blob: a1844244246f8e8e8da60da61e2aaabd2750e58e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/libfs.c
3 * Library for filesystems writers.
4 */
5
Paul Gortmaker630d9c42011-11-16 23:57:37 -05006#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/pagemap.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09008#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/mount.h>
10#include <linux/vfs.h>
npiggin@suse.de7bb46a62010-05-27 01:05:33 +100011#include <linux/quotaops.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080012#include <linux/mutex.h>
Al Viro87dc8002013-09-16 10:30:04 -040013#include <linux/namei.h>
Christoph Hellwig25961102007-10-21 16:42:05 -070014#include <linux/exportfs.h>
Al Virod5aacad2009-06-07 14:56:44 -040015#include <linux/writeback.h>
Al Viroff01bb42011-09-16 02:31:11 -040016#include <linux/buffer_head.h> /* sync_mapping_buffers */
Ingo Molnar7cf34c72006-03-23 03:00:36 -080017
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <asm/uaccess.h>
19
Al Viroa4464db2011-07-07 15:03:58 -040020#include "internal.h"
21
Nick Pigginda502952011-01-07 17:49:33 +110022static inline int simple_positive(struct dentry *dentry)
23{
24 return dentry->d_inode && !d_unhashed(dentry);
25}
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
28 struct kstat *stat)
29{
30 struct inode *inode = dentry->d_inode;
31 generic_fillattr(inode, stat);
32 stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
33 return 0;
34}
Al Viro12f38872013-09-15 21:20:49 -040035EXPORT_SYMBOL(simple_getattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
David Howells726c3342006-06-23 02:02:58 -070037int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070038{
David Howells726c3342006-06-23 02:02:58 -070039 buf->f_type = dentry->d_sb->s_magic;
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 buf->f_bsize = PAGE_CACHE_SIZE;
41 buf->f_namelen = NAME_MAX;
42 return 0;
43}
Al Viro12f38872013-09-15 21:20:49 -040044EXPORT_SYMBOL(simple_statfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
46/*
47 * Retaining negative dentries for an in-memory filesystem just wastes
48 * memory and lookup time: arrange for them to be deleted immediately.
49 */
Al Virob26d4cd2013-10-25 18:47:37 -040050int always_delete_dentry(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070051{
52 return 1;
53}
Al Virob26d4cd2013-10-25 18:47:37 -040054EXPORT_SYMBOL(always_delete_dentry);
55
56const struct dentry_operations simple_dentry_operations = {
57 .d_delete = always_delete_dentry,
58};
59EXPORT_SYMBOL(simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/*
62 * Lookup the data. This is trivial - if the dentry didn't already
63 * exist, we know it is negative. Set d_op to delete negative dentries.
64 */
Al Viro00cd8dd2012-06-10 17:13:09 -040065struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 if (dentry->d_name.len > NAME_MAX)
68 return ERR_PTR(-ENAMETOOLONG);
Al Viro74931da2013-07-14 17:43:25 +040069 if (!dentry->d_sb->s_d_op)
70 d_set_d_op(dentry, &simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 d_add(dentry, NULL);
72 return NULL;
73}
Al Viro12f38872013-09-15 21:20:49 -040074EXPORT_SYMBOL(simple_lookup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Linus Torvalds1da177e2005-04-16 15:20:36 -070076int dcache_dir_open(struct inode *inode, struct file *file)
77{
Linus Torvalds26fe5752012-05-10 13:14:12 -070078 static struct qstr cursor_name = QSTR_INIT(".", 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080080 file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
82 return file->private_data ? 0 : -ENOMEM;
83}
Al Viro12f38872013-09-15 21:20:49 -040084EXPORT_SYMBOL(dcache_dir_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
86int dcache_dir_close(struct inode *inode, struct file *file)
87{
88 dput(file->private_data);
89 return 0;
90}
Al Viro12f38872013-09-15 21:20:49 -040091EXPORT_SYMBOL(dcache_dir_close);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
Andrew Morton965c8e52012-12-17 15:59:39 -080093loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -070094{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110095 struct dentry *dentry = file->f_path.dentry;
96 mutex_lock(&dentry->d_inode->i_mutex);
Andrew Morton965c8e52012-12-17 15:59:39 -080097 switch (whence) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 case 1:
99 offset += file->f_pos;
100 case 0:
101 if (offset >= 0)
102 break;
103 default:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100104 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 return -EINVAL;
106 }
107 if (offset != file->f_pos) {
108 file->f_pos = offset;
109 if (file->f_pos >= 2) {
110 struct list_head *p;
111 struct dentry *cursor = file->private_data;
112 loff_t n = file->f_pos - 2;
113
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100114 spin_lock(&dentry->d_lock);
115 /* d_lock not required for cursor */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800116 list_del(&cursor->d_u.d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100117 p = dentry->d_subdirs.next;
118 while (n && p != &dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 struct dentry *next;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800120 next = list_entry(p, struct dentry, d_u.d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100121 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Nick Pigginda502952011-01-07 17:49:33 +1100122 if (simple_positive(next))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 n--;
Nick Pigginda502952011-01-07 17:49:33 +1100124 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 p = p->next;
126 }
Eric Dumazet5160ee62006-01-08 01:03:32 -0800127 list_add_tail(&cursor->d_u.d_child, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100128 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 }
130 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100131 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 return offset;
133}
Al Viro12f38872013-09-15 21:20:49 -0400134EXPORT_SYMBOL(dcache_dir_lseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136/* Relationship between i_mode and the DT_xxx types */
137static inline unsigned char dt_type(struct inode *inode)
138{
139 return (inode->i_mode >> 12) & 15;
140}
141
142/*
143 * Directory is locked and all positive dentries in it are safe, since
144 * for ramfs-type trees they can't go away without unlink() or rmdir(),
145 * both impossible due to the lock on directory.
146 */
147
Al Viro5f99f4e2013-05-15 20:23:06 -0400148int dcache_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
Al Viro5f99f4e2013-05-15 20:23:06 -0400150 struct dentry *dentry = file->f_path.dentry;
151 struct dentry *cursor = file->private_data;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800152 struct list_head *p, *q = &cursor->d_u.d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Al Viro5f99f4e2013-05-15 20:23:06 -0400154 if (!dir_emit_dots(file, ctx))
155 return 0;
156 spin_lock(&dentry->d_lock);
157 if (ctx->pos == 2)
158 list_move(q, &dentry->d_subdirs);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700159
Al Viro5f99f4e2013-05-15 20:23:06 -0400160 for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
161 struct dentry *next = list_entry(p, struct dentry, d_u.d_child);
162 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
163 if (!simple_positive(next)) {
164 spin_unlock(&next->d_lock);
165 continue;
166 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Al Viro5f99f4e2013-05-15 20:23:06 -0400168 spin_unlock(&next->d_lock);
169 spin_unlock(&dentry->d_lock);
170 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
171 next->d_inode->i_ino, dt_type(next->d_inode)))
172 return 0;
173 spin_lock(&dentry->d_lock);
174 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
175 /* next is still alive */
176 list_move(q, p);
177 spin_unlock(&next->d_lock);
178 p = q;
179 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
Al Viro5f99f4e2013-05-15 20:23:06 -0400181 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 return 0;
183}
Al Viro12f38872013-09-15 21:20:49 -0400184EXPORT_SYMBOL(dcache_readdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
186ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
187{
188 return -EISDIR;
189}
Al Viro12f38872013-09-15 21:20:49 -0400190EXPORT_SYMBOL(generic_read_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800192const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 .open = dcache_dir_open,
194 .release = dcache_dir_close,
195 .llseek = dcache_dir_lseek,
196 .read = generic_read_dir,
Al Viro5f99f4e2013-05-15 20:23:06 -0400197 .iterate = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200198 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199};
Al Viro12f38872013-09-15 21:20:49 -0400200EXPORT_SYMBOL(simple_dir_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800202const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 .lookup = simple_lookup,
204};
Al Viro12f38872013-09-15 21:20:49 -0400205EXPORT_SYMBOL(simple_dir_inode_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Hugh Dickins759b9772007-03-05 00:30:28 -0800207static const struct super_operations simple_super_operations = {
208 .statfs = simple_statfs,
209};
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211/*
212 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
213 * will never be mountable)
214 */
Al Viro51139ad2010-07-25 23:47:46 +0400215struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
Al Viroc74a1cb2011-01-12 16:59:34 -0500216 const struct super_operations *ops,
217 const struct dentry_operations *dops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
David Howells9249e172012-06-25 12:55:37 +0100219 struct super_block *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 struct dentry *dentry;
221 struct inode *root;
Linus Torvalds26fe5752012-05-10 13:14:12 -0700222 struct qstr d_name = QSTR_INIT(name, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
David Howells9249e172012-06-25 12:55:37 +0100224 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400226 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
Jeff Layton89a4eb42009-08-18 14:11:08 -0700228 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700229 s->s_blocksize = PAGE_SIZE;
230 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800232 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 s->s_time_gran = 1;
234 root = new_inode(s);
235 if (!root)
236 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700237 /*
238 * since this is the first inode, make it number 1. New inodes created
239 * after this must take care not to collide with it (by passing
240 * max_reserved of 1 to iunique).
241 */
242 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
Al Viroa4464db2011-07-07 15:03:58 -0400245 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 if (!dentry) {
247 iput(root);
248 goto Enomem;
249 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 d_instantiate(dentry, root);
251 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500252 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400254 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
256Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400257 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400258 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259}
Al Viro12f38872013-09-15 21:20:49 -0400260EXPORT_SYMBOL(mount_pseudo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
Stephen Boyd20955e82012-04-05 14:25:09 -0700262int simple_open(struct inode *inode, struct file *file)
263{
264 if (inode->i_private)
265 file->private_data = inode->i_private;
266 return 0;
267}
Al Viro12f38872013-09-15 21:20:49 -0400268EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
271{
272 struct inode *inode = old_dentry->d_inode;
273
274 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700275 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400276 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 dget(dentry);
278 d_instantiate(dentry, inode);
279 return 0;
280}
Al Viro12f38872013-09-15 21:20:49 -0400281EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283int simple_empty(struct dentry *dentry)
284{
285 struct dentry *child;
286 int ret = 0;
287
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100288 spin_lock(&dentry->d_lock);
Nick Pigginda502952011-01-07 17:49:33 +1100289 list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
290 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
291 if (simple_positive(child)) {
292 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100294 }
295 spin_unlock(&child->d_lock);
296 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 ret = 1;
298out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100299 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 return ret;
301}
Al Viro12f38872013-09-15 21:20:49 -0400302EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304int simple_unlink(struct inode *dir, struct dentry *dentry)
305{
306 struct inode *inode = dentry->d_inode;
307
308 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700309 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 dput(dentry);
311 return 0;
312}
Al Viro12f38872013-09-15 21:20:49 -0400313EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314
315int simple_rmdir(struct inode *dir, struct dentry *dentry)
316{
317 if (!simple_empty(dentry))
318 return -ENOTEMPTY;
319
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700320 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700322 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 return 0;
324}
Al Viro12f38872013-09-15 21:20:49 -0400325EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
328 struct inode *new_dir, struct dentry *new_dentry)
329{
330 struct inode *inode = old_dentry->d_inode;
331 int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode);
332
333 if (!simple_empty(new_dentry))
334 return -ENOTEMPTY;
335
336 if (new_dentry->d_inode) {
337 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400338 if (they_are_dirs) {
339 drop_nlink(new_dentry->d_inode);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700340 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400341 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700343 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700344 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 }
346
347 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
348 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
349
350 return 0;
351}
Al Viro12f38872013-09-15 21:20:49 -0400352EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000354/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200355 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000356 * @dentry: dentry
357 * @iattr: iattr structure
358 *
359 * Returns 0 on success, -error on failure.
360 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200361 * simple_setattr is a simple ->setattr implementation without a proper
362 * implementation of size changes.
363 *
364 * It can either be used for in-memory filesystems or special files
365 * on simple regular filesystems. Anything that needs to change on-disk
366 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000367 */
368int simple_setattr(struct dentry *dentry, struct iattr *iattr)
369{
370 struct inode *inode = dentry->d_inode;
371 int error;
372
373 error = inode_change_ok(inode, iattr);
374 if (error)
375 return error;
376
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200377 if (iattr->ia_valid & ATTR_SIZE)
378 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200379 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200380 mark_inode_dirty(inode);
381 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000382}
383EXPORT_SYMBOL(simple_setattr);
384
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385int simple_readpage(struct file *file, struct page *page)
386{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700387 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 flush_dcache_page(page);
389 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 unlock_page(page);
391 return 0;
392}
Al Viro12f38872013-09-15 21:20:49 -0400393EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
Nick Pigginafddba42007-10-16 01:25:01 -0700395int simple_write_begin(struct file *file, struct address_space *mapping,
396 loff_t pos, unsigned len, unsigned flags,
397 struct page **pagep, void **fsdata)
398{
399 struct page *page;
400 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700401
402 index = pos >> PAGE_CACHE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700403
Nick Piggin54566b22009-01-04 12:00:53 -0800404 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700405 if (!page)
406 return -ENOMEM;
407
408 *pagep = page;
409
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200410 if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
411 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
412
413 zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
414 }
415 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700416}
Al Viro12f38872013-09-15 21:20:49 -0400417EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700418
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200419/**
420 * simple_write_end - .write_end helper for non-block-device FSes
421 * @available: See .write_end of address_space_operations
422 * @file: "
423 * @mapping: "
424 * @pos: "
425 * @len: "
426 * @copied: "
427 * @page: "
428 * @fsdata: "
429 *
430 * simple_write_end does the minimum needed for updating a page after writing is
431 * done. It has the same API signature as the .write_end of
432 * address_space_operations vector. So it can just be set onto .write_end for
433 * FSes that don't need any other processing. i_mutex is assumed to be held.
434 * Block based filesystems should use generic_write_end().
435 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
436 * is not called, so a filesystem that actually does store data in .write_inode
437 * should extend on what's done here with a call to mark_inode_dirty() in the
438 * case that i_size has changed.
439 */
440int simple_write_end(struct file *file, struct address_space *mapping,
441 loff_t pos, unsigned len, unsigned copied,
442 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443{
444 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200445 loff_t last_pos = pos + copied;
446
447 /* zero the stale part of the page if we did a short copy */
448 if (copied < len) {
449 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
450
451 zero_user(page, from + copied, len - copied);
452 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Nick Piggin955eff52007-02-20 13:58:08 -0800454 if (!PageUptodate(page))
455 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 /*
457 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800458 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200460 if (last_pos > inode->i_size)
461 i_size_write(inode, last_pos);
462
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700464 unlock_page(page);
465 page_cache_release(page);
466
467 return copied;
468}
Al Viro12f38872013-09-15 21:20:49 -0400469EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700470
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700471/*
472 * the inodes created here are not hashed. If you use iunique to generate
473 * unique inode values later for this filesystem, then you must take care
474 * to pass it an appropriate max_reserved value to avoid collisions.
475 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200476int simple_fill_super(struct super_block *s, unsigned long magic,
477 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 struct inode *inode;
480 struct dentry *root;
481 struct dentry *dentry;
482 int i;
483
484 s->s_blocksize = PAGE_CACHE_SIZE;
485 s->s_blocksize_bits = PAGE_CACHE_SHIFT;
486 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800487 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 s->s_time_gran = 1;
489
490 inode = new_inode(s);
491 if (!inode)
492 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700493 /*
494 * because the root inode is 1, the files array must not contain an
495 * entry at index 1
496 */
497 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
500 inode->i_op = &simple_dir_inode_operations;
501 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200502 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500503 root = d_make_root(inode);
504 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 for (i = 0; !files->name || files->name[0]; i++, files++) {
507 if (!files->name)
508 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700509
510 /* warn if it tries to conflict with the root inode */
511 if (unlikely(i == 1))
512 printk(KERN_WARNING "%s: %s passed in a files array"
513 "with an index of 1!\n", __func__,
514 s->s_type->name);
515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 dentry = d_alloc_name(root, files->name);
517 if (!dentry)
518 goto out;
519 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300520 if (!inode) {
521 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300523 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
526 inode->i_fop = files->ops;
527 inode->i_ino = i;
528 d_add(dentry, inode);
529 }
530 s->s_root = root;
531 return 0;
532out:
533 d_genocide(root);
Al Viro640946f2012-04-02 19:22:25 -0400534 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 dput(root);
536 return -ENOMEM;
537}
Al Viro12f38872013-09-15 21:20:49 -0400538EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540static DEFINE_SPINLOCK(pin_fs_lock);
541
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400542int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543{
544 struct vfsmount *mnt = NULL;
545 spin_lock(&pin_fs_lock);
546 if (unlikely(!*mount)) {
547 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400548 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 if (IS_ERR(mnt))
550 return PTR_ERR(mnt);
551 spin_lock(&pin_fs_lock);
552 if (!*mount)
553 *mount = mnt;
554 }
555 mntget(*mount);
556 ++*count;
557 spin_unlock(&pin_fs_lock);
558 mntput(mnt);
559 return 0;
560}
Al Viro12f38872013-09-15 21:20:49 -0400561EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
563void simple_release_fs(struct vfsmount **mount, int *count)
564{
565 struct vfsmount *mnt;
566 spin_lock(&pin_fs_lock);
567 mnt = *mount;
568 if (!--*count)
569 *mount = NULL;
570 spin_unlock(&pin_fs_lock);
571 mntput(mnt);
572}
Al Viro12f38872013-09-15 21:20:49 -0400573EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700575/**
576 * simple_read_from_buffer - copy data from the buffer to user space
577 * @to: the user space buffer to read to
578 * @count: the maximum number of bytes to read
579 * @ppos: the current position in the buffer
580 * @from: the buffer to read from
581 * @available: the size of the buffer
582 *
583 * The simple_read_from_buffer() function reads up to @count bytes from the
584 * buffer @from at offset @ppos into the user space address starting at @to.
585 *
586 * On success, the number of bytes read is returned and the offset @ppos is
587 * advanced by this number, or negative value is returned on error.
588 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
590 const void *from, size_t available)
591{
592 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700593 size_t ret;
594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 if (pos < 0)
596 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700597 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 return 0;
599 if (count > available - pos)
600 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700601 ret = copy_to_user(to, from + pos, count);
602 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700604 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 *ppos = pos + count;
606 return count;
607}
Al Viro12f38872013-09-15 21:20:49 -0400608EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700610/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200611 * simple_write_to_buffer - copy data from user space to the buffer
612 * @to: the buffer to write to
613 * @available: the size of the buffer
614 * @ppos: the current position in the buffer
615 * @from: the user space buffer to read from
616 * @count: the maximum number of bytes to read
617 *
618 * The simple_write_to_buffer() function reads up to @count bytes from the user
619 * space address starting at @from into the buffer @to at offset @ppos.
620 *
621 * On success, the number of bytes written is returned and the offset @ppos is
622 * advanced by this number, or negative value is returned on error.
623 **/
624ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
625 const void __user *from, size_t count)
626{
627 loff_t pos = *ppos;
628 size_t res;
629
630 if (pos < 0)
631 return -EINVAL;
632 if (pos >= available || !count)
633 return 0;
634 if (count > available - pos)
635 count = available - pos;
636 res = copy_from_user(to + pos, from, count);
637 if (res == count)
638 return -EFAULT;
639 count -= res;
640 *ppos = pos + count;
641 return count;
642}
Al Viro12f38872013-09-15 21:20:49 -0400643EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200644
645/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700646 * memory_read_from_buffer - copy data from the buffer
647 * @to: the kernel space buffer to read to
648 * @count: the maximum number of bytes to read
649 * @ppos: the current position in the buffer
650 * @from: the buffer to read from
651 * @available: the size of the buffer
652 *
653 * The memory_read_from_buffer() function reads up to @count bytes from the
654 * buffer @from at offset @ppos into the kernel space address starting at @to.
655 *
656 * On success, the number of bytes read is returned and the offset @ppos is
657 * advanced by this number, or negative value is returned on error.
658 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700659ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
660 const void *from, size_t available)
661{
662 loff_t pos = *ppos;
663
664 if (pos < 0)
665 return -EINVAL;
666 if (pos >= available)
667 return 0;
668 if (count > available - pos)
669 count = available - pos;
670 memcpy(to, from + pos, count);
671 *ppos = pos + count;
672
673 return count;
674}
Al Viro12f38872013-09-15 21:20:49 -0400675EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677/*
678 * Transaction based IO.
679 * The file expects a single write which triggers the transaction, and then
680 * possibly a read which collects the result - which is stored in a
681 * file-local buffer.
682 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100683
684void simple_transaction_set(struct file *file, size_t n)
685{
686 struct simple_transaction_argresp *ar = file->private_data;
687
688 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
689
690 /*
691 * The barrier ensures that ar->size will really remain zero until
692 * ar->data is ready for reading.
693 */
694 smp_mb();
695 ar->size = n;
696}
Al Viro12f38872013-09-15 21:20:49 -0400697EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100698
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
700{
701 struct simple_transaction_argresp *ar;
702 static DEFINE_SPINLOCK(simple_transaction_lock);
703
704 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
705 return ERR_PTR(-EFBIG);
706
707 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
708 if (!ar)
709 return ERR_PTR(-ENOMEM);
710
711 spin_lock(&simple_transaction_lock);
712
713 /* only one write allowed per open */
714 if (file->private_data) {
715 spin_unlock(&simple_transaction_lock);
716 free_page((unsigned long)ar);
717 return ERR_PTR(-EBUSY);
718 }
719
720 file->private_data = ar;
721
722 spin_unlock(&simple_transaction_lock);
723
724 if (copy_from_user(ar->data, buf, size))
725 return ERR_PTR(-EFAULT);
726
727 return ar->data;
728}
Al Viro12f38872013-09-15 21:20:49 -0400729EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
731ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
732{
733 struct simple_transaction_argresp *ar = file->private_data;
734
735 if (!ar)
736 return 0;
737 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
738}
Al Viro12f38872013-09-15 21:20:49 -0400739EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
741int simple_transaction_release(struct inode *inode, struct file *file)
742{
743 free_page((unsigned long)file->private_data);
744 return 0;
745}
Al Viro12f38872013-09-15 21:20:49 -0400746EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200748/* Simple attribute files */
749
750struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800751 int (*get)(void *, u64 *);
752 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200753 char get_buf[24]; /* enough to store a u64 and "\n\0" */
754 char set_buf[24];
755 void *data;
756 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800757 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200758};
759
760/* simple_attr_open is called by an actual attribute open file operation
761 * to set the attribute specific access operations. */
762int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800763 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200764 const char *fmt)
765{
766 struct simple_attr *attr;
767
768 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
769 if (!attr)
770 return -ENOMEM;
771
772 attr->get = get;
773 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700774 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200775 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800776 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200777
778 file->private_data = attr;
779
780 return nonseekable_open(inode, file);
781}
Al Viro12f38872013-09-15 21:20:49 -0400782EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200783
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800784int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200785{
786 kfree(file->private_data);
787 return 0;
788}
Al Viro12f38872013-09-15 21:20:49 -0400789EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200790
791/* read from the buffer that is filled with the get function */
792ssize_t simple_attr_read(struct file *file, char __user *buf,
793 size_t len, loff_t *ppos)
794{
795 struct simple_attr *attr;
796 size_t size;
797 ssize_t ret;
798
799 attr = file->private_data;
800
801 if (!attr->get)
802 return -EACCES;
803
Christoph Hellwig92613032008-02-08 04:20:27 -0800804 ret = mutex_lock_interruptible(&attr->mutex);
805 if (ret)
806 return ret;
807
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800808 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200809 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800810 } else { /* first read */
811 u64 val;
812 ret = attr->get(attr->data, &val);
813 if (ret)
814 goto out;
815
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200816 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800817 attr->fmt, (unsigned long long)val);
818 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200819
820 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800821out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800822 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200823 return ret;
824}
Al Viro12f38872013-09-15 21:20:49 -0400825EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200826
827/* interpret the buffer as a number to call the set function with */
828ssize_t simple_attr_write(struct file *file, const char __user *buf,
829 size_t len, loff_t *ppos)
830{
831 struct simple_attr *attr;
832 u64 val;
833 size_t size;
834 ssize_t ret;
835
836 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200837 if (!attr->set)
838 return -EACCES;
839
Christoph Hellwig92613032008-02-08 04:20:27 -0800840 ret = mutex_lock_interruptible(&attr->mutex);
841 if (ret)
842 return ret;
843
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200844 ret = -EFAULT;
845 size = min(sizeof(attr->set_buf) - 1, len);
846 if (copy_from_user(attr->set_buf, buf, size))
847 goto out;
848
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200849 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700850 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700851 ret = attr->set(attr->data, val);
852 if (ret == 0)
853 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200854out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800855 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200856 return ret;
857}
Al Viro12f38872013-09-15 21:20:49 -0400858EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200859
Christoph Hellwig25961102007-10-21 16:42:05 -0700860/**
861 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
862 * @sb: filesystem to do the file handle conversion on
863 * @fid: file handle to convert
864 * @fh_len: length of the file handle in bytes
865 * @fh_type: type of file handle
866 * @get_inode: filesystem callback to retrieve inode
867 *
868 * This function decodes @fid as long as it has one of the well-known
869 * Linux filehandle types and calls @get_inode on it to retrieve the
870 * inode for the object specified in the file handle.
871 */
872struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
873 int fh_len, int fh_type, struct inode *(*get_inode)
874 (struct super_block *sb, u64 ino, u32 gen))
875{
876 struct inode *inode = NULL;
877
878 if (fh_len < 2)
879 return NULL;
880
881 switch (fh_type) {
882 case FILEID_INO32_GEN:
883 case FILEID_INO32_GEN_PARENT:
884 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
885 break;
886 }
887
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200888 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700889}
890EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
891
892/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800893 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700894 * @sb: filesystem to do the file handle conversion on
895 * @fid: file handle to convert
896 * @fh_len: length of the file handle in bytes
897 * @fh_type: type of file handle
898 * @get_inode: filesystem callback to retrieve inode
899 *
900 * This function decodes @fid as long as it has one of the well-known
901 * Linux filehandle types and calls @get_inode on it to retrieve the
902 * inode for the _parent_ object specified in the file handle if it
903 * is specified in the file handle, or NULL otherwise.
904 */
905struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
906 int fh_len, int fh_type, struct inode *(*get_inode)
907 (struct super_block *sb, u64 ino, u32 gen))
908{
909 struct inode *inode = NULL;
910
911 if (fh_len <= 2)
912 return NULL;
913
914 switch (fh_type) {
915 case FILEID_INO32_GEN_PARENT:
916 inode = get_inode(sb, fid->i32.parent_ino,
917 (fh_len > 3 ? fid->i32.parent_gen : 0));
918 break;
919 }
920
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200921 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700922}
923EXPORT_SYMBOL_GPL(generic_fh_to_parent);
924
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200925/**
926 * generic_file_fsync - generic fsync implementation for simple filesystems
927 * @file: file to synchronize
928 * @datasync: only synchronize essential metadata if true
929 *
930 * This is a generic implementation of the fsync method for simple
931 * filesystems which track all non-inode metadata in the buffers list
932 * hanging off the address_space structure.
933 */
Josef Bacik02c24a82011-07-16 20:44:56 -0400934int generic_file_fsync(struct file *file, loff_t start, loff_t end,
935 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400936{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200937 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400938 int err;
939 int ret;
940
Josef Bacik02c24a82011-07-16 20:44:56 -0400941 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
942 if (err)
943 return err;
944
945 mutex_lock(&inode->i_mutex);
Al Virod5aacad2009-06-07 14:56:44 -0400946 ret = sync_mapping_buffers(inode->i_mapping);
947 if (!(inode->i_state & I_DIRTY))
Josef Bacik02c24a82011-07-16 20:44:56 -0400948 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400949 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400950 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400951
Christoph Hellwigc37650162010-10-06 10:48:20 +0200952 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400953 if (ret == 0)
954 ret = err;
Josef Bacik02c24a82011-07-16 20:44:56 -0400955out:
956 mutex_unlock(&inode->i_mutex);
Al Virod5aacad2009-06-07 14:56:44 -0400957 return ret;
958}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200959EXPORT_SYMBOL(generic_file_fsync);
960
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700961/**
962 * generic_check_addressable - Check addressability of file system
963 * @blocksize_bits: log of file system block size
964 * @num_blocks: number of blocks in file system
965 *
966 * Determine whether a file system with @num_blocks blocks (and a
967 * block size of 2**@blocksize_bits) is addressable by the sector_t
968 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
969 */
970int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
971{
972 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -0700973 u64 last_fs_page =
974 last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700975
976 if (unlikely(num_blocks == 0))
977 return 0;
978
979 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
980 return -EINVAL;
981
Joel Beckera33f13e2010-08-16 12:10:17 -0700982 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
983 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700984 return -EFBIG;
985 }
986 return 0;
987}
988EXPORT_SYMBOL(generic_check_addressable);
989
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200990/*
991 * No-op implementation of ->fsync for in-memory filesystems.
992 */
Josef Bacik02c24a82011-07-16 20:44:56 -0400993int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200994{
995 return 0;
996}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200997EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -0400998
999void kfree_put_link(struct dentry *dentry, struct nameidata *nd,
1000 void *cookie)
1001{
1002 char *s = nd_get_link(nd);
1003 if (!IS_ERR(s))
1004 kfree(s);
1005}
1006EXPORT_SYMBOL(kfree_put_link);
Al Viro69878432013-10-02 22:35:11 -04001007
1008/*
1009 * nop .set_page_dirty method so that people can use .page_mkwrite on
1010 * anon inodes.
1011 */
1012static int anon_set_page_dirty(struct page *page)
1013{
1014 return 0;
1015};
1016
1017/*
1018 * A single inode exists for all anon_inode files. Contrary to pipes,
1019 * anon_inode inodes have no associated per-instance data, so we need
1020 * only allocate one of them.
1021 */
1022struct inode *alloc_anon_inode(struct super_block *s)
1023{
1024 static const struct address_space_operations anon_aops = {
1025 .set_page_dirty = anon_set_page_dirty,
1026 };
1027 struct inode *inode = new_inode_pseudo(s);
1028
1029 if (!inode)
1030 return ERR_PTR(-ENOMEM);
1031
1032 inode->i_ino = get_next_ino();
1033 inode->i_mapping->a_ops = &anon_aops;
1034
1035 /*
1036 * Mark the inode dirty from the very beginning,
1037 * that way it will never be moved to the dirty
1038 * list because mark_inode_dirty() will think
1039 * that it already _is_ on the dirty list.
1040 */
1041 inode->i_state = I_DIRTY;
1042 inode->i_mode = S_IRUSR | S_IWUSR;
1043 inode->i_uid = current_fsuid();
1044 inode->i_gid = current_fsgid();
1045 inode->i_flags |= S_PRIVATE;
1046 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1047 return inode;
1048}
1049EXPORT_SYMBOL(alloc_anon_inode);