[PATCH v2 1/4] NFSD/blocklayout: Fix minlength check in proc_layoutget

[Sergey Bashirov <sergeybashirov@gmail.com>]

Minor fix as part of the functional changes. The extent returned by
the file system may have a smaller offset than the segment offset
requested by the client. In this case, the minimum segment length
must be checked against the requested range. Otherwise, the client
may not be able to continue the read/write operation.

Signed-off-by: Sergey Bashirov <sergeybashirov@gmail.com>
---
 fs/nfsd/blocklayout.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index fde5539cf6a6..425648565ab2 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -23,6 +23,7 @@ nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 {
 	struct nfsd4_layout_seg *seg = &args->lg_seg;
 	struct super_block *sb = inode->i_sb;
+	u64 length;
 	u32 block_size = i_blocksize(inode);
 	struct pnfs_block_extent *bex;
 	struct iomap iomap;
@@ -56,7 +57,8 @@ nfsd4_block_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 		goto out_error;
 	}
 
-	if (iomap.length < args->lg_minlength) {
+	length = iomap.offset + iomap.length - seg->offset;
+	if (length < args->lg_minlength) {
 		dprintk("pnfsd: extent smaller than minlength\n");
 		goto out_layoutunavailable;
 	}
-- 
2.43.0