blob: 48826d4da189ec0373f24c16a89e4f1066815200 [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 */
Andreas Gruenbacherbba0bd32016-09-29 17:48:35 +0200239struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
240 const struct super_operations *ops, const struct xattr_handler **xattr,
Al Viroc74a1cb2011-01-12 16:59:34 -0500241 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;
Andreas Gruenbacherbba0bd32016-09-29 17:48:35 +0200257 s->s_xattr = xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 s->s_time_gran = 1;
259 root = new_inode(s);
260 if (!root)
261 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700262 /*
263 * since this is the first inode, make it number 1. New inodes created
264 * after this must take care not to collide with it (by passing
265 * max_reserved of 1 to iunique).
266 */
267 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Deepa Dinamani078cd822016-09-14 07:48:04 -0700269 root->i_atime = root->i_mtime = root->i_ctime = current_time(root);
Al Viroa4464db2011-07-07 15:03:58 -0400270 dentry = __d_alloc(s, &d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 if (!dentry) {
272 iput(root);
273 goto Enomem;
274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 d_instantiate(dentry, root);
276 s->s_root = dentry;
Al Viroc74a1cb2011-01-12 16:59:34 -0500277 s->s_d_op = dops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400279 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400282 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400283 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284}
Andreas Gruenbacherbba0bd32016-09-29 17:48:35 +0200285EXPORT_SYMBOL(mount_pseudo_xattr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
Stephen Boyd20955e82012-04-05 14:25:09 -0700287int simple_open(struct inode *inode, struct file *file)
288{
289 if (inode->i_private)
290 file->private_data = inode->i_private;
291 return 0;
292}
Al Viro12f38872013-09-15 21:20:49 -0400293EXPORT_SYMBOL(simple_open);
Stephen Boyd20955e82012-04-05 14:25:09 -0700294
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
296{
David Howellsdea655c2015-03-17 22:26:15 +0000297 struct inode *inode = d_inode(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Deepa Dinamani078cd822016-09-14 07:48:04 -0700299 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
Dave Hansend8c76e62006-09-30 23:29:04 -0700300 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400301 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 dget(dentry);
303 d_instantiate(dentry, inode);
304 return 0;
305}
Al Viro12f38872013-09-15 21:20:49 -0400306EXPORT_SYMBOL(simple_link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308int simple_empty(struct dentry *dentry)
309{
310 struct dentry *child;
311 int ret = 0;
312
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100313 spin_lock(&dentry->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400314 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
Nick Pigginda502952011-01-07 17:49:33 +1100315 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
316 if (simple_positive(child)) {
317 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100319 }
320 spin_unlock(&child->d_lock);
321 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 ret = 1;
323out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100324 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 return ret;
326}
Al Viro12f38872013-09-15 21:20:49 -0400327EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328
329int simple_unlink(struct inode *dir, struct dentry *dentry)
330{
David Howellsdea655c2015-03-17 22:26:15 +0000331 struct inode *inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332
Deepa Dinamani078cd822016-09-14 07:48:04 -0700333 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700334 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 dput(dentry);
336 return 0;
337}
Al Viro12f38872013-09-15 21:20:49 -0400338EXPORT_SYMBOL(simple_unlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
340int simple_rmdir(struct inode *dir, struct dentry *dentry)
341{
342 if (!simple_empty(dentry))
343 return -ENOTEMPTY;
344
David Howellsdea655c2015-03-17 22:26:15 +0000345 drop_nlink(d_inode(dentry));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700347 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 return 0;
349}
Al Viro12f38872013-09-15 21:20:49 -0400350EXPORT_SYMBOL(simple_rmdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
352int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
Miklos Szeredie0e0be82016-09-27 11:03:57 +0200353 struct inode *new_dir, struct dentry *new_dentry,
354 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355{
David Howellsdea655c2015-03-17 22:26:15 +0000356 struct inode *inode = d_inode(old_dentry);
David Howellse36cb0b2015-01-29 12:02:35 +0000357 int they_are_dirs = d_is_dir(old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358
Miklos Szeredie0e0be82016-09-27 11:03:57 +0200359 if (flags & ~RENAME_NOREPLACE)
360 return -EINVAL;
361
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 if (!simple_empty(new_dentry))
363 return -ENOTEMPTY;
364
David Howellsdea655c2015-03-17 22:26:15 +0000365 if (d_really_is_positive(new_dentry)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 simple_unlink(new_dir, new_dentry);
Al Viro841590c2011-07-21 15:49:09 -0400367 if (they_are_dirs) {
David Howellsdea655c2015-03-17 22:26:15 +0000368 drop_nlink(d_inode(new_dentry));
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700369 drop_nlink(old_dir);
Al Viro841590c2011-07-21 15:49:09 -0400370 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700372 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700373 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 }
375
376 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
Deepa Dinamani078cd822016-09-14 07:48:04 -0700377 new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378
379 return 0;
380}
Al Viro12f38872013-09-15 21:20:49 -0400381EXPORT_SYMBOL(simple_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000383/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200384 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000385 * @dentry: dentry
386 * @iattr: iattr structure
387 *
388 * Returns 0 on success, -error on failure.
389 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200390 * simple_setattr is a simple ->setattr implementation without a proper
391 * implementation of size changes.
392 *
393 * It can either be used for in-memory filesystems or special files
394 * on simple regular filesystems. Anything that needs to change on-disk
395 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000396 */
397int simple_setattr(struct dentry *dentry, struct iattr *iattr)
398{
David Howellsdea655c2015-03-17 22:26:15 +0000399 struct inode *inode = d_inode(dentry);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000400 int error;
401
Jan Kara31051c82016-05-26 16:55:18 +0200402 error = setattr_prepare(dentry, iattr);
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000403 if (error)
404 return error;
405
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200406 if (iattr->ia_valid & ATTR_SIZE)
407 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200408 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200409 mark_inode_dirty(inode);
410 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000411}
412EXPORT_SYMBOL(simple_setattr);
413
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414int simple_readpage(struct file *file, struct page *page)
415{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700416 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 flush_dcache_page(page);
418 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 unlock_page(page);
420 return 0;
421}
Al Viro12f38872013-09-15 21:20:49 -0400422EXPORT_SYMBOL(simple_readpage);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
Nick Pigginafddba42007-10-16 01:25:01 -0700424int simple_write_begin(struct file *file, struct address_space *mapping,
425 loff_t pos, unsigned len, unsigned flags,
426 struct page **pagep, void **fsdata)
427{
428 struct page *page;
429 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700430
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300431 index = pos >> PAGE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700432
Nick Piggin54566b22009-01-04 12:00:53 -0800433 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700434 if (!page)
435 return -ENOMEM;
436
437 *pagep = page;
438
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300439 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
440 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200441
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300442 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200443 }
444 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700445}
Al Viro12f38872013-09-15 21:20:49 -0400446EXPORT_SYMBOL(simple_write_begin);
Nick Pigginafddba42007-10-16 01:25:01 -0700447
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200448/**
449 * simple_write_end - .write_end helper for non-block-device FSes
450 * @available: See .write_end of address_space_operations
451 * @file: "
452 * @mapping: "
453 * @pos: "
454 * @len: "
455 * @copied: "
456 * @page: "
457 * @fsdata: "
458 *
459 * simple_write_end does the minimum needed for updating a page after writing is
460 * done. It has the same API signature as the .write_end of
461 * address_space_operations vector. So it can just be set onto .write_end for
462 * FSes that don't need any other processing. i_mutex is assumed to be held.
463 * Block based filesystems should use generic_write_end().
464 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
465 * is not called, so a filesystem that actually does store data in .write_inode
466 * should extend on what's done here with a call to mark_inode_dirty() in the
467 * case that i_size has changed.
468 */
469int simple_write_end(struct file *file, struct address_space *mapping,
470 loff_t pos, unsigned len, unsigned copied,
471 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472{
473 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200474 loff_t last_pos = pos + copied;
475
476 /* zero the stale part of the page if we did a short copy */
477 if (copied < len) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300478 unsigned from = pos & (PAGE_SIZE - 1);
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200479
480 zero_user(page, from + copied, len - copied);
481 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482
Nick Piggin955eff52007-02-20 13:58:08 -0800483 if (!PageUptodate(page))
484 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 /*
486 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800487 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200489 if (last_pos > inode->i_size)
490 i_size_write(inode, last_pos);
491
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700493 unlock_page(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300494 put_page(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700495
496 return copied;
497}
Al Viro12f38872013-09-15 21:20:49 -0400498EXPORT_SYMBOL(simple_write_end);
Nick Pigginafddba42007-10-16 01:25:01 -0700499
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700500/*
501 * the inodes created here are not hashed. If you use iunique to generate
502 * unique inode values later for this filesystem, then you must take care
503 * to pass it an appropriate max_reserved value to avoid collisions.
504 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200505int simple_fill_super(struct super_block *s, unsigned long magic,
506 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 struct inode *inode;
509 struct dentry *root;
510 struct dentry *dentry;
511 int i;
512
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300513 s->s_blocksize = PAGE_SIZE;
514 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800516 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 s->s_time_gran = 1;
518
519 inode = new_inode(s);
520 if (!inode)
521 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700522 /*
523 * because the root inode is 1, the files array must not contain an
524 * entry at index 1
525 */
526 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 inode->i_mode = S_IFDIR | 0755;
Deepa Dinamani078cd822016-09-14 07:48:04 -0700528 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 inode->i_op = &simple_dir_inode_operations;
530 inode->i_fop = &simple_dir_operations;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200531 set_nlink(inode, 2);
Al Viro48fde702012-01-08 22:15:13 -0500532 root = d_make_root(inode);
533 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 for (i = 0; !files->name || files->name[0]; i++, files++) {
536 if (!files->name)
537 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700538
539 /* warn if it tries to conflict with the root inode */
540 if (unlikely(i == 1))
541 printk(KERN_WARNING "%s: %s passed in a files array"
542 "with an index of 1!\n", __func__,
543 s->s_type->name);
544
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 dentry = d_alloc_name(root, files->name);
546 if (!dentry)
547 goto out;
548 inode = new_inode(s);
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300549 if (!inode) {
550 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 goto out;
Konstantin Khlebnikov32096ea2011-11-01 16:12:33 +0300552 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 inode->i_mode = S_IFREG | files->mode;
Deepa Dinamani078cd822016-09-14 07:48:04 -0700554 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 inode->i_fop = files->ops;
556 inode->i_ino = i;
557 d_add(dentry, inode);
558 }
559 s->s_root = root;
560 return 0;
561out:
562 d_genocide(root);
Al Viro640946f22012-04-02 19:22:25 -0400563 shrink_dcache_parent(root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 dput(root);
565 return -ENOMEM;
566}
Al Viro12f38872013-09-15 21:20:49 -0400567EXPORT_SYMBOL(simple_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
569static DEFINE_SPINLOCK(pin_fs_lock);
570
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400571int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572{
573 struct vfsmount *mnt = NULL;
574 spin_lock(&pin_fs_lock);
575 if (unlikely(!*mount)) {
576 spin_unlock(&pin_fs_lock);
Al Viro24529922012-03-17 02:13:52 -0400577 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 if (IS_ERR(mnt))
579 return PTR_ERR(mnt);
580 spin_lock(&pin_fs_lock);
581 if (!*mount)
582 *mount = mnt;
583 }
584 mntget(*mount);
585 ++*count;
586 spin_unlock(&pin_fs_lock);
587 mntput(mnt);
588 return 0;
589}
Al Viro12f38872013-09-15 21:20:49 -0400590EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
592void simple_release_fs(struct vfsmount **mount, int *count)
593{
594 struct vfsmount *mnt;
595 spin_lock(&pin_fs_lock);
596 mnt = *mount;
597 if (!--*count)
598 *mount = NULL;
599 spin_unlock(&pin_fs_lock);
600 mntput(mnt);
601}
Al Viro12f38872013-09-15 21:20:49 -0400602EXPORT_SYMBOL(simple_release_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700604/**
605 * simple_read_from_buffer - copy data from the buffer to user space
606 * @to: the user space buffer to read to
607 * @count: the maximum number of bytes to read
608 * @ppos: the current position in the buffer
609 * @from: the buffer to read from
610 * @available: the size of the buffer
611 *
612 * The simple_read_from_buffer() function reads up to @count bytes from the
613 * buffer @from at offset @ppos into the user space address starting at @to.
614 *
615 * On success, the number of bytes read is returned and the offset @ppos is
616 * advanced by this number, or negative value is returned on error.
617 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
619 const void *from, size_t available)
620{
621 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700622 size_t ret;
623
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 if (pos < 0)
625 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700626 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 return 0;
628 if (count > available - pos)
629 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700630 ret = copy_to_user(to, from + pos, count);
631 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700633 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 *ppos = pos + count;
635 return count;
636}
Al Viro12f38872013-09-15 21:20:49 -0400637EXPORT_SYMBOL(simple_read_from_buffer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700639/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200640 * simple_write_to_buffer - copy data from user space to the buffer
641 * @to: the buffer to write to
642 * @available: the size of the buffer
643 * @ppos: the current position in the buffer
644 * @from: the user space buffer to read from
645 * @count: the maximum number of bytes to read
646 *
647 * The simple_write_to_buffer() function reads up to @count bytes from the user
648 * space address starting at @from into the buffer @to at offset @ppos.
649 *
650 * On success, the number of bytes written is returned and the offset @ppos is
651 * advanced by this number, or negative value is returned on error.
652 **/
653ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
654 const void __user *from, size_t count)
655{
656 loff_t pos = *ppos;
657 size_t res;
658
659 if (pos < 0)
660 return -EINVAL;
661 if (pos >= available || !count)
662 return 0;
663 if (count > available - pos)
664 count = available - pos;
665 res = copy_from_user(to + pos, from, count);
666 if (res == count)
667 return -EFAULT;
668 count -= res;
669 *ppos = pos + count;
670 return count;
671}
Al Viro12f38872013-09-15 21:20:49 -0400672EXPORT_SYMBOL(simple_write_to_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200673
674/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700675 * memory_read_from_buffer - copy data from the buffer
676 * @to: the kernel space buffer to read to
677 * @count: the maximum number of bytes to read
678 * @ppos: the current position in the buffer
679 * @from: the buffer to read from
680 * @available: the size of the buffer
681 *
682 * The memory_read_from_buffer() function reads up to @count bytes from the
683 * buffer @from at offset @ppos into the kernel space address starting at @to.
684 *
685 * On success, the number of bytes read is returned and the offset @ppos is
686 * advanced by this number, or negative value is returned on error.
687 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700688ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
689 const void *from, size_t available)
690{
691 loff_t pos = *ppos;
692
693 if (pos < 0)
694 return -EINVAL;
695 if (pos >= available)
696 return 0;
697 if (count > available - pos)
698 count = available - pos;
699 memcpy(to, from + pos, count);
700 *ppos = pos + count;
701
702 return count;
703}
Al Viro12f38872013-09-15 21:20:49 -0400704EXPORT_SYMBOL(memory_read_from_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706/*
707 * Transaction based IO.
708 * The file expects a single write which triggers the transaction, and then
709 * possibly a read which collects the result - which is stored in a
710 * file-local buffer.
711 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100712
713void simple_transaction_set(struct file *file, size_t n)
714{
715 struct simple_transaction_argresp *ar = file->private_data;
716
717 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
718
719 /*
720 * The barrier ensures that ar->size will really remain zero until
721 * ar->data is ready for reading.
722 */
723 smp_mb();
724 ar->size = n;
725}
Al Viro12f38872013-09-15 21:20:49 -0400726EXPORT_SYMBOL(simple_transaction_set);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100727
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
729{
730 struct simple_transaction_argresp *ar;
731 static DEFINE_SPINLOCK(simple_transaction_lock);
732
733 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
734 return ERR_PTR(-EFBIG);
735
736 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
737 if (!ar)
738 return ERR_PTR(-ENOMEM);
739
740 spin_lock(&simple_transaction_lock);
741
742 /* only one write allowed per open */
743 if (file->private_data) {
744 spin_unlock(&simple_transaction_lock);
745 free_page((unsigned long)ar);
746 return ERR_PTR(-EBUSY);
747 }
748
749 file->private_data = ar;
750
751 spin_unlock(&simple_transaction_lock);
752
753 if (copy_from_user(ar->data, buf, size))
754 return ERR_PTR(-EFAULT);
755
756 return ar->data;
757}
Al Viro12f38872013-09-15 21:20:49 -0400758EXPORT_SYMBOL(simple_transaction_get);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759
760ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
761{
762 struct simple_transaction_argresp *ar = file->private_data;
763
764 if (!ar)
765 return 0;
766 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
767}
Al Viro12f38872013-09-15 21:20:49 -0400768EXPORT_SYMBOL(simple_transaction_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769
770int simple_transaction_release(struct inode *inode, struct file *file)
771{
772 free_page((unsigned long)file->private_data);
773 return 0;
774}
Al Viro12f38872013-09-15 21:20:49 -0400775EXPORT_SYMBOL(simple_transaction_release);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200777/* Simple attribute files */
778
779struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800780 int (*get)(void *, u64 *);
781 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200782 char get_buf[24]; /* enough to store a u64 and "\n\0" */
783 char set_buf[24];
784 void *data;
785 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800786 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200787};
788
789/* simple_attr_open is called by an actual attribute open file operation
790 * to set the attribute specific access operations. */
791int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800792 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200793 const char *fmt)
794{
795 struct simple_attr *attr;
796
797 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
798 if (!attr)
799 return -ENOMEM;
800
801 attr->get = get;
802 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700803 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200804 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800805 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200806
807 file->private_data = attr;
808
809 return nonseekable_open(inode, file);
810}
Al Viro12f38872013-09-15 21:20:49 -0400811EXPORT_SYMBOL_GPL(simple_attr_open);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200812
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800813int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200814{
815 kfree(file->private_data);
816 return 0;
817}
Al Viro12f38872013-09-15 21:20:49 -0400818EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200819
820/* read from the buffer that is filled with the get function */
821ssize_t simple_attr_read(struct file *file, char __user *buf,
822 size_t len, loff_t *ppos)
823{
824 struct simple_attr *attr;
825 size_t size;
826 ssize_t ret;
827
828 attr = file->private_data;
829
830 if (!attr->get)
831 return -EACCES;
832
Christoph Hellwig92613032008-02-08 04:20:27 -0800833 ret = mutex_lock_interruptible(&attr->mutex);
834 if (ret)
835 return ret;
836
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800837 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200838 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800839 } else { /* first read */
840 u64 val;
841 ret = attr->get(attr->data, &val);
842 if (ret)
843 goto out;
844
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200845 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800846 attr->fmt, (unsigned long long)val);
847 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200848
849 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800850out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800851 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200852 return ret;
853}
Al Viro12f38872013-09-15 21:20:49 -0400854EXPORT_SYMBOL_GPL(simple_attr_read);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200855
856/* interpret the buffer as a number to call the set function with */
857ssize_t simple_attr_write(struct file *file, const char __user *buf,
858 size_t len, loff_t *ppos)
859{
860 struct simple_attr *attr;
861 u64 val;
862 size_t size;
863 ssize_t ret;
864
865 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200866 if (!attr->set)
867 return -EACCES;
868
Christoph Hellwig92613032008-02-08 04:20:27 -0800869 ret = mutex_lock_interruptible(&attr->mutex);
870 if (ret)
871 return ret;
872
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200873 ret = -EFAULT;
874 size = min(sizeof(attr->set_buf) - 1, len);
875 if (copy_from_user(attr->set_buf, buf, size))
876 goto out;
877
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200878 attr->set_buf[size] = '\0';
Akinobu Mitaf7b88632011-07-19 08:49:25 -0700879 val = simple_strtoll(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700880 ret = attr->set(attr->data, val);
881 if (ret == 0)
882 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200883out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800884 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200885 return ret;
886}
Al Viro12f38872013-09-15 21:20:49 -0400887EXPORT_SYMBOL_GPL(simple_attr_write);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200888
Christoph Hellwig25961102007-10-21 16:42:05 -0700889/**
890 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
891 * @sb: filesystem to do the file handle conversion on
892 * @fid: file handle to convert
893 * @fh_len: length of the file handle in bytes
894 * @fh_type: type of file handle
895 * @get_inode: filesystem callback to retrieve inode
896 *
897 * This function decodes @fid as long as it has one of the well-known
898 * Linux filehandle types and calls @get_inode on it to retrieve the
899 * inode for the object specified in the file handle.
900 */
901struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
902 int fh_len, int fh_type, struct inode *(*get_inode)
903 (struct super_block *sb, u64 ino, u32 gen))
904{
905 struct inode *inode = NULL;
906
907 if (fh_len < 2)
908 return NULL;
909
910 switch (fh_type) {
911 case FILEID_INO32_GEN:
912 case FILEID_INO32_GEN_PARENT:
913 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
914 break;
915 }
916
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200917 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700918}
919EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
920
921/**
Yanchuan Nianca186832012-09-05 16:31:29 +0800922 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
Christoph Hellwig25961102007-10-21 16:42:05 -0700923 * @sb: filesystem to do the file handle conversion on
924 * @fid: file handle to convert
925 * @fh_len: length of the file handle in bytes
926 * @fh_type: type of file handle
927 * @get_inode: filesystem callback to retrieve inode
928 *
929 * This function decodes @fid as long as it has one of the well-known
930 * Linux filehandle types and calls @get_inode on it to retrieve the
931 * inode for the _parent_ object specified in the file handle if it
932 * is specified in the file handle, or NULL otherwise.
933 */
934struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
935 int fh_len, int fh_type, struct inode *(*get_inode)
936 (struct super_block *sb, u64 ino, u32 gen))
937{
938 struct inode *inode = NULL;
939
940 if (fh_len <= 2)
941 return NULL;
942
943 switch (fh_type) {
944 case FILEID_INO32_GEN_PARENT:
945 inode = get_inode(sb, fid->i32.parent_ino,
946 (fh_len > 3 ? fid->i32.parent_gen : 0));
947 break;
948 }
949
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200950 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700951}
952EXPORT_SYMBOL_GPL(generic_fh_to_parent);
953
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200954/**
Fabian Frederickac13a822014-06-04 16:06:27 -0700955 * __generic_file_fsync - generic fsync implementation for simple filesystems
956 *
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200957 * @file: file to synchronize
Fabian Frederickac13a822014-06-04 16:06:27 -0700958 * @start: start offset in bytes
959 * @end: end offset in bytes (inclusive)
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200960 * @datasync: only synchronize essential metadata if true
961 *
962 * This is a generic implementation of the fsync method for simple
963 * filesystems which track all non-inode metadata in the buffers list
964 * hanging off the address_space structure.
965 */
Fabian Frederickac13a822014-06-04 16:06:27 -0700966int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
967 int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400968{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200969 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400970 int err;
971 int ret;
972
Josef Bacik02c24a82011-07-16 20:44:56 -0400973 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
974 if (err)
975 return err;
976
Al Viro59551022016-01-22 15:40:57 -0500977 inode_lock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400978 ret = sync_mapping_buffers(inode->i_mapping);
Theodore Ts'o0ae45f62015-02-02 00:37:00 -0500979 if (!(inode->i_state & I_DIRTY_ALL))
Josef Bacik02c24a82011-07-16 20:44:56 -0400980 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400981 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
Josef Bacik02c24a82011-07-16 20:44:56 -0400982 goto out;
Al Virod5aacad2009-06-07 14:56:44 -0400983
Christoph Hellwigc37650162010-10-06 10:48:20 +0200984 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400985 if (ret == 0)
986 ret = err;
Fabian Frederickac13a822014-06-04 16:06:27 -0700987
Josef Bacik02c24a82011-07-16 20:44:56 -0400988out:
Al Viro59551022016-01-22 15:40:57 -0500989 inode_unlock(inode);
Al Virod5aacad2009-06-07 14:56:44 -0400990 return ret;
991}
Fabian Frederickac13a822014-06-04 16:06:27 -0700992EXPORT_SYMBOL(__generic_file_fsync);
993
994/**
995 * generic_file_fsync - generic fsync implementation for simple filesystems
996 * with flush
997 * @file: file to synchronize
998 * @start: start offset in bytes
999 * @end: end offset in bytes (inclusive)
1000 * @datasync: only synchronize essential metadata if true
1001 *
1002 */
1003
1004int generic_file_fsync(struct file *file, loff_t start, loff_t end,
1005 int datasync)
1006{
1007 struct inode *inode = file->f_mapping->host;
1008 int err;
1009
1010 err = __generic_file_fsync(file, start, end, datasync);
1011 if (err)
1012 return err;
1013 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
1014}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001015EXPORT_SYMBOL(generic_file_fsync);
1016
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001017/**
1018 * generic_check_addressable - Check addressability of file system
1019 * @blocksize_bits: log of file system block size
1020 * @num_blocks: number of blocks in file system
1021 *
1022 * Determine whether a file system with @num_blocks blocks (and a
1023 * block size of 2**@blocksize_bits) is addressable by the sector_t
1024 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
1025 */
1026int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
1027{
1028 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -07001029 u64 last_fs_page =
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001030 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001031
1032 if (unlikely(num_blocks == 0))
1033 return 0;
1034
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001035 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001036 return -EINVAL;
1037
Joel Beckera33f13e2010-08-16 12:10:17 -07001038 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1039 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -07001040 return -EFBIG;
1041 }
1042 return 0;
1043}
1044EXPORT_SYMBOL(generic_check_addressable);
1045
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001046/*
1047 * No-op implementation of ->fsync for in-memory filesystems.
1048 */
Josef Bacik02c24a82011-07-16 20:44:56 -04001049int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001050{
1051 return 0;
1052}
Christoph Hellwig1b061d92010-05-26 17:53:41 +02001053EXPORT_SYMBOL(noop_fsync);
Al Viro87dc8002013-09-16 10:30:04 -04001054
Al Virofceef392015-12-29 15:58:39 -05001055/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1056void kfree_link(void *p)
Al Viro87dc8002013-09-16 10:30:04 -04001057{
Al Virofceef392015-12-29 15:58:39 -05001058 kfree(p);
Al Viro87dc8002013-09-16 10:30:04 -04001059}
Al Virofceef392015-12-29 15:58:39 -05001060EXPORT_SYMBOL(kfree_link);
Al Viro69878432013-10-02 22:35:11 -04001061
1062/*
1063 * nop .set_page_dirty method so that people can use .page_mkwrite on
1064 * anon inodes.
1065 */
1066static int anon_set_page_dirty(struct page *page)
1067{
1068 return 0;
1069};
1070
1071/*
1072 * A single inode exists for all anon_inode files. Contrary to pipes,
1073 * anon_inode inodes have no associated per-instance data, so we need
1074 * only allocate one of them.
1075 */
1076struct inode *alloc_anon_inode(struct super_block *s)
1077{
1078 static const struct address_space_operations anon_aops = {
1079 .set_page_dirty = anon_set_page_dirty,
1080 };
1081 struct inode *inode = new_inode_pseudo(s);
1082
1083 if (!inode)
1084 return ERR_PTR(-ENOMEM);
1085
1086 inode->i_ino = get_next_ino();
1087 inode->i_mapping->a_ops = &anon_aops;
1088
1089 /*
1090 * Mark the inode dirty from the very beginning,
1091 * that way it will never be moved to the dirty
1092 * list because mark_inode_dirty() will think
1093 * that it already _is_ on the dirty list.
1094 */
1095 inode->i_state = I_DIRTY;
1096 inode->i_mode = S_IRUSR | S_IWUSR;
1097 inode->i_uid = current_fsuid();
1098 inode->i_gid = current_fsgid();
1099 inode->i_flags |= S_PRIVATE;
Deepa Dinamani078cd822016-09-14 07:48:04 -07001100 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
Al Viro69878432013-10-02 22:35:11 -04001101 return inode;
1102}
1103EXPORT_SYMBOL(alloc_anon_inode);
Jeff Layton1c994a02014-08-27 06:49:41 -04001104
1105/**
1106 * simple_nosetlease - generic helper for prohibiting leases
1107 * @filp: file pointer
1108 * @arg: type of lease to obtain
1109 * @flp: new lease supplied for insertion
Jeff Laytone6f5c782014-08-22 10:40:25 -04001110 * @priv: private data for lm_setup operation
Jeff Layton1c994a02014-08-27 06:49:41 -04001111 *
1112 * Generic helper for filesystems that do not wish to allow leases to be set.
1113 * All arguments are ignored and it just returns -EINVAL.
1114 */
1115int
Jeff Laytone6f5c782014-08-22 10:40:25 -04001116simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1117 void **priv)
Jeff Layton1c994a02014-08-27 06:49:41 -04001118{
1119 return -EINVAL;
1120}
1121EXPORT_SYMBOL(simple_nosetlease);
Al Viro61ba64f2015-05-02 09:54:06 -04001122
Al Viro6b255392015-11-17 10:20:54 -05001123const char *simple_get_link(struct dentry *dentry, struct inode *inode,
Al Virofceef392015-12-29 15:58:39 -05001124 struct delayed_call *done)
Al Viro61ba64f2015-05-02 09:54:06 -04001125{
Al Viro6b255392015-11-17 10:20:54 -05001126 return inode->i_link;
Al Viro61ba64f2015-05-02 09:54:06 -04001127}
Al Viro6b255392015-11-17 10:20:54 -05001128EXPORT_SYMBOL(simple_get_link);
Al Viro61ba64f2015-05-02 09:54:06 -04001129
1130const struct inode_operations simple_symlink_inode_operations = {
Al Viro6b255392015-11-17 10:20:54 -05001131 .get_link = simple_get_link,
Al Viro61ba64f2015-05-02 09:54:06 -04001132 .readlink = generic_readlink
1133};
1134EXPORT_SYMBOL(simple_symlink_inode_operations);
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001135
1136/*
1137 * Operations for a permanently empty directory.
1138 */
1139static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1140{
1141 return ERR_PTR(-ENOENT);
1142}
1143
1144static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
1145 struct kstat *stat)
1146{
1147 struct inode *inode = d_inode(dentry);
1148 generic_fillattr(inode, stat);
1149 return 0;
1150}
1151
1152static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1153{
1154 return -EPERM;
1155}
1156
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001157static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1158{
1159 return -EOPNOTSUPP;
1160}
1161
1162static const struct inode_operations empty_dir_inode_operations = {
1163 .lookup = empty_dir_lookup,
1164 .permission = generic_permission,
1165 .setattr = empty_dir_setattr,
1166 .getattr = empty_dir_getattr,
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001167 .listxattr = empty_dir_listxattr,
1168};
1169
1170static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1171{
1172 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1173 return generic_file_llseek_size(file, offset, whence, 2, 2);
1174}
1175
1176static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1177{
1178 dir_emit_dots(file, ctx);
1179 return 0;
1180}
1181
1182static const struct file_operations empty_dir_operations = {
1183 .llseek = empty_dir_llseek,
1184 .read = generic_read_dir,
Al Viroc51da202016-04-30 22:37:34 -04001185 .iterate_shared = empty_dir_readdir,
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001186 .fsync = noop_fsync,
1187};
1188
1189
1190void make_empty_dir_inode(struct inode *inode)
1191{
1192 set_nlink(inode, 2);
1193 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1194 inode->i_uid = GLOBAL_ROOT_UID;
1195 inode->i_gid = GLOBAL_ROOT_GID;
1196 inode->i_rdev = 0;
Eric W. Biederman4b75de862015-08-12 15:00:12 -05001197 inode->i_size = 0;
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001198 inode->i_blkbits = PAGE_SHIFT;
1199 inode->i_blocks = 0;
1200
1201 inode->i_op = &empty_dir_inode_operations;
Andreas Gruenbacherf5c24432016-09-29 17:48:41 +02001202 inode->i_opflags &= ~IOP_XATTR;
Eric W. Biedermanfbabfd02015-05-09 15:54:49 -05001203 inode->i_fop = &empty_dir_operations;
1204}
1205
1206bool is_empty_dir_inode(struct inode *inode)
1207{
1208 return (inode->i_fop == &empty_dir_operations) &&
1209 (inode->i_op == &empty_dir_inode_operations);
1210}