[PATCH 31/36] db: enable metadump on CRC filesystems

Dave Chinner
2013-11-13T06:41:29Z

Now that we can calculate CRCs through xfs_db, we can add support
for recalculating CRCs on obfuscated metadump images. This simply
requires us to call the write verifier manually before writing the
buffer to the metadump image.

We don't need to do anything special to mdrestore, as the metadata
blocks it reads from the image file will already have all the
correct CRCs in them. Hence it can be mostly oblivious to the fact
that the filesystem it is restoring contains CRCs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
db/metadump.c | 24 +++++++++++++++++++-----
mdrestore/xfs_mdrestore.c | 3 ---
2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/db/metadump.c b/db/metadump.c
index ac6a4d6..117dc42 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -172,6 +172,22 @@ write_buf(
__int64_t off;
int i;

+ /*
+ * Run the write verifier to recalculate the buffer CRCs and check
+ * we are writing something valid to disk
+ */
+ if (buf->bp && buf->bp->b_ops) {
+ buf->bp->b_error = 0;
+ buf->bp->b_ops->verify_write(buf->bp);
+ if (buf->bp->b_error) {
+ fprintf(stderr,
+ _("%s: write verifer failed on bno 0x%llx/0x%x\n"),
+ __func__, (long long)buf->bp->b_bn,
+ buf->bp->b_bcount);
+ return buf->bp->b_error;
+ }
+ }
+
for (i = 0, off = buf->bb, data = buf->data;
i < buf->blen;
i++, off++, data += BBSIZE) {
@@ -1727,6 +1743,9 @@ copy_inode_chunk(

if (!process_inode(agno, agino + i, dip))
goto pop_out;
+
+ /* calculate the new CRC for the inode */
+ xfs_dinode_calc_crc(mp, dip);
}
skip_processing:
if (!write_buf(iocur_top))
@@ -2053,11 +2072,6 @@ metadump_f(
return 0;
}

- if (xfs_sb_version_hascrc(&mp->m_sb) && dont_obfuscate == 0) {
- print_warning("Can't obfuscate CRC enabled filesystems yet.");
- return 0;
- }
-
metablock = (xfs_metablock_t *)calloc(BBSIZE + 1, BBSIZE);
if (metablock == NULL) {
print_warning("memory allocation failure");
diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index fe61766..e57bdb2 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -109,9 +109,6 @@ perform_restore(
if (sb.sb_magicnum != XFS_SB_MAGIC)
fatal("bad magic number for primary superblock\n");

- if (xfs_sb_version_hascrc(&sb))
- fatal("Can't restore CRC enabled filesystems yet.\n");
-
((xfs_dsb_t*)block_buffer)->sb_inprogress = 1;

if (is_target_file) {