blob: 74dc8b9e7f53ab394113783c96fb754c045735fa [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/libfs.c
3 * Library for filesystems writers.
4 */
5
Fabian Frederickac13a822014-06-04 16:06:27 -07006#include <linux/blkdev.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -05007#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/pagemap.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09009#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/mount.h>
11#include <linux/vfs.h>
npiggin@suse.de7bb46a62010-05-27 01:05:33 +100012#include <linux/quotaops.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080013#include <linux/mutex.h>
Al Viro87dc8002013-09-16 10:30:04 -040014#include <linux/namei.h>
Christoph Hellwig25961102007-10-21 16:42:05 -070015#include <linux/exportfs.h>
Al Virod5aacad2009-06-07 14:56:44 -040016#include <linux/writeback.h>
Al Viroff01bb42011-09-16 02:31:11 -040017#include <linux/buffer_head.h> /* sync_mapping_buffers */
Ingo Molnar7cf34c72006-03-23 03:00:36 -080018
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <asm/uaccess.h>
20
Al Viroa4464db2011-07-07 15:03:58 -040021#include "internal.h"
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
24 struct kstat *stat)
25{
David Howellsdea655c2015-03-17 22:26:15 +000026 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 generic_fillattr(inode, stat);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +030028 stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 return 0;
30}
Al Viro12f38872013-09-15 21:20:49 -040031EXPORT_SYMBOL(simple_getattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
David Howells726c3342006-06-23 02:02:58 -070033int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070034{
David Howells726c3342006-06-23 02:02:58 -070035 buf->f_type = dentry->d_sb->s_magic;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +030036 buf->f_bsize = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 buf->f_namelen = NAME_MAX;
38 return 0;
39}
Al Viro12f38872013-09-15 21:20:49 -040040EXPORT_SYMBOL(simple_statfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42/*
43 * Retaining negative dentries for an in-memory filesystem just wastes
44 * memory and lookup time: arrange for them to be deleted immediately.
45 */
Al Virob26d4cd2013-10-25 18:47:37 -040046int always_delete_dentry(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
48 return 1;
49}
Al Virob26d4cd2013-10-25 18:47:37 -040050EXPORT_SYMBOL(always_delete_dentry);
51
52const struct dentry_operations simple_dentry_operations = {
53 .d_delete = always_delete_dentry,
54};
55EXPORT_SYMBOL(simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/*
58 * Lookup the data. This is trivial - if the dentry didn't already
59 * exist, we know it is negative. Set d_op to delete negative dentries.
60 */
Al Viro00cd8dd2012-06-10 17:13:09 -040061struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 if (dentry->d_name.len > NAME_MAX)
64 return ERR_PTR(-ENAMETOOLONG);
Al Viro74931da2013-07-14 17:43:25 +040065 if (!dentry->d_sb->s_d_op)
66 d_set_d_op(dentry, &simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 d_add(dentry, NULL);
68 return NULL;
69}
Al Viro12f38872013-09-15 21:20:49 -040070EXPORT_SYMBOL(simple_lookup);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Linus Torvalds1da177e2005-04-16 15:20:36 -070072int dcache_dir_open(struct inode *inode, struct file *file)
73{
Al Viroba65dc52016-06-10 11:32:47 -040074 file->private_data = d_alloc_cursor(file->f_path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76 return file->private_data ? 0 : -ENOMEM;
77}
Al Viro12f38872013-09-15 21:20:49 -040078EXPORT_SYMBOL(dcache_dir_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
80int dcache_dir_close(struct inode *inode, struct file *file)
81{
82 dput(file->private_data);
83 return 0;
84}
Al Viro12f38872013-09-15 21:20:49 -040085EXPORT_SYMBOL(dcache_dir_close);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Al Viro4f42c1b2016-06-06 19:37:13 -040087/* parent is locked at least shared */
88static struct dentry *next_positive(struct dentry *parent,
89 struct list_head *from,
90 int count)
91{
Al Viroebaaa802016-06-06 20:55:34 -040092 unsigned *seq = &parent->d_inode->i_dir_seq, n;
93 struct dentry *res;
Al Viro4f42c1b2016-06-06 19:37:13 -040094 struct list_head *p;
Al Viroebaaa802016-06-06 20:55:34 -040095 bool skipped;
96 int i;
Al Viro4f42c1b2016-06-06 19:37:13 -040097
Al Viroebaaa802016-06-06 20:55:34 -040098retry:
99 i = count;
100 skipped = false;
101 n = smp_load_acquire(seq) & ~1;
102 res = NULL;
103 rcu_read_lock();
Al Viro4f42c1b2016-06-06 19:37:13 -0400104 for (p = from->next; p != &parent->d_subdirs; p = p->next) {
105 struct dentry *d = list_entry(p, struct dentry, d_child);
Al Viroebaaa802016-06-06 20:55:34 -0400106 if (!simple_positive(d)) {
107 skipped = true;
108 } else if (!--i) {
Al Viro4f42c1b2016-06-06 19:37:13 -0400109 res = d;
110 break;
111 }
112 }
Al Viroebaaa802016-06-06 20:55:34 -0400113 rcu_read_unlock();
114 if (skipped) {
115 smp_rmb();
116 if (unlikely(*seq != n))
117 goto retry;
118 }
Al Viro4f42c1b2016-06-06 19:37:13 -0400119 return res;
120}
121
122static void move_cursor(struct dentry *cursor, struct list_head *after)
123{
124 struct dentry *parent = cursor->d_parent;
Al Viroebaaa802016-06-06 20:55:34 -0400125 unsigned n, *seq = &parent->d_inode->i_dir_seq;
Al Viro4f42c1b2016-06-06 19:37:13 -0400126 spin_lock(&parent->d_lock);
Al Viroebaaa802016-06-06 20:55:34 -0400127 for (;;) {
128 n = *seq;
129 if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
130 break;
131 cpu_relax();
132 }
Al Viro4f42c1b2016-06-06 19:37:13 -0400133 __list_del(cursor->d_child.prev, cursor->d_child.next);
134 if (after)
135 list_add(&cursor->d_child, after);
136 else
137 list_add_tail(&cursor->d_child, &parent->d_subdirs);
Al Viroebaaa802016-06-06 20:55:34 -0400138 smp_store_release(seq, n + 2);
Al Viro4f42c1b2016-06-06 19:37:13 -0400139 spin_unlock(&parent->d_lock);
140}
141
Andrew Morton965c8e52012-12-17 15:59:39 -0800142loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100144 struct dentry *dentry = file->f_path.dentry;
Andrew Morton965c8e52012-12-17 15:59:39 -0800145 switch (whence) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 case 1:
147 offset += file->f_pos;
148 case 0:
149 if (offset >= 0)
150 break;
151 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 return -EINVAL;
153 }
154 if (offset != file->f_pos) {
155 file->f_pos = offset;
156 if (file->f_pos >= 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 struct dentry *cursor = file->private_data;
Al Viro4f42c1b2016-06-06 19:37:13 -0400158 struct dentry *to;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 loff_t n = file->f_pos - 2;
160
Al Viro274f5b02016-06-06 18:55:57 -0400161 inode_lock_shared(dentry->d_inode);
Al Viro4f42c1b2016-06-06 19:37:13 -0400162 to = next_positive(dentry, &dentry->d_subdirs, n);
163 move_cursor(cursor, to ? &to->d_child : NULL);
Al Viro274f5b02016-06-06 18:55:57 -0400164 inode_unlock_shared(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 }
166 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 return offset;
168}
Al Viro12f38872013-09-15 21:20:49 -0400169EXPORT_SYMBOL(dcache_dir_lseek);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
171/* Relationship between i_mode and the DT_xxx types */
172static inline unsigned char dt_type(struct inode *inode)
173{
174 return (inode->i_mode >> 12) & 15;
175}
176
177/*
178 * Directory is locked and all positive dentries in it are safe, since
179 * for ramfs-type trees they can't go away without unlink() or rmdir(),
180 * both impossible due to the lock on directory.
181 */
182
Al Viro5f99f4e2013-05-15 20:23:06 -0400183int dcache_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184{
Al Viro5f99f4e2013-05-15 20:23:06 -0400185 struct dentry *dentry = file->f_path.dentry;
186 struct dentry *cursor = file->private_data;
Al Viro4f42c1b2016-06-06 19:37:13 -0400187 struct list_head *p = &cursor->d_child;
188 struct dentry *next;
189 bool moved = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
Al Viro5f99f4e2013-05-15 20:23:06 -0400191 if (!dir_emit_dots(file, ctx))
192 return 0;
Al Viro4f42c1b2016-06-06 19:37:13 -0400193
Al Viro5f99f4e2013-05-15 20:23:06 -0400194 if (ctx->pos == 2)
Al Viro4f42c1b2016-06-06 19:37:13 -0400195 p = &dentry->d_subdirs;
196 while ((next = next_positive(dentry, p, 1)) != NULL) {
Al Viro5f99f4e2013-05-15 20:23:06 -0400197 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
David Howellsdea655c2015-03-17 22:26:15 +0000198 d_inode(next)->i_ino, dt_type(d_inode(next))))
Al Viro4f42c1b2016-06-06 19:37:13 -0400199 break;
200 moved = true;
201 p = &next->d_child;
Al Viro5f99f4e2013-05-15 20:23:06 -0400202 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 }
Al Viro4f42c1b2016-06-06 19:37:13 -0400204 if (moved)
205 move_cursor(cursor, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 return 0;
207}
Al Viro12f38872013-09-15 21:20:49 -0400208EXPORT_SYMBOL(dcache_readdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
211{
212 return -EISDIR;
213}
Al Viro12f38872013-09-15 21:20:49 -0400214EXPORT_SYMBOL(generic_read_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800216const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 .open = dcache_dir_open,
218 .release = dcache_dir_close,
219 .llseek = dcache_dir_lseek,
220 .read = generic_read_dir,
Al Viro4e829012016-04-20 19:52:15 -0400221 .iterate_shared = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200222 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223};
Al Viro12f38872013-09-15 21:20:49 -0400224EXPORT_SYMBOL(simple_dir_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800226const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 .lookup = simple_lookup,
228};
Al Viro12f38872013-09-15 21:20:49 -0400229EXPORT_SYMBOL(simple_dir_inode_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Hugh Dickins759b9772007-03-05 00:30:28 -0800231static const struct super_operations simple_super_operations = {
232 .statfs = simple_statfs,
233};
234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235/*
236 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
237 * will never be mountable)
238 */
Al Viro51139ad2010-07-25 23:47:46 +0400239struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
Al Viroc74a1cb2011-01-12 16:59:34 -0500240 const struct super_operations *ops,
241 const struct dentry_operations *dops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242{
David Howells9249e172012-06-25 12:55:37 +0100243 struct super_block *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 struct dentry *dentry;
245 struct inode *root;
Linus Torvalds26fe5752012-05-10 13:14:12 -0700246 struct qstr d_name = QSTR_INIT(name, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
David Howells9249e172012-06-25 12:55:37 +0100248 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400250 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
Jeff Layton89a4eb42009-08-18 14:11:08 -0700252 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700253 s->s_blocksize = PAGE_SIZE;
254 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800256 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 s->s_time_gran = 1;
258 root = new_inode(s);
259 if (!root)
260 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700261 /*
262 * since this is the first inode, make it number 1. New inodes created
263 * after this must take care not to collide with it (by passing
264 * max_reserved of 1 to iunique).
265 */
266 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
Al Viroa4464db2011-07-07 15:03:58 -0400269 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 if (!dentry) {
271 iput(root);
272 goto Enomem;
273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 d_instantiate(dentry, root);
275 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500276 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400278 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400281 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400282 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283}
Al Viro12f38872013-09-15 21:20:49 -0400284EXPORT_SYMBOL(mount_pseudo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285
Stephen Boyd20955e82012-04-05 14:25:09 -0700286int simple_open(struct inode *inode, struct file *file)
287{
288 if (inode->i_private)
289 file->private_data = inode->i_private;
290 return 0;
291}
Al Viro12f38872013-09-15 21:20:49 -0400292EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
295{
David Howellsdea655c2015-03-17 22:26:15 +0000296 struct inode *inode = d_inode(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
298 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700299 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400300 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 dget(dentry);
302 d_instantiate(dentry, inode);
303 return 0;
304}
Al Viro12f38872013-09-15 21:20:49 -0400305EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307int simple_empty(struct dentry *dentry)
308{
309 struct dentry *child;
310 int ret = 0;
311
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100312 spin_lock(&dentry->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400313 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
Nick Pigginda502952011-01-07 17:49:33 +1100314 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
315 if (simple_positive(child)) {
316 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100318 }
319 spin_unlock(&child->d_lock);
320 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 ret = 1;
322out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100323 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 return ret;
325}
Al Viro12f38872013-09-15 21:20:49 -0400326EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
328int simple_unlink(struct inode *dir, struct dentry *dentry)
329{
David Howellsdea655c2015-03-17 22:26:15 +0000330 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
332 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700333 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 dput(dentry);
335 return 0;
336}
Al Viro12f38872013-09-15 21:20:49 -0400337EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339int simple_rmdir(struct inode *dir, struct dentry *dentry)
340{
341 if (!simple_empty(dentry))
342 return -ENOTEMPTY;
343
David Howellsdea655c2015-03-17 22:26:15 +0000344 drop_nlink(d_inode(dentry));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700346 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return 0;
348}
Al Viro12f38872013-09-15 21:20:49 -0400349EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
351int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
352 struct inode *new_dir, struct dentry *new_dentry)
353{
David Howellsdea655c2015-03-17 22:26:15 +0000354 struct inode *inode = d_inode(old_dentry);
David Howellse36cb0b2015-01-29 12:02:35 +0000355 int they_are_dirs = d_is_dir(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
357 if (!simple_empty(new_dentry))
358 return -ENOTEMPTY;
359
David Howellsdea655c2015-03-17 22:26:15 +0000360 if (d_really_is_positive(new_dentry)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400362 if (they_are_dirs) {
David Howellsdea655c2015-03-17 22:26:15 +0000363 drop_nlink(d_inode(new_dentry));
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700364 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400365 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700367 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700368 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 }
370
371 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
372 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
373
374 return 0;
375}
Al Viro12f38872013-09-15 21:20:49 -0400376EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000378/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200379 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000380 * @dentry: dentry
381 * @iattr: iattr structure
382 *
383 * Returns 0 on success, -error on failure.
384 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200385 * simple_setattr is a simple ->setattr implementation without a proper
386 * implementation of size changes.
387 *
388 * It can either be used for in-memory filesystems or special files
389 * on simple regular filesystems. Anything that needs to change on-disk
390 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000391 */
392int simple_setattr(struct dentry *dentry, struct iattr *iattr)
393{
David Howellsdea655c2015-03-17 22:26:15 +0000394 struct inode *inode = d_inode(dentry);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000395 int error;
396
397 error = inode_change_ok(inode, iattr);
398 if (error)
399 return error;
400
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200401 if (iattr->ia_valid & ATTR_SIZE)
402 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200403 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200404 mark_inode_dirty(inode);
405 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000406}
407EXPORT_SYMBOL(simple_setattr);
408
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409int simple_readpage(struct file *file, struct page *page)
410{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700411 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 flush_dcache_page(page);
413 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 unlock_page(page);
415 return 0;
416}
Al Viro12f38872013-09-15 21:20:49 -0400417EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
Nick Pigginafddba42007-10-16 01:25:01 -0700419int simple_write_begin(struct file *file, struct address_space *mapping,
420 loff_t pos, unsigned len, unsigned flags,
421 struct page **pagep, void **fsdata)
422{
423 struct page *page;
424 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700425
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300426 index = pos >> PAGE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700427
Nick Piggin54566b22009-01-04 12:00:53 -0800428 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700429 if (!page)
430 return -ENOMEM;
431
432 *pagep = page;
433
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300434 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
435 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200436
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300437 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200438 }
439 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700440}
Al Viro12f38872013-09-15 21:20:49 -0400441EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700442
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200443/**
444 * simple_write_end - .write_end helper for non-block-device FSes
445 * @available: See .write_end of address_space_operations
446 * @file: "
447 * @mapping: "
448 * @pos: "
449 * @len: "
450 * @copied: "
451 * @page: "
452 * @fsdata: "
453 *
454 * simple_write_end does the minimum needed for updating a page after writing is
455 * done. It has the same API signature as the .write_end of
456 * address_space_operations vector. So it can just be set onto .write_end for
457 * FSes that don't need any other processing. i_mutex is assumed to be held.
458 * Block based filesystems should use generic_write_end().
459 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
460 * is not called, so a filesystem that actually does store data in .write_inode
461 * should extend on what's done here with a call to mark_inode_dirty() in the
462 * case that i_size has changed.
463 */
464int simple_write_end(struct file *file, struct address_space *mapping,
465 loff_t pos, unsigned len, unsigned copied,
466 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
468 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200469 loff_t last_pos = pos + copied;
470
471 /* zero the stale part of the page if we did a short copy */
472 if (copied < len) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300473 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200474
475 zero_user(page, from + copied, len - copied);
476 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477
Nick Piggin955eff52007-02-20 13:58:08 -0800478 if (!PageUptodate(page))
479 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 /*
481 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800482 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200484 if (last_pos > inode->i_size)
485 i_size_write(inode, last_pos);
486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700488 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300489 put_page(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700490
491 return copied;
492}
Al Viro12f38872013-09-15 21:20:49 -0400493EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700494
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700495/*
496 * the inodes created here are not hashed. If you use iunique to generate
497 * unique inode values later for this filesystem, then you must take care
498 * to pass it an appropriate max_reserved value to avoid collisions.
499 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200500int simple_fill_super(struct super_block *s, unsigned long magic,
501 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 struct inode *inode;
504 struct dentry *root;
505 struct dentry *dentry;
506 int i;
507
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300508 s->s_blocksize = PAGE_SIZE;
509 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800511 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 s->s_time_gran = 1;
513
514 inode = new_inode(s);
515 if (!inode)
516 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700517 /*
518 * because the root inode is 1, the files array must not contain an
519 * entry at index 1
520 */
521 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
524 inode->i_op = &simple_dir_inode_operations;
525 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200526 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500527 root = d_make_root(inode);
528 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 for (i = 0; !files->name || files->name[0]; i++, files++) {
531 if (!files->name)
532 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700533
534 /* warn if it tries to conflict with the root inode */
535 if (unlikely(i == 1))
536 printk(KERN_WARNING "%s: %s passed in a files array"
537 "with an index of 1!\n", __func__,
538 s->s_type->name);
539
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 dentry = d_alloc_name(root, files->name);
541 if (!dentry)
542 goto out;
543 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300544 if (!inode) {
545 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300547 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
550 inode->i_fop = files->ops;
551 inode->i_ino = i;
552 d_add(dentry, inode);
553 }
554 s->s_root = root;
555 return 0;
556out:
557 d_genocide(root);
Al Viro640946f2012-04-02 19:22:25 -0400558 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 dput(root);
560 return -ENOMEM;
561}
Al Viro12f38872013-09-15 21:20:49 -0400562EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564static DEFINE_SPINLOCK(pin_fs_lock);
565
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400566int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567{
568 struct vfsmount *mnt = NULL;
569 spin_lock(&pin_fs_lock);
570 if (unlikely(!*mount)) {
571 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400572 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 if (IS_ERR(mnt))
574 return PTR_ERR(mnt);
575 spin_lock(&pin_fs_lock);
576 if (!*mount)
577 *mount = mnt;
578 }
579 mntget(*mount);
580 ++*count;
581 spin_unlock(&pin_fs_lock);
582 mntput(mnt);
583 return 0;
584}
Al Viro12f38872013-09-15 21:20:49 -0400585EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587void simple_release_fs(struct vfsmount **mount, int *count)
588{
589 struct vfsmount *mnt;
590 spin_lock(&pin_fs_lock);
591 mnt = *mount;
592 if (!--*count)
593 *mount = NULL;
594 spin_unlock(&pin_fs_lock);
595 mntput(mnt);
596}
Al Viro12f38872013-09-15 21:20:49 -0400597EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700599/**
600 * simple_read_from_buffer - copy data from the buffer to user space
601 * @to: the user space buffer to read to
602 * @count: the maximum number of bytes to read
603 * @ppos: the current position in the buffer
604 * @from: the buffer to read from
605 * @available: the size of the buffer
606 *
607 * The simple_read_from_buffer() function reads up to @count bytes from the
608 * buffer @from at offset @ppos into the user space address starting at @to.
609 *
610 * On success, the number of bytes read is returned and the offset @ppos is
611 * advanced by this number, or negative value is returned on error.
612 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
614 const void *from, size_t available)
615{
616 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700617 size_t ret;
618
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 if (pos < 0)
620 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700621 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 return 0;
623 if (count > available - pos)
624 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700625 ret = copy_to_user(to, from + pos, count);
626 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700628 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 *ppos = pos + count;
630 return count;
631}
Al Viro12f38872013-09-15 21:20:49 -0400632EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700634/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200635 * simple_write_to_buffer - copy data from user space to the buffer
636 * @to: the buffer to write to
637 * @available: the size of the buffer
638 * @ppos: the current position in the buffer
639 * @from: the user space buffer to read from
640 * @count: the maximum number of bytes to read
641 *
642 * The simple_write_to_buffer() function reads up to @count bytes from the user
643 * space address starting at @from into the buffer @to at offset @ppos.
644 *
645 * On success, the number of bytes written is returned and the offset @ppos is
646 * advanced by this number, or negative value is returned on error.
647 **/
648ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
649 const void __user *from, size_t count)
650{
651 loff_t pos = *ppos;
652 size_t res;
653
654 if (pos < 0)
655 return -EINVAL;
656 if (pos >= available || !count)
657 return 0;
658 if (count > available - pos)
659 count = available - pos;
660 res = copy_from_user(to + pos, from, count);
661 if (res == count)
662 return -EFAULT;
663 count -= res;
664 *ppos = pos + count;
665 return count;
666}
Al Viro12f38872013-09-15 21:20:49 -0400667EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200668
669/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700670 * memory_read_from_buffer - copy data from the buffer
671 * @to: the kernel space buffer to read to
672 * @count: the maximum number of bytes to read
673 * @ppos: the current position in the buffer
674 * @from: the buffer to read from
675 * @available: the size of the buffer
676 *
677 * The memory_read_from_buffer() function reads up to @count bytes from the
678 * buffer @from at offset @ppos into the kernel space address starting at @to.
679 *
680 * On success, the number of bytes read is returned and the offset @ppos is
681 * advanced by this number, or negative value is returned on error.
682 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700683ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
684 const void *from, size_t available)
685{
686 loff_t pos = *ppos;
687
688 if (pos < 0)
689 return -EINVAL;
690 if (pos >= available)
691 return 0;
692 if (count > available - pos)
693 count = available - pos;
694 memcpy(to, from + pos, count);
695 *ppos = pos + count;
696
697 return count;
698}
Al Viro12f38872013-09-15 21:20:49 -0400699EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700700
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701/*
702 * Transaction based IO.
703 * The file expects a single write which triggers the transaction, and then
704 * possibly a read which collects the result - which is stored in a
705 * file-local buffer.
706 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100707
708void simple_transaction_set(struct file *file, size_t n)
709{
710 struct simple_transaction_argresp *ar = file->private_data;
711
712 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
713
714 /*
715 * The barrier ensures that ar->size will really remain zero until
716 * ar->data is ready for reading.
717 */
718 smp_mb();
719 ar->size = n;
720}
Al Viro12f38872013-09-15 21:20:49 -0400721EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100722
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
724{
725 struct simple_transaction_argresp *ar;
726 static DEFINE_SPINLOCK(simple_transaction_lock);
727
728 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
729 return ERR_PTR(-EFBIG);
730
731 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
732 if (!ar)
733 return ERR_PTR(-ENOMEM);
734
735 spin_lock(&simple_transaction_lock);
736
737 /* only one write allowed per open */
738 if (file->private_data) {
739 spin_unlock(&simple_transaction_lock);
740 free_page((unsigned long)ar);
741 return ERR_PTR(-EBUSY);
742 }
743
744 file->private_data = ar;
745
746 spin_unlock(&simple_transaction_lock);
747
748 if (copy_from_user(ar->data, buf, size))
749 return ERR_PTR(-EFAULT);
750
751 return ar->data;
752}
Al Viro12f38872013-09-15 21:20:49 -0400753EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754
755ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
756{
757 struct simple_transaction_argresp *ar = file->private_data;
758
759 if (!ar)
760 return 0;
761 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
762}
Al Viro12f38872013-09-15 21:20:49 -0400763EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
765int simple_transaction_release(struct inode *inode, struct file *file)
766{
767 free_page((unsigned long)file->private_data);
768 return 0;
769}
Al Viro12f38872013-09-15 21:20:49 -0400770EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200772/* Simple attribute files */
773
774struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800775 int (*get)(void *, u64 *);
776 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200777 char get_buf[24]; /* enough to store a u64 and "\n\0" */
778 char set_buf[24];
779 void *data;
780 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800781 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200782};
783
784/* simple_attr_open is called by an actual attribute open file operation
785 * to set the attribute specific access operations. */
786int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800787 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200788 const char *fmt)
789{
790 struct simple_attr *attr;
791
792 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
793 if (!attr)
794 return -ENOMEM;
795
796 attr->get = get;
797 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700798 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200799 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800800 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200801
802 file->private_data = attr;
803
804 return nonseekable_open(inode, file);
805}
Al Viro12f38872013-09-15 21:20:49 -0400806EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200807
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800808int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200809{
810 kfree(file->private_data);
811 return 0;
812}
Al Viro12f38872013-09-15 21:20:49 -0400813EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200814
815/* read from the buffer that is filled with the get function */
816ssize_t simple_attr_read(struct file *file, char __user *buf,
817 size_t len, loff_t *ppos)
818{
819 struct simple_attr *attr;
820 size_t size;
821 ssize_t ret;
822
823 attr = file->private_data;
824
825 if (!attr->get)
826 return -EACCES;
827
Christoph Hellwig92613032008-02-08 04:20:27 -0800828 ret = mutex_lock_interruptible(&attr->mutex);
829 if (ret)
830 return ret;
831
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800832 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200833 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800834 } else { /* first read */
835 u64 val;
836 ret = attr->get(attr->data, &val);
837 if (ret)
838 goto out;
839
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200840 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800841 attr->fmt, (unsigned long long)val);
842 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200843
844 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800845out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800846 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200847 return ret;
848}
Al Viro12f38872013-09-15 21:20:49 -0400849EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200850
851/* interpret the buffer as a number to call the set function with */
852ssize_t simple_attr_write(struct file *file, const char __user *buf,
853 size_t len, loff_t *ppos)
854{
855 struct simple_attr *attr;
856 u64 val;
857 size_t size;
858 ssize_t ret;
859
860 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200861 if (!attr->set)
862 return -EACCES;
863
Christoph Hellwig92613032008-02-08 04:20:27 -0800864 ret = mutex_lock_interruptible(&attr->mutex);
865 if (ret)
866 return ret;
867
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200868 ret = -EFAULT;
869 size = min(sizeof(attr->set_buf) - 1, len);
870 if (copy_from_user(attr->set_buf, buf, size))
871 goto out;
872
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200873 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700874 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700875 ret = attr->set(attr->data, val);
876 if (ret == 0)
877 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200878out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800879 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200880 return ret;
881}
Al Viro12f38872013-09-15 21:20:49 -0400882EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200883
Christoph Hellwig25961102007-10-21 16:42:05 -0700884/**
885 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
886 * @sb: filesystem to do the file handle conversion on
887 * @fid: file handle to convert
888 * @fh_len: length of the file handle in bytes
889 * @fh_type: type of file handle
890 * @get_inode: filesystem callback to retrieve inode
891 *
892 * This function decodes @fid as long as it has one of the well-known
893 * Linux filehandle types and calls @get_inode on it to retrieve the
894 * inode for the object specified in the file handle.
895 */
896struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
897 int fh_len, int fh_type, struct inode *(*get_inode)
898 (struct super_block *sb, u64 ino, u32 gen))
899{
900 struct inode *inode = NULL;
901
902 if (fh_len < 2)
903 return NULL;
904
905 switch (fh_type) {
906 case FILEID_INO32_GEN:
907 case FILEID_INO32_GEN_PARENT:
908 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
909 break;
910 }
911
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200912 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700913}
914EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
915
916/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800917 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700918 * @sb: filesystem to do the file handle conversion on
919 * @fid: file handle to convert
920 * @fh_len: length of the file handle in bytes
921 * @fh_type: type of file handle
922 * @get_inode: filesystem callback to retrieve inode
923 *
924 * This function decodes @fid as long as it has one of the well-known
925 * Linux filehandle types and calls @get_inode on it to retrieve the
926 * inode for the _parent_ object specified in the file handle if it
927 * is specified in the file handle, or NULL otherwise.
928 */
929struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
930 int fh_len, int fh_type, struct inode *(*get_inode)
931 (struct super_block *sb, u64 ino, u32 gen))
932{
933 struct inode *inode = NULL;
934
935 if (fh_len <= 2)
936 return NULL;
937
938 switch (fh_type) {
939 case FILEID_INO32_GEN_PARENT:
940 inode = get_inode(sb, fid->i32.parent_ino,
941 (fh_len > 3 ? fid->i32.parent_gen : 0));
942 break;
943 }
944
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200945 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700946}
947EXPORT_SYMBOL_GPL(generic_fh_to_parent);
948
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200949/**
Fabian Frederickac13a822014-06-04 16:06:27 -0700950 * __generic_file_fsync - generic fsync implementation for simple filesystems
951 *
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200952 * @file: file to synchronize
Fabian Frederickac13a822014-06-04 16:06:27 -0700953 * @start: start offset in bytes
954 * @end: end offset in bytes (inclusive)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200955 * @datasync: only synchronize essential metadata if true
956 *
957 * This is a generic implementation of the fsync method for simple
958 * filesystems which track all non-inode metadata in the buffers list
959 * hanging off the address_space structure.
960 */
Fabian Frederickac13a822014-06-04 16:06:27 -0700961int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
962 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400963{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200964 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400965 int err;
966 int ret;
967
Josef Bacik02c24a82011-07-16 20:44:56 -0400968 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
969 if (err)
970 return err;
971
Al Viro59551022016-01-22 15:40:57 -0500972 inode_lock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400973 ret = sync_mapping_buffers(inode->i_mapping);
Theodore Ts'o0ae45f62015-02-02 00:37:00 -0500974 if (!(inode->i_state & I_DIRTY_ALL))
Josef Bacik02c24a82011-07-16 20:44:56 -0400975 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400976 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400977 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400978
Christoph Hellwigc37650162010-10-06 10:48:20 +0200979 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400980 if (ret == 0)
981 ret = err;
Fabian Frederickac13a822014-06-04 16:06:27 -0700982
Josef Bacik02c24a82011-07-16 20:44:56 -0400983out:
Al Viro59551022016-01-22 15:40:57 -0500984 inode_unlock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400985 return ret;
986}
Fabian Frederickac13a822014-06-04 16:06:27 -0700987EXPORT_SYMBOL(__generic_file_fsync);
988
989/**
990 * generic_file_fsync - generic fsync implementation for simple filesystems
991 * with flush
992 * @file: file to synchronize
993 * @start: start offset in bytes
994 * @end: end offset in bytes (inclusive)
995 * @datasync: only synchronize essential metadata if true
996 *
997 */
998
999int generic_file_fsync(struct file *file, loff_t start, loff_t end,
1000 int datasync)
1001{
1002 struct inode *inode = file->f_mapping->host;
1003 int err;
1004
1005 err = __generic_file_fsync(file, start, end, datasync);
1006 if (err)
1007 return err;
1008 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
1009}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001010EXPORT_SYMBOL(generic_file_fsync);
1011
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001012/**
1013 * generic_check_addressable - Check addressability of file system
1014 * @blocksize_bits: log of file system block size
1015 * @num_blocks: number of blocks in file system
1016 *
1017 * Determine whether a file system with @num_blocks blocks (and a
1018 * block size of 2**@blocksize_bits) is addressable by the sector_t
1019 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
1020 */
1021int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
1022{
1023 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -07001024 u64 last_fs_page =
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001025 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001026
1027 if (unlikely(num_blocks == 0))
1028 return 0;
1029
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001030 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001031 return -EINVAL;
1032
Joel Beckera33f13e2010-08-16 12:10:17 -07001033 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1034 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001035 return -EFBIG;
1036 }
1037 return 0;
1038}
1039EXPORT_SYMBOL(generic_check_addressable);
1040
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001041/*
1042 * No-op implementation of ->fsync for in-memory filesystems.
1043 */
Josef Bacik02c24a82011-07-16 20:44:56 -04001044int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001045{
1046 return 0;
1047}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001048EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -04001049
Al Virofceef392015-12-29 15:58:39 -05001050/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1051void kfree_link(void *p)
Al Viro87dc8002013-09-16 10:30:04 -04001052{
Al Virofceef392015-12-29 15:58:39 -05001053 kfree(p);
Al Viro87dc8002013-09-16 10:30:04 -04001054}
Al Virofceef392015-12-29 15:58:39 -05001055EXPORT_SYMBOL(kfree_link);
Al Viro69878432013-10-02 22:35:11 -04001056
1057/*
1058 * nop .set_page_dirty method so that people can use .page_mkwrite on
1059 * anon inodes.
1060 */
1061static int anon_set_page_dirty(struct page *page)
1062{
1063 return 0;
1064};
1065
1066/*
1067 * A single inode exists for all anon_inode files. Contrary to pipes,
1068 * anon_inode inodes have no associated per-instance data, so we need
1069 * only allocate one of them.
1070 */
1071struct inode *alloc_anon_inode(struct super_block *s)
1072{
1073 static const struct address_space_operations anon_aops = {
1074 .set_page_dirty = anon_set_page_dirty,
1075 };
1076 struct inode *inode = new_inode_pseudo(s);
1077
1078 if (!inode)
1079 return ERR_PTR(-ENOMEM);
1080
1081 inode->i_ino = get_next_ino();
1082 inode->i_mapping->a_ops = &anon_aops;
1083
1084 /*
1085 * Mark the inode dirty from the very beginning,
1086 * that way it will never be moved to the dirty
1087 * list because mark_inode_dirty() will think
1088 * that it already _is_ on the dirty list.
1089 */
1090 inode->i_state = I_DIRTY;
1091 inode->i_mode = S_IRUSR | S_IWUSR;
1092 inode->i_uid = current_fsuid();
1093 inode->i_gid = current_fsgid();
1094 inode->i_flags |= S_PRIVATE;
1095 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1096 return inode;
1097}
1098EXPORT_SYMBOL(alloc_anon_inode);
Jeff Layton1c994a02014-08-27 06:49:41 -04001099
1100/**
1101 * simple_nosetlease - generic helper for prohibiting leases
1102 * @filp: file pointer
1103 * @arg: type of lease to obtain
1104 * @flp: new lease supplied for insertion
Jeff Laytone6f5c782014-08-22 10:40:25 -04001105 * @priv: private data for lm_setup operation
Jeff Layton1c994a02014-08-27 06:49:41 -04001106 *
1107 * Generic helper for filesystems that do not wish to allow leases to be set.
1108 * All arguments are ignored and it just returns -EINVAL.
1109 */
1110int
Jeff Laytone6f5c782014-08-22 10:40:25 -04001111simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1112 void **priv)
Jeff Layton1c994a02014-08-27 06:49:41 -04001113{
1114 return -EINVAL;
1115}
1116EXPORT_SYMBOL(simple_nosetlease);
Al Viro61ba64f2015-05-02 09:54:06 -04001117
Al Viro6b255392015-11-17 10:20:54 -05001118const char *simple_get_link(struct dentry *dentry, struct inode *inode,
Al Virofceef392015-12-29 15:58:39 -05001119 struct delayed_call *done)
Al Viro61ba64f2015-05-02 09:54:06 -04001120{
Al Viro6b255392015-11-17 10:20:54 -05001121 return inode->i_link;
Al Viro61ba64f2015-05-02 09:54:06 -04001122}
Al Viro6b255392015-11-17 10:20:54 -05001123EXPORT_SYMBOL(simple_get_link);
Al Viro61ba64f2015-05-02 09:54:06 -04001124
1125const struct inode_operations simple_symlink_inode_operations = {
Al Viro6b255392015-11-17 10:20:54 -05001126 .get_link = simple_get_link,
Al Viro61ba64f2015-05-02 09:54:06 -04001127 .readlink = generic_readlink
1128};
1129EXPORT_SYMBOL(simple_symlink_inode_operations);
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001130
1131/*
1132 * Operations for a permanently empty directory.
1133 */
1134static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1135{
1136 return ERR_PTR(-ENOENT);
1137}
1138
1139static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
1140 struct kstat *stat)
1141{
1142 struct inode *inode = d_inode(dentry);
1143 generic_fillattr(inode, stat);
1144 return 0;
1145}
1146
1147static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1148{
1149 return -EPERM;
1150}
1151
Al Viro3767e252016-05-27 11:06:05 -04001152static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
1153 const char *name, const void *value,
1154 size_t size, int flags)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001155{
1156 return -EOPNOTSUPP;
1157}
1158
Al Viroce23e642016-04-11 00:48:00 -04001159static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
1160 const char *name, void *value, size_t size)
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001161{
1162 return -EOPNOTSUPP;
1163}
1164
1165static int empty_dir_removexattr(struct dentry *dentry, const char *name)
1166{
1167 return -EOPNOTSUPP;
1168}
1169
1170static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1171{
1172 return -EOPNOTSUPP;
1173}
1174
1175static const struct inode_operations empty_dir_inode_operations = {
1176 .lookup = empty_dir_lookup,
1177 .permission = generic_permission,
1178 .setattr = empty_dir_setattr,
1179 .getattr = empty_dir_getattr,
1180 .setxattr = empty_dir_setxattr,
1181 .getxattr = empty_dir_getxattr,
1182 .removexattr = empty_dir_removexattr,
1183 .listxattr = empty_dir_listxattr,
1184};
1185
1186static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1187{
1188 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1189 return generic_file_llseek_size(file, offset, whence, 2, 2);
1190}
1191
1192static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1193{
1194 dir_emit_dots(file, ctx);
1195 return 0;
1196}
1197
1198static const struct file_operations empty_dir_operations = {
1199 .llseek = empty_dir_llseek,
1200 .read = generic_read_dir,
Al Viroc51da202016-04-30 22:37:34 -04001201 .iterate_shared = empty_dir_readdir,
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001202 .fsync = noop_fsync,
1203};
1204
1205
1206void make_empty_dir_inode(struct inode *inode)
1207{
1208 set_nlink(inode, 2);
1209 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1210 inode->i_uid = GLOBAL_ROOT_UID;
1211 inode->i_gid = GLOBAL_ROOT_GID;
1212 inode->i_rdev = 0;
Eric W. Biederman4b75de862015-08-12 15:00:12 -05001213 inode->i_size = 0;
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001214 inode->i_blkbits = PAGE_SHIFT;
1215 inode->i_blocks = 0;
1216
1217 inode->i_op = &empty_dir_inode_operations;
1218 inode->i_fop = &empty_dir_operations;
1219}
1220
1221bool is_empty_dir_inode(struct inode *inode)
1222{
1223 return (inode->i_fop == &empty_dir_operations) &&
1224 (inode->i_op == &empty_dir_inode_operations);
1225}