This is necessary because unless userspace explicitly requests fstype
"nfs4" (either via "mount -t nfs4" or by calling the "mount.nfs4" helper
directly), the fstype will default to "nfs".
This was fine on older kernels because the super_block->s_type was set
via mount_info->nfs_mod->nfs_fs, which was set when parsing the mount
options and subsequently passed in the "type" argument of sget().
After commit f2aedb713c28 ("NFS: Add fs_context support."), sget_fc(),
which has no "type" argument, is called instead. In sget_fc(), the
super_block->s_type is set via fs_context->fs_type, which was set when
the filesystem context was initially created.
Reported-by: Patrick Steinhardt <[email protected]>
Fixes: f2aedb713c28 ("NFS: Add fs_context support.")
Signed-off-by: Scott Mayhew <[email protected]>
---
fs/nfs/fs_context.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index e1b938457ab9..b616263b0eb6 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -1240,6 +1240,13 @@ static int nfs_fs_context_validate(struct fs_context *fc)
}
ctx->nfs_mod = nfs_mod;
}
+
+ /* Ensure the filesystem context has the correct fs_type */
+ if (fc->fs_type != ctx->nfs_mod->nfs_fs) {
+ module_put(fc->fs_type->owner);
+ __module_get(ctx->nfs_mod->nfs_fs->owner);
+ fc->fs_type = ctx->nfs_mod->nfs_fs;
+ }
return 0;
out_no_device_name:
--
2.24.1