blob: cedeacbae303a9483fea836ba4a5cc24cb022f41 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/libfs.c
3 * Library for filesystems writers.
4 */
5
Fabian Frederickac13a822014-06-04 16:06:27 -07006#include <linux/blkdev.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -05007#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/pagemap.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09009#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/mount.h>
11#include <linux/vfs.h>
npiggin@suse.de7bb46a62010-05-27 01:05:33 +100012#include <linux/quotaops.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080013#include <linux/mutex.h>
Al Viro87dc8002013-09-16 10:30:04 -040014#include <linux/namei.h>
Christoph Hellwig25961102007-10-21 16:42:05 -070015#include <linux/exportfs.h>
Al Virod5aacad2009-06-07 14:56:44 -040016#include <linux/writeback.h>
Al Viroff01bb42011-09-16 02:31:11 -040017#include <linux/buffer_head.h> /* sync_mapping_buffers */
Ingo Molnar7cf34c72006-03-23 03:00:36 -080018
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <asm/uaccess.h>
20
Al Viroa4464db2011-07-07 15:03:58 -040021#include "internal.h"
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
24 struct kstat *stat)
25{
David Howellsdea655c2015-03-17 22:26:15 +000026 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 generic_fillattr(inode, stat);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +030028 stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 return 0;
30}
Al Viro12f38872013-09-15 21:20:49 -040031EXPORT_SYMBOL(simple_getattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
David Howells726c3342006-06-23 02:02:58 -070033int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070034{
David Howells726c3342006-06-23 02:02:58 -070035 buf->f_type = dentry->d_sb->s_magic;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +030036 buf->f_bsize = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 buf->f_namelen = NAME_MAX;
38 return 0;
39}
Al Viro12f38872013-09-15 21:20:49 -040040EXPORT_SYMBOL(simple_statfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42/*
43 * Retaining negative dentries for an in-memory filesystem just wastes
44 * memory and lookup time: arrange for them to be deleted immediately.
45 */
Al Virob26d4cd2013-10-25 18:47:37 -040046int always_delete_dentry(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
48 return 1;
49}
Al Virob26d4cd2013-10-25 18:47:37 -040050EXPORT_SYMBOL(always_delete_dentry);
51
52const struct dentry_operations simple_dentry_operations = {
53 .d_delete = always_delete_dentry,
54};
55EXPORT_SYMBOL(simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/*
58 * Lookup the data. This is trivial - if the dentry didn't already
59 * exist, we know it is negative. Set d_op to delete negative dentries.
60 */
Al Viro00cd8dd2012-06-10 17:13:09 -040061struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 if (dentry->d_name.len > NAME_MAX)
64 return ERR_PTR(-ENAMETOOLONG);
Al Viro74931da2013-07-14 17:43:25 +040065 if (!dentry->d_sb->s_d_op)
66 d_set_d_op(dentry, &simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 d_add(dentry, NULL);
68 return NULL;
69}
Al Viro12f38872013-09-15 21:20:49 -040070EXPORT_SYMBOL(simple_lookup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Linus Torvalds1da177e2005-04-16 15:20:36 -070072int dcache_dir_open(struct inode *inode, struct file *file)
73{
Al Viroba65dc52016-06-10 11:32:47 -040074 file->private_data = d_alloc_cursor(file->f_path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76 return file->private_data ? 0 : -ENOMEM;
77}
Al Viro12f38872013-09-15 21:20:49 -040078EXPORT_SYMBOL(dcache_dir_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
80int dcache_dir_close(struct inode *inode, struct file *file)
81{
82 dput(file->private_data);
83 return 0;
84}
Al Viro12f38872013-09-15 21:20:49 -040085EXPORT_SYMBOL(dcache_dir_close);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Andrew Morton965c8e52012-12-17 15:59:39 -080087loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -070088{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110089 struct dentry *dentry = file->f_path.dentry;
Andrew Morton965c8e52012-12-17 15:59:39 -080090 switch (whence) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 case 1:
92 offset += file->f_pos;
93 case 0:
94 if (offset >= 0)
95 break;
96 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 return -EINVAL;
98 }
99 if (offset != file->f_pos) {
100 file->f_pos = offset;
101 if (file->f_pos >= 2) {
102 struct list_head *p;
103 struct dentry *cursor = file->private_data;
104 loff_t n = file->f_pos - 2;
105
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100106 spin_lock(&dentry->d_lock);
107 /* d_lock not required for cursor */
Al Viro946e51f2014-10-26 19:19:16 -0400108 list_del(&cursor->d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100109 p = dentry->d_subdirs.next;
110 while (n && p != &dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 struct dentry *next;
Al Viro946e51f2014-10-26 19:19:16 -0400112 next = list_entry(p, struct dentry, d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100113 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Nick Pigginda502952011-01-07 17:49:33 +1100114 if (simple_positive(next))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 n--;
Nick Pigginda502952011-01-07 17:49:33 +1100116 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 p = p->next;
118 }
Al Viro946e51f2014-10-26 19:19:16 -0400119 list_add_tail(&cursor->d_child, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100120 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 }
122 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 return offset;
124}
Al Viro12f38872013-09-15 21:20:49 -0400125EXPORT_SYMBOL(dcache_dir_lseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127/* Relationship between i_mode and the DT_xxx types */
128static inline unsigned char dt_type(struct inode *inode)
129{
130 return (inode->i_mode >> 12) & 15;
131}
132
133/*
134 * Directory is locked and all positive dentries in it are safe, since
135 * for ramfs-type trees they can't go away without unlink() or rmdir(),
136 * both impossible due to the lock on directory.
137 */
138
Al Viro5f99f4e2013-05-15 20:23:06 -0400139int dcache_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140{
Al Viro5f99f4e2013-05-15 20:23:06 -0400141 struct dentry *dentry = file->f_path.dentry;
142 struct dentry *cursor = file->private_data;
Al Viro946e51f2014-10-26 19:19:16 -0400143 struct list_head *p, *q = &cursor->d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
Al Viro5f99f4e2013-05-15 20:23:06 -0400145 if (!dir_emit_dots(file, ctx))
146 return 0;
147 spin_lock(&dentry->d_lock);
148 if (ctx->pos == 2)
149 list_move(q, &dentry->d_subdirs);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700150
Al Viro5f99f4e2013-05-15 20:23:06 -0400151 for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
Al Viro946e51f2014-10-26 19:19:16 -0400152 struct dentry *next = list_entry(p, struct dentry, d_child);
Al Viro5f99f4e2013-05-15 20:23:06 -0400153 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
154 if (!simple_positive(next)) {
155 spin_unlock(&next->d_lock);
156 continue;
157 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Al Viro5f99f4e2013-05-15 20:23:06 -0400159 spin_unlock(&next->d_lock);
160 spin_unlock(&dentry->d_lock);
161 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
David Howellsdea655c2015-03-17 22:26:15 +0000162 d_inode(next)->i_ino, dt_type(d_inode(next))))
Al Viro5f99f4e2013-05-15 20:23:06 -0400163 return 0;
164 spin_lock(&dentry->d_lock);
165 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
166 /* next is still alive */
167 list_move(q, p);
168 spin_unlock(&next->d_lock);
169 p = q;
170 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 }
Al Viro5f99f4e2013-05-15 20:23:06 -0400172 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 return 0;
174}
Al Viro12f38872013-09-15 21:20:49 -0400175EXPORT_SYMBOL(dcache_readdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
178{
179 return -EISDIR;
180}
Al Viro12f38872013-09-15 21:20:49 -0400181EXPORT_SYMBOL(generic_read_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800183const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 .open = dcache_dir_open,
185 .release = dcache_dir_close,
186 .llseek = dcache_dir_lseek,
187 .read = generic_read_dir,
Al Viro4e829012016-04-20 19:52:15 -0400188 .iterate_shared = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200189 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190};
Al Viro12f38872013-09-15 21:20:49 -0400191EXPORT_SYMBOL(simple_dir_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800193const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 .lookup = simple_lookup,
195};
Al Viro12f38872013-09-15 21:20:49 -0400196EXPORT_SYMBOL(simple_dir_inode_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Hugh Dickins759b9772007-03-05 00:30:28 -0800198static const struct super_operations simple_super_operations = {
199 .statfs = simple_statfs,
200};
201
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202/*
203 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
204 * will never be mountable)
205 */
Al Viro51139ad2010-07-25 23:47:46 +0400206struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
Al Viroc74a1cb2011-01-12 16:59:34 -0500207 const struct super_operations *ops,
208 const struct dentry_operations *dops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
David Howells9249e172012-06-25 12:55:37 +0100210 struct super_block *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 struct dentry *dentry;
212 struct inode *root;
Linus Torvalds26fe5752012-05-10 13:14:12 -0700213 struct qstr d_name = QSTR_INIT(name, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
David Howells9249e172012-06-25 12:55:37 +0100215 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400217 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Jeff Layton89a4eb42009-08-18 14:11:08 -0700219 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700220 s->s_blocksize = PAGE_SIZE;
221 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800223 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 s->s_time_gran = 1;
225 root = new_inode(s);
226 if (!root)
227 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700228 /*
229 * since this is the first inode, make it number 1. New inodes created
230 * after this must take care not to collide with it (by passing
231 * max_reserved of 1 to iunique).
232 */
233 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
Al Viroa4464db2011-07-07 15:03:58 -0400236 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 if (!dentry) {
238 iput(root);
239 goto Enomem;
240 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 d_instantiate(dentry, root);
242 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500243 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400245 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
247Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400248 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400249 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250}
Al Viro12f38872013-09-15 21:20:49 -0400251EXPORT_SYMBOL(mount_pseudo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
Stephen Boyd20955e82012-04-05 14:25:09 -0700253int simple_open(struct inode *inode, struct file *file)
254{
255 if (inode->i_private)
256 file->private_data = inode->i_private;
257 return 0;
258}
Al Viro12f38872013-09-15 21:20:49 -0400259EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700260
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
262{
David Howellsdea655c2015-03-17 22:26:15 +0000263 struct inode *inode = d_inode(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700266 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400267 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 dget(dentry);
269 d_instantiate(dentry, inode);
270 return 0;
271}
Al Viro12f38872013-09-15 21:20:49 -0400272EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274int simple_empty(struct dentry *dentry)
275{
276 struct dentry *child;
277 int ret = 0;
278
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100279 spin_lock(&dentry->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400280 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
Nick Pigginda502952011-01-07 17:49:33 +1100281 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
282 if (simple_positive(child)) {
283 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100285 }
286 spin_unlock(&child->d_lock);
287 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 ret = 1;
289out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100290 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 return ret;
292}
Al Viro12f38872013-09-15 21:20:49 -0400293EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
295int simple_unlink(struct inode *dir, struct dentry *dentry)
296{
David Howellsdea655c2015-03-17 22:26:15 +0000297 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
299 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700300 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 dput(dentry);
302 return 0;
303}
Al Viro12f38872013-09-15 21:20:49 -0400304EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305
306int simple_rmdir(struct inode *dir, struct dentry *dentry)
307{
308 if (!simple_empty(dentry))
309 return -ENOTEMPTY;
310
David Howellsdea655c2015-03-17 22:26:15 +0000311 drop_nlink(d_inode(dentry));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700313 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 return 0;
315}
Al Viro12f38872013-09-15 21:20:49 -0400316EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
318int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
319 struct inode *new_dir, struct dentry *new_dentry)
320{
David Howellsdea655c2015-03-17 22:26:15 +0000321 struct inode *inode = d_inode(old_dentry);
David Howellse36cb0b2015-01-29 12:02:35 +0000322 int they_are_dirs = d_is_dir(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
324 if (!simple_empty(new_dentry))
325 return -ENOTEMPTY;
326
David Howellsdea655c2015-03-17 22:26:15 +0000327 if (d_really_is_positive(new_dentry)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400329 if (they_are_dirs) {
David Howellsdea655c2015-03-17 22:26:15 +0000330 drop_nlink(d_inode(new_dentry));
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700331 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400332 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700334 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700335 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 }
337
338 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
339 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
340
341 return 0;
342}
Al Viro12f38872013-09-15 21:20:49 -0400343EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000345/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200346 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000347 * @dentry: dentry
348 * @iattr: iattr structure
349 *
350 * Returns 0 on success, -error on failure.
351 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200352 * simple_setattr is a simple ->setattr implementation without a proper
353 * implementation of size changes.
354 *
355 * It can either be used for in-memory filesystems or special files
356 * on simple regular filesystems. Anything that needs to change on-disk
357 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000358 */
359int simple_setattr(struct dentry *dentry, struct iattr *iattr)
360{
David Howellsdea655c2015-03-17 22:26:15 +0000361 struct inode *inode = d_inode(dentry);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000362 int error;
363
364 error = inode_change_ok(inode, iattr);
365 if (error)
366 return error;
367
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200368 if (iattr->ia_valid & ATTR_SIZE)
369 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200370 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200371 mark_inode_dirty(inode);
372 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000373}
374EXPORT_SYMBOL(simple_setattr);
375
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376int simple_readpage(struct file *file, struct page *page)
377{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700378 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 flush_dcache_page(page);
380 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 unlock_page(page);
382 return 0;
383}
Al Viro12f38872013-09-15 21:20:49 -0400384EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385
Nick Pigginafddba42007-10-16 01:25:01 -0700386int simple_write_begin(struct file *file, struct address_space *mapping,
387 loff_t pos, unsigned len, unsigned flags,
388 struct page **pagep, void **fsdata)
389{
390 struct page *page;
391 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700392
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300393 index = pos >> PAGE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700394
Nick Piggin54566b22009-01-04 12:00:53 -0800395 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700396 if (!page)
397 return -ENOMEM;
398
399 *pagep = page;
400
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300401 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
402 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200403
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300404 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200405 }
406 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700407}
Al Viro12f38872013-09-15 21:20:49 -0400408EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700409
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200410/**
411 * simple_write_end - .write_end helper for non-block-device FSes
412 * @available: See .write_end of address_space_operations
413 * @file: "
414 * @mapping: "
415 * @pos: "
416 * @len: "
417 * @copied: "
418 * @page: "
419 * @fsdata: "
420 *
421 * simple_write_end does the minimum needed for updating a page after writing is
422 * done. It has the same API signature as the .write_end of
423 * address_space_operations vector. So it can just be set onto .write_end for
424 * FSes that don't need any other processing. i_mutex is assumed to be held.
425 * Block based filesystems should use generic_write_end().
426 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
427 * is not called, so a filesystem that actually does store data in .write_inode
428 * should extend on what's done here with a call to mark_inode_dirty() in the
429 * case that i_size has changed.
430 */
431int simple_write_end(struct file *file, struct address_space *mapping,
432 loff_t pos, unsigned len, unsigned copied,
433 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434{
435 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200436 loff_t last_pos = pos + copied;
437
438 /* zero the stale part of the page if we did a short copy */
439 if (copied < len) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300440 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200441
442 zero_user(page, from + copied, len - copied);
443 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444
Nick Piggin955eff52007-02-20 13:58:08 -0800445 if (!PageUptodate(page))
446 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 /*
448 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800449 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200451 if (last_pos > inode->i_size)
452 i_size_write(inode, last_pos);
453
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700455 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300456 put_page(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700457
458 return copied;
459}
Al Viro12f38872013-09-15 21:20:49 -0400460EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700461
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700462/*
463 * the inodes created here are not hashed. If you use iunique to generate
464 * unique inode values later for this filesystem, then you must take care
465 * to pass it an appropriate max_reserved value to avoid collisions.
466 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200467int simple_fill_super(struct super_block *s, unsigned long magic,
468 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 struct inode *inode;
471 struct dentry *root;
472 struct dentry *dentry;
473 int i;
474
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300475 s->s_blocksize = PAGE_SIZE;
476 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800478 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 s->s_time_gran = 1;
480
481 inode = new_inode(s);
482 if (!inode)
483 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700484 /*
485 * because the root inode is 1, the files array must not contain an
486 * entry at index 1
487 */
488 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
491 inode->i_op = &simple_dir_inode_operations;
492 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200493 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500494 root = d_make_root(inode);
495 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 for (i = 0; !files->name || files->name[0]; i++, files++) {
498 if (!files->name)
499 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700500
501 /* warn if it tries to conflict with the root inode */
502 if (unlikely(i == 1))
503 printk(KERN_WARNING "%s: %s passed in a files array"
504 "with an index of 1!\n", __func__,
505 s->s_type->name);
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 dentry = d_alloc_name(root, files->name);
508 if (!dentry)
509 goto out;
510 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300511 if (!inode) {
512 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300514 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
517 inode->i_fop = files->ops;
518 inode->i_ino = i;
519 d_add(dentry, inode);
520 }
521 s->s_root = root;
522 return 0;
523out:
524 d_genocide(root);
Al Viro640946f2012-04-02 19:22:25 -0400525 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 dput(root);
527 return -ENOMEM;
528}
Al Viro12f38872013-09-15 21:20:49 -0400529EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531static DEFINE_SPINLOCK(pin_fs_lock);
532
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400533int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534{
535 struct vfsmount *mnt = NULL;
536 spin_lock(&pin_fs_lock);
537 if (unlikely(!*mount)) {
538 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400539 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 if (IS_ERR(mnt))
541 return PTR_ERR(mnt);
542 spin_lock(&pin_fs_lock);
543 if (!*mount)
544 *mount = mnt;
545 }
546 mntget(*mount);
547 ++*count;
548 spin_unlock(&pin_fs_lock);
549 mntput(mnt);
550 return 0;
551}
Al Viro12f38872013-09-15 21:20:49 -0400552EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
554void simple_release_fs(struct vfsmount **mount, int *count)
555{
556 struct vfsmount *mnt;
557 spin_lock(&pin_fs_lock);
558 mnt = *mount;
559 if (!--*count)
560 *mount = NULL;
561 spin_unlock(&pin_fs_lock);
562 mntput(mnt);
563}
Al Viro12f38872013-09-15 21:20:49 -0400564EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700566/**
567 * simple_read_from_buffer - copy data from the buffer to user space
568 * @to: the user space buffer to read to
569 * @count: the maximum number of bytes to read
570 * @ppos: the current position in the buffer
571 * @from: the buffer to read from
572 * @available: the size of the buffer
573 *
574 * The simple_read_from_buffer() function reads up to @count bytes from the
575 * buffer @from at offset @ppos into the user space address starting at @to.
576 *
577 * On success, the number of bytes read is returned and the offset @ppos is
578 * advanced by this number, or negative value is returned on error.
579 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
581 const void *from, size_t available)
582{
583 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700584 size_t ret;
585
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 if (pos < 0)
587 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700588 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 return 0;
590 if (count > available - pos)
591 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700592 ret = copy_to_user(to, from + pos, count);
593 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700595 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 *ppos = pos + count;
597 return count;
598}
Al Viro12f38872013-09-15 21:20:49 -0400599EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700601/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200602 * simple_write_to_buffer - copy data from user space to the buffer
603 * @to: the buffer to write to
604 * @available: the size of the buffer
605 * @ppos: the current position in the buffer
606 * @from: the user space buffer to read from
607 * @count: the maximum number of bytes to read
608 *
609 * The simple_write_to_buffer() function reads up to @count bytes from the user
610 * space address starting at @from into the buffer @to at offset @ppos.
611 *
612 * On success, the number of bytes written is returned and the offset @ppos is
613 * advanced by this number, or negative value is returned on error.
614 **/
615ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
616 const void __user *from, size_t count)
617{
618 loff_t pos = *ppos;
619 size_t res;
620
621 if (pos < 0)
622 return -EINVAL;
623 if (pos >= available || !count)
624 return 0;
625 if (count > available - pos)
626 count = available - pos;
627 res = copy_from_user(to + pos, from, count);
628 if (res == count)
629 return -EFAULT;
630 count -= res;
631 *ppos = pos + count;
632 return count;
633}
Al Viro12f38872013-09-15 21:20:49 -0400634EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200635
636/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700637 * memory_read_from_buffer - copy data from the buffer
638 * @to: the kernel space buffer to read to
639 * @count: the maximum number of bytes to read
640 * @ppos: the current position in the buffer
641 * @from: the buffer to read from
642 * @available: the size of the buffer
643 *
644 * The memory_read_from_buffer() function reads up to @count bytes from the
645 * buffer @from at offset @ppos into the kernel space address starting at @to.
646 *
647 * On success, the number of bytes read is returned and the offset @ppos is
648 * advanced by this number, or negative value is returned on error.
649 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700650ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
651 const void *from, size_t available)
652{
653 loff_t pos = *ppos;
654
655 if (pos < 0)
656 return -EINVAL;
657 if (pos >= available)
658 return 0;
659 if (count > available - pos)
660 count = available - pos;
661 memcpy(to, from + pos, count);
662 *ppos = pos + count;
663
664 return count;
665}
Al Viro12f38872013-09-15 21:20:49 -0400666EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700667
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668/*
669 * Transaction based IO.
670 * The file expects a single write which triggers the transaction, and then
671 * possibly a read which collects the result - which is stored in a
672 * file-local buffer.
673 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100674
675void simple_transaction_set(struct file *file, size_t n)
676{
677 struct simple_transaction_argresp *ar = file->private_data;
678
679 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
680
681 /*
682 * The barrier ensures that ar->size will really remain zero until
683 * ar->data is ready for reading.
684 */
685 smp_mb();
686 ar->size = n;
687}
Al Viro12f38872013-09-15 21:20:49 -0400688EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100689
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
691{
692 struct simple_transaction_argresp *ar;
693 static DEFINE_SPINLOCK(simple_transaction_lock);
694
695 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
696 return ERR_PTR(-EFBIG);
697
698 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
699 if (!ar)
700 return ERR_PTR(-ENOMEM);
701
702 spin_lock(&simple_transaction_lock);
703
704 /* only one write allowed per open */
705 if (file->private_data) {
706 spin_unlock(&simple_transaction_lock);
707 free_page((unsigned long)ar);
708 return ERR_PTR(-EBUSY);
709 }
710
711 file->private_data = ar;
712
713 spin_unlock(&simple_transaction_lock);
714
715 if (copy_from_user(ar->data, buf, size))
716 return ERR_PTR(-EFAULT);
717
718 return ar->data;
719}
Al Viro12f38872013-09-15 21:20:49 -0400720EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
722ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
723{
724 struct simple_transaction_argresp *ar = file->private_data;
725
726 if (!ar)
727 return 0;
728 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
729}
Al Viro12f38872013-09-15 21:20:49 -0400730EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
732int simple_transaction_release(struct inode *inode, struct file *file)
733{
734 free_page((unsigned long)file->private_data);
735 return 0;
736}
Al Viro12f38872013-09-15 21:20:49 -0400737EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200739/* Simple attribute files */
740
741struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800742 int (*get)(void *, u64 *);
743 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200744 char get_buf[24]; /* enough to store a u64 and "\n\0" */
745 char set_buf[24];
746 void *data;
747 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800748 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200749};
750
751/* simple_attr_open is called by an actual attribute open file operation
752 * to set the attribute specific access operations. */
753int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800754 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200755 const char *fmt)
756{
757 struct simple_attr *attr;
758
759 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
760 if (!attr)
761 return -ENOMEM;
762
763 attr->get = get;
764 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700765 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200766 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800767 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200768
769 file->private_data = attr;
770
771 return nonseekable_open(inode, file);
772}
Al Viro12f38872013-09-15 21:20:49 -0400773EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200774
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800775int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200776{
777 kfree(file->private_data);
778 return 0;
779}
Al Viro12f38872013-09-15 21:20:49 -0400780EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200781
782/* read from the buffer that is filled with the get function */
783ssize_t simple_attr_read(struct file *file, char __user *buf,
784 size_t len, loff_t *ppos)
785{
786 struct simple_attr *attr;
787 size_t size;
788 ssize_t ret;
789
790 attr = file->private_data;
791
792 if (!attr->get)
793 return -EACCES;
794
Christoph Hellwig92613032008-02-08 04:20:27 -0800795 ret = mutex_lock_interruptible(&attr->mutex);
796 if (ret)
797 return ret;
798
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800799 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200800 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800801 } else { /* first read */
802 u64 val;
803 ret = attr->get(attr->data, &val);
804 if (ret)
805 goto out;
806
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200807 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800808 attr->fmt, (unsigned long long)val);
809 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200810
811 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800812out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800813 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200814 return ret;
815}
Al Viro12f38872013-09-15 21:20:49 -0400816EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200817
818/* interpret the buffer as a number to call the set function with */
819ssize_t simple_attr_write(struct file *file, const char __user *buf,
820 size_t len, loff_t *ppos)
821{
822 struct simple_attr *attr;
823 u64 val;
824 size_t size;
825 ssize_t ret;
826
827 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200828 if (!attr->set)
829 return -EACCES;
830
Christoph Hellwig92613032008-02-08 04:20:27 -0800831 ret = mutex_lock_interruptible(&attr->mutex);
832 if (ret)
833 return ret;
834
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200835 ret = -EFAULT;
836 size = min(sizeof(attr->set_buf) - 1, len);
837 if (copy_from_user(attr->set_buf, buf, size))
838 goto out;
839
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200840 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700841 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700842 ret = attr->set(attr->data, val);
843 if (ret == 0)
844 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200845out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800846 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200847 return ret;
848}
Al Viro12f38872013-09-15 21:20:49 -0400849EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200850
Christoph Hellwig25961102007-10-21 16:42:05 -0700851/**
852 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
853 * @sb: filesystem to do the file handle conversion on
854 * @fid: file handle to convert
855 * @fh_len: length of the file handle in bytes
856 * @fh_type: type of file handle
857 * @get_inode: filesystem callback to retrieve inode
858 *
859 * This function decodes @fid as long as it has one of the well-known
860 * Linux filehandle types and calls @get_inode on it to retrieve the
861 * inode for the object specified in the file handle.
862 */
863struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
864 int fh_len, int fh_type, struct inode *(*get_inode)
865 (struct super_block *sb, u64 ino, u32 gen))
866{
867 struct inode *inode = NULL;
868
869 if (fh_len < 2)
870 return NULL;
871
872 switch (fh_type) {
873 case FILEID_INO32_GEN:
874 case FILEID_INO32_GEN_PARENT:
875 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
876 break;
877 }
878
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200879 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700880}
881EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
882
883/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800884 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700885 * @sb: filesystem to do the file handle conversion on
886 * @fid: file handle to convert
887 * @fh_len: length of the file handle in bytes
888 * @fh_type: type of file handle
889 * @get_inode: filesystem callback to retrieve inode
890 *
891 * This function decodes @fid as long as it has one of the well-known
892 * Linux filehandle types and calls @get_inode on it to retrieve the
893 * inode for the _parent_ object specified in the file handle if it
894 * is specified in the file handle, or NULL otherwise.
895 */
896struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
897 int fh_len, int fh_type, struct inode *(*get_inode)
898 (struct super_block *sb, u64 ino, u32 gen))
899{
900 struct inode *inode = NULL;
901
902 if (fh_len <= 2)
903 return NULL;
904
905 switch (fh_type) {
906 case FILEID_INO32_GEN_PARENT:
907 inode = get_inode(sb, fid->i32.parent_ino,
908 (fh_len > 3 ? fid->i32.parent_gen : 0));
909 break;
910 }
911
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200912 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700913}
914EXPORT_SYMBOL_GPL(generic_fh_to_parent);
915
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200916/**
Fabian Frederickac13a822014-06-04 16:06:27 -0700917 * __generic_file_fsync - generic fsync implementation for simple filesystems
918 *
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200919 * @file: file to synchronize
Fabian Frederickac13a822014-06-04 16:06:27 -0700920 * @start: start offset in bytes
921 * @end: end offset in bytes (inclusive)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200922 * @datasync: only synchronize essential metadata if true
923 *
924 * This is a generic implementation of the fsync method for simple
925 * filesystems which track all non-inode metadata in the buffers list
926 * hanging off the address_space structure.
927 */
Fabian Frederickac13a822014-06-04 16:06:27 -0700928int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
929 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400930{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200931 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400932 int err;
933 int ret;
934
Josef Bacik02c24a82011-07-16 20:44:56 -0400935 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
936 if (err)
937 return err;
938
Al Viro59551022016-01-22 15:40:57 -0500939 inode_lock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400940 ret = sync_mapping_buffers(inode->i_mapping);
Theodore Ts'o0ae45f62015-02-02 00:37:00 -0500941 if (!(inode->i_state & I_DIRTY_ALL))
Josef Bacik02c24a82011-07-16 20:44:56 -0400942 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400943 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400944 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400945
Christoph Hellwigc37650162010-10-06 10:48:20 +0200946 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400947 if (ret == 0)
948 ret = err;
Fabian Frederickac13a822014-06-04 16:06:27 -0700949
Josef Bacik02c24a82011-07-16 20:44:56 -0400950out:
Al Viro59551022016-01-22 15:40:57 -0500951 inode_unlock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400952 return ret;
953}
Fabian Frederickac13a822014-06-04 16:06:27 -0700954EXPORT_SYMBOL(__generic_file_fsync);
955
956/**
957 * generic_file_fsync - generic fsync implementation for simple filesystems
958 * with flush
959 * @file: file to synchronize
960 * @start: start offset in bytes
961 * @end: end offset in bytes (inclusive)
962 * @datasync: only synchronize essential metadata if true
963 *
964 */
965
966int generic_file_fsync(struct file *file, loff_t start, loff_t end,
967 int datasync)
968{
969 struct inode *inode = file->f_mapping->host;
970 int err;
971
972 err = __generic_file_fsync(file, start, end, datasync);
973 if (err)
974 return err;
975 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
976}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200977EXPORT_SYMBOL(generic_file_fsync);
978
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700979/**
980 * generic_check_addressable - Check addressability of file system
981 * @blocksize_bits: log of file system block size
982 * @num_blocks: number of blocks in file system
983 *
984 * Determine whether a file system with @num_blocks blocks (and a
985 * block size of 2**@blocksize_bits) is addressable by the sector_t
986 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
987 */
988int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
989{
990 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -0700991 u64 last_fs_page =
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300992 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700993
994 if (unlikely(num_blocks == 0))
995 return 0;
996
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300997 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700998 return -EINVAL;
999
Joel Beckera33f13e2010-08-16 12:10:17 -07001000 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1001 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001002 return -EFBIG;
1003 }
1004 return 0;
1005}
1006EXPORT_SYMBOL(generic_check_addressable);
1007
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001008/*
1009 * No-op implementation of ->fsync for in-memory filesystems.
1010 */
Josef Bacik02c24a82011-07-16 20:44:56 -04001011int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001012{
1013 return 0;
1014}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001015EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -04001016
Al Virofceef392015-12-29 15:58:39 -05001017/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1018void kfree_link(void *p)
Al Viro87dc8002013-09-16 10:30:04 -04001019{
Al Virofceef392015-12-29 15:58:39 -05001020 kfree(p);
Al Viro87dc8002013-09-16 10:30:04 -04001021}
Al Virofceef392015-12-29 15:58:39 -05001022EXPORT_SYMBOL(kfree_link);
Al Viro69878432013-10-02 22:35:11 -04001023
1024/*
1025 * nop .set_page_dirty method so that people can use .page_mkwrite on
1026 * anon inodes.
1027 */
1028static int anon_set_page_dirty(struct page *page)
1029{
1030 return 0;
1031};
1032
1033/*
1034 * A single inode exists for all anon_inode files. Contrary to pipes,
1035 * anon_inode inodes have no associated per-instance data, so we need
1036 * only allocate one of them.
1037 */
1038struct inode *alloc_anon_inode(struct super_block *s)
1039{
1040 static const struct address_space_operations anon_aops = {
1041 .set_page_dirty = anon_set_page_dirty,
1042 };
1043 struct inode *inode = new_inode_pseudo(s);
1044
1045 if (!inode)
1046 return ERR_PTR(-ENOMEM);
1047
1048 inode->i_ino = get_next_ino();
1049 inode->i_mapping->a_ops = &anon_aops;
1050
1051 /*
1052 * Mark the inode dirty from the very beginning,
1053 * that way it will never be moved to the dirty
1054 * list because mark_inode_dirty() will think
1055 * that it already _is_ on the dirty list.
1056 */
1057 inode->i_state = I_DIRTY;
1058 inode->i_mode = S_IRUSR | S_IWUSR;
1059 inode->i_uid = current_fsuid();
1060 inode->i_gid = current_fsgid();
1061 inode->i_flags |= S_PRIVATE;
1062 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1063 return inode;
1064}
1065EXPORT_SYMBOL(alloc_anon_inode);
Jeff Layton1c994a02014-08-27 06:49:41 -04001066
1067/**
1068 * simple_nosetlease - generic helper for prohibiting leases
1069 * @filp: file pointer
1070 * @arg: type of lease to obtain
1071 * @flp: new lease supplied for insertion
Jeff Laytone6f5c782014-08-22 10:40:25 -04001072 * @priv: private data for lm_setup operation
Jeff Layton1c994a02014-08-27 06:49:41 -04001073 *
1074 * Generic helper for filesystems that do not wish to allow leases to be set.
1075 * All arguments are ignored and it just returns -EINVAL.
1076 */
1077int
Jeff Laytone6f5c782014-08-22 10:40:25 -04001078simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1079 void **priv)
Jeff Layton1c994a02014-08-27 06:49:41 -04001080{
1081 return -EINVAL;
1082}
1083EXPORT_SYMBOL(simple_nosetlease);
Al Viro61ba64f2015-05-02 09:54:06 -04001084
Al Viro6b255392015-11-17 10:20:54 -05001085const char *simple_get_link(struct dentry *dentry, struct inode *inode,
Al Virofceef392015-12-29 15:58:39 -05001086 struct delayed_call *done)
Al Viro61ba64f2015-05-02 09:54:06 -04001087{
Al Viro6b255392015-11-17 10:20:54 -05001088 return inode->i_link;
Al Viro61ba64f2015-05-02 09:54:06 -04001089}
Al Viro6b255392015-11-17 10:20:54 -05001090EXPORT_SYMBOL(simple_get_link);
Al Viro61ba64f2015-05-02 09:54:06 -04001091
1092const struct inode_operations simple_symlink_inode_operations = {
Al Viro6b255392015-11-17 10:20:54 -05001093 .get_link = simple_get_link,
Al Viro61ba64f2015-05-02 09:54:06 -04001094 .readlink = generic_readlink
1095};
1096EXPORT_SYMBOL(simple_symlink_inode_operations);
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001097
1098/*
1099 * Operations for a permanently empty directory.
1100 */
1101static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1102{
1103 return ERR_PTR(-ENOENT);
1104}
1105
1106static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
1107 struct kstat *stat)
1108{
1109 struct inode *inode = d_inode(dentry);
1110 generic_fillattr(inode, stat);
1111 return 0;
1112}
1113
1114static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1115{
1116 return -EPERM;
1117}
1118
Al Viro3767e252016-05-27 11:06:05 -04001119static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
1120 const char *name, const void *value,
1121 size_t size, int flags)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001122{
1123 return -EOPNOTSUPP;
1124}
1125
Al Viroce23e642016-04-11 00:48:00 -04001126static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
1127 const char *name, void *value, size_t size)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001128{
1129 return -EOPNOTSUPP;
1130}
1131
1132static int empty_dir_removexattr(struct dentry *dentry, const char *name)
1133{
1134 return -EOPNOTSUPP;
1135}
1136
1137static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1138{
1139 return -EOPNOTSUPP;
1140}
1141
1142static const struct inode_operations empty_dir_inode_operations = {
1143 .lookup = empty_dir_lookup,
1144 .permission = generic_permission,
1145 .setattr = empty_dir_setattr,
1146 .getattr = empty_dir_getattr,
1147 .setxattr = empty_dir_setxattr,
1148 .getxattr = empty_dir_getxattr,
1149 .removexattr = empty_dir_removexattr,
1150 .listxattr = empty_dir_listxattr,
1151};
1152
1153static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1154{
1155 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1156 return generic_file_llseek_size(file, offset, whence, 2, 2);
1157}
1158
1159static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1160{
1161 dir_emit_dots(file, ctx);
1162 return 0;
1163}
1164
1165static const struct file_operations empty_dir_operations = {
1166 .llseek = empty_dir_llseek,
1167 .read = generic_read_dir,
Al Viroc51da202016-04-30 22:37:34 -04001168 .iterate_shared = empty_dir_readdir,
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001169 .fsync = noop_fsync,
1170};
1171
1172
1173void make_empty_dir_inode(struct inode *inode)
1174{
1175 set_nlink(inode, 2);
1176 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1177 inode->i_uid = GLOBAL_ROOT_UID;
1178 inode->i_gid = GLOBAL_ROOT_GID;
1179 inode->i_rdev = 0;
Eric W. Biederman4b75de862015-08-12 15:00:12 -05001180 inode->i_size = 0;
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001181 inode->i_blkbits = PAGE_SHIFT;
1182 inode->i_blocks = 0;
1183
1184 inode->i_op = &empty_dir_inode_operations;
1185 inode->i_fop = &empty_dir_operations;
1186}
1187
1188bool is_empty_dir_inode(struct inode *inode)
1189{
1190 return (inode->i_fop == &empty_dir_operations) &&
1191 (inode->i_op == &empty_dir_inode_operations);
1192}