = -errno;
+                       fprintf(stderr, "Couldn't open %s: %s\n",
+                               path, strerror(errno));
+                       goto out;
+               }
                ret = check_mounted_where(fd, path, mp, sizeof(mp),
                                          &fs_devices_mnt);
-               if (!ret)
-                       return -EINVAL;
+               if (!ret) {
+                       ret = -EINVAL;
+                       goto out;
+               }
                if (ret < 0)
-                       return ret;
+                       goto out;
+               path = mp;
+               /* Only fill in this one device */
                fi_args->num_devices = 1;
                fi_args->max_id = fs_devices_mnt->latest_devid;
                i = fs_devices_mnt->latest_devid;
                memcpy(fi_args->fsid, fs_devices_mnt->fsid, BTRFS_FSID_SIZE);
                close(fd);
-               fd = open_file_or_dir(mp);
-               if (fd < 0)
-                       return -errno;
-       } else if (ret) {
-               return -errno;
+       }
+
+       /* at this point path must not be for a block device */
+       fd = open_file_or_dir(path);
+       if (fd < 0) {
+               ret = -errno;
+               goto out;
+       }
+
+       /* fill in fi_args if not just a single device */
+       if (fi_args->num_devices != 1) {
+               ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
+               if (ret < 0) {
+                       ret = -errno;
+                       goto out;
+               }
        }
 
        if (!fi_args->num_devices)
-               return 0;
+               goto out;
 
        di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
-       if (!di_args)
-               return -errno;
+       if (!di_args) {
+               ret = -errno;
+               goto out;
+       }
 
        for (; i <= fi_args->max_id; ++i) {
                BUG_ON(ndevs >= fi_args->num_devices);
@@ -1593,13 +1627,16 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                if (ret == -ENODEV)
                        continue;
                if (ret)
-                       return ret;
+                       goto out;
                ndevs++;
        }
 
        BUG_ON(ndevs == 0);
-
-       return 0;
+       ret = 0;
+out:
+       if (fd != -1)
+               close(fd);
+       return ret;
 }
 
 #define isoctal(c)     (((c) & ~7) == '0')