diff mbox series

[18/29] xfs: don't store trailing zeroes of merkle tree blocks

Message ID 171175868859.1988170.3655437906964376707.stgit@frogsfrogsfrogs (mailing list archive)
State New
Headers show
Series [01/29] xfs: use unsigned ints for non-negative quantities in xfs_attr_remote.c | expand

Commit Message

Darrick J. Wong March 30, 2024, 12:40 a.m. UTC 
From: Darrick J. Wong <djwong@kernel.org>

As a minor space optimization, don't store trailing zeroes of merkle
tree blocks to reduce space consumption and copying overhead.  This
really only affects the rightmost blocks at each level of the tree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
---
 fs/xfs/xfs_fsverity.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/fs/xfs/xfs_fsverity.c b/fs/xfs/xfs_fsverity.c
index d675b0f71bde5..8d87d411a9ccb 100644
--- a/fs/xfs/xfs_fsverity.c
+++ b/fs/xfs/xfs_fsverity.c
@@ -667,11 +667,6 @@  xfs_fsverity_read_merkle(
 	if (error)
 		goto out_new_mk;
 
-	if (!args.valuelen) {
-		error = -ENODATA;
-		goto out_new_mk;
-	}
-
 	mk = xfs_fsverity_cache_store(ip, key, new_mk);
 	if (mk != new_mk) {
 		/*
@@ -722,6 +717,12 @@  xfs_fsverity_write_merkle(
 		.value			= (void *)buf,
 		.valuelen		= size,
 	};
+	const char			*p = buf + size - 1;
+
+	/* Don't store trailing zeroes. */
+	while (p >= (const char *)buf && *p == 0)
+		p--;
+	args.valuelen = p - (const char *)buf + 1;
 
 	xfs_fsverity_init_merkle_args(ip, &name, pos, &args);
 	return xfs_attr_setname(&args, false);