blob: cb1fb4b9b6377b09b669b833cc3437b259b622f6 [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
Nick Pigginda502952011-01-07 17:49:33 +110023static inline int simple_positive(struct dentry *dentry)
24{
David Howellsdea655c2015-03-17 22:26:15 +000025 return d_really_is_positive(dentry) && !d_unhashed(dentry);
Nick Pigginda502952011-01-07 17:49:33 +110026}
27
Linus Torvalds1da177e2005-04-16 15:20:36 -070028int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
29 struct kstat *stat)
30{
David Howellsdea655c2015-03-17 22:26:15 +000031 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 generic_fillattr(inode, stat);
33 stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
34 return 0;
35}
Al Viro12f38872013-09-15 21:20:49 -040036EXPORT_SYMBOL(simple_getattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
David Howells726c3342006-06-23 02:02:58 -070038int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070039{
David Howells726c3342006-06-23 02:02:58 -070040 buf->f_type = dentry->d_sb->s_magic;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 buf->f_bsize = PAGE_CACHE_SIZE;
42 buf->f_namelen = NAME_MAX;
43 return 0;
44}
Al Viro12f38872013-09-15 21:20:49 -040045EXPORT_SYMBOL(simple_statfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
47/*
48 * Retaining negative dentries for an in-memory filesystem just wastes
49 * memory and lookup time: arrange for them to be deleted immediately.
50 */
Al Virob26d4cd2013-10-25 18:47:37 -040051int always_delete_dentry(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
53 return 1;
54}
Al Virob26d4cd2013-10-25 18:47:37 -040055EXPORT_SYMBOL(always_delete_dentry);
56
57const struct dentry_operations simple_dentry_operations = {
58 .d_delete = always_delete_dentry,
59};
60EXPORT_SYMBOL(simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62/*
63 * Lookup the data. This is trivial - if the dentry didn't already
64 * exist, we know it is negative. Set d_op to delete negative dentries.
65 */
Al Viro00cd8dd2012-06-10 17:13:09 -040066struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067{
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 if (dentry->d_name.len > NAME_MAX)
69 return ERR_PTR(-ENAMETOOLONG);
Al Viro74931da2013-07-14 17:43:25 +040070 if (!dentry->d_sb->s_d_op)
71 d_set_d_op(dentry, &simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 d_add(dentry, NULL);
73 return NULL;
74}
Al Viro12f38872013-09-15 21:20:49 -040075EXPORT_SYMBOL(simple_lookup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Linus Torvalds1da177e2005-04-16 15:20:36 -070077int dcache_dir_open(struct inode *inode, struct file *file)
78{
Linus Torvalds26fe5752012-05-10 13:14:12 -070079 static struct qstr cursor_name = QSTR_INIT(".", 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080081 file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
83 return file->private_data ? 0 : -ENOMEM;
84}
Al Viro12f38872013-09-15 21:20:49 -040085EXPORT_SYMBOL(dcache_dir_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87int dcache_dir_close(struct inode *inode, struct file *file)
88{
89 dput(file->private_data);
90 return 0;
91}
Al Viro12f38872013-09-15 21:20:49 -040092EXPORT_SYMBOL(dcache_dir_close);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Andrew Morton965c8e52012-12-17 15:59:39 -080094loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110096 struct dentry *dentry = file->f_path.dentry;
David Howellsdea655c2015-03-17 22:26:15 +000097 mutex_lock(&d_inode(dentry)->i_mutex);
Andrew Morton965c8e52012-12-17 15:59:39 -080098 switch (whence) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 case 1:
100 offset += file->f_pos;
101 case 0:
102 if (offset >= 0)
103 break;
104 default:
David Howellsdea655c2015-03-17 22:26:15 +0000105 mutex_unlock(&d_inode(dentry)->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 return -EINVAL;
107 }
108 if (offset != file->f_pos) {
109 file->f_pos = offset;
110 if (file->f_pos >= 2) {
111 struct list_head *p;
112 struct dentry *cursor = file->private_data;
113 loff_t n = file->f_pos - 2;
114
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100115 spin_lock(&dentry->d_lock);
116 /* d_lock not required for cursor */
Al Viro946e51f2014-10-26 19:19:16 -0400117 list_del(&cursor->d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100118 p = dentry->d_subdirs.next;
119 while (n && p != &dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 struct dentry *next;
Al Viro946e51f2014-10-26 19:19:16 -0400121 next = list_entry(p, struct dentry, d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100122 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Nick Pigginda502952011-01-07 17:49:33 +1100123 if (simple_positive(next))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 n--;
Nick Pigginda502952011-01-07 17:49:33 +1100125 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 p = p->next;
127 }
Al Viro946e51f2014-10-26 19:19:16 -0400128 list_add_tail(&cursor->d_child, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100129 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 }
131 }
David Howellsdea655c2015-03-17 22:26:15 +0000132 mutex_unlock(&d_inode(dentry)->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 return offset;
134}
Al Viro12f38872013-09-15 21:20:49 -0400135EXPORT_SYMBOL(dcache_dir_lseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137/* Relationship between i_mode and the DT_xxx types */
138static inline unsigned char dt_type(struct inode *inode)
139{
140 return (inode->i_mode >> 12) & 15;
141}
142
143/*
144 * Directory is locked and all positive dentries in it are safe, since
145 * for ramfs-type trees they can't go away without unlink() or rmdir(),
146 * both impossible due to the lock on directory.
147 */
148
Al Viro5f99f4e2013-05-15 20:23:06 -0400149int dcache_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
Al Viro5f99f4e2013-05-15 20:23:06 -0400151 struct dentry *dentry = file->f_path.dentry;
152 struct dentry *cursor = file->private_data;
Al Viro946e51f2014-10-26 19:19:16 -0400153 struct list_head *p, *q = &cursor->d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
Al Viro5f99f4e2013-05-15 20:23:06 -0400155 if (!dir_emit_dots(file, ctx))
156 return 0;
157 spin_lock(&dentry->d_lock);
158 if (ctx->pos == 2)
159 list_move(q, &dentry->d_subdirs);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700160
Al Viro5f99f4e2013-05-15 20:23:06 -0400161 for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
Al Viro946e51f2014-10-26 19:19:16 -0400162 struct dentry *next = list_entry(p, struct dentry, d_child);
Al Viro5f99f4e2013-05-15 20:23:06 -0400163 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
164 if (!simple_positive(next)) {
165 spin_unlock(&next->d_lock);
166 continue;
167 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Al Viro5f99f4e2013-05-15 20:23:06 -0400169 spin_unlock(&next->d_lock);
170 spin_unlock(&dentry->d_lock);
171 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
David Howellsdea655c2015-03-17 22:26:15 +0000172 d_inode(next)->i_ino, dt_type(d_inode(next))))
Al Viro5f99f4e2013-05-15 20:23:06 -0400173 return 0;
174 spin_lock(&dentry->d_lock);
175 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
176 /* next is still alive */
177 list_move(q, p);
178 spin_unlock(&next->d_lock);
179 p = q;
180 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 }
Al Viro5f99f4e2013-05-15 20:23:06 -0400182 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 return 0;
184}
Al Viro12f38872013-09-15 21:20:49 -0400185EXPORT_SYMBOL(dcache_readdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
187ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
188{
189 return -EISDIR;
190}
Al Viro12f38872013-09-15 21:20:49 -0400191EXPORT_SYMBOL(generic_read_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800193const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 .open = dcache_dir_open,
195 .release = dcache_dir_close,
196 .llseek = dcache_dir_lseek,
197 .read = generic_read_dir,
Al Viro5f99f4e2013-05-15 20:23:06 -0400198 .iterate = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200199 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200};
Al Viro12f38872013-09-15 21:20:49 -0400201EXPORT_SYMBOL(simple_dir_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800203const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 .lookup = simple_lookup,
205};
Al Viro12f38872013-09-15 21:20:49 -0400206EXPORT_SYMBOL(simple_dir_inode_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
Hugh Dickins759b9772007-03-05 00:30:28 -0800208static const struct super_operations simple_super_operations = {
209 .statfs = simple_statfs,
210};
211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212/*
213 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
214 * will never be mountable)
215 */
Al Viro51139ad2010-07-25 23:47:46 +0400216struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
Al Viroc74a1cb2011-01-12 16:59:34 -0500217 const struct super_operations *ops,
218 const struct dentry_operations *dops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
David Howells9249e172012-06-25 12:55:37 +0100220 struct super_block *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 struct dentry *dentry;
222 struct inode *root;
Linus Torvalds26fe5752012-05-10 13:14:12 -0700223 struct qstr d_name = QSTR_INIT(name, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
David Howells9249e172012-06-25 12:55:37 +0100225 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400227 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Jeff Layton89a4eb42009-08-18 14:11:08 -0700229 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700230 s->s_blocksize = PAGE_SIZE;
231 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800233 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 s->s_time_gran = 1;
235 root = new_inode(s);
236 if (!root)
237 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700238 /*
239 * since this is the first inode, make it number 1. New inodes created
240 * after this must take care not to collide with it (by passing
241 * max_reserved of 1 to iunique).
242 */
243 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
Al Viroa4464db2011-07-07 15:03:58 -0400246 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 if (!dentry) {
248 iput(root);
249 goto Enomem;
250 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 d_instantiate(dentry, root);
252 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500253 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400255 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
257Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400258 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400259 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
Al Viro12f38872013-09-15 21:20:49 -0400261EXPORT_SYMBOL(mount_pseudo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
Stephen Boyd20955e82012-04-05 14:25:09 -0700263int simple_open(struct inode *inode, struct file *file)
264{
265 if (inode->i_private)
266 file->private_data = inode->i_private;
267 return 0;
268}
Al Viro12f38872013-09-15 21:20:49 -0400269EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
272{
David Howellsdea655c2015-03-17 22:26:15 +0000273 struct inode *inode = d_inode(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700276 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400277 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 dget(dentry);
279 d_instantiate(dentry, inode);
280 return 0;
281}
Al Viro12f38872013-09-15 21:20:49 -0400282EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284int simple_empty(struct dentry *dentry)
285{
286 struct dentry *child;
287 int ret = 0;
288
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100289 spin_lock(&dentry->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400290 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
Nick Pigginda502952011-01-07 17:49:33 +1100291 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
292 if (simple_positive(child)) {
293 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100295 }
296 spin_unlock(&child->d_lock);
297 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 ret = 1;
299out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100300 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 return ret;
302}
Al Viro12f38872013-09-15 21:20:49 -0400303EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
305int simple_unlink(struct inode *dir, struct dentry *dentry)
306{
David Howellsdea655c2015-03-17 22:26:15 +0000307 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
309 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700310 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 dput(dentry);
312 return 0;
313}
Al Viro12f38872013-09-15 21:20:49 -0400314EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316int simple_rmdir(struct inode *dir, struct dentry *dentry)
317{
318 if (!simple_empty(dentry))
319 return -ENOTEMPTY;
320
David Howellsdea655c2015-03-17 22:26:15 +0000321 drop_nlink(d_inode(dentry));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700323 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 return 0;
325}
Al Viro12f38872013-09-15 21:20:49 -0400326EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
328int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
329 struct inode *new_dir, struct dentry *new_dentry)
330{
David Howellsdea655c2015-03-17 22:26:15 +0000331 struct inode *inode = d_inode(old_dentry);
David Howellse36cb0b2015-01-29 12:02:35 +0000332 int they_are_dirs = d_is_dir(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
334 if (!simple_empty(new_dentry))
335 return -ENOTEMPTY;
336
David Howellsdea655c2015-03-17 22:26:15 +0000337 if (d_really_is_positive(new_dentry)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400339 if (they_are_dirs) {
David Howellsdea655c2015-03-17 22:26:15 +0000340 drop_nlink(d_inode(new_dentry));
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700341 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400342 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700344 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700345 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 }
347
348 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
349 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
350
351 return 0;
352}
Al Viro12f38872013-09-15 21:20:49 -0400353EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000355/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200356 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000357 * @dentry: dentry
358 * @iattr: iattr structure
359 *
360 * Returns 0 on success, -error on failure.
361 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200362 * simple_setattr is a simple ->setattr implementation without a proper
363 * implementation of size changes.
364 *
365 * It can either be used for in-memory filesystems or special files
366 * on simple regular filesystems. Anything that needs to change on-disk
367 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000368 */
369int simple_setattr(struct dentry *dentry, struct iattr *iattr)
370{
David Howellsdea655c2015-03-17 22:26:15 +0000371 struct inode *inode = d_inode(dentry);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000372 int error;
373
374 error = inode_change_ok(inode, iattr);
375 if (error)
376 return error;
377
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200378 if (iattr->ia_valid & ATTR_SIZE)
379 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200380 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200381 mark_inode_dirty(inode);
382 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000383}
384EXPORT_SYMBOL(simple_setattr);
385
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386int simple_readpage(struct file *file, struct page *page)
387{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700388 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 flush_dcache_page(page);
390 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 unlock_page(page);
392 return 0;
393}
Al Viro12f38872013-09-15 21:20:49 -0400394EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395
Nick Pigginafddba42007-10-16 01:25:01 -0700396int simple_write_begin(struct file *file, struct address_space *mapping,
397 loff_t pos, unsigned len, unsigned flags,
398 struct page **pagep, void **fsdata)
399{
400 struct page *page;
401 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700402
403 index = pos >> PAGE_CACHE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700404
Nick Piggin54566b22009-01-04 12:00:53 -0800405 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700406 if (!page)
407 return -ENOMEM;
408
409 *pagep = page;
410
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200411 if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
412 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
413
414 zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
415 }
416 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700417}
Al Viro12f38872013-09-15 21:20:49 -0400418EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700419
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200420/**
421 * simple_write_end - .write_end helper for non-block-device FSes
422 * @available: See .write_end of address_space_operations
423 * @file: "
424 * @mapping: "
425 * @pos: "
426 * @len: "
427 * @copied: "
428 * @page: "
429 * @fsdata: "
430 *
431 * simple_write_end does the minimum needed for updating a page after writing is
432 * done. It has the same API signature as the .write_end of
433 * address_space_operations vector. So it can just be set onto .write_end for
434 * FSes that don't need any other processing. i_mutex is assumed to be held.
435 * Block based filesystems should use generic_write_end().
436 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
437 * is not called, so a filesystem that actually does store data in .write_inode
438 * should extend on what's done here with a call to mark_inode_dirty() in the
439 * case that i_size has changed.
440 */
441int simple_write_end(struct file *file, struct address_space *mapping,
442 loff_t pos, unsigned len, unsigned copied,
443 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444{
445 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200446 loff_t last_pos = pos + copied;
447
448 /* zero the stale part of the page if we did a short copy */
449 if (copied < len) {
450 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
451
452 zero_user(page, from + copied, len - copied);
453 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
Nick Piggin955eff52007-02-20 13:58:08 -0800455 if (!PageUptodate(page))
456 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 /*
458 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800459 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200461 if (last_pos > inode->i_size)
462 i_size_write(inode, last_pos);
463
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700465 unlock_page(page);
466 page_cache_release(page);
467
468 return copied;
469}
Al Viro12f38872013-09-15 21:20:49 -0400470EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700471
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700472/*
473 * the inodes created here are not hashed. If you use iunique to generate
474 * unique inode values later for this filesystem, then you must take care
475 * to pass it an appropriate max_reserved value to avoid collisions.
476 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200477int simple_fill_super(struct super_block *s, unsigned long magic,
478 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 struct inode *inode;
481 struct dentry *root;
482 struct dentry *dentry;
483 int i;
484
485 s->s_blocksize = PAGE_CACHE_SIZE;
486 s->s_blocksize_bits = PAGE_CACHE_SHIFT;
487 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800488 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 s->s_time_gran = 1;
490
491 inode = new_inode(s);
492 if (!inode)
493 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700494 /*
495 * because the root inode is 1, the files array must not contain an
496 * entry at index 1
497 */
498 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
501 inode->i_op = &simple_dir_inode_operations;
502 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200503 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500504 root = d_make_root(inode);
505 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 for (i = 0; !files->name || files->name[0]; i++, files++) {
508 if (!files->name)
509 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700510
511 /* warn if it tries to conflict with the root inode */
512 if (unlikely(i == 1))
513 printk(KERN_WARNING "%s: %s passed in a files array"
514 "with an index of 1!\n", __func__,
515 s->s_type->name);
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 dentry = d_alloc_name(root, files->name);
518 if (!dentry)
519 goto out;
520 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300521 if (!inode) {
522 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300524 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
527 inode->i_fop = files->ops;
528 inode->i_ino = i;
529 d_add(dentry, inode);
530 }
531 s->s_root = root;
532 return 0;
533out:
534 d_genocide(root);
Al Viro640946f2012-04-02 19:22:25 -0400535 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 dput(root);
537 return -ENOMEM;
538}
Al Viro12f38872013-09-15 21:20:49 -0400539EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
541static DEFINE_SPINLOCK(pin_fs_lock);
542
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400543int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544{
545 struct vfsmount *mnt = NULL;
546 spin_lock(&pin_fs_lock);
547 if (unlikely(!*mount)) {
548 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400549 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 if (IS_ERR(mnt))
551 return PTR_ERR(mnt);
552 spin_lock(&pin_fs_lock);
553 if (!*mount)
554 *mount = mnt;
555 }
556 mntget(*mount);
557 ++*count;
558 spin_unlock(&pin_fs_lock);
559 mntput(mnt);
560 return 0;
561}
Al Viro12f38872013-09-15 21:20:49 -0400562EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564void simple_release_fs(struct vfsmount **mount, int *count)
565{
566 struct vfsmount *mnt;
567 spin_lock(&pin_fs_lock);
568 mnt = *mount;
569 if (!--*count)
570 *mount = NULL;
571 spin_unlock(&pin_fs_lock);
572 mntput(mnt);
573}
Al Viro12f38872013-09-15 21:20:49 -0400574EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700576/**
577 * simple_read_from_buffer - copy data from the buffer to user space
578 * @to: the user space buffer to read to
579 * @count: the maximum number of bytes to read
580 * @ppos: the current position in the buffer
581 * @from: the buffer to read from
582 * @available: the size of the buffer
583 *
584 * The simple_read_from_buffer() function reads up to @count bytes from the
585 * buffer @from at offset @ppos into the user space address starting at @to.
586 *
587 * On success, the number of bytes read is returned and the offset @ppos is
588 * advanced by this number, or negative value is returned on error.
589 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
591 const void *from, size_t available)
592{
593 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700594 size_t ret;
595
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 if (pos < 0)
597 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700598 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 return 0;
600 if (count > available - pos)
601 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700602 ret = copy_to_user(to, from + pos, count);
603 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700605 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 *ppos = pos + count;
607 return count;
608}
Al Viro12f38872013-09-15 21:20:49 -0400609EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700611/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200612 * simple_write_to_buffer - copy data from user space to the buffer
613 * @to: the buffer to write to
614 * @available: the size of the buffer
615 * @ppos: the current position in the buffer
616 * @from: the user space buffer to read from
617 * @count: the maximum number of bytes to read
618 *
619 * The simple_write_to_buffer() function reads up to @count bytes from the user
620 * space address starting at @from into the buffer @to at offset @ppos.
621 *
622 * On success, the number of bytes written is returned and the offset @ppos is
623 * advanced by this number, or negative value is returned on error.
624 **/
625ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
626 const void __user *from, size_t count)
627{
628 loff_t pos = *ppos;
629 size_t res;
630
631 if (pos < 0)
632 return -EINVAL;
633 if (pos >= available || !count)
634 return 0;
635 if (count > available - pos)
636 count = available - pos;
637 res = copy_from_user(to + pos, from, count);
638 if (res == count)
639 return -EFAULT;
640 count -= res;
641 *ppos = pos + count;
642 return count;
643}
Al Viro12f38872013-09-15 21:20:49 -0400644EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200645
646/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700647 * memory_read_from_buffer - copy data from the buffer
648 * @to: the kernel space buffer to read to
649 * @count: the maximum number of bytes to read
650 * @ppos: the current position in the buffer
651 * @from: the buffer to read from
652 * @available: the size of the buffer
653 *
654 * The memory_read_from_buffer() function reads up to @count bytes from the
655 * buffer @from at offset @ppos into the kernel space address starting at @to.
656 *
657 * On success, the number of bytes read is returned and the offset @ppos is
658 * advanced by this number, or negative value is returned on error.
659 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700660ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
661 const void *from, size_t available)
662{
663 loff_t pos = *ppos;
664
665 if (pos < 0)
666 return -EINVAL;
667 if (pos >= available)
668 return 0;
669 if (count > available - pos)
670 count = available - pos;
671 memcpy(to, from + pos, count);
672 *ppos = pos + count;
673
674 return count;
675}
Al Viro12f38872013-09-15 21:20:49 -0400676EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700677
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678/*
679 * Transaction based IO.
680 * The file expects a single write which triggers the transaction, and then
681 * possibly a read which collects the result - which is stored in a
682 * file-local buffer.
683 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100684
685void simple_transaction_set(struct file *file, size_t n)
686{
687 struct simple_transaction_argresp *ar = file->private_data;
688
689 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
690
691 /*
692 * The barrier ensures that ar->size will really remain zero until
693 * ar->data is ready for reading.
694 */
695 smp_mb();
696 ar->size = n;
697}
Al Viro12f38872013-09-15 21:20:49 -0400698EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
701{
702 struct simple_transaction_argresp *ar;
703 static DEFINE_SPINLOCK(simple_transaction_lock);
704
705 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
706 return ERR_PTR(-EFBIG);
707
708 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
709 if (!ar)
710 return ERR_PTR(-ENOMEM);
711
712 spin_lock(&simple_transaction_lock);
713
714 /* only one write allowed per open */
715 if (file->private_data) {
716 spin_unlock(&simple_transaction_lock);
717 free_page((unsigned long)ar);
718 return ERR_PTR(-EBUSY);
719 }
720
721 file->private_data = ar;
722
723 spin_unlock(&simple_transaction_lock);
724
725 if (copy_from_user(ar->data, buf, size))
726 return ERR_PTR(-EFAULT);
727
728 return ar->data;
729}
Al Viro12f38872013-09-15 21:20:49 -0400730EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
732ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
733{
734 struct simple_transaction_argresp *ar = file->private_data;
735
736 if (!ar)
737 return 0;
738 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
739}
Al Viro12f38872013-09-15 21:20:49 -0400740EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741
742int simple_transaction_release(struct inode *inode, struct file *file)
743{
744 free_page((unsigned long)file->private_data);
745 return 0;
746}
Al Viro12f38872013-09-15 21:20:49 -0400747EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200749/* Simple attribute files */
750
751struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800752 int (*get)(void *, u64 *);
753 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200754 char get_buf[24]; /* enough to store a u64 and "\n\0" */
755 char set_buf[24];
756 void *data;
757 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800758 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200759};
760
761/* simple_attr_open is called by an actual attribute open file operation
762 * to set the attribute specific access operations. */
763int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800764 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200765 const char *fmt)
766{
767 struct simple_attr *attr;
768
769 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
770 if (!attr)
771 return -ENOMEM;
772
773 attr->get = get;
774 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700775 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200776 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800777 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200778
779 file->private_data = attr;
780
781 return nonseekable_open(inode, file);
782}
Al Viro12f38872013-09-15 21:20:49 -0400783EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200784
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800785int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200786{
787 kfree(file->private_data);
788 return 0;
789}
Al Viro12f38872013-09-15 21:20:49 -0400790EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200791
792/* read from the buffer that is filled with the get function */
793ssize_t simple_attr_read(struct file *file, char __user *buf,
794 size_t len, loff_t *ppos)
795{
796 struct simple_attr *attr;
797 size_t size;
798 ssize_t ret;
799
800 attr = file->private_data;
801
802 if (!attr->get)
803 return -EACCES;
804
Christoph Hellwig92613032008-02-08 04:20:27 -0800805 ret = mutex_lock_interruptible(&attr->mutex);
806 if (ret)
807 return ret;
808
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800809 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200810 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800811 } else { /* first read */
812 u64 val;
813 ret = attr->get(attr->data, &val);
814 if (ret)
815 goto out;
816
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200817 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800818 attr->fmt, (unsigned long long)val);
819 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200820
821 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800822out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800823 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200824 return ret;
825}
Al Viro12f38872013-09-15 21:20:49 -0400826EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200827
828/* interpret the buffer as a number to call the set function with */
829ssize_t simple_attr_write(struct file *file, const char __user *buf,
830 size_t len, loff_t *ppos)
831{
832 struct simple_attr *attr;
833 u64 val;
834 size_t size;
835 ssize_t ret;
836
837 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200838 if (!attr->set)
839 return -EACCES;
840
Christoph Hellwig92613032008-02-08 04:20:27 -0800841 ret = mutex_lock_interruptible(&attr->mutex);
842 if (ret)
843 return ret;
844
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200845 ret = -EFAULT;
846 size = min(sizeof(attr->set_buf) - 1, len);
847 if (copy_from_user(attr->set_buf, buf, size))
848 goto out;
849
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200850 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700851 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700852 ret = attr->set(attr->data, val);
853 if (ret == 0)
854 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200855out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800856 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200857 return ret;
858}
Al Viro12f38872013-09-15 21:20:49 -0400859EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200860
Christoph Hellwig25961102007-10-21 16:42:05 -0700861/**
862 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
863 * @sb: filesystem to do the file handle conversion on
864 * @fid: file handle to convert
865 * @fh_len: length of the file handle in bytes
866 * @fh_type: type of file handle
867 * @get_inode: filesystem callback to retrieve inode
868 *
869 * This function decodes @fid as long as it has one of the well-known
870 * Linux filehandle types and calls @get_inode on it to retrieve the
871 * inode for the object specified in the file handle.
872 */
873struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
874 int fh_len, int fh_type, struct inode *(*get_inode)
875 (struct super_block *sb, u64 ino, u32 gen))
876{
877 struct inode *inode = NULL;
878
879 if (fh_len < 2)
880 return NULL;
881
882 switch (fh_type) {
883 case FILEID_INO32_GEN:
884 case FILEID_INO32_GEN_PARENT:
885 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
886 break;
887 }
888
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200889 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700890}
891EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
892
893/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800894 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700895 * @sb: filesystem to do the file handle conversion on
896 * @fid: file handle to convert
897 * @fh_len: length of the file handle in bytes
898 * @fh_type: type of file handle
899 * @get_inode: filesystem callback to retrieve inode
900 *
901 * This function decodes @fid as long as it has one of the well-known
902 * Linux filehandle types and calls @get_inode on it to retrieve the
903 * inode for the _parent_ object specified in the file handle if it
904 * is specified in the file handle, or NULL otherwise.
905 */
906struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
907 int fh_len, int fh_type, struct inode *(*get_inode)
908 (struct super_block *sb, u64 ino, u32 gen))
909{
910 struct inode *inode = NULL;
911
912 if (fh_len <= 2)
913 return NULL;
914
915 switch (fh_type) {
916 case FILEID_INO32_GEN_PARENT:
917 inode = get_inode(sb, fid->i32.parent_ino,
918 (fh_len > 3 ? fid->i32.parent_gen : 0));
919 break;
920 }
921
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200922 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700923}
924EXPORT_SYMBOL_GPL(generic_fh_to_parent);
925
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200926/**
Fabian Frederickac13a822014-06-04 16:06:27 -0700927 * __generic_file_fsync - generic fsync implementation for simple filesystems
928 *
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200929 * @file: file to synchronize
Fabian Frederickac13a822014-06-04 16:06:27 -0700930 * @start: start offset in bytes
931 * @end: end offset in bytes (inclusive)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200932 * @datasync: only synchronize essential metadata if true
933 *
934 * This is a generic implementation of the fsync method for simple
935 * filesystems which track all non-inode metadata in the buffers list
936 * hanging off the address_space structure.
937 */
Fabian Frederickac13a822014-06-04 16:06:27 -0700938int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
939 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400940{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200941 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400942 int err;
943 int ret;
944
Josef Bacik02c24a82011-07-16 20:44:56 -0400945 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
946 if (err)
947 return err;
948
949 mutex_lock(&inode->i_mutex);
Al Virod5aacad2009-06-07 14:56:44 -0400950 ret = sync_mapping_buffers(inode->i_mapping);
Theodore Ts'o0ae45f62015-02-02 00:37:00 -0500951 if (!(inode->i_state & I_DIRTY_ALL))
Josef Bacik02c24a82011-07-16 20:44:56 -0400952 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400953 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400954 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400955
Christoph Hellwigc37650162010-10-06 10:48:20 +0200956 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400957 if (ret == 0)
958 ret = err;
Fabian Frederickac13a822014-06-04 16:06:27 -0700959
Josef Bacik02c24a82011-07-16 20:44:56 -0400960out:
961 mutex_unlock(&inode->i_mutex);
Al Virod5aacad2009-06-07 14:56:44 -0400962 return ret;
963}
Fabian Frederickac13a822014-06-04 16:06:27 -0700964EXPORT_SYMBOL(__generic_file_fsync);
965
966/**
967 * generic_file_fsync - generic fsync implementation for simple filesystems
968 * with flush
969 * @file: file to synchronize
970 * @start: start offset in bytes
971 * @end: end offset in bytes (inclusive)
972 * @datasync: only synchronize essential metadata if true
973 *
974 */
975
976int generic_file_fsync(struct file *file, loff_t start, loff_t end,
977 int datasync)
978{
979 struct inode *inode = file->f_mapping->host;
980 int err;
981
982 err = __generic_file_fsync(file, start, end, datasync);
983 if (err)
984 return err;
985 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
986}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200987EXPORT_SYMBOL(generic_file_fsync);
988
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700989/**
990 * generic_check_addressable - Check addressability of file system
991 * @blocksize_bits: log of file system block size
992 * @num_blocks: number of blocks in file system
993 *
994 * Determine whether a file system with @num_blocks blocks (and a
995 * block size of 2**@blocksize_bits) is addressable by the sector_t
996 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
997 */
998int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
999{
1000 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -07001001 u64 last_fs_page =
1002 last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001003
1004 if (unlikely(num_blocks == 0))
1005 return 0;
1006
1007 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
1008 return -EINVAL;
1009
Joel Beckera33f13e2010-08-16 12:10:17 -07001010 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1011 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001012 return -EFBIG;
1013 }
1014 return 0;
1015}
1016EXPORT_SYMBOL(generic_check_addressable);
1017
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001018/*
1019 * No-op implementation of ->fsync for in-memory filesystems.
1020 */
Josef Bacik02c24a82011-07-16 20:44:56 -04001021int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001022{
1023 return 0;
1024}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001025EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -04001026
1027void kfree_put_link(struct dentry *dentry, struct nameidata *nd,
1028 void *cookie)
1029{
1030 char *s = nd_get_link(nd);
1031 if (!IS_ERR(s))
1032 kfree(s);
1033}
1034EXPORT_SYMBOL(kfree_put_link);
Al Viro69878432013-10-02 22:35:11 -04001035
1036/*
1037 * nop .set_page_dirty method so that people can use .page_mkwrite on
1038 * anon inodes.
1039 */
1040static int anon_set_page_dirty(struct page *page)
1041{
1042 return 0;
1043};
1044
1045/*
1046 * A single inode exists for all anon_inode files. Contrary to pipes,
1047 * anon_inode inodes have no associated per-instance data, so we need
1048 * only allocate one of them.
1049 */
1050struct inode *alloc_anon_inode(struct super_block *s)
1051{
1052 static const struct address_space_operations anon_aops = {
1053 .set_page_dirty = anon_set_page_dirty,
1054 };
1055 struct inode *inode = new_inode_pseudo(s);
1056
1057 if (!inode)
1058 return ERR_PTR(-ENOMEM);
1059
1060 inode->i_ino = get_next_ino();
1061 inode->i_mapping->a_ops = &anon_aops;
1062
1063 /*
1064 * Mark the inode dirty from the very beginning,
1065 * that way it will never be moved to the dirty
1066 * list because mark_inode_dirty() will think
1067 * that it already _is_ on the dirty list.
1068 */
1069 inode->i_state = I_DIRTY;
1070 inode->i_mode = S_IRUSR | S_IWUSR;
1071 inode->i_uid = current_fsuid();
1072 inode->i_gid = current_fsgid();
1073 inode->i_flags |= S_PRIVATE;
1074 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1075 return inode;
1076}
1077EXPORT_SYMBOL(alloc_anon_inode);
Jeff Layton1c994a02014-08-27 06:49:41 -04001078
1079/**
1080 * simple_nosetlease - generic helper for prohibiting leases
1081 * @filp: file pointer
1082 * @arg: type of lease to obtain
1083 * @flp: new lease supplied for insertion
Jeff Laytone6f5c782014-08-22 10:40:25 -04001084 * @priv: private data for lm_setup operation
Jeff Layton1c994a02014-08-27 06:49:41 -04001085 *
1086 * Generic helper for filesystems that do not wish to allow leases to be set.
1087 * All arguments are ignored and it just returns -EINVAL.
1088 */
1089int
Jeff Laytone6f5c782014-08-22 10:40:25 -04001090simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1091 void **priv)
Jeff Layton1c994a02014-08-27 06:49:41 -04001092{
1093 return -EINVAL;
1094}
1095EXPORT_SYMBOL(simple_nosetlease);