Commit 0f900f11 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Initialise verifiers for visible dentries in _nfs4_open_and_get_state 



Ensure that the verifiers are initialised before calling
d_splice_alias() in _nfs4_open_and_get_state().

Reported-by: default avatarMichael Stoler <michael.stoler@vastdata.com>
Fixes: cf5b4059 ("NFSv4: Fix races between open and dentry revalidation")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 518c32a1

fs/nfs/nfs4proc.c

+14 −13
Original line number Diff line number Diff line
@@ -3174,18 +3174,6 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata, 
	if (opendata->o_res.rflags & NFS4_OPEN_RESULT_PRESERVE_UNLINKED)

		set_bit(NFS_INO_PRESERVE_UNLINKED, &NFS_I(state->inode)->flags);



	dentry = opendata->dentry;

	if (d_really_is_negative(dentry)) {

		struct dentry *alias;

		d_drop(dentry);

		alias = d_splice_alias(igrab(state->inode), dentry);

		/* d_splice_alias() can't fail here - it's a non-directory */

		if (alias) {

			dput(ctx->dentry);

			ctx->dentry = dentry = alias;

		}

	}



	switch(opendata->o_arg.claim) {

	default:

		break;
@@ -3196,7 +3184,20 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata, 
			break;

		if (opendata->o_res.delegation.type != 0)

			dir_verifier = nfs_save_change_attribute(dir);

	}



	dentry = opendata->dentry;

	nfs_set_verifier(dentry, dir_verifier);

	if (d_really_is_negative(dentry)) {

		struct dentry *alias;

		d_drop(dentry);

		alias = d_splice_alias(igrab(state->inode), dentry);

		/* d_splice_alias() can't fail here - it's a non-directory */

		if (alias) {

			dput(ctx->dentry);

			nfs_set_verifier(alias, dir_verifier);

			ctx->dentry = dentry = alias;

		}

	}



	/* Parse layoutget results before we check for access */