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Commit d530838b authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Fix problem with OPEN_DOWNGRADE 



 RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
 bits specified must be exactly equal to the union of the share_access and
 share_deny bits specified for some subset of the OPENs in effect for
 current openowner on the current file.

 Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
 it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
 OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
 with O_WRONLY access mode.

 Fix the problem by replacing nfs4_find_state() with a modified version of
 nfs_find_open_context().

 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 4cecb76f

fs/nfs/inode.c

+6 −1
Original line number Diff line number Diff line
@@ -1009,13 +1009,18 @@ void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx) 
	spin_unlock(&inode->i_lock);

}



struct nfs_open_context *nfs_find_open_context(struct inode *inode, int mode)

/*

 * Given an inode, search for an open context with the desired characteristics

 */

struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, int mode)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs_open_context *pos, *ctx = NULL;



	spin_lock(&inode->i_lock);

	list_for_each_entry(pos, &nfsi->open_files, list) {

		if (cred != NULL && pos->cred != cred)

			continue;

		if ((pos->mode & mode) == mode) {

			ctx = get_nfs_open_context(pos);

			break;

fs/nfs/nfs4_fs.h

+0 −1
Original line number Diff line number Diff line
@@ -247,7 +247,6 @@ extern void nfs4_drop_state_owner(struct nfs4_state_owner *); 
extern struct nfs4_state * nfs4_get_open_state(struct inode *, struct nfs4_state_owner *);

extern void nfs4_put_open_state(struct nfs4_state *);

extern void nfs4_close_state(struct nfs4_state *, mode_t);

extern struct nfs4_state *nfs4_find_state(struct inode *, struct rpc_cred *, mode_t mode);

extern void nfs4_state_set_mode_locked(struct nfs4_state *, mode_t);

extern void nfs4_schedule_state_recovery(struct nfs4_client *);

extern void nfs4_put_lock_state(struct nfs4_lock_state *lsp);

fs/nfs/nfs4proc.c

+10 −13
Original line number Diff line number Diff line
@@ -214,7 +214,7 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, 
	struct inode *inode = state->inode;



	open_flags &= (FMODE_READ|FMODE_WRITE);

	/* Protect against nfs4_find_state() */

	/* Protect against nfs4_find_state_byowner() */

	spin_lock(&state->owner->so_lock);

	spin_lock(&inode->i_lock);

	memcpy(&state->stateid, stateid, sizeof(state->stateid));
@@ -1274,7 +1274,8 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr, 
{

	struct rpc_cred *cred;

	struct inode *inode = dentry->d_inode;

	struct nfs4_state *state;

	struct nfs_open_context *ctx;

	struct nfs4_state *state = NULL;

	int status;



	nfs_fattr_init(fattr);
@@ -1282,22 +1283,18 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr, 
	cred = rpcauth_lookupcred(NFS_SERVER(inode)->client->cl_auth, 0);

	if (IS_ERR(cred))

		return PTR_ERR(cred);

	/* Search for an existing WRITE delegation first */

	state = nfs4_open_delegated(inode, FMODE_WRITE, cred);

	if (!IS_ERR(state)) {

		/* NB: nfs4_open_delegated() bumps the inode->i_count */

		iput(inode);

	} else {

		/* Search for an existing open(O_WRITE) stateid */

		state = nfs4_find_state(inode, cred, FMODE_WRITE);

	}



	/* Search for an existing open(O_WRITE) file */

	ctx = nfs_find_open_context(inode, cred, FMODE_WRITE);

	if (ctx != NULL)

		state = ctx->state;



	status = nfs4_do_setattr(NFS_SERVER(inode), fattr,

			NFS_FH(inode), sattr, state);

	if (status == 0)

		nfs_setattr_update_inode(inode, sattr);

	if (state != NULL)

		nfs4_close_state(state, FMODE_WRITE);

	if (ctx != NULL)

		put_nfs_open_context(ctx);

	put_rpccred(cred);

	return status;

}

fs/nfs/nfs4state.c

+0 −33
Original line number Diff line number Diff line
@@ -383,28 +383,6 @@ nfs4_state_set_mode_locked(struct nfs4_state *state, mode_t mode) 
	state->state = mode;

}



static struct nfs4_state *

__nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs4_state *state;



	mode &= (FMODE_READ|FMODE_WRITE);

	list_for_each_entry(state, &nfsi->open_states, inode_states) {

		if (state->owner->so_cred != cred)

			continue;

		if ((state->state & mode) != mode)

			continue;

		atomic_inc(&state->count);

		if (mode & FMODE_READ)

			state->nreaders++;

		if (mode & FMODE_WRITE)

			state->nwriters++;

		return state;

	}

	return NULL;

}



static struct nfs4_state *

__nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner)

{
@@ -423,17 +401,6 @@ __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner) 
	return NULL;

}



struct nfs4_state *

nfs4_find_state(struct inode *inode, struct rpc_cred *cred, mode_t mode)

{

	struct nfs4_state *state;



	spin_lock(&inode->i_lock);

	state = __nfs4_find_state(inode, cred, mode);

	spin_unlock(&inode->i_lock);

	return state;

}



static void

nfs4_free_open_state(struct nfs4_state *state)

{

fs/nfs/read.c

+2 −2
Original line number Diff line number Diff line
@@ -507,7 +507,7 @@ int nfs_readpage(struct file *file, struct page *page) 
		goto out_error;



	if (file == NULL) {

		ctx = nfs_find_open_context(inode, FMODE_READ);

		ctx = nfs_find_open_context(inode, NULL, FMODE_READ);

		if (ctx == NULL)

			return -EBADF;

	} else
@@ -576,7 +576,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, 
			nr_pages);



	if (filp == NULL) {

		desc.ctx = nfs_find_open_context(inode, FMODE_READ);

		desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);

		if (desc.ctx == NULL)

			return -EBADF;

	} else