blob: 3db2721144c27d133cc7f8652d269900c9865ea5 [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 Viroff01bb482011-09-16 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{
Linus Torvalds26fe5752012-05-10 13:14:12 -070074 static struct qstr cursor_name = QSTR_INIT(".", 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080076 file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
78 return file->private_data ? 0 : -ENOMEM;
79}
Al Viro12f38872013-09-15 21:20:49 -040080EXPORT_SYMBOL(dcache_dir_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
82int dcache_dir_close(struct inode *inode, struct file *file)
83{
84 dput(file->private_data);
85 return 0;
86}
Al Viro12f38872013-09-15 21:20:49 -040087EXPORT_SYMBOL(dcache_dir_close);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
Andrew Morton965c8e52012-12-17 15:59:39 -080089loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110091 struct dentry *dentry = file->f_path.dentry;
Andrew Morton965c8e52012-12-17 15:59:39 -080092 switch (whence) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 case 1:
94 offset += file->f_pos;
95 case 0:
96 if (offset >= 0)
97 break;
98 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 return -EINVAL;
100 }
101 if (offset != file->f_pos) {
102 file->f_pos = offset;
103 if (file->f_pos >= 2) {
104 struct list_head *p;
105 struct dentry *cursor = file->private_data;
106 loff_t n = file->f_pos - 2;
107
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100108 spin_lock(&dentry->d_lock);
109 /* d_lock not required for cursor */
Al Viro946e51f2014-10-26 19:19:16 -0400110 list_del(&cursor->d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100111 p = dentry->d_subdirs.next;
112 while (n && p != &dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 struct dentry *next;
Al Viro946e51f2014-10-26 19:19:16 -0400114 next = list_entry(p, struct dentry, d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100115 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Nick Pigginda502952011-01-07 17:49:33 +1100116 if (simple_positive(next))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 n--;
Nick Pigginda502952011-01-07 17:49:33 +1100118 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 p = p->next;
120 }
Al Viro946e51f2014-10-26 19:19:16 -0400121 list_add_tail(&cursor->d_child, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100122 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 }
124 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 return offset;
126}
Al Viro12f38872013-09-15 21:20:49 -0400127EXPORT_SYMBOL(dcache_dir_lseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129/* Relationship between i_mode and the DT_xxx types */
130static inline unsigned char dt_type(struct inode *inode)
131{
132 return (inode->i_mode >> 12) & 15;
133}
134
135/*
136 * Directory is locked and all positive dentries in it are safe, since
137 * for ramfs-type trees they can't go away without unlink() or rmdir(),
138 * both impossible due to the lock on directory.
139 */
140
Al Viro5f99f4e2013-05-15 20:23:06 -0400141int dcache_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142{
Al Viro5f99f4e2013-05-15 20:23:06 -0400143 struct dentry *dentry = file->f_path.dentry;
144 struct dentry *cursor = file->private_data;
Al Viro946e51f2014-10-26 19:19:16 -0400145 struct list_head *p, *q = &cursor->d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
Al Viro5f99f4e2013-05-15 20:23:06 -0400147 if (!dir_emit_dots(file, ctx))
148 return 0;
149 spin_lock(&dentry->d_lock);
150 if (ctx->pos == 2)
151 list_move(q, &dentry->d_subdirs);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700152
Al Viro5f99f4e2013-05-15 20:23:06 -0400153 for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
Al Viro946e51f2014-10-26 19:19:16 -0400154 struct dentry *next = list_entry(p, struct dentry, d_child);
Al Viro5f99f4e2013-05-15 20:23:06 -0400155 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
156 if (!simple_positive(next)) {
157 spin_unlock(&next->d_lock);
158 continue;
159 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
Al Viro5f99f4e2013-05-15 20:23:06 -0400161 spin_unlock(&next->d_lock);
162 spin_unlock(&dentry->d_lock);
163 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
David Howellsdea655c2015-03-17 22:26:15 +0000164 d_inode(next)->i_ino, dt_type(d_inode(next))))
Al Viro5f99f4e2013-05-15 20:23:06 -0400165 return 0;
166 spin_lock(&dentry->d_lock);
167 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
168 /* next is still alive */
169 list_move(q, p);
170 spin_unlock(&next->d_lock);
171 p = q;
172 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 }
Al Viro5f99f4e2013-05-15 20:23:06 -0400174 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 return 0;
176}
Al Viro12f38872013-09-15 21:20:49 -0400177EXPORT_SYMBOL(dcache_readdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
180{
181 return -EISDIR;
182}
Al Viro12f38872013-09-15 21:20:49 -0400183EXPORT_SYMBOL(generic_read_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800185const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 .open = dcache_dir_open,
187 .release = dcache_dir_close,
188 .llseek = dcache_dir_lseek,
189 .read = generic_read_dir,
Al Viro4e829012016-04-20 19:52:15 -0400190 .iterate_shared = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200191 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192};
Al Viro12f38872013-09-15 21:20:49 -0400193EXPORT_SYMBOL(simple_dir_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800195const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 .lookup = simple_lookup,
197};
Al Viro12f38872013-09-15 21:20:49 -0400198EXPORT_SYMBOL(simple_dir_inode_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Hugh Dickins759b9772007-03-05 00:30:28 -0800200static const struct super_operations simple_super_operations = {
201 .statfs = simple_statfs,
202};
203
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204/*
205 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
206 * will never be mountable)
207 */
Al Viro51139ad2010-07-25 23:47:46 +0400208struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
Al Viroc74a1cb2011-01-12 16:59:34 -0500209 const struct super_operations *ops,
210 const struct dentry_operations *dops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211{
David Howells9249e172012-06-25 12:55:37 +0100212 struct super_block *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 struct dentry *dentry;
214 struct inode *root;
Linus Torvalds26fe5752012-05-10 13:14:12 -0700215 struct qstr d_name = QSTR_INIT(name, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
David Howells9249e172012-06-25 12:55:37 +0100217 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400219 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220
Jeff Layton89a4eb42009-08-18 14:11:08 -0700221 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700222 s->s_blocksize = PAGE_SIZE;
223 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800225 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 s->s_time_gran = 1;
227 root = new_inode(s);
228 if (!root)
229 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700230 /*
231 * since this is the first inode, make it number 1. New inodes created
232 * after this must take care not to collide with it (by passing
233 * max_reserved of 1 to iunique).
234 */
235 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
Al Viroa4464db2011-07-07 15:03:58 -0400238 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 if (!dentry) {
240 iput(root);
241 goto Enomem;
242 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 d_instantiate(dentry, root);
244 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500245 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400247 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400250 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400251 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252}
Al Viro12f38872013-09-15 21:20:49 -0400253EXPORT_SYMBOL(mount_pseudo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Stephen Boyd20955e82012-04-05 14:25:09 -0700255int simple_open(struct inode *inode, struct file *file)
256{
257 if (inode->i_private)
258 file->private_data = inode->i_private;
259 return 0;
260}
Al Viro12f38872013-09-15 21:20:49 -0400261EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
264{
David Howellsdea655c2015-03-17 22:26:15 +0000265 struct inode *inode = d_inode(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
267 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700268 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400269 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 dget(dentry);
271 d_instantiate(dentry, inode);
272 return 0;
273}
Al Viro12f38872013-09-15 21:20:49 -0400274EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276int simple_empty(struct dentry *dentry)
277{
278 struct dentry *child;
279 int ret = 0;
280
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100281 spin_lock(&dentry->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400282 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
Nick Pigginda502952011-01-07 17:49:33 +1100283 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
284 if (simple_positive(child)) {
285 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100287 }
288 spin_unlock(&child->d_lock);
289 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 ret = 1;
291out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100292 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return ret;
294}
Al Viro12f38872013-09-15 21:20:49 -0400295EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
297int simple_unlink(struct inode *dir, struct dentry *dentry)
298{
David Howellsdea655c2015-03-17 22:26:15 +0000299 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
301 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700302 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 dput(dentry);
304 return 0;
305}
Al Viro12f38872013-09-15 21:20:49 -0400306EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
308int simple_rmdir(struct inode *dir, struct dentry *dentry)
309{
310 if (!simple_empty(dentry))
311 return -ENOTEMPTY;
312
David Howellsdea655c2015-03-17 22:26:15 +0000313 drop_nlink(d_inode(dentry));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700315 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 return 0;
317}
Al Viro12f38872013-09-15 21:20:49 -0400318EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
320int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
321 struct inode *new_dir, struct dentry *new_dentry)
322{
David Howellsdea655c2015-03-17 22:26:15 +0000323 struct inode *inode = d_inode(old_dentry);
David Howellse36cb0b2015-01-29 12:02:35 +0000324 int they_are_dirs = d_is_dir(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
326 if (!simple_empty(new_dentry))
327 return -ENOTEMPTY;
328
David Howellsdea655c2015-03-17 22:26:15 +0000329 if (d_really_is_positive(new_dentry)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400331 if (they_are_dirs) {
David Howellsdea655c2015-03-17 22:26:15 +0000332 drop_nlink(d_inode(new_dentry));
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700333 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400334 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700336 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700337 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 }
339
340 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
341 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
342
343 return 0;
344}
Al Viro12f38872013-09-15 21:20:49 -0400345EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000347/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200348 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000349 * @dentry: dentry
350 * @iattr: iattr structure
351 *
352 * Returns 0 on success, -error on failure.
353 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200354 * simple_setattr is a simple ->setattr implementation without a proper
355 * implementation of size changes.
356 *
357 * It can either be used for in-memory filesystems or special files
358 * on simple regular filesystems. Anything that needs to change on-disk
359 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000360 */
361int simple_setattr(struct dentry *dentry, struct iattr *iattr)
362{
David Howellsdea655c2015-03-17 22:26:15 +0000363 struct inode *inode = d_inode(dentry);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000364 int error;
365
366 error = inode_change_ok(inode, iattr);
367 if (error)
368 return error;
369
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200370 if (iattr->ia_valid & ATTR_SIZE)
371 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200372 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200373 mark_inode_dirty(inode);
374 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000375}
376EXPORT_SYMBOL(simple_setattr);
377
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378int simple_readpage(struct file *file, struct page *page)
379{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700380 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 flush_dcache_page(page);
382 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 unlock_page(page);
384 return 0;
385}
Al Viro12f38872013-09-15 21:20:49 -0400386EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387
Nick Pigginafddba42007-10-16 01:25:01 -0700388int simple_write_begin(struct file *file, struct address_space *mapping,
389 loff_t pos, unsigned len, unsigned flags,
390 struct page **pagep, void **fsdata)
391{
392 struct page *page;
393 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700394
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300395 index = pos >> PAGE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700396
Nick Piggin54566b22009-01-04 12:00:53 -0800397 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700398 if (!page)
399 return -ENOMEM;
400
401 *pagep = page;
402
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300403 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
404 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200405
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300406 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200407 }
408 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700409}
Al Viro12f38872013-09-15 21:20:49 -0400410EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700411
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200412/**
413 * simple_write_end - .write_end helper for non-block-device FSes
414 * @available: See .write_end of address_space_operations
415 * @file: "
416 * @mapping: "
417 * @pos: "
418 * @len: "
419 * @copied: "
420 * @page: "
421 * @fsdata: "
422 *
423 * simple_write_end does the minimum needed for updating a page after writing is
424 * done. It has the same API signature as the .write_end of
425 * address_space_operations vector. So it can just be set onto .write_end for
426 * FSes that don't need any other processing. i_mutex is assumed to be held.
427 * Block based filesystems should use generic_write_end().
428 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
429 * is not called, so a filesystem that actually does store data in .write_inode
430 * should extend on what's done here with a call to mark_inode_dirty() in the
431 * case that i_size has changed.
432 */
433int simple_write_end(struct file *file, struct address_space *mapping,
434 loff_t pos, unsigned len, unsigned copied,
435 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436{
437 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200438 loff_t last_pos = pos + copied;
439
440 /* zero the stale part of the page if we did a short copy */
441 if (copied < len) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300442 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200443
444 zero_user(page, from + copied, len - copied);
445 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
Nick Piggin955eff52007-02-20 13:58:08 -0800447 if (!PageUptodate(page))
448 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 /*
450 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800451 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200453 if (last_pos > inode->i_size)
454 i_size_write(inode, last_pos);
455
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700457 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300458 put_page(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700459
460 return copied;
461}
Al Viro12f38872013-09-15 21:20:49 -0400462EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700463
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700464/*
465 * the inodes created here are not hashed. If you use iunique to generate
466 * unique inode values later for this filesystem, then you must take care
467 * to pass it an appropriate max_reserved value to avoid collisions.
468 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200469int simple_fill_super(struct super_block *s, unsigned long magic,
470 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 struct inode *inode;
473 struct dentry *root;
474 struct dentry *dentry;
475 int i;
476
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300477 s->s_blocksize = PAGE_SIZE;
478 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800480 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 s->s_time_gran = 1;
482
483 inode = new_inode(s);
484 if (!inode)
485 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700486 /*
487 * because the root inode is 1, the files array must not contain an
488 * entry at index 1
489 */
490 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
493 inode->i_op = &simple_dir_inode_operations;
494 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200495 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500496 root = d_make_root(inode);
497 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 for (i = 0; !files->name || files->name[0]; i++, files++) {
500 if (!files->name)
501 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700502
503 /* warn if it tries to conflict with the root inode */
504 if (unlikely(i == 1))
505 printk(KERN_WARNING "%s: %s passed in a files array"
506 "with an index of 1!\n", __func__,
507 s->s_type->name);
508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 dentry = d_alloc_name(root, files->name);
510 if (!dentry)
511 goto out;
512 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300513 if (!inode) {
514 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300516 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
519 inode->i_fop = files->ops;
520 inode->i_ino = i;
521 d_add(dentry, inode);
522 }
523 s->s_root = root;
524 return 0;
525out:
526 d_genocide(root);
Al Viro640946f2012-04-02 19:22:25 -0400527 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 dput(root);
529 return -ENOMEM;
530}
Al Viro12f38872013-09-15 21:20:49 -0400531EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532
533static DEFINE_SPINLOCK(pin_fs_lock);
534
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400535int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536{
537 struct vfsmount *mnt = NULL;
538 spin_lock(&pin_fs_lock);
539 if (unlikely(!*mount)) {
540 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400541 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 if (IS_ERR(mnt))
543 return PTR_ERR(mnt);
544 spin_lock(&pin_fs_lock);
545 if (!*mount)
546 *mount = mnt;
547 }
548 mntget(*mount);
549 ++*count;
550 spin_unlock(&pin_fs_lock);
551 mntput(mnt);
552 return 0;
553}
Al Viro12f38872013-09-15 21:20:49 -0400554EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
556void simple_release_fs(struct vfsmount **mount, int *count)
557{
558 struct vfsmount *mnt;
559 spin_lock(&pin_fs_lock);
560 mnt = *mount;
561 if (!--*count)
562 *mount = NULL;
563 spin_unlock(&pin_fs_lock);
564 mntput(mnt);
565}
Al Viro12f38872013-09-15 21:20:49 -0400566EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700568/**
569 * simple_read_from_buffer - copy data from the buffer to user space
570 * @to: the user space buffer to read to
571 * @count: the maximum number of bytes to read
572 * @ppos: the current position in the buffer
573 * @from: the buffer to read from
574 * @available: the size of the buffer
575 *
576 * The simple_read_from_buffer() function reads up to @count bytes from the
577 * buffer @from at offset @ppos into the user space address starting at @to.
578 *
579 * On success, the number of bytes read is returned and the offset @ppos is
580 * advanced by this number, or negative value is returned on error.
581 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
583 const void *from, size_t available)
584{
585 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700586 size_t ret;
587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 if (pos < 0)
589 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700590 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 return 0;
592 if (count > available - pos)
593 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700594 ret = copy_to_user(to, from + pos, count);
595 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700597 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 *ppos = pos + count;
599 return count;
600}
Al Viro12f38872013-09-15 21:20:49 -0400601EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700603/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200604 * simple_write_to_buffer - copy data from user space to the buffer
605 * @to: the buffer to write to
606 * @available: the size of the buffer
607 * @ppos: the current position in the buffer
608 * @from: the user space buffer to read from
609 * @count: the maximum number of bytes to read
610 *
611 * The simple_write_to_buffer() function reads up to @count bytes from the user
612 * space address starting at @from into the buffer @to at offset @ppos.
613 *
614 * On success, the number of bytes written is returned and the offset @ppos is
615 * advanced by this number, or negative value is returned on error.
616 **/
617ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
618 const void __user *from, size_t count)
619{
620 loff_t pos = *ppos;
621 size_t res;
622
623 if (pos < 0)
624 return -EINVAL;
625 if (pos >= available || !count)
626 return 0;
627 if (count > available - pos)
628 count = available - pos;
629 res = copy_from_user(to + pos, from, count);
630 if (res == count)
631 return -EFAULT;
632 count -= res;
633 *ppos = pos + count;
634 return count;
635}
Al Viro12f38872013-09-15 21:20:49 -0400636EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200637
638/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700639 * memory_read_from_buffer - copy data from the buffer
640 * @to: the kernel space buffer to read to
641 * @count: the maximum number of bytes to read
642 * @ppos: the current position in the buffer
643 * @from: the buffer to read from
644 * @available: the size of the buffer
645 *
646 * The memory_read_from_buffer() function reads up to @count bytes from the
647 * buffer @from at offset @ppos into the kernel space address starting at @to.
648 *
649 * On success, the number of bytes read is returned and the offset @ppos is
650 * advanced by this number, or negative value is returned on error.
651 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700652ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
653 const void *from, size_t available)
654{
655 loff_t pos = *ppos;
656
657 if (pos < 0)
658 return -EINVAL;
659 if (pos >= available)
660 return 0;
661 if (count > available - pos)
662 count = available - pos;
663 memcpy(to, from + pos, count);
664 *ppos = pos + count;
665
666 return count;
667}
Al Viro12f38872013-09-15 21:20:49 -0400668EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700669
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670/*
671 * Transaction based IO.
672 * The file expects a single write which triggers the transaction, and then
673 * possibly a read which collects the result - which is stored in a
674 * file-local buffer.
675 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100676
677void simple_transaction_set(struct file *file, size_t n)
678{
679 struct simple_transaction_argresp *ar = file->private_data;
680
681 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
682
683 /*
684 * The barrier ensures that ar->size will really remain zero until
685 * ar->data is ready for reading.
686 */
687 smp_mb();
688 ar->size = n;
689}
Al Viro12f38872013-09-15 21:20:49 -0400690EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
693{
694 struct simple_transaction_argresp *ar;
695 static DEFINE_SPINLOCK(simple_transaction_lock);
696
697 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
698 return ERR_PTR(-EFBIG);
699
700 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
701 if (!ar)
702 return ERR_PTR(-ENOMEM);
703
704 spin_lock(&simple_transaction_lock);
705
706 /* only one write allowed per open */
707 if (file->private_data) {
708 spin_unlock(&simple_transaction_lock);
709 free_page((unsigned long)ar);
710 return ERR_PTR(-EBUSY);
711 }
712
713 file->private_data = ar;
714
715 spin_unlock(&simple_transaction_lock);
716
717 if (copy_from_user(ar->data, buf, size))
718 return ERR_PTR(-EFAULT);
719
720 return ar->data;
721}
Al Viro12f38872013-09-15 21:20:49 -0400722EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723
724ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
725{
726 struct simple_transaction_argresp *ar = file->private_data;
727
728 if (!ar)
729 return 0;
730 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
731}
Al Viro12f38872013-09-15 21:20:49 -0400732EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733
734int simple_transaction_release(struct inode *inode, struct file *file)
735{
736 free_page((unsigned long)file->private_data);
737 return 0;
738}
Al Viro12f38872013-09-15 21:20:49 -0400739EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200741/* Simple attribute files */
742
743struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800744 int (*get)(void *, u64 *);
745 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200746 char get_buf[24]; /* enough to store a u64 and "\n\0" */
747 char set_buf[24];
748 void *data;
749 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800750 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200751};
752
753/* simple_attr_open is called by an actual attribute open file operation
754 * to set the attribute specific access operations. */
755int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800756 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200757 const char *fmt)
758{
759 struct simple_attr *attr;
760
761 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
762 if (!attr)
763 return -ENOMEM;
764
765 attr->get = get;
766 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700767 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200768 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800769 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200770
771 file->private_data = attr;
772
773 return nonseekable_open(inode, file);
774}
Al Viro12f38872013-09-15 21:20:49 -0400775EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200776
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800777int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200778{
779 kfree(file->private_data);
780 return 0;
781}
Al Viro12f38872013-09-15 21:20:49 -0400782EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200783
784/* read from the buffer that is filled with the get function */
785ssize_t simple_attr_read(struct file *file, char __user *buf,
786 size_t len, loff_t *ppos)
787{
788 struct simple_attr *attr;
789 size_t size;
790 ssize_t ret;
791
792 attr = file->private_data;
793
794 if (!attr->get)
795 return -EACCES;
796
Christoph Hellwig92613032008-02-08 04:20:27 -0800797 ret = mutex_lock_interruptible(&attr->mutex);
798 if (ret)
799 return ret;
800
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800801 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200802 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800803 } else { /* first read */
804 u64 val;
805 ret = attr->get(attr->data, &val);
806 if (ret)
807 goto out;
808
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200809 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800810 attr->fmt, (unsigned long long)val);
811 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200812
813 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800814out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800815 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200816 return ret;
817}
Al Viro12f38872013-09-15 21:20:49 -0400818EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200819
820/* interpret the buffer as a number to call the set function with */
821ssize_t simple_attr_write(struct file *file, const char __user *buf,
822 size_t len, loff_t *ppos)
823{
824 struct simple_attr *attr;
825 u64 val;
826 size_t size;
827 ssize_t ret;
828
829 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200830 if (!attr->set)
831 return -EACCES;
832
Christoph Hellwig92613032008-02-08 04:20:27 -0800833 ret = mutex_lock_interruptible(&attr->mutex);
834 if (ret)
835 return ret;
836
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200837 ret = -EFAULT;
838 size = min(sizeof(attr->set_buf) - 1, len);
839 if (copy_from_user(attr->set_buf, buf, size))
840 goto out;
841
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200842 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700843 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700844 ret = attr->set(attr->data, val);
845 if (ret == 0)
846 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200847out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800848 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200849 return ret;
850}
Al Viro12f38872013-09-15 21:20:49 -0400851EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200852
Christoph Hellwig25961102007-10-21 16:42:05 -0700853/**
854 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
855 * @sb: filesystem to do the file handle conversion on
856 * @fid: file handle to convert
857 * @fh_len: length of the file handle in bytes
858 * @fh_type: type of file handle
859 * @get_inode: filesystem callback to retrieve inode
860 *
861 * This function decodes @fid as long as it has one of the well-known
862 * Linux filehandle types and calls @get_inode on it to retrieve the
863 * inode for the object specified in the file handle.
864 */
865struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
866 int fh_len, int fh_type, struct inode *(*get_inode)
867 (struct super_block *sb, u64 ino, u32 gen))
868{
869 struct inode *inode = NULL;
870
871 if (fh_len < 2)
872 return NULL;
873
874 switch (fh_type) {
875 case FILEID_INO32_GEN:
876 case FILEID_INO32_GEN_PARENT:
877 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
878 break;
879 }
880
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200881 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700882}
883EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
884
885/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800886 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700887 * @sb: filesystem to do the file handle conversion on
888 * @fid: file handle to convert
889 * @fh_len: length of the file handle in bytes
890 * @fh_type: type of file handle
891 * @get_inode: filesystem callback to retrieve inode
892 *
893 * This function decodes @fid as long as it has one of the well-known
894 * Linux filehandle types and calls @get_inode on it to retrieve the
895 * inode for the _parent_ object specified in the file handle if it
896 * is specified in the file handle, or NULL otherwise.
897 */
898struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
899 int fh_len, int fh_type, struct inode *(*get_inode)
900 (struct super_block *sb, u64 ino, u32 gen))
901{
902 struct inode *inode = NULL;
903
904 if (fh_len <= 2)
905 return NULL;
906
907 switch (fh_type) {
908 case FILEID_INO32_GEN_PARENT:
909 inode = get_inode(sb, fid->i32.parent_ino,
910 (fh_len > 3 ? fid->i32.parent_gen : 0));
911 break;
912 }
913
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200914 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700915}
916EXPORT_SYMBOL_GPL(generic_fh_to_parent);
917
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200918/**
Fabian Frederickac13a822014-06-04 16:06:27 -0700919 * __generic_file_fsync - generic fsync implementation for simple filesystems
920 *
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200921 * @file: file to synchronize
Fabian Frederickac13a822014-06-04 16:06:27 -0700922 * @start: start offset in bytes
923 * @end: end offset in bytes (inclusive)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200924 * @datasync: only synchronize essential metadata if true
925 *
926 * This is a generic implementation of the fsync method for simple
927 * filesystems which track all non-inode metadata in the buffers list
928 * hanging off the address_space structure.
929 */
Fabian Frederickac13a822014-06-04 16:06:27 -0700930int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
931 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400932{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200933 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400934 int err;
935 int ret;
936
Josef Bacik02c24a82011-07-16 20:44:56 -0400937 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
938 if (err)
939 return err;
940
Al Viro59551022016-01-22 15:40:57 -0500941 inode_lock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400942 ret = sync_mapping_buffers(inode->i_mapping);
Theodore Ts'o0ae45f62015-02-02 00:37:00 -0500943 if (!(inode->i_state & I_DIRTY_ALL))
Josef Bacik02c24a82011-07-16 20:44:56 -0400944 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400945 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400946 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400947
Christoph Hellwigc37650162010-10-06 10:48:20 +0200948 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400949 if (ret == 0)
950 ret = err;
Fabian Frederickac13a822014-06-04 16:06:27 -0700951
Josef Bacik02c24a82011-07-16 20:44:56 -0400952out:
Al Viro59551022016-01-22 15:40:57 -0500953 inode_unlock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400954 return ret;
955}
Fabian Frederickac13a822014-06-04 16:06:27 -0700956EXPORT_SYMBOL(__generic_file_fsync);
957
958/**
959 * generic_file_fsync - generic fsync implementation for simple filesystems
960 * with flush
961 * @file: file to synchronize
962 * @start: start offset in bytes
963 * @end: end offset in bytes (inclusive)
964 * @datasync: only synchronize essential metadata if true
965 *
966 */
967
968int generic_file_fsync(struct file *file, loff_t start, loff_t end,
969 int datasync)
970{
971 struct inode *inode = file->f_mapping->host;
972 int err;
973
974 err = __generic_file_fsync(file, start, end, datasync);
975 if (err)
976 return err;
977 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
978}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200979EXPORT_SYMBOL(generic_file_fsync);
980
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700981/**
982 * generic_check_addressable - Check addressability of file system
983 * @blocksize_bits: log of file system block size
984 * @num_blocks: number of blocks in file system
985 *
986 * Determine whether a file system with @num_blocks blocks (and a
987 * block size of 2**@blocksize_bits) is addressable by the sector_t
988 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
989 */
990int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
991{
992 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -0700993 u64 last_fs_page =
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300994 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700995
996 if (unlikely(num_blocks == 0))
997 return 0;
998
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300999 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001000 return -EINVAL;
1001
Joel Beckera33f13e2010-08-16 12:10:17 -07001002 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1003 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001004 return -EFBIG;
1005 }
1006 return 0;
1007}
1008EXPORT_SYMBOL(generic_check_addressable);
1009
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001010/*
1011 * No-op implementation of ->fsync for in-memory filesystems.
1012 */
Josef Bacik02c24a82011-07-16 20:44:56 -04001013int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001014{
1015 return 0;
1016}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001017EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -04001018
Al Virofceef392015-12-29 15:58:39 -05001019/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1020void kfree_link(void *p)
Al Viro87dc8002013-09-16 10:30:04 -04001021{
Al Virofceef392015-12-29 15:58:39 -05001022 kfree(p);
Al Viro87dc8002013-09-16 10:30:04 -04001023}
Al Virofceef392015-12-29 15:58:39 -05001024EXPORT_SYMBOL(kfree_link);
Al Viro69878432013-10-02 22:35:11 -04001025
1026/*
1027 * nop .set_page_dirty method so that people can use .page_mkwrite on
1028 * anon inodes.
1029 */
1030static int anon_set_page_dirty(struct page *page)
1031{
1032 return 0;
1033};
1034
1035/*
1036 * A single inode exists for all anon_inode files. Contrary to pipes,
1037 * anon_inode inodes have no associated per-instance data, so we need
1038 * only allocate one of them.
1039 */
1040struct inode *alloc_anon_inode(struct super_block *s)
1041{
1042 static const struct address_space_operations anon_aops = {
1043 .set_page_dirty = anon_set_page_dirty,
1044 };
1045 struct inode *inode = new_inode_pseudo(s);
1046
1047 if (!inode)
1048 return ERR_PTR(-ENOMEM);
1049
1050 inode->i_ino = get_next_ino();
1051 inode->i_mapping->a_ops = &anon_aops;
1052
1053 /*
1054 * Mark the inode dirty from the very beginning,
1055 * that way it will never be moved to the dirty
1056 * list because mark_inode_dirty() will think
1057 * that it already _is_ on the dirty list.
1058 */
1059 inode->i_state = I_DIRTY;
1060 inode->i_mode = S_IRUSR | S_IWUSR;
1061 inode->i_uid = current_fsuid();
1062 inode->i_gid = current_fsgid();
1063 inode->i_flags |= S_PRIVATE;
1064 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1065 return inode;
1066}
1067EXPORT_SYMBOL(alloc_anon_inode);
Jeff Layton1c994a02014-08-27 06:49:41 -04001068
1069/**
1070 * simple_nosetlease - generic helper for prohibiting leases
1071 * @filp: file pointer
1072 * @arg: type of lease to obtain
1073 * @flp: new lease supplied for insertion
Jeff Laytone6f5c782014-08-22 10:40:25 -04001074 * @priv: private data for lm_setup operation
Jeff Layton1c994a02014-08-27 06:49:41 -04001075 *
1076 * Generic helper for filesystems that do not wish to allow leases to be set.
1077 * All arguments are ignored and it just returns -EINVAL.
1078 */
1079int
Jeff Laytone6f5c782014-08-22 10:40:25 -04001080simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1081 void **priv)
Jeff Layton1c994a02014-08-27 06:49:41 -04001082{
1083 return -EINVAL;
1084}
1085EXPORT_SYMBOL(simple_nosetlease);
Al Viro61ba64f2015-05-02 09:54:06 -04001086
Al Viro6b255392015-11-17 10:20:54 -05001087const char *simple_get_link(struct dentry *dentry, struct inode *inode,
Al Virofceef392015-12-29 15:58:39 -05001088 struct delayed_call *done)
Al Viro61ba64f2015-05-02 09:54:06 -04001089{
Al Viro6b255392015-11-17 10:20:54 -05001090 return inode->i_link;
Al Viro61ba64f2015-05-02 09:54:06 -04001091}
Al Viro6b255392015-11-17 10:20:54 -05001092EXPORT_SYMBOL(simple_get_link);
Al Viro61ba64f2015-05-02 09:54:06 -04001093
1094const struct inode_operations simple_symlink_inode_operations = {
Al Viro6b255392015-11-17 10:20:54 -05001095 .get_link = simple_get_link,
Al Viro61ba64f2015-05-02 09:54:06 -04001096 .readlink = generic_readlink
1097};
1098EXPORT_SYMBOL(simple_symlink_inode_operations);
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001099
1100/*
1101 * Operations for a permanently empty directory.
1102 */
1103static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1104{
1105 return ERR_PTR(-ENOENT);
1106}
1107
1108static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
1109 struct kstat *stat)
1110{
1111 struct inode *inode = d_inode(dentry);
1112 generic_fillattr(inode, stat);
1113 return 0;
1114}
1115
1116static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1117{
1118 return -EPERM;
1119}
1120
Al Viro3767e252016-05-27 11:06:05 -04001121static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
1122 const char *name, const void *value,
1123 size_t size, int flags)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001124{
1125 return -EOPNOTSUPP;
1126}
1127
Al Viroce23e642016-04-11 00:48:00 -04001128static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
1129 const char *name, void *value, size_t size)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001130{
1131 return -EOPNOTSUPP;
1132}
1133
1134static int empty_dir_removexattr(struct dentry *dentry, const char *name)
1135{
1136 return -EOPNOTSUPP;
1137}
1138
1139static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1140{
1141 return -EOPNOTSUPP;
1142}
1143
1144static const struct inode_operations empty_dir_inode_operations = {
1145 .lookup = empty_dir_lookup,
1146 .permission = generic_permission,
1147 .setattr = empty_dir_setattr,
1148 .getattr = empty_dir_getattr,
1149 .setxattr = empty_dir_setxattr,
1150 .getxattr = empty_dir_getxattr,
1151 .removexattr = empty_dir_removexattr,
1152 .listxattr = empty_dir_listxattr,
1153};
1154
1155static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1156{
1157 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1158 return generic_file_llseek_size(file, offset, whence, 2, 2);
1159}
1160
1161static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1162{
1163 dir_emit_dots(file, ctx);
1164 return 0;
1165}
1166
1167static const struct file_operations empty_dir_operations = {
1168 .llseek = empty_dir_llseek,
1169 .read = generic_read_dir,
Al Viroc51da202016-04-30 22:37:34 -04001170 .iterate_shared = empty_dir_readdir,
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001171 .fsync = noop_fsync,
1172};
1173
1174
1175void make_empty_dir_inode(struct inode *inode)
1176{
1177 set_nlink(inode, 2);
1178 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1179 inode->i_uid = GLOBAL_ROOT_UID;
1180 inode->i_gid = GLOBAL_ROOT_GID;
1181 inode->i_rdev = 0;
Eric W. Biederman4b75de862015-08-12 15:00:12 -05001182 inode->i_size = 0;
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001183 inode->i_blkbits = PAGE_SHIFT;
1184 inode->i_blocks = 0;
1185
1186 inode->i_op = &empty_dir_inode_operations;
1187 inode->i_fop = &empty_dir_operations;
1188}
1189
1190bool is_empty_dir_inode(struct inode *inode)
1191{
1192 return (inode->i_fop == &empty_dir_operations) &&
1193 (inode->i_op == &empty_dir_inode_operations);
1194}