pull mnt_want_write()/mnt_drop_write() into kern_path_create()/done_path_create() resp.

One side effect - attempt to create a cross-device link on a read-only fs fails with EROFS instead of EXDEV now. Makes more sense, POSIX allows, etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

pull mnt_want_write()/mnt_drop_write() into kern_path_create()/done_path_create() resp.
One side effect - attempt to create a cross-device link on a read-only fs fails with EROFS instead of EXDEV now. Makes more sense, POSIX allows, etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
1 parent 8e4bfca1d1
Showing 3 changed files with 18 additions and 50 deletions Side-by-side Diff
fs/namei.c
fs/ocfs2/refcounttree.c
net/unix/af_unix.c
@@ -2865,10 +2865,11 @@
 	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 	dentry = lookup_hash(&nd);
 	if (IS_ERR(dentry))
-		goto fail;
+		goto unlock;
  
+	error = -EEXIST;
 	if (dentry->d_inode)
-		goto eexist;
+		goto fail;
 	/*
 	 * Special case - lookup gave negative, but... we had foo/bar/
 	 * From the vfs_mknod() POV we just have a negative dentry -
  
  
  
@@ -2876,16 +2877,18 @@
 	 * been asking for (non-existent) directory. -ENOENT for you.
 	 */
 	if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
-		dput(dentry);
-		dentry = ERR_PTR(-ENOENT);
+		error = -ENOENT;
 		goto fail;
 	}
+	error = mnt_want_write(nd.path.mnt);
+	if (error)
+		goto fail;
 	*path = nd.path;
 	return dentry;
-eexist:
-	dput(dentry);
-	dentry = ERR_PTR(-EEXIST);
 fail:
+	dput(dentry);
+	dentry = ERR_PTR(error);
+unlock:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 out:
 	path_put(&nd.path);
@@ -2897,6 +2900,7 @@
 {
 	dput(dentry);
 	mutex_unlock(&path->dentry->d_inode->i_mutex);
+	mnt_drop_write(path->mnt);
 	path_put(path);
 }
 EXPORT_SYMBOL(done_path_create);
  
@@ -2974,12 +2978,9 @@
  
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
-	error = mnt_want_write(path.mnt);
-	if (error)
-		goto out_dput;
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
-		goto out_drop_write;
+		goto out;
 	switch (mode & S_IFMT) {
 		case 0: case S_IFREG:
 			error = vfs_create(path.dentry->d_inode,dentry,mode,true);
  
@@ -2992,11 +2993,8 @@
 			error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
 			break;
 	}
-out_drop_write:
-	mnt_drop_write(path.mnt);
-out_dput:
+out:
 	done_path_create(&path, dentry);
-
 	return error;
 }
  
  
@@ -3042,16 +3040,9 @@
  
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
-	error = mnt_want_write(path.mnt);
-	if (error)
-		goto out_dput;
 	error = security_path_mkdir(&path, dentry, mode);
-	if (error)
-		goto out_drop_write;
-	error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
-out_drop_write:
-	mnt_drop_write(path.mnt);
-out_dput:
+	if (!error)
+		error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
 	done_path_create(&path, dentry);
 	return error;
 }
  
@@ -3326,16 +3317,9 @@
 	if (IS_ERR(dentry))
 		goto out_putname;
  
-	error = mnt_want_write(path.mnt);
-	if (error)
-		goto out_dput;
 	error = security_path_symlink(&path, dentry, from);
-	if (error)
-		goto out_drop_write;
-	error = vfs_symlink(path.dentry->d_inode, dentry, from);
-out_drop_write:
-	mnt_drop_write(path.mnt);
-out_dput:
+	if (!error)
+		error = vfs_symlink(path.dentry->d_inode, dentry, from);
 	done_path_create(&path, dentry);
 out_putname:
 	putname(from);
  
  
@@ -3436,15 +3420,10 @@
 	error = -EXDEV;
 	if (old_path.mnt != new_path.mnt)
 		goto out_dput;
-	error = mnt_want_write(new_path.mnt);
-	if (error)
-		goto out_dput;
 	error = security_path_link(old_path.dentry, &new_path, new_dentry);
 	if (error)
-		goto out_drop_write;
+		goto out_dput;
 	error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
-out_drop_write:
-	mnt_drop_write(new_path.mnt);
 out_dput:
 	done_path_create(&new_path, new_dentry);
 out:
@@ -4466,16 +4466,9 @@
 		goto out_dput;
 	}
  
-	error = mnt_want_write(new_path.mnt);
-	if (error) {
-		mlog_errno(error);
-		goto out_dput;
-	}
-
 	error = ocfs2_vfs_reflink(old_path.dentry,
 				  new_path.dentry->d_inode,
 				  new_dentry, preserve);
-	mnt_drop_write(new_path.mnt);
 out_dput:
 	done_path_create(&new_path, new_dentry);
 out:
@@ -876,15 +876,11 @@
 		 */
 		mode = S_IFSOCK |
 		       (SOCK_INODE(sock)->i_mode & ~current_umask());
-		err = mnt_want_write(path.mnt);
-		if (err)
-			goto out_mknod_dput;
 		err = security_path_mknod(&path, dentry, mode, 0);
 		if (err)
 			goto out_mknod_drop_write;
 		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
 out_mknod_drop_write:
-		mnt_drop_write(path.mnt);
 		if (err)
 			goto out_mknod_dput;
 		mntget(path.mnt);
...	...	@@ -2865,10 +2865,11 @@
2865	2865	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
2866	2866	dentry = lookup_hash(&nd);
2867	2867	if (IS_ERR(dentry))
2868		- goto fail;
	2868	+ goto unlock;
2869	2869
	2870	+ error = -EEXIST;
2870	2871	if (dentry->d_inode)
2871		- goto eexist;
	2872	+ goto fail;
2872	2873	/*
2873	2874	* Special case - lookup gave negative, but... we had foo/bar/
2874	2875	* From the vfs_mknod() POV we just have a negative dentry -
2875	2876
2876	2877
2877	2878
...	...	@@ -2876,16 +2877,18 @@
2876	2877	* been asking for (non-existent) directory. -ENOENT for you.
2877	2878	*/
2878	2879	if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
2879		- dput(dentry);
2880		- dentry = ERR_PTR(-ENOENT);
	2880	+ error = -ENOENT;
2881	2881	goto fail;
2882	2882	}
	2883	+ error = mnt_want_write(nd.path.mnt);
	2884	+ if (error)
	2885	+ goto fail;
2883	2886	*path = nd.path;
2884	2887	return dentry;
2885		-eexist:
2886		- dput(dentry);
2887		- dentry = ERR_PTR(-EEXIST);
2888	2888	fail:
	2889	+ dput(dentry);
	2890	+ dentry = ERR_PTR(error);
	2891	+unlock:
2889	2892	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2890	2893	out:
2891	2894	path_put(&nd.path);
...	...	@@ -2897,6 +2900,7 @@
2897	2900	{
2898	2901	dput(dentry);
2899	2902	mutex_unlock(&path->dentry->d_inode->i_mutex);
	2903	+ mnt_drop_write(path->mnt);
2900	2904	path_put(path);
2901	2905	}
2902	2906	EXPORT_SYMBOL(done_path_create);
2903	2907
...	...	@@ -2974,12 +2978,9 @@
2974	2978
2975	2979	if (!IS_POSIXACL(path.dentry->d_inode))
2976	2980	mode &= ~current_umask();
2977		- error = mnt_want_write(path.mnt);
2978		- if (error)
2979		- goto out_dput;
2980	2981	error = security_path_mknod(&path, dentry, mode, dev);
2981	2982	if (error)
2982		- goto out_drop_write;
	2983	+ goto out;
2983	2984	switch (mode & S_IFMT) {
2984	2985	case 0: case S_IFREG:
2985	2986	error = vfs_create(path.dentry->d_inode,dentry,mode,true);
2986	2987
...	...	@@ -2992,11 +2993,8 @@
2992	2993	error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
2993	2994	break;
2994	2995	}
2995		-out_drop_write:
2996		- mnt_drop_write(path.mnt);
2997		-out_dput:
	2996	+out:
2998	2997	done_path_create(&path, dentry);
2999		-
3000	2998	return error;
3001	2999	}
3002	3000
3003	3001
...	...	@@ -3042,16 +3040,9 @@
3042	3040
3043	3041	if (!IS_POSIXACL(path.dentry->d_inode))
3044	3042	mode &= ~current_umask();
3045		- error = mnt_want_write(path.mnt);
3046		- if (error)
3047		- goto out_dput;
3048	3043	error = security_path_mkdir(&path, dentry, mode);
3049		- if (error)
3050		- goto out_drop_write;
3051		- error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
3052		-out_drop_write:
3053		- mnt_drop_write(path.mnt);
3054		-out_dput:
	3044	+ if (!error)
	3045	+ error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
3055	3046	done_path_create(&path, dentry);
3056	3047	return error;
3057	3048	}
3058	3049
...	...	@@ -3326,16 +3317,9 @@
3326	3317	if (IS_ERR(dentry))
3327	3318	goto out_putname;
3328	3319
3329		- error = mnt_want_write(path.mnt);
3330		- if (error)
3331		- goto out_dput;
3332	3320	error = security_path_symlink(&path, dentry, from);
3333		- if (error)
3334		- goto out_drop_write;
3335		- error = vfs_symlink(path.dentry->d_inode, dentry, from);
3336		-out_drop_write:
3337		- mnt_drop_write(path.mnt);
3338		-out_dput:
	3321	+ if (!error)
	3322	+ error = vfs_symlink(path.dentry->d_inode, dentry, from);
3339	3323	done_path_create(&path, dentry);
3340	3324	out_putname:
3341	3325	putname(from);
3342	3326
3343	3327
...	...	@@ -3436,15 +3420,10 @@
3436	3420	error = -EXDEV;
3437	3421	if (old_path.mnt != new_path.mnt)
3438	3422	goto out_dput;
3439		- error = mnt_want_write(new_path.mnt);
3440		- if (error)
3441		- goto out_dput;
3442	3423	error = security_path_link(old_path.dentry, &new_path, new_dentry);
3443	3424	if (error)
3444		- goto out_drop_write;
	3425	+ goto out_dput;
3445	3426	error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
3446		-out_drop_write:
3447		- mnt_drop_write(new_path.mnt);
3448	3427	out_dput:
3449	3428	done_path_create(&new_path, new_dentry);
3450	3429	out:
...	...	@@ -4466,16 +4466,9 @@
4466	4466	goto out_dput;
4467	4467	}
4468	4468
4469		- error = mnt_want_write(new_path.mnt);
4470		- if (error) {
4471		- mlog_errno(error);
4472		- goto out_dput;
4473		- }
4474		-
4475	4469	error = ocfs2_vfs_reflink(old_path.dentry,
4476	4470	new_path.dentry->d_inode,
4477	4471	new_dentry, preserve);
4478		- mnt_drop_write(new_path.mnt);
4479	4472	out_dput:
4480	4473	done_path_create(&new_path, new_dentry);
4481	4474	out:
...	...	@@ -876,15 +876,11 @@
876	876	*/
877	877	mode = S_IFSOCK \|
878	878	(SOCK_INODE(sock)->i_mode & ~current_umask());
879		- err = mnt_want_write(path.mnt);
880		- if (err)
881		- goto out_mknod_dput;
882	879	err = security_path_mknod(&path, dentry, mode, 0);
883	880	if (err)
884	881	goto out_mknod_drop_write;
885	882	err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
886	883	out_mknod_drop_write:
887		- mnt_drop_write(path.mnt);
888	884	if (err)
889	885	goto out_mknod_dput;
890	886	mntget(path.mnt);