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Commit 4a55c101 authored by Jan Kara's avatar Jan Kara Committed by Al Viro
Browse files

nfsd: Push mnt_want_write() outside of i_mutex 



When mnt_want_write() starts to handle freezing it will get a full lock
semantics requiring proper lock ordering. So push mnt_want_write() call
consistently outside of i_mutex.

CC: linux-nfs@vger.kernel.org
CC: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e7848683

fs/nfsd/nfs4recover.c

+5 −4
Original line number Diff line number Diff line
@@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) 
	if (status < 0)

		return;



	status = mnt_want_write_file(rec_file);

	if (status)

		return;



	dir = rec_file->f_path.dentry;

	/* lock the parent */

	mutex_lock(&dir->d_inode->i_mutex);
@@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) 
		 * as well be forgiving and just succeed silently.

		 */

		goto out_put;

	status = mnt_want_write_file(rec_file);

	if (status)

		goto out_put;

	status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);

	mnt_drop_write_file(rec_file);

out_put:

	dput(dentry);

out_unlock:
@@ -189,6 +189,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) 
				" (err %d); please check that %s exists"

				" and is writeable", status,

				user_recovery_dirname);

	mnt_drop_write_file(rec_file);

	nfs4_reset_creds(original_cred);

}

fs/nfsd/nfsfh.c

+1 −0
Original line number Diff line number Diff line
@@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) 
		fhp->fh_post_saved = 0;

#endif

	}

	fh_drop_write(fhp);

	if (exp) {

		exp_put(exp);

		fhp->fh_export = NULL;

fs/nfsd/nfsproc.c

+8 −1
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, 
	struct dentry	*dchild;

	int		type, mode;

	__be32		nfserr;

	int		hosterr;

	dev_t		rdev = 0, wanted = new_decode_dev(attr->ia_size);



	dprintk("nfsd: CREATE   %s %.*s\n",
@@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, 
	nfserr = nfserr_exist;

	if (isdotent(argp->name, argp->len))

		goto done;

	hosterr = fh_want_write(dirfhp);

	if (hosterr) {

		nfserr = nfserrno(hosterr);

		goto done;

	}



	fh_lock_nested(dirfhp, I_MUTEX_PARENT);

	dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len);

	if (IS_ERR(dchild)) {
@@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, 
out_unlock:

	/* We don't really need to unlock, as fh_put does it. */

	fh_unlock(dirfhp);



	fh_drop_write(dirfhp);

done:

	fh_put(dirfhp);

	return nfsd_return_dirop(nfserr, resp);

fs/nfsd/vfs.c

+40 −39
Original line number Diff line number Diff line
@@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	 * If it has, the parent directory should already be locked.

	 */

	if (!resfhp->fh_dentry) {

		host_err = fh_want_write(fhp);

		if (host_err)

			goto out_nfserr;



		/* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */

		fh_lock_nested(fhp, I_MUTEX_PARENT);

		dchild = lookup_one_len(fname, dentry, flen);
@@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
		goto out;

	}



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;



	/*

	 * Get the dir op function pointer.

	 */

	err = 0;

	host_err = 0;

	switch (type) {

	case S_IFREG:

		host_err = vfs_create(dirp, dchild, iap->ia_mode, true);
@@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);

		break;

	}

	if (host_err < 0) {

		fh_drop_write(fhp);

	if (host_err < 0)

		goto out_nfserr;

	}



	err = nfsd_create_setattr(rqstp, resfhp, iap);
@@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	err2 = nfserrno(commit_metadata(fhp));

	if (err2)

		err = err2;

	fh_drop_write(fhp);

	/*

	 * Update the file handle to get the new inode info.

	 */
@@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	err = nfserr_notdir;

	if (!dirp->i_op->lookup)

		goto out;



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;



	fh_lock_nested(fhp, I_MUTEX_PARENT);



	/*
@@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
		v_atime = verifier[1]&0x7fffffff;

	}

	

	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;

	if (dchild->d_inode) {

		err = 0;
@@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	if (!err)

		err = nfserrno(commit_metadata(fhp));



	fh_drop_write(fhp);

	/*

	 * Update the filehandle to get the new inode info.

	 */
@@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	fh_unlock(fhp);

	if (dchild && !IS_ERR(dchild))

		dput(dchild);

	fh_drop_write(fhp);

 	return err;

 

 out_nfserr:
@@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);

	if (err)

		goto out;



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;



	fh_lock(fhp);

	dentry = fhp->fh_dentry;

	dnew = lookup_one_len(fname, dentry, flen);
@@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	if (IS_ERR(dnew))

		goto out_nfserr;



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;



	if (unlikely(path[plen] != 0)) {

		char *path_alloced = kmalloc(plen+1, GFP_KERNEL);

		if (path_alloced == NULL)
@@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 
	if (isdotent(name, len))

		goto out;



	host_err = fh_want_write(tfhp);

	if (host_err) {

		err = nfserrno(host_err);

		goto out;

	}



	fh_lock_nested(ffhp, I_MUTEX_PARENT);

	ddir = ffhp->fh_dentry;

	dirp = ddir->d_inode;
@@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 


	dold = tfhp->fh_dentry;



	host_err = fh_want_write(tfhp);

	if (host_err) {

		err = nfserrno(host_err);

		goto out_dput;

	}

	err = nfserr_noent;

	if (!dold->d_inode)

		goto out_drop_write;

		goto out_dput;

	host_err = nfsd_break_lease(dold->d_inode);

	if (host_err) {

		err = nfserrno(host_err);

		goto out_drop_write;

		goto out_dput;

	}

	host_err = vfs_link(dold, dirp, dnew);

	if (!host_err) {
@@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, 
		else

			err = nfserrno(host_err);

	}

out_drop_write:

	fh_drop_write(tfhp);

out_dput:

	dput(dnew);

out_unlock:

	fh_unlock(ffhp);

	fh_drop_write(tfhp);

out:

	return err;
@@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 
	if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))

		goto out;



	host_err = fh_want_write(ffhp);

	if (host_err) {

		err = nfserrno(host_err);

		goto out;

	}



	/* cannot use fh_lock as we need deadlock protective ordering

	 * so do it by hand */

	trap = lock_rename(tdentry, fdentry);
@@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 
	host_err = -EXDEV;

	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)

		goto out_dput_new;

	host_err = fh_want_write(ffhp);

	if (host_err)

		goto out_dput_new;



	host_err = nfsd_break_lease(odentry->d_inode);

	if (host_err)

		goto out_drop_write;

		goto out_dput_new;

	if (ndentry->d_inode) {

		host_err = nfsd_break_lease(ndentry->d_inode);

		if (host_err)

			goto out_drop_write;

			goto out_dput_new;

	}

	host_err = vfs_rename(fdir, odentry, tdir, ndentry);

	if (!host_err) {
@@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 
		if (!host_err)

			host_err = commit_metadata(ffhp);

	}

out_drop_write:

	fh_drop_write(ffhp);

 out_dput_new:

	dput(ndentry);

 out_dput_old:
@@ -1831,6 +1833,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, 
	fill_post_wcc(tfhp);

	unlock_rename(tdentry, fdentry);

	ffhp->fh_locked = tfhp->fh_locked = 0;

	fh_drop_write(ffhp);



out:

	return err;
@@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 
	if (err)

		goto out;



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_nfserr;



	fh_lock_nested(fhp, I_MUTEX_PARENT);

	dentry = fhp->fh_dentry;

	dirp = dentry->d_inode;
@@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, 
	if (!type)

		type = rdentry->d_inode->i_mode & S_IFMT;



	host_err = fh_want_write(fhp);

	if (host_err)

		goto out_put;



	host_err = nfsd_break_lease(rdentry->d_inode);

	if (host_err)

		goto out_drop_write;

		goto out_put;

	if (type != S_IFDIR)

		host_err = vfs_unlink(dirp, rdentry);

	else

		host_err = vfs_rmdir(dirp, rdentry);

	if (!host_err)

		host_err = commit_metadata(fhp);

out_drop_write:

	fh_drop_write(fhp);

out_put:

	dput(rdentry);

fs/nfsd/vfs.h

+9 −2
Original line number Diff line number Diff line
@@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); 


static inline int fh_want_write(struct svc_fh *fh)

{

	return mnt_want_write(fh->fh_export->ex_path.mnt);

	int ret = mnt_want_write(fh->fh_export->ex_path.mnt);



	if (!ret)

		fh->fh_want_write = 1;

	return ret;

}



static inline void fh_drop_write(struct svc_fh *fh)

{

	if (fh->fh_want_write) {

		fh->fh_want_write = 0;

		mnt_drop_write(fh->fh_export->ex_path.mnt);

	}

}



#endif /* LINUX_NFSD_VFS_H */