@@ -1112,9 +1112,12 @@ static int nfs23_parse_monolithic(struct fs_context *fc,
ctx->acdirmax = data->acdirmax;
ctx->need_mount = false;
- memcpy(sap, &data->addr, sizeof(data->addr));
- ctx->nfs_server.addrlen = sizeof(data->addr);
- ctx->nfs_server.port = ntohs(data->addr.sin_port);
+ if (!is_remount_fc(fc)) {
+ memcpy(sap, &data->addr, sizeof(data->addr));
+ ctx->nfs_server.addrlen = sizeof(data->addr);
+ ctx->nfs_server.port = ntohs(data->addr.sin_port);
+ }
+
if (sap->ss_family != AF_INET ||
!nfs_verify_server_address(sap))
goto out_no_address;
With newer kernels that use fs_context for nfs mounts, remounts fail with -EINVAL. $ mount -t nfs -o nolock 10.0.0.1:/tmp/test /mnt/test/ $ mount -t nfs -o remount /mnt/test/ mount: mounting 10.0.0.1:/tmp/test on /mnt/test failed: Invalid argument For remounts, the nfs server address and port are populated by nfs_init_fs_context and later overwritten with 0x00 bytes by nfs23_parse_monolithic. The remount then fails as the server address is invalid. Fix this by not overwriting nfs server info in nfs23_parse_monolithic if we're doing a remount. Fixes: f2aedb713c28 ("NFS: Add fs_context support.") Signed-off-by: Martin Kaiser <martin@kaiser.cx> --- v4: - rebased against linux-next from 20th May 2024 v3: - rebased against linux-next from 12th April 2024 v2: - rebased against linux-next from 26th February 2024 Dear all, I'm resending this patch again. The problem that I'm trying to fix is still present in today's linux-next. It affects (amongst others) systems where the rootfs is mounted via nfs2/3. If the rootfs is mounted read-only first and remounted read-write later, the remount will fail and the system won't boot. Thanks in advance for any reviews and comments. I guess that we're taking this path for remounts do_remount fs_context_for_reconfigure alloc_fs_context init_fs_context == nfs_init_fs_context fc->root is set for remounts ctx->nfs_server is populated parse_monolithic_mount_data nfs_fs_context_parse_monolithic nfs23_parse_monolithic ctx->nfs_server is overwritten with data from mount request An alternative to checking for !is_remount_fc(fc) would be to check if (ctx->nfs_server.addrlen == 0) fs/nfs/fs_context.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)