NFSD/blocklayout: Fix minlength check in proc_layoutget

[ Upstream commit 3524b021b0ec620a76c89aee78e9d4b4130fb711 ]

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.

Fixes: 8650b8a05850 ("nfsd: pNFS block layout driver")
Signed-off-by: Sergey Bashirov <sergeybashirov@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 0822d8a119c6fa16d3d32d69a24444896d923300..eefe50a17c4a092b4451bab1f62be57c6e5d8b73 100644 (file)
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -23,6 +23,7 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
 {
        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;
@@ -53,7 +54,8 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
                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;
        }