diff mbox series

[12/26] xfs_copy: use uncached buffer reads to get the superblock

Message ID 158293305300.1549542.7853811535219027135.stgit@magnolia (mailing list archive)
State Accepted
Headers show
Series xfsprogs: refactor buffer function names | expand

Commit Message

Darrick J. Wong Feb. 28, 2020, 11:37 p.m. UTC 
From: Darrick J. Wong <darrick.wong@oracle.com>

Upon startup, xfs_copy needs to read the filesystem superblock to mount
the filesystem.  We cannot know the filesystem sector size until we read
the superblock, but we also do not want to introduce aliasing in the
buffer cache.  Convert this code to the new uncached buffer read API so
that we can stop open-coding it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 copy/xfs_copy.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/copy/xfs_copy.c b/copy/xfs_copy.c
index 9e9719a0..5cab1a5f 100644
--- a/copy/xfs_copy.c
+++ b/copy/xfs_copy.c
@@ -562,6 +562,7 @@  main(int argc, char **argv)
 	libxfs_init_t	xargs;
 	thread_args	*tcarg;
 	struct stat	statbuf;
+	int		error;
 
 	progname = basename(argv[0]);
 
@@ -710,14 +711,20 @@  main(int argc, char **argv)
 
 	/* We don't yet know the sector size, so read maximal size */
 	libxfs_buftarg_init(&mbuf, xargs.ddev, xargs.logdev, xargs.rtdev);
-	sbp = libxfs_buf_read(mbuf.m_ddev_targp, XFS_SB_DADDR,
-			     1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, NULL);
+	error = -libxfs_buf_read_uncached(mbuf.m_ddev_targp, XFS_SB_DADDR,
+			1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, &sbp, NULL);
+	if (error) {
+		do_log(_("%s: couldn't read superblock, error=%d\n"),
+				progname, error);
+		exit(1);
+	}
+
 	sb = &mbuf.m_sb;
 	libxfs_sb_from_disk(sb, XFS_BUF_TO_SBP(sbp));
 
 	/* Do it again, now with proper length and verifier */
 	libxfs_buf_relse(sbp);
-	libxfs_purgebuf(sbp);
+
 	sbp = libxfs_buf_read(mbuf.m_ddev_targp, XFS_SB_DADDR,
 			     1 << (sb->sb_sectlog - BBSHIFT),
 			     0, &xfs_sb_buf_ops);