xfs_mdrestore: Don't rewind source file stream
Today, xfs_mdrestore from stdin will fail if the -i flag is
specified, because it attempts to rewind the stream after
the initial read of the metablock. This fails, and
results in an abort with "specified file is not a metadata
dump."
Read the metablock exactly once in main(), validate the magic,
print informational flags if requested, and then pass it to
perform_restore() which will then continue the restore process.
Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index 0bb4ac8..c9d4b0c 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -51,57 +51,55 @@
progress_since_warning = 1;
}
+/*
+ * perform_restore() -- do the actual work to restore the metadump
+ *
+ * @src_f: A FILE pointer to the source metadump
+ * @dst_fd: the file descriptor for the target file
+ * @is_target_file: designates whether the target is a regular file
+ * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
+ *
+ * src_f should be positioned just past a read the previously validated metablock
+ */
static void
perform_restore(
FILE *src_f,
int dst_fd,
- int is_target_file)
+ int is_target_file,
+ const struct xfs_metablock *mbp)
{
- xfs_metablock_t *metablock; /* header + index + blocks */
+ struct xfs_metablock *metablock; /* header + index + blocks */
__be64 *block_index;
char *block_buffer;
int block_size;
int max_indices;
int cur_index;
int mb_count;
- xfs_metablock_t tmb;
xfs_sb_t sb;
int64_t bytes_read;
- /*
- * read in first blocks (superblock 0), set "inprogress" flag for it,
- * read in the rest of the file, and if complete, clear SB 0's
- * "inprogress flag"
- */
-
- if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
- fatal("error reading from file: %s\n", strerror(errno));
-
- if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
- fatal("specified file is not a metadata dump\n");
-
- block_size = 1 << tmb.mb_blocklog;
+ block_size = 1 << mbp->mb_blocklog;
max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
metablock = (xfs_metablock_t *)calloc(max_indices + 1, block_size);
if (metablock == NULL)
fatal("memory allocation failure\n");
- mb_count = be16_to_cpu(tmb.mb_count);
+ mb_count = be16_to_cpu(mbp->mb_count);
if (mb_count == 0 || mb_count > max_indices)
fatal("bad block count: %u\n", mb_count);
block_index = (__be64 *)((char *)metablock + sizeof(xfs_metablock_t));
block_buffer = (char *)metablock + block_size;
- if (fread(block_index, block_size - sizeof(tmb), 1, src_f) != 1)
+ if (fread(block_index, block_size - sizeof(struct xfs_metablock), 1, src_f) != 1)
fatal("error reading from file: %s\n", strerror(errno));
if (block_index[0] != 0)
fatal("first block is not the primary superblock\n");
- if (fread(block_buffer, mb_count << tmb.mb_blocklog,
+ if (fread(block_buffer, mb_count << mbp->mb_blocklog,
1, src_f) != 1)
fatal("error reading from file: %s\n", strerror(errno));
@@ -148,7 +146,7 @@
for (cur_index = 0; cur_index < mb_count; cur_index++) {
if (pwrite(dst_fd, &block_buffer[cur_index <<
- tmb.mb_blocklog], block_size,
+ mbp->mb_blocklog], block_size,
be64_to_cpu(block_index[cur_index]) <<
BBSHIFT) < 0)
fatal("error writing block %llu: %s\n",
@@ -167,11 +165,11 @@
if (mb_count > max_indices)
fatal("bad block count: %u\n", mb_count);
- if (fread(block_buffer, mb_count << tmb.mb_blocklog,
+ if (fread(block_buffer, mb_count << mbp->mb_blocklog,
1, src_f) != 1)
fatal("error reading from file: %s\n", strerror(errno));
- bytes_read += block_size + (mb_count << tmb.mb_blocklog);
+ bytes_read += block_size + (mb_count << mbp->mb_blocklog);
}
if (progress_since_warning)
@@ -211,6 +209,7 @@
int open_flags;
struct stat statbuf;
int is_target_file;
+ struct xfs_metablock mb;
progname = basename(argv[0]);
@@ -237,7 +236,12 @@
if (!show_info && argc - optind != 2)
usage();
- /* open source */
+ /*
+ * open source and test if this really is a dump. The first metadump block
+ * will be passed to perform_restore() which will continue to read the
+ * file from this point. This avoids rewind the stream, which causes
+ * restore to fail when source was being read from stdin.
+ */
if (strcmp(argv[optind], "-") == 0) {
src_f = stdin;
if (isatty(fileno(stdin)))
@@ -248,15 +252,12 @@
fatal("cannot open source dump file\n");
}
+ if (fread(&mb, sizeof(mb), 1, src_f) != 1)
+ fatal("error reading from file: %s\n", strerror(errno));
+ if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
+ fatal("specified file is not a metadata dump\n");
+
if (show_info) {
- xfs_metablock_t mb;
-
- if (fread(&mb, sizeof(mb), 1, src_f) != 1)
- fatal("error reading from file: %s\n", strerror(errno));
-
- if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
- fatal("specified file is not a metadata dump\n");
-
if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
argv[optind],
@@ -270,9 +271,6 @@
if (argc - optind == 1)
exit(0);
-
- /* Go back to the beginning for the restore function */
- fseek(src_f, 0L, SEEK_SET);
}
optind++;
@@ -301,7 +299,7 @@
if (dst_fd < 0)
fatal("couldn't open target \"%s\"\n", argv[optind]);
- perform_restore(src_f, dst_fd, is_target_file);
+ perform_restore(src_f, dst_fd, is_target_file, &mb);
close(dst_fd);
if (src_f != stdin)
