Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/libfs.c |
| 3 | * Library for filesystems writers. |
| 4 | */ |
| 5 | |
| 6 | #include <linux/module.h> |
| 7 | #include <linux/pagemap.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 8 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | #include <linux/mount.h> |
| 10 | #include <linux/vfs.h> |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 11 | #include <linux/quotaops.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 12 | #include <linux/mutex.h> |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 13 | #include <linux/exportfs.h> |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 14 | #include <linux/writeback.h> |
| 15 | #include <linux/buffer_head.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 16 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <asm/uaccess.h> |
| 18 | |
| 19 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
| 20 | struct kstat *stat) |
| 21 | { |
| 22 | struct inode *inode = dentry->d_inode; |
| 23 | generic_fillattr(inode, stat); |
| 24 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); |
| 25 | return 0; |
| 26 | } |
| 27 | |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 28 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | { |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 30 | buf->f_type = dentry->d_sb->s_magic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | buf->f_bsize = PAGE_CACHE_SIZE; |
| 32 | buf->f_namelen = NAME_MAX; |
| 33 | return 0; |
| 34 | } |
| 35 | |
| 36 | /* |
| 37 | * Retaining negative dentries for an in-memory filesystem just wastes |
| 38 | * memory and lookup time: arrange for them to be deleted immediately. |
| 39 | */ |
| 40 | static int simple_delete_dentry(struct dentry *dentry) |
| 41 | { |
| 42 | return 1; |
| 43 | } |
| 44 | |
| 45 | /* |
| 46 | * Lookup the data. This is trivial - if the dentry didn't already |
| 47 | * exist, we know it is negative. Set d_op to delete negative dentries. |
| 48 | */ |
| 49 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) |
| 50 | { |
Al Viro | 3ba13d1 | 2009-02-20 06:02:22 +0000 | [diff] [blame] | 51 | static const struct dentry_operations simple_dentry_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | .d_delete = simple_delete_dentry, |
| 53 | }; |
| 54 | |
| 55 | if (dentry->d_name.len > NAME_MAX) |
| 56 | return ERR_PTR(-ENAMETOOLONG); |
| 57 | dentry->d_op = &simple_dentry_operations; |
| 58 | d_add(dentry, NULL); |
| 59 | return NULL; |
| 60 | } |
| 61 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | int dcache_dir_open(struct inode *inode, struct file *file) |
| 63 | { |
| 64 | static struct qstr cursor_name = {.len = 1, .name = "."}; |
| 65 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 66 | file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
| 68 | return file->private_data ? 0 : -ENOMEM; |
| 69 | } |
| 70 | |
| 71 | int dcache_dir_close(struct inode *inode, struct file *file) |
| 72 | { |
| 73 | dput(file->private_data); |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) |
| 78 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 79 | mutex_lock(&file->f_path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | switch (origin) { |
| 81 | case 1: |
| 82 | offset += file->f_pos; |
| 83 | case 0: |
| 84 | if (offset >= 0) |
| 85 | break; |
| 86 | default: |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 87 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | return -EINVAL; |
| 89 | } |
| 90 | if (offset != file->f_pos) { |
| 91 | file->f_pos = offset; |
| 92 | if (file->f_pos >= 2) { |
| 93 | struct list_head *p; |
| 94 | struct dentry *cursor = file->private_data; |
| 95 | loff_t n = file->f_pos - 2; |
| 96 | |
| 97 | spin_lock(&dcache_lock); |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 98 | list_del(&cursor->d_u.d_child); |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 99 | p = file->f_path.dentry->d_subdirs.next; |
| 100 | while (n && p != &file->f_path.dentry->d_subdirs) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | struct dentry *next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 102 | next = list_entry(p, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | if (!d_unhashed(next) && next->d_inode) |
| 104 | n--; |
| 105 | p = p->next; |
| 106 | } |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 107 | list_add_tail(&cursor->d_u.d_child, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | spin_unlock(&dcache_lock); |
| 109 | } |
| 110 | } |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 111 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | return offset; |
| 113 | } |
| 114 | |
| 115 | /* Relationship between i_mode and the DT_xxx types */ |
| 116 | static inline unsigned char dt_type(struct inode *inode) |
| 117 | { |
| 118 | return (inode->i_mode >> 12) & 15; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Directory is locked and all positive dentries in it are safe, since |
| 123 | * for ramfs-type trees they can't go away without unlink() or rmdir(), |
| 124 | * both impossible due to the lock on directory. |
| 125 | */ |
| 126 | |
| 127 | int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) |
| 128 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 129 | struct dentry *dentry = filp->f_path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | struct dentry *cursor = filp->private_data; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 131 | struct list_head *p, *q = &cursor->d_u.d_child; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | ino_t ino; |
| 133 | int i = filp->f_pos; |
| 134 | |
| 135 | switch (i) { |
| 136 | case 0: |
| 137 | ino = dentry->d_inode->i_ino; |
| 138 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
| 139 | break; |
| 140 | filp->f_pos++; |
| 141 | i++; |
| 142 | /* fallthrough */ |
| 143 | case 1: |
| 144 | ino = parent_ino(dentry); |
| 145 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
| 146 | break; |
| 147 | filp->f_pos++; |
| 148 | i++; |
| 149 | /* fallthrough */ |
| 150 | default: |
| 151 | spin_lock(&dcache_lock); |
Akinobu Mita | 1bfba4e | 2006-06-26 00:24:40 -0700 | [diff] [blame] | 152 | if (filp->f_pos == 2) |
| 153 | list_move(q, &dentry->d_subdirs); |
| 154 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | for (p=q->next; p != &dentry->d_subdirs; p=p->next) { |
| 156 | struct dentry *next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 157 | next = list_entry(p, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | if (d_unhashed(next) || !next->d_inode) |
| 159 | continue; |
| 160 | |
| 161 | spin_unlock(&dcache_lock); |
Ronni Nielsen | 0f8952c2 | 2007-05-09 06:44:57 +0200 | [diff] [blame] | 162 | if (filldir(dirent, next->d_name.name, |
| 163 | next->d_name.len, filp->f_pos, |
| 164 | next->d_inode->i_ino, |
| 165 | dt_type(next->d_inode)) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | return 0; |
| 167 | spin_lock(&dcache_lock); |
| 168 | /* next is still alive */ |
Akinobu Mita | 1bfba4e | 2006-06-26 00:24:40 -0700 | [diff] [blame] | 169 | list_move(q, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | p = q; |
| 171 | filp->f_pos++; |
| 172 | } |
| 173 | spin_unlock(&dcache_lock); |
| 174 | } |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) |
| 179 | { |
| 180 | return -EISDIR; |
| 181 | } |
| 182 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 183 | const struct file_operations simple_dir_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | .open = dcache_dir_open, |
| 185 | .release = dcache_dir_close, |
| 186 | .llseek = dcache_dir_lseek, |
| 187 | .read = generic_read_dir, |
| 188 | .readdir = dcache_readdir, |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 189 | .fsync = noop_fsync, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | }; |
| 191 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 192 | const struct inode_operations simple_dir_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | .lookup = simple_lookup, |
| 194 | }; |
| 195 | |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 196 | static const struct super_operations simple_super_operations = { |
| 197 | .statfs = simple_statfs, |
| 198 | }; |
| 199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | /* |
| 201 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that |
| 202 | * will never be mountable) |
| 203 | */ |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 204 | int get_sb_pseudo(struct file_system_type *fs_type, char *name, |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 205 | const struct super_operations *ops, unsigned long magic, |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 206 | struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | { |
| 208 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | struct dentry *dentry; |
| 210 | struct inode *root; |
| 211 | struct qstr d_name = {.name = name, .len = strlen(name)}; |
| 212 | |
| 213 | if (IS_ERR(s)) |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 214 | return PTR_ERR(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
| 216 | s->s_flags = MS_NOUSER; |
Jeff Layton | 89a4eb4 | 2009-08-18 14:11:08 -0700 | [diff] [blame] | 217 | s->s_maxbytes = MAX_LFS_FILESIZE; |
Alex Nixon | 3971e1a | 2008-07-29 22:33:03 -0700 | [diff] [blame] | 218 | s->s_blocksize = PAGE_SIZE; |
| 219 | s->s_blocksize_bits = PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | s->s_magic = magic; |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 221 | s->s_op = ops ? ops : &simple_super_operations; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | s->s_time_gran = 1; |
| 223 | root = new_inode(s); |
| 224 | if (!root) |
| 225 | goto Enomem; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 226 | /* |
| 227 | * since this is the first inode, make it number 1. New inodes created |
| 228 | * after this must take care not to collide with it (by passing |
| 229 | * max_reserved of 1 to iunique). |
| 230 | */ |
| 231 | root->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
| 234 | dentry = d_alloc(NULL, &d_name); |
| 235 | if (!dentry) { |
| 236 | iput(root); |
| 237 | goto Enomem; |
| 238 | } |
| 239 | dentry->d_sb = s; |
| 240 | dentry->d_parent = dentry; |
| 241 | d_instantiate(dentry, root); |
| 242 | s->s_root = dentry; |
| 243 | s->s_flags |= MS_ACTIVE; |
Sukadev Bhattiprolu | a3ec947 | 2009-03-04 12:06:34 -0800 | [diff] [blame] | 244 | simple_set_mnt(mnt, s); |
| 245 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | |
| 247 | Enomem: |
Al Viro | 6f5bbff | 2009-05-06 01:34:22 -0400 | [diff] [blame] | 248 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 249 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | } |
| 251 | |
| 252 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| 253 | { |
| 254 | struct inode *inode = old_dentry->d_inode; |
| 255 | |
| 256 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 257 | inc_nlink(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | atomic_inc(&inode->i_count); |
| 259 | dget(dentry); |
| 260 | d_instantiate(dentry, inode); |
| 261 | return 0; |
| 262 | } |
| 263 | |
| 264 | static inline int simple_positive(struct dentry *dentry) |
| 265 | { |
| 266 | return dentry->d_inode && !d_unhashed(dentry); |
| 267 | } |
| 268 | |
| 269 | int simple_empty(struct dentry *dentry) |
| 270 | { |
| 271 | struct dentry *child; |
| 272 | int ret = 0; |
| 273 | |
| 274 | spin_lock(&dcache_lock); |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 275 | list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | if (simple_positive(child)) |
| 277 | goto out; |
| 278 | ret = 1; |
| 279 | out: |
| 280 | spin_unlock(&dcache_lock); |
| 281 | return ret; |
| 282 | } |
| 283 | |
| 284 | int simple_unlink(struct inode *dir, struct dentry *dentry) |
| 285 | { |
| 286 | struct inode *inode = dentry->d_inode; |
| 287 | |
| 288 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 289 | drop_nlink(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | dput(dentry); |
| 291 | return 0; |
| 292 | } |
| 293 | |
| 294 | int simple_rmdir(struct inode *dir, struct dentry *dentry) |
| 295 | { |
| 296 | if (!simple_empty(dentry)) |
| 297 | return -ENOTEMPTY; |
| 298 | |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 299 | drop_nlink(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | simple_unlink(dir, dentry); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 301 | drop_nlink(dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | return 0; |
| 303 | } |
| 304 | |
| 305 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 306 | struct inode *new_dir, struct dentry *new_dentry) |
| 307 | { |
| 308 | struct inode *inode = old_dentry->d_inode; |
| 309 | int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); |
| 310 | |
| 311 | if (!simple_empty(new_dentry)) |
| 312 | return -ENOTEMPTY; |
| 313 | |
| 314 | if (new_dentry->d_inode) { |
| 315 | simple_unlink(new_dir, new_dentry); |
| 316 | if (they_are_dirs) |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 317 | drop_nlink(old_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | } else if (they_are_dirs) { |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 319 | drop_nlink(old_dir); |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 320 | inc_nlink(new_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | } |
| 322 | |
| 323 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = |
| 324 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 325 | |
| 326 | return 0; |
| 327 | } |
| 328 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 329 | /** |
| 330 | * simple_setsize - handle core mm and vfs requirements for file size change |
| 331 | * @inode: inode |
| 332 | * @newsize: new file size |
| 333 | * |
| 334 | * Returns 0 on success, -error on failure. |
| 335 | * |
| 336 | * simple_setsize must be called with inode_mutex held. |
| 337 | * |
| 338 | * simple_setsize will check that the requested new size is OK (see |
| 339 | * inode_newsize_ok), and then will perform the necessary i_size update |
| 340 | * and pagecache truncation (if necessary). It will be typically be called |
| 341 | * from the filesystem's setattr function when ATTR_SIZE is passed in. |
| 342 | * |
| 343 | * The inode itself must have correct permissions and attributes to allow |
| 344 | * i_size to be changed, this function then just checks that the new size |
| 345 | * requested is valid. |
| 346 | * |
| 347 | * In the case of simple in-memory filesystems with inodes stored solely |
| 348 | * in the inode cache, and file data in the pagecache, nothing more needs |
| 349 | * to be done to satisfy a truncate request. Filesystems with on-disk |
| 350 | * blocks for example will need to free them in the case of truncate, in |
| 351 | * that case it may be easier not to use simple_setsize (but each of its |
| 352 | * components will likely be required at some point to update pagecache |
| 353 | * and inode etc). |
| 354 | */ |
| 355 | int simple_setsize(struct inode *inode, loff_t newsize) |
| 356 | { |
| 357 | loff_t oldsize; |
| 358 | int error; |
| 359 | |
| 360 | error = inode_newsize_ok(inode, newsize); |
| 361 | if (error) |
| 362 | return error; |
| 363 | |
| 364 | oldsize = inode->i_size; |
| 365 | i_size_write(inode, newsize); |
| 366 | truncate_pagecache(inode, oldsize, newsize); |
| 367 | |
| 368 | return error; |
| 369 | } |
| 370 | EXPORT_SYMBOL(simple_setsize); |
| 371 | |
| 372 | /** |
| 373 | * simple_setattr - setattr for simple in-memory filesystem |
| 374 | * @dentry: dentry |
| 375 | * @iattr: iattr structure |
| 376 | * |
| 377 | * Returns 0 on success, -error on failure. |
| 378 | * |
| 379 | * simple_setattr implements setattr for an in-memory filesystem which |
| 380 | * does not store its own file data or metadata (eg. uses the page cache |
| 381 | * and inode cache as its data store). |
| 382 | */ |
| 383 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) |
| 384 | { |
| 385 | struct inode *inode = dentry->d_inode; |
| 386 | int error; |
| 387 | |
| 388 | error = inode_change_ok(inode, iattr); |
| 389 | if (error) |
| 390 | return error; |
| 391 | |
| 392 | if (iattr->ia_valid & ATTR_SIZE) { |
| 393 | error = simple_setsize(inode, iattr->ia_size); |
| 394 | if (error) |
| 395 | return error; |
| 396 | } |
| 397 | |
| 398 | generic_setattr(inode, iattr); |
| 399 | |
| 400 | return error; |
| 401 | } |
| 402 | EXPORT_SYMBOL(simple_setattr); |
| 403 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | int simple_readpage(struct file *file, struct page *page) |
| 405 | { |
Pekka J Enberg | c0d92cb | 2006-09-29 01:59:09 -0700 | [diff] [blame] | 406 | clear_highpage(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | flush_dcache_page(page); |
| 408 | SetPageUptodate(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | unlock_page(page); |
| 410 | return 0; |
| 411 | } |
| 412 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 413 | int simple_write_begin(struct file *file, struct address_space *mapping, |
| 414 | loff_t pos, unsigned len, unsigned flags, |
| 415 | struct page **pagep, void **fsdata) |
| 416 | { |
| 417 | struct page *page; |
| 418 | pgoff_t index; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 419 | |
| 420 | index = pos >> PAGE_CACHE_SHIFT; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 421 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 422 | page = grab_cache_page_write_begin(mapping, index, flags); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 423 | if (!page) |
| 424 | return -ENOMEM; |
| 425 | |
| 426 | *pagep = page; |
| 427 | |
Boaz Harrosh | 193cf4b | 2010-01-12 16:18:08 +0200 | [diff] [blame] | 428 | if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { |
| 429 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| 430 | |
| 431 | zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); |
| 432 | } |
| 433 | return 0; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 434 | } |
| 435 | |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 436 | /** |
| 437 | * simple_write_end - .write_end helper for non-block-device FSes |
| 438 | * @available: See .write_end of address_space_operations |
| 439 | * @file: " |
| 440 | * @mapping: " |
| 441 | * @pos: " |
| 442 | * @len: " |
| 443 | * @copied: " |
| 444 | * @page: " |
| 445 | * @fsdata: " |
| 446 | * |
| 447 | * simple_write_end does the minimum needed for updating a page after writing is |
| 448 | * done. It has the same API signature as the .write_end of |
| 449 | * address_space_operations vector. So it can just be set onto .write_end for |
| 450 | * FSes that don't need any other processing. i_mutex is assumed to be held. |
| 451 | * Block based filesystems should use generic_write_end(). |
| 452 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty |
| 453 | * is not called, so a filesystem that actually does store data in .write_inode |
| 454 | * should extend on what's done here with a call to mark_inode_dirty() in the |
| 455 | * case that i_size has changed. |
| 456 | */ |
| 457 | int simple_write_end(struct file *file, struct address_space *mapping, |
| 458 | loff_t pos, unsigned len, unsigned copied, |
| 459 | struct page *page, void *fsdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | { |
| 461 | struct inode *inode = page->mapping->host; |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 462 | loff_t last_pos = pos + copied; |
| 463 | |
| 464 | /* zero the stale part of the page if we did a short copy */ |
| 465 | if (copied < len) { |
| 466 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| 467 | |
| 468 | zero_user(page, from + copied, len - copied); |
| 469 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | |
Nick Piggin | 955eff5 | 2007-02-20 13:58:08 -0800 | [diff] [blame] | 471 | if (!PageUptodate(page)) |
| 472 | SetPageUptodate(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | /* |
| 474 | * No need to use i_size_read() here, the i_size |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 475 | * cannot change under us because we hold the i_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | */ |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 477 | if (last_pos > inode->i_size) |
| 478 | i_size_write(inode, last_pos); |
| 479 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | set_page_dirty(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 481 | unlock_page(page); |
| 482 | page_cache_release(page); |
| 483 | |
| 484 | return copied; |
| 485 | } |
| 486 | |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 487 | /* |
| 488 | * the inodes created here are not hashed. If you use iunique to generate |
| 489 | * unique inode values later for this filesystem, then you must take care |
| 490 | * to pass it an appropriate max_reserved value to avoid collisions. |
| 491 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) |
| 493 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | struct inode *inode; |
| 495 | struct dentry *root; |
| 496 | struct dentry *dentry; |
| 497 | int i; |
| 498 | |
| 499 | s->s_blocksize = PAGE_CACHE_SIZE; |
| 500 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| 501 | s->s_magic = magic; |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 502 | s->s_op = &simple_super_operations; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | s->s_time_gran = 1; |
| 504 | |
| 505 | inode = new_inode(s); |
| 506 | if (!inode) |
| 507 | return -ENOMEM; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 508 | /* |
| 509 | * because the root inode is 1, the files array must not contain an |
| 510 | * entry at index 1 |
| 511 | */ |
| 512 | inode->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | inode->i_mode = S_IFDIR | 0755; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 515 | inode->i_op = &simple_dir_inode_operations; |
| 516 | inode->i_fop = &simple_dir_operations; |
Vincent Hanquez | 7656f32 | 2006-02-03 03:04:48 -0800 | [diff] [blame] | 517 | inode->i_nlink = 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | root = d_alloc_root(inode); |
| 519 | if (!root) { |
| 520 | iput(inode); |
| 521 | return -ENOMEM; |
| 522 | } |
| 523 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
| 524 | if (!files->name) |
| 525 | continue; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 526 | |
| 527 | /* warn if it tries to conflict with the root inode */ |
| 528 | if (unlikely(i == 1)) |
| 529 | printk(KERN_WARNING "%s: %s passed in a files array" |
| 530 | "with an index of 1!\n", __func__, |
| 531 | s->s_type->name); |
| 532 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 533 | dentry = d_alloc_name(root, files->name); |
| 534 | if (!dentry) |
| 535 | goto out; |
| 536 | inode = new_inode(s); |
| 537 | if (!inode) |
| 538 | goto out; |
| 539 | inode->i_mode = S_IFREG | files->mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 541 | inode->i_fop = files->ops; |
| 542 | inode->i_ino = i; |
| 543 | d_add(dentry, inode); |
| 544 | } |
| 545 | s->s_root = root; |
| 546 | return 0; |
| 547 | out: |
| 548 | d_genocide(root); |
| 549 | dput(root); |
| 550 | return -ENOMEM; |
| 551 | } |
| 552 | |
| 553 | static DEFINE_SPINLOCK(pin_fs_lock); |
| 554 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 555 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | { |
| 557 | struct vfsmount *mnt = NULL; |
| 558 | spin_lock(&pin_fs_lock); |
| 559 | if (unlikely(!*mount)) { |
| 560 | spin_unlock(&pin_fs_lock); |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 561 | mnt = vfs_kern_mount(type, 0, type->name, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | if (IS_ERR(mnt)) |
| 563 | return PTR_ERR(mnt); |
| 564 | spin_lock(&pin_fs_lock); |
| 565 | if (!*mount) |
| 566 | *mount = mnt; |
| 567 | } |
| 568 | mntget(*mount); |
| 569 | ++*count; |
| 570 | spin_unlock(&pin_fs_lock); |
| 571 | mntput(mnt); |
| 572 | return 0; |
| 573 | } |
| 574 | |
| 575 | void simple_release_fs(struct vfsmount **mount, int *count) |
| 576 | { |
| 577 | struct vfsmount *mnt; |
| 578 | spin_lock(&pin_fs_lock); |
| 579 | mnt = *mount; |
| 580 | if (!--*count) |
| 581 | *mount = NULL; |
| 582 | spin_unlock(&pin_fs_lock); |
| 583 | mntput(mnt); |
| 584 | } |
| 585 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 586 | /** |
| 587 | * simple_read_from_buffer - copy data from the buffer to user space |
| 588 | * @to: the user space buffer to read to |
| 589 | * @count: the maximum number of bytes to read |
| 590 | * @ppos: the current position in the buffer |
| 591 | * @from: the buffer to read from |
| 592 | * @available: the size of the buffer |
| 593 | * |
| 594 | * The simple_read_from_buffer() function reads up to @count bytes from the |
| 595 | * buffer @from at offset @ppos into the user space address starting at @to. |
| 596 | * |
| 597 | * On success, the number of bytes read is returned and the offset @ppos is |
| 598 | * advanced by this number, or negative value is returned on error. |
| 599 | **/ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
| 601 | const void *from, size_t available) |
| 602 | { |
| 603 | loff_t pos = *ppos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 604 | size_t ret; |
| 605 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | if (pos < 0) |
| 607 | return -EINVAL; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 608 | if (pos >= available || !count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | return 0; |
| 610 | if (count > available - pos) |
| 611 | count = available - pos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 612 | ret = copy_to_user(to, from + pos, count); |
| 613 | if (ret == count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | return -EFAULT; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 615 | count -= ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | *ppos = pos + count; |
| 617 | return count; |
| 618 | } |
| 619 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 620 | /** |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 621 | * simple_write_to_buffer - copy data from user space to the buffer |
| 622 | * @to: the buffer to write to |
| 623 | * @available: the size of the buffer |
| 624 | * @ppos: the current position in the buffer |
| 625 | * @from: the user space buffer to read from |
| 626 | * @count: the maximum number of bytes to read |
| 627 | * |
| 628 | * The simple_write_to_buffer() function reads up to @count bytes from the user |
| 629 | * space address starting at @from into the buffer @to at offset @ppos. |
| 630 | * |
| 631 | * On success, the number of bytes written is returned and the offset @ppos is |
| 632 | * advanced by this number, or negative value is returned on error. |
| 633 | **/ |
| 634 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, |
| 635 | const void __user *from, size_t count) |
| 636 | { |
| 637 | loff_t pos = *ppos; |
| 638 | size_t res; |
| 639 | |
| 640 | if (pos < 0) |
| 641 | return -EINVAL; |
| 642 | if (pos >= available || !count) |
| 643 | return 0; |
| 644 | if (count > available - pos) |
| 645 | count = available - pos; |
| 646 | res = copy_from_user(to + pos, from, count); |
| 647 | if (res == count) |
| 648 | return -EFAULT; |
| 649 | count -= res; |
| 650 | *ppos = pos + count; |
| 651 | return count; |
| 652 | } |
| 653 | |
| 654 | /** |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 655 | * memory_read_from_buffer - copy data from the buffer |
| 656 | * @to: the kernel space buffer to read to |
| 657 | * @count: the maximum number of bytes to read |
| 658 | * @ppos: the current position in the buffer |
| 659 | * @from: the buffer to read from |
| 660 | * @available: the size of the buffer |
| 661 | * |
| 662 | * The memory_read_from_buffer() function reads up to @count bytes from the |
| 663 | * buffer @from at offset @ppos into the kernel space address starting at @to. |
| 664 | * |
| 665 | * On success, the number of bytes read is returned and the offset @ppos is |
| 666 | * advanced by this number, or negative value is returned on error. |
| 667 | **/ |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 668 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
| 669 | const void *from, size_t available) |
| 670 | { |
| 671 | loff_t pos = *ppos; |
| 672 | |
| 673 | if (pos < 0) |
| 674 | return -EINVAL; |
| 675 | if (pos >= available) |
| 676 | return 0; |
| 677 | if (count > available - pos) |
| 678 | count = available - pos; |
| 679 | memcpy(to, from + pos, count); |
| 680 | *ppos = pos + count; |
| 681 | |
| 682 | return count; |
| 683 | } |
| 684 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | /* |
| 686 | * Transaction based IO. |
| 687 | * The file expects a single write which triggers the transaction, and then |
| 688 | * possibly a read which collects the result - which is stored in a |
| 689 | * file-local buffer. |
| 690 | */ |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 691 | |
| 692 | void simple_transaction_set(struct file *file, size_t n) |
| 693 | { |
| 694 | struct simple_transaction_argresp *ar = file->private_data; |
| 695 | |
| 696 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); |
| 697 | |
| 698 | /* |
| 699 | * The barrier ensures that ar->size will really remain zero until |
| 700 | * ar->data is ready for reading. |
| 701 | */ |
| 702 | smp_mb(); |
| 703 | ar->size = n; |
| 704 | } |
| 705 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
| 707 | { |
| 708 | struct simple_transaction_argresp *ar; |
| 709 | static DEFINE_SPINLOCK(simple_transaction_lock); |
| 710 | |
| 711 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) |
| 712 | return ERR_PTR(-EFBIG); |
| 713 | |
| 714 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); |
| 715 | if (!ar) |
| 716 | return ERR_PTR(-ENOMEM); |
| 717 | |
| 718 | spin_lock(&simple_transaction_lock); |
| 719 | |
| 720 | /* only one write allowed per open */ |
| 721 | if (file->private_data) { |
| 722 | spin_unlock(&simple_transaction_lock); |
| 723 | free_page((unsigned long)ar); |
| 724 | return ERR_PTR(-EBUSY); |
| 725 | } |
| 726 | |
| 727 | file->private_data = ar; |
| 728 | |
| 729 | spin_unlock(&simple_transaction_lock); |
| 730 | |
| 731 | if (copy_from_user(ar->data, buf, size)) |
| 732 | return ERR_PTR(-EFAULT); |
| 733 | |
| 734 | return ar->data; |
| 735 | } |
| 736 | |
| 737 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) |
| 738 | { |
| 739 | struct simple_transaction_argresp *ar = file->private_data; |
| 740 | |
| 741 | if (!ar) |
| 742 | return 0; |
| 743 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); |
| 744 | } |
| 745 | |
| 746 | int simple_transaction_release(struct inode *inode, struct file *file) |
| 747 | { |
| 748 | free_page((unsigned long)file->private_data); |
| 749 | return 0; |
| 750 | } |
| 751 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 752 | /* Simple attribute files */ |
| 753 | |
| 754 | struct simple_attr { |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 755 | int (*get)(void *, u64 *); |
| 756 | int (*set)(void *, u64); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 757 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
| 758 | char set_buf[24]; |
| 759 | void *data; |
| 760 | const char *fmt; /* format for read operation */ |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 761 | struct mutex mutex; /* protects access to these buffers */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 762 | }; |
| 763 | |
| 764 | /* simple_attr_open is called by an actual attribute open file operation |
| 765 | * to set the attribute specific access operations. */ |
| 766 | int simple_attr_open(struct inode *inode, struct file *file, |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 767 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 768 | const char *fmt) |
| 769 | { |
| 770 | struct simple_attr *attr; |
| 771 | |
| 772 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); |
| 773 | if (!attr) |
| 774 | return -ENOMEM; |
| 775 | |
| 776 | attr->get = get; |
| 777 | attr->set = set; |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 778 | attr->data = inode->i_private; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 779 | attr->fmt = fmt; |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 780 | mutex_init(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 781 | |
| 782 | file->private_data = attr; |
| 783 | |
| 784 | return nonseekable_open(inode, file); |
| 785 | } |
| 786 | |
Christoph Hellwig | 74bedc4 | 2008-02-08 04:20:28 -0800 | [diff] [blame] | 787 | int simple_attr_release(struct inode *inode, struct file *file) |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 788 | { |
| 789 | kfree(file->private_data); |
| 790 | return 0; |
| 791 | } |
| 792 | |
| 793 | /* read from the buffer that is filled with the get function */ |
| 794 | ssize_t simple_attr_read(struct file *file, char __user *buf, |
| 795 | size_t len, loff_t *ppos) |
| 796 | { |
| 797 | struct simple_attr *attr; |
| 798 | size_t size; |
| 799 | ssize_t ret; |
| 800 | |
| 801 | attr = file->private_data; |
| 802 | |
| 803 | if (!attr->get) |
| 804 | return -EACCES; |
| 805 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 806 | ret = mutex_lock_interruptible(&attr->mutex); |
| 807 | if (ret) |
| 808 | return ret; |
| 809 | |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 810 | if (*ppos) { /* continued read */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 811 | size = strlen(attr->get_buf); |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 812 | } else { /* first read */ |
| 813 | u64 val; |
| 814 | ret = attr->get(attr->data, &val); |
| 815 | if (ret) |
| 816 | goto out; |
| 817 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 818 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 819 | attr->fmt, (unsigned long long)val); |
| 820 | } |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 821 | |
| 822 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 823 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 824 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 825 | return ret; |
| 826 | } |
| 827 | |
| 828 | /* interpret the buffer as a number to call the set function with */ |
| 829 | ssize_t simple_attr_write(struct file *file, const char __user *buf, |
| 830 | size_t len, loff_t *ppos) |
| 831 | { |
| 832 | struct simple_attr *attr; |
| 833 | u64 val; |
| 834 | size_t size; |
| 835 | ssize_t ret; |
| 836 | |
| 837 | attr = file->private_data; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 838 | if (!attr->set) |
| 839 | return -EACCES; |
| 840 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 841 | ret = mutex_lock_interruptible(&attr->mutex); |
| 842 | if (ret) |
| 843 | return ret; |
| 844 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 845 | ret = -EFAULT; |
| 846 | size = min(sizeof(attr->set_buf) - 1, len); |
| 847 | if (copy_from_user(attr->set_buf, buf, size)) |
| 848 | goto out; |
| 849 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 850 | attr->set_buf[size] = '\0'; |
| 851 | val = simple_strtol(attr->set_buf, NULL, 0); |
Wu Fengguang | 05cc0ce | 2009-09-18 13:06:03 -0700 | [diff] [blame] | 852 | ret = attr->set(attr->data, val); |
| 853 | if (ret == 0) |
| 854 | ret = len; /* on success, claim we got the whole input */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 855 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 856 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 857 | return ret; |
| 858 | } |
| 859 | |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 860 | /** |
| 861 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation |
| 862 | * @sb: filesystem to do the file handle conversion on |
| 863 | * @fid: file handle to convert |
| 864 | * @fh_len: length of the file handle in bytes |
| 865 | * @fh_type: type of file handle |
| 866 | * @get_inode: filesystem callback to retrieve inode |
| 867 | * |
| 868 | * This function decodes @fid as long as it has one of the well-known |
| 869 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 870 | * inode for the object specified in the file handle. |
| 871 | */ |
| 872 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, |
| 873 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 874 | (struct super_block *sb, u64 ino, u32 gen)) |
| 875 | { |
| 876 | struct inode *inode = NULL; |
| 877 | |
| 878 | if (fh_len < 2) |
| 879 | return NULL; |
| 880 | |
| 881 | switch (fh_type) { |
| 882 | case FILEID_INO32_GEN: |
| 883 | case FILEID_INO32_GEN_PARENT: |
| 884 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); |
| 885 | break; |
| 886 | } |
| 887 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 888 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 889 | } |
| 890 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); |
| 891 | |
| 892 | /** |
| 893 | * generic_fh_to_dentry - generic helper for the fh_to_parent export operation |
| 894 | * @sb: filesystem to do the file handle conversion on |
| 895 | * @fid: file handle to convert |
| 896 | * @fh_len: length of the file handle in bytes |
| 897 | * @fh_type: type of file handle |
| 898 | * @get_inode: filesystem callback to retrieve inode |
| 899 | * |
| 900 | * This function decodes @fid as long as it has one of the well-known |
| 901 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 902 | * inode for the _parent_ object specified in the file handle if it |
| 903 | * is specified in the file handle, or NULL otherwise. |
| 904 | */ |
| 905 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, |
| 906 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 907 | (struct super_block *sb, u64 ino, u32 gen)) |
| 908 | { |
| 909 | struct inode *inode = NULL; |
| 910 | |
| 911 | if (fh_len <= 2) |
| 912 | return NULL; |
| 913 | |
| 914 | switch (fh_type) { |
| 915 | case FILEID_INO32_GEN_PARENT: |
| 916 | inode = get_inode(sb, fid->i32.parent_ino, |
| 917 | (fh_len > 3 ? fid->i32.parent_gen : 0)); |
| 918 | break; |
| 919 | } |
| 920 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 921 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 922 | } |
| 923 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
| 924 | |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 925 | /** |
| 926 | * generic_file_fsync - generic fsync implementation for simple filesystems |
| 927 | * @file: file to synchronize |
| 928 | * @datasync: only synchronize essential metadata if true |
| 929 | * |
| 930 | * This is a generic implementation of the fsync method for simple |
| 931 | * filesystems which track all non-inode metadata in the buffers list |
| 932 | * hanging off the address_space structure. |
| 933 | */ |
| 934 | int generic_file_fsync(struct file *file, int datasync) |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 935 | { |
| 936 | struct writeback_control wbc = { |
| 937 | .sync_mode = WB_SYNC_ALL, |
| 938 | .nr_to_write = 0, /* metadata-only; caller takes care of data */ |
| 939 | }; |
Christoph Hellwig | 7ea8085 | 2010-05-26 17:53:25 +0200 | [diff] [blame] | 940 | struct inode *inode = file->f_mapping->host; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 941 | int err; |
| 942 | int ret; |
| 943 | |
| 944 | ret = sync_mapping_buffers(inode->i_mapping); |
| 945 | if (!(inode->i_state & I_DIRTY)) |
| 946 | return ret; |
| 947 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
| 948 | return ret; |
| 949 | |
| 950 | err = sync_inode(inode, &wbc); |
| 951 | if (ret == 0) |
| 952 | ret = err; |
| 953 | return ret; |
| 954 | } |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 955 | EXPORT_SYMBOL(generic_file_fsync); |
| 956 | |
| 957 | /* |
| 958 | * No-op implementation of ->fsync for in-memory filesystems. |
| 959 | */ |
| 960 | int noop_fsync(struct file *file, int datasync) |
| 961 | { |
| 962 | return 0; |
| 963 | } |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 964 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 965 | EXPORT_SYMBOL(dcache_dir_close); |
| 966 | EXPORT_SYMBOL(dcache_dir_lseek); |
| 967 | EXPORT_SYMBOL(dcache_dir_open); |
| 968 | EXPORT_SYMBOL(dcache_readdir); |
| 969 | EXPORT_SYMBOL(generic_read_dir); |
| 970 | EXPORT_SYMBOL(get_sb_pseudo); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 971 | EXPORT_SYMBOL(simple_write_begin); |
| 972 | EXPORT_SYMBOL(simple_write_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 973 | EXPORT_SYMBOL(simple_dir_inode_operations); |
| 974 | EXPORT_SYMBOL(simple_dir_operations); |
| 975 | EXPORT_SYMBOL(simple_empty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | EXPORT_SYMBOL(simple_fill_super); |
| 977 | EXPORT_SYMBOL(simple_getattr); |
| 978 | EXPORT_SYMBOL(simple_link); |
| 979 | EXPORT_SYMBOL(simple_lookup); |
| 980 | EXPORT_SYMBOL(simple_pin_fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | EXPORT_SYMBOL(simple_readpage); |
| 982 | EXPORT_SYMBOL(simple_release_fs); |
| 983 | EXPORT_SYMBOL(simple_rename); |
| 984 | EXPORT_SYMBOL(simple_rmdir); |
| 985 | EXPORT_SYMBOL(simple_statfs); |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 986 | EXPORT_SYMBOL(noop_fsync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | EXPORT_SYMBOL(simple_unlink); |
| 988 | EXPORT_SYMBOL(simple_read_from_buffer); |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 989 | EXPORT_SYMBOL(simple_write_to_buffer); |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 990 | EXPORT_SYMBOL(memory_read_from_buffer); |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 991 | EXPORT_SYMBOL(simple_transaction_set); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 992 | EXPORT_SYMBOL(simple_transaction_get); |
| 993 | EXPORT_SYMBOL(simple_transaction_read); |
| 994 | EXPORT_SYMBOL(simple_transaction_release); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 995 | EXPORT_SYMBOL_GPL(simple_attr_open); |
Christoph Hellwig | 74bedc4 | 2008-02-08 04:20:28 -0800 | [diff] [blame] | 996 | EXPORT_SYMBOL_GPL(simple_attr_release); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 997 | EXPORT_SYMBOL_GPL(simple_attr_read); |
| 998 | EXPORT_SYMBOL_GPL(simple_attr_write); |