fs: Preserve error code in get_empty_filp(), part 2

Allocating a file structure in function get_empty_filp() might fail because of several reasons: - not enough memory for file structures - operation is not allowed - user is over its limit Currently the function returns NULL in all cases and we loose the exact reason of the error. All callers of get_empty_filp() assume that the function can fail with ENFILE only. Return error through pointer. Change all callers to preserve this error code. [AV: cleaned up a bit, carved the get_empty_filp() part out into a separate commit (things remaining here deal with alloc_file()), removed pipe(2) behaviour change] Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: Preserve error code in get_empty_filp(), part 2
Allocating a file structure in function get_empty_filp() might fail because of several reasons: - not enough memory for file structures - operation is not allowed - user is over its limit Currently the function returns NULL in all cases and we loose the exact reason of the error. All callers of get_empty_filp() assume that the function can fail with ENFILE only. Return error through pointer. Change all callers to preserve this error code. [AV: cleaned up a bit, carved the get_empty_filp() part out into a separate commit (things remaining here deal with alloc_file()), removed pipe(2) behaviour change] Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Anatol Pomozov · Al Viro
1 parent 1afc99beaf
Showing 8 changed files with 19 additions and 22 deletions Side-by-side Diff
arch/ia64/kernel/perfmon.c
fs/anon_inodes.c
fs/file_table.c
fs/hugetlbfs/inode.c
fs/pipe.c
ipc/shm.c
mm/shmem.c
net/socket.c
@@ -2221,9 +2221,9 @@
 	d_add(path.dentry, inode);
  
 	file = alloc_file(&path, FMODE_READ, &pfm_file_ops);
-	if (!file) {
+	if (IS_ERR(file)) {
 		path_put(&path);
-		return ERR_PTR(-ENFILE);
+		return file;
 	}
  
 	file->f_flags = O_RDONLY;
@@ -131,7 +131,6 @@
 	struct qstr this;
 	struct path path;
 	struct file *file;
-	int error;
  
 	if (IS_ERR(anon_inode_inode))
 		return ERR_PTR(-ENODEV);
@@ -143,7 +142,7 @@
 	 * Link the inode to a directory entry by creating a unique name
 	 * using the inode sequence number.
 	 */
-	error = -ENOMEM;
+	file = ERR_PTR(-ENOMEM);
 	this.name = name;
 	this.len = strlen(name);
 	this.hash = 0;
  
@@ -160,9 +159,8 @@
  
 	d_instantiate(path.dentry, anon_inode_inode);
  
-	error = -ENFILE;
 	file = alloc_file(&path, OPEN_FMODE(flags), fops);
-	if (!file)
+	if (IS_ERR(file))
 		goto err_dput;
 	file->f_mapping = anon_inode_inode->i_mapping;
  
@@ -177,7 +175,7 @@
 	path_put(&path);
 err_module:
 	module_put(fops->owner);
-	return ERR_PTR(error);
+	return file;
 }
 EXPORT_SYMBOL_GPL(anon_inode_getfile);
  
@@ -173,7 +173,7 @@
  
 	file = get_empty_filp();
 	if (IS_ERR(file))
-		return NULL;
+		return file;
  
 	file->f_path = *path;
 	file->f_mapping = path->dentry->d_inode->i_mapping;
@@ -923,8 +923,7 @@
 				struct user_struct **user,
 				int creat_flags, int page_size_log)
 {
-	int error = -ENOMEM;
-	struct file *file;
+	struct file *file = ERR_PTR(-ENOMEM);
 	struct inode *inode;
 	struct path path;
 	struct dentry *root;
@@ -964,7 +963,7 @@
 		goto out_shm_unlock;
  
 	path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
-	error = -ENOSPC;
+	file = ERR_PTR(-ENOSPC);
 	inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
 	if (!inode)
 		goto out_dentry;
@@ -973,7 +972,7 @@
 	size += addr & ~huge_page_mask(hstate);
 	num_pages = ALIGN(size, huge_page_size(hstate)) >>
 			huge_page_shift(hstate);
-	error = -ENOMEM;
+	file = ERR_PTR(-ENOMEM);
 	if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
 		goto out_inode;
  
  
@@ -981,10 +980,9 @@
 	inode->i_size = size;
 	clear_nlink(inode);
  
-	error = -ENFILE;
 	file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 			&hugetlbfs_file_operations);
-	if (!file)
+	if (IS_ERR(file))
 		goto out_dentry; /* inode is already attached */
  
 	return file;
@@ -998,7 +996,7 @@
 		user_shm_unlock(size, *user);
 		*user = NULL;
 	}
-	return ERR_PTR(error);
+	return file;
 }
  
 static int __init init_hugetlbfs_fs(void)
@@ -1037,13 +1037,13 @@
  
 	err = -ENFILE;
 	f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops);
-	if (!f)
+	if (IS_ERR(f))
 		goto err_dentry;
  
 	f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT));
  
 	res[0] = alloc_file(&path, FMODE_READ, &read_pipefifo_fops);
-	if (!res[0])
+	if (IS_ERR(res[0]))
 		goto err_file;
  
 	path_get(&path);
@@ -1042,7 +1042,8 @@
 			  is_file_hugepages(shp->shm_file) ?
 				&shm_file_operations_huge :
 				&shm_file_operations);
-	if (!file)
+	err = PTR_ERR(file);
+	if (IS_ERR(file))
 		goto out_free;
  
 	file->private_data = sfd;
@@ -2913,10 +2913,10 @@
 		goto put_dentry;
 #endif
  
-	error = -ENFILE;
 	file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 		  &shmem_file_operations);
-	if (!file)
+	error = PTR_ERR(file);
+	if (IS_ERR(file))
 		goto put_dentry;
  
 	return file;
@@ -370,11 +370,11 @@
  
 	file = alloc_file(&path, FMODE_READ | FMODE_WRITE,
 		  &socket_file_ops);
-	if (unlikely(!file)) {
+	if (unlikely(IS_ERR(file))) {
 		/* drop dentry, keep inode */
 		ihold(path.dentry->d_inode);
 		path_put(&path);
-		return ERR_PTR(-ENFILE);
+		return file;
 	}
  
 	sock->file = file;
...	...	@@ -2221,9 +2221,9 @@
2221	2221	d_add(path.dentry, inode);
2222	2222
2223	2223	file = alloc_file(&path, FMODE_READ, &pfm_file_ops);
2224		- if (!file) {
	2224	+ if (IS_ERR(file)) {
2225	2225	path_put(&path);
2226		- return ERR_PTR(-ENFILE);
	2226	+ return file;
2227	2227	}
2228	2228
2229	2229	file->f_flags = O_RDONLY;
...	...	@@ -131,7 +131,6 @@
131	131	struct qstr this;
132	132	struct path path;
133	133	struct file *file;
134		- int error;
135	134
136	135	if (IS_ERR(anon_inode_inode))
137	136	return ERR_PTR(-ENODEV);
...	...	@@ -143,7 +142,7 @@
143	142	* Link the inode to a directory entry by creating a unique name
144	143	* using the inode sequence number.
145	144	*/
146		- error = -ENOMEM;
	145	+ file = ERR_PTR(-ENOMEM);
147	146	this.name = name;
148	147	this.len = strlen(name);
149	148	this.hash = 0;
150	149
...	...	@@ -160,9 +159,8 @@
160	159
161	160	d_instantiate(path.dentry, anon_inode_inode);
162	161
163		- error = -ENFILE;
164	162	file = alloc_file(&path, OPEN_FMODE(flags), fops);
165		- if (!file)
	163	+ if (IS_ERR(file))
166	164	goto err_dput;
167	165	file->f_mapping = anon_inode_inode->i_mapping;
168	166
...	...	@@ -177,7 +175,7 @@
177	175	path_put(&path);
178	176	err_module:
179	177	module_put(fops->owner);
180		- return ERR_PTR(error);
	178	+ return file;
181	179	}
182	180	EXPORT_SYMBOL_GPL(anon_inode_getfile);
183	181
...	...	@@ -173,7 +173,7 @@
173	173
174	174	file = get_empty_filp();
175	175	if (IS_ERR(file))
176		- return NULL;
	176	+ return file;
177	177
178	178	file->f_path = *path;
179	179	file->f_mapping = path->dentry->d_inode->i_mapping;
...	...	@@ -923,8 +923,7 @@
923	923	struct user_struct **user,
924	924	int creat_flags, int page_size_log)
925	925	{
926		- int error = -ENOMEM;
927		- struct file *file;
	926	+ struct file *file = ERR_PTR(-ENOMEM);
928	927	struct inode *inode;
929	928	struct path path;
930	929	struct dentry *root;
...	...	@@ -964,7 +963,7 @@
964	963	goto out_shm_unlock;
965	964
966	965	path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
967		- error = -ENOSPC;
	966	+ file = ERR_PTR(-ENOSPC);
968	967	inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG \| S_IRWXUGO, 0);
969	968	if (!inode)
970	969	goto out_dentry;
...	...	@@ -973,7 +972,7 @@
973	972	size += addr & ~huge_page_mask(hstate);
974	973	num_pages = ALIGN(size, huge_page_size(hstate)) >>
975	974	huge_page_shift(hstate);
976		- error = -ENOMEM;
	975	+ file = ERR_PTR(-ENOMEM);
977	976	if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
978	977	goto out_inode;
979	978
980	979
...	...	@@ -981,10 +980,9 @@
981	980	inode->i_size = size;
982	981	clear_nlink(inode);
983	982
984		- error = -ENFILE;
985	983	file = alloc_file(&path, FMODE_WRITE \| FMODE_READ,
986	984	&hugetlbfs_file_operations);
987		- if (!file)
	985	+ if (IS_ERR(file))
988	986	goto out_dentry; /* inode is already attached */
989	987
990	988	return file;
...	...	@@ -998,7 +996,7 @@
998	996	user_shm_unlock(size, *user);
999	997	*user = NULL;
1000	998	}
1001		- return ERR_PTR(error);
	999	+ return file;
1002	1000	}
1003	1001
1004	1002	static int __init init_hugetlbfs_fs(void)
...	...	@@ -1037,13 +1037,13 @@
1037	1037
1038	1038	err = -ENFILE;
1039	1039	f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops);
1040		- if (!f)
	1040	+ if (IS_ERR(f))
1041	1041	goto err_dentry;
1042	1042
1043	1043	f->f_flags = O_WRONLY \| (flags & (O_NONBLOCK \| O_DIRECT));
1044	1044
1045	1045	res[0] = alloc_file(&path, FMODE_READ, &read_pipefifo_fops);
1046		- if (!res[0])
	1046	+ if (IS_ERR(res[0]))
1047	1047	goto err_file;
1048	1048
1049	1049	path_get(&path);
...	...	@@ -1042,7 +1042,8 @@
1042	1042	is_file_hugepages(shp->shm_file) ?
1043	1043	&shm_file_operations_huge :
1044	1044	&shm_file_operations);
1045		- if (!file)
	1045	+ err = PTR_ERR(file);
	1046	+ if (IS_ERR(file))
1046	1047	goto out_free;
1047	1048
1048	1049	file->private_data = sfd;
...	...	@@ -2913,10 +2913,10 @@
2913	2913	goto put_dentry;
2914	2914	#endif
2915	2915
2916		- error = -ENFILE;
2917	2916	file = alloc_file(&path, FMODE_WRITE \| FMODE_READ,
2918	2917	&shmem_file_operations);
2919		- if (!file)
	2918	+ error = PTR_ERR(file);
	2919	+ if (IS_ERR(file))
2920	2920	goto put_dentry;
2921	2921
2922	2922	return file;
...	...	@@ -370,11 +370,11 @@
370	370
371	371	file = alloc_file(&path, FMODE_READ \| FMODE_WRITE,
372	372	&socket_file_ops);
373		- if (unlikely(!file)) {
	373	+ if (unlikely(IS_ERR(file))) {
374	374	/* drop dentry, keep inode */
375	375	ihold(path.dentry->d_inode);
376	376	path_put(&path);
377		- return ERR_PTR(-ENFILE);
	377	+ return file;
378	378	}
379	379
380	380	sock->file = file;