ret = stat(filename, &st);
if (ret < 0) {
- error("cannot stat '%s': %s", filename, strerror(errno));
+ error("cannot stat '%s': %m", filename);
return NULL;
}
if (!(((st.st_mode & S_IFMT) == S_IFREG) || ((st.st_mode & S_IFMT) == S_IFBLK))) {
fp = open(filename, oflags);
if (fp < 0) {
- error("cannot open '%s': %s", filename, strerror(errno));
+ error("cannot open '%s': %m", filename);
return NULL;
}
info = __open_ctree_fd(fp, filename, sb_bytenr, root_tree_bytenr,
return -EIO;
}
+/*
+ * btrfs_read_dev_super - read a valid superblock from a block device
+ * @fd: file descriptor of the device
+ * @sb: buffer where the superblock is going to be read in
+ * @sb_bytenr: offset of the particular superblock copy we want
+ * @sbflags: flags controlling how the superblock is read
+ *
+ * This function is used by various btrfs comands to obtain a valid superblock.
+ *
+ * It's mode of operation is controlled by the @sb_bytenr and @sbdflags
+ * parameters. If SBREAD_RECOVER flag is set and @sb_bytenr is
+ * BTRFS_SUPER_INFO_OFFSET then the function reads all 3 superblock copies and
+ * returns the newest one. If SBREAD_RECOVER is not set then only a single
+ * copy is read, which one is decided by @sb_bytenr. If @sb_bytenr !=
+ * BTRFS_SUPER_INFO_OFFSET then the @sbflags is effectively ignored and only a
+ * single copy is read.
+ */
int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr,
unsigned sbflags)
{
if (ret > 0)
fprintf(stderr, "WARNING: failed to write all sb data\n");
else
- fprintf(stderr, "WARNING: failed to write sb: %s\n",
- strerror(errno));
+ fprintf(stderr, "WARNING: failed to write sb: %m\n");
return ret;
}