3 * Library for filesystems writers.
6 #include <linux/blkdev.h>
7 #include <linux/export.h>
8 #include <linux/pagemap.h>
9 #include <linux/slab.h>
10 #include <linux/mount.h>
11 #include <linux/vfs.h>
12 #include <linux/quotaops.h>
13 #include <linux/mutex.h>
14 #include <linux/namei.h>
15 #include <linux/exportfs.h>
16 #include <linux/writeback.h>
17 #include <linux/buffer_head.h> /* sync_mapping_buffers */
19 #include <asm/uaccess.h>
23 int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
26 struct inode *inode = d_inode(dentry);
27 generic_fillattr(inode, stat);
28 stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
31 EXPORT_SYMBOL(simple_getattr);
33 int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
35 buf->f_type = dentry->d_sb->s_magic;
36 buf->f_bsize = PAGE_SIZE;
37 buf->f_namelen = NAME_MAX;
40 EXPORT_SYMBOL(simple_statfs);
43 * Retaining negative dentries for an in-memory filesystem just wastes
44 * memory and lookup time: arrange for them to be deleted immediately.
46 int always_delete_dentry(const struct dentry *dentry)
50 EXPORT_SYMBOL(always_delete_dentry);
52 const struct dentry_operations simple_dentry_operations = {
53 .d_delete = always_delete_dentry,
55 EXPORT_SYMBOL(simple_dentry_operations);
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.
61 struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
63 if (dentry->d_name.len > NAME_MAX)
64 return ERR_PTR(-ENAMETOOLONG);
65 if (!dentry->d_sb->s_d_op)
66 d_set_d_op(dentry, &simple_dentry_operations);
70 EXPORT_SYMBOL(simple_lookup);
72 int dcache_dir_open(struct inode *inode, struct file *file)
74 file->private_data = d_alloc_cursor(file->f_path.dentry);
76 return file->private_data ? 0 : -ENOMEM;
78 EXPORT_SYMBOL(dcache_dir_open);
80 int dcache_dir_close(struct inode *inode, struct file *file)
82 dput(file->private_data);
85 EXPORT_SYMBOL(dcache_dir_close);
87 /* parent is locked at least shared */
88 static struct dentry *next_positive(struct dentry *parent,
89 struct list_head *from,
92 unsigned *seq = &parent->d_inode->i_dir_seq, n;
101 n = smp_load_acquire(seq) & ~1;
104 for (p = from->next; p != &parent->d_subdirs; p = p->next) {
105 struct dentry *d = list_entry(p, struct dentry, d_child);
106 if (!simple_positive(d)) {
116 if (unlikely(*seq != n))
122 static void move_cursor(struct dentry *cursor, struct list_head *after)
124 struct dentry *parent = cursor->d_parent;
125 unsigned n, *seq = &parent->d_inode->i_dir_seq;
126 spin_lock(&parent->d_lock);
129 if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
133 __list_del(cursor->d_child.prev, cursor->d_child.next);
135 list_add(&cursor->d_child, after);
137 list_add_tail(&cursor->d_child, &parent->d_subdirs);
138 smp_store_release(seq, n + 2);
139 spin_unlock(&parent->d_lock);
142 loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
144 struct dentry *dentry = file->f_path.dentry;
147 offset += file->f_pos;
154 if (offset != file->f_pos) {
155 file->f_pos = offset;
156 if (file->f_pos >= 2) {
157 struct dentry *cursor = file->private_data;
159 loff_t n = file->f_pos - 2;
161 inode_lock_shared(dentry->d_inode);
162 to = next_positive(dentry, &dentry->d_subdirs, n);
163 move_cursor(cursor, to ? &to->d_child : NULL);
164 inode_unlock_shared(dentry->d_inode);
169 EXPORT_SYMBOL(dcache_dir_lseek);
171 /* Relationship between i_mode and the DT_xxx types */
172 static inline unsigned char dt_type(struct inode *inode)
174 return (inode->i_mode >> 12) & 15;
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.
183 int dcache_readdir(struct file *file, struct dir_context *ctx)
185 struct dentry *dentry = file->f_path.dentry;
186 struct dentry *cursor = file->private_data;
187 struct list_head *p = &cursor->d_child;
191 if (!dir_emit_dots(file, ctx))
195 p = &dentry->d_subdirs;
196 while ((next = next_positive(dentry, p, 1)) != NULL) {
197 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
198 d_inode(next)->i_ino, dt_type(d_inode(next))))
205 move_cursor(cursor, p);
208 EXPORT_SYMBOL(dcache_readdir);
210 ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
214 EXPORT_SYMBOL(generic_read_dir);
216 const struct file_operations simple_dir_operations = {
217 .open = dcache_dir_open,
218 .release = dcache_dir_close,
219 .llseek = dcache_dir_lseek,
220 .read = generic_read_dir,
221 .iterate_shared = dcache_readdir,
224 EXPORT_SYMBOL(simple_dir_operations);
226 const struct inode_operations simple_dir_inode_operations = {
227 .lookup = simple_lookup,
229 EXPORT_SYMBOL(simple_dir_inode_operations);
231 static const struct super_operations simple_super_operations = {
232 .statfs = simple_statfs,
236 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
237 * will never be mountable)
239 struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
240 const struct super_operations *ops, const struct xattr_handler **xattr,
241 const struct dentry_operations *dops, unsigned long magic)
243 struct super_block *s;
244 struct dentry *dentry;
246 struct qstr d_name = QSTR_INIT(name, strlen(name));
248 s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
252 s->s_maxbytes = MAX_LFS_FILESIZE;
253 s->s_blocksize = PAGE_SIZE;
254 s->s_blocksize_bits = PAGE_SHIFT;
256 s->s_op = ops ? ops : &simple_super_operations;
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).
268 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
269 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
270 dentry = __d_alloc(s, &d_name);
275 d_instantiate(dentry, root);
278 s->s_flags |= MS_ACTIVE;
279 return dget(s->s_root);
282 deactivate_locked_super(s);
283 return ERR_PTR(-ENOMEM);
285 EXPORT_SYMBOL(mount_pseudo_xattr);
287 int simple_open(struct inode *inode, struct file *file)
289 if (inode->i_private)
290 file->private_data = inode->i_private;
293 EXPORT_SYMBOL(simple_open);
295 int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
297 struct inode *inode = d_inode(old_dentry);
299 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
303 d_instantiate(dentry, inode);
306 EXPORT_SYMBOL(simple_link);
308 int simple_empty(struct dentry *dentry)
310 struct dentry *child;
313 spin_lock(&dentry->d_lock);
314 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
315 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
316 if (simple_positive(child)) {
317 spin_unlock(&child->d_lock);
320 spin_unlock(&child->d_lock);
324 spin_unlock(&dentry->d_lock);
327 EXPORT_SYMBOL(simple_empty);
329 int simple_unlink(struct inode *dir, struct dentry *dentry)
331 struct inode *inode = d_inode(dentry);
333 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
338 EXPORT_SYMBOL(simple_unlink);
340 int simple_rmdir(struct inode *dir, struct dentry *dentry)
342 if (!simple_empty(dentry))
345 drop_nlink(d_inode(dentry));
346 simple_unlink(dir, dentry);
350 EXPORT_SYMBOL(simple_rmdir);
352 int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
353 struct inode *new_dir, struct dentry *new_dentry)
355 struct inode *inode = d_inode(old_dentry);
356 int they_are_dirs = d_is_dir(old_dentry);
358 if (!simple_empty(new_dentry))
361 if (d_really_is_positive(new_dentry)) {
362 simple_unlink(new_dir, new_dentry);
364 drop_nlink(d_inode(new_dentry));
367 } else if (they_are_dirs) {
372 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
373 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
377 EXPORT_SYMBOL(simple_rename);
380 * simple_setattr - setattr for simple filesystem
382 * @iattr: iattr structure
384 * Returns 0 on success, -error on failure.
386 * simple_setattr is a simple ->setattr implementation without a proper
387 * implementation of size changes.
389 * It can either be used for in-memory filesystems or special files
390 * on simple regular filesystems. Anything that needs to change on-disk
391 * or wire state on size changes needs its own setattr method.
393 int simple_setattr(struct dentry *dentry, struct iattr *iattr)
395 struct inode *inode = d_inode(dentry);
398 error = inode_change_ok(inode, iattr);
402 if (iattr->ia_valid & ATTR_SIZE)
403 truncate_setsize(inode, iattr->ia_size);
404 setattr_copy(inode, iattr);
405 mark_inode_dirty(inode);
408 EXPORT_SYMBOL(simple_setattr);
410 int simple_readpage(struct file *file, struct page *page)
412 clear_highpage(page);
413 flush_dcache_page(page);
414 SetPageUptodate(page);
418 EXPORT_SYMBOL(simple_readpage);
420 int simple_write_begin(struct file *file, struct address_space *mapping,
421 loff_t pos, unsigned len, unsigned flags,
422 struct page **pagep, void **fsdata)
427 index = pos >> PAGE_SHIFT;
429 page = grab_cache_page_write_begin(mapping, index, flags);
435 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
436 unsigned from = pos & (PAGE_SIZE - 1);
438 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
442 EXPORT_SYMBOL(simple_write_begin);
445 * simple_write_end - .write_end helper for non-block-device FSes
446 * @available: See .write_end of address_space_operations
455 * simple_write_end does the minimum needed for updating a page after writing is
456 * done. It has the same API signature as the .write_end of
457 * address_space_operations vector. So it can just be set onto .write_end for
458 * FSes that don't need any other processing. i_mutex is assumed to be held.
459 * Block based filesystems should use generic_write_end().
460 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
461 * is not called, so a filesystem that actually does store data in .write_inode
462 * should extend on what's done here with a call to mark_inode_dirty() in the
463 * case that i_size has changed.
465 int simple_write_end(struct file *file, struct address_space *mapping,
466 loff_t pos, unsigned len, unsigned copied,
467 struct page *page, void *fsdata)
469 struct inode *inode = page->mapping->host;
470 loff_t last_pos = pos + copied;
472 /* zero the stale part of the page if we did a short copy */
474 unsigned from = pos & (PAGE_SIZE - 1);
476 zero_user(page, from + copied, len - copied);
479 if (!PageUptodate(page))
480 SetPageUptodate(page);
482 * No need to use i_size_read() here, the i_size
483 * cannot change under us because we hold the i_mutex.
485 if (last_pos > inode->i_size)
486 i_size_write(inode, last_pos);
488 set_page_dirty(page);
494 EXPORT_SYMBOL(simple_write_end);
497 * the inodes created here are not hashed. If you use iunique to generate
498 * unique inode values later for this filesystem, then you must take care
499 * to pass it an appropriate max_reserved value to avoid collisions.
501 int simple_fill_super(struct super_block *s, unsigned long magic,
502 struct tree_descr *files)
506 struct dentry *dentry;
509 s->s_blocksize = PAGE_SIZE;
510 s->s_blocksize_bits = PAGE_SHIFT;
512 s->s_op = &simple_super_operations;
515 inode = new_inode(s);
519 * because the root inode is 1, the files array must not contain an
523 inode->i_mode = S_IFDIR | 0755;
524 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
525 inode->i_op = &simple_dir_inode_operations;
526 inode->i_fop = &simple_dir_operations;
528 root = d_make_root(inode);
531 for (i = 0; !files->name || files->name[0]; i++, files++) {
535 /* warn if it tries to conflict with the root inode */
536 if (unlikely(i == 1))
537 printk(KERN_WARNING "%s: %s passed in a files array"
538 "with an index of 1!\n", __func__,
541 dentry = d_alloc_name(root, files->name);
544 inode = new_inode(s);
549 inode->i_mode = S_IFREG | files->mode;
550 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
551 inode->i_fop = files->ops;
553 d_add(dentry, inode);
559 shrink_dcache_parent(root);
563 EXPORT_SYMBOL(simple_fill_super);
565 static DEFINE_SPINLOCK(pin_fs_lock);
567 int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
569 struct vfsmount *mnt = NULL;
570 spin_lock(&pin_fs_lock);
571 if (unlikely(!*mount)) {
572 spin_unlock(&pin_fs_lock);
573 mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
576 spin_lock(&pin_fs_lock);
582 spin_unlock(&pin_fs_lock);
586 EXPORT_SYMBOL(simple_pin_fs);
588 void simple_release_fs(struct vfsmount **mount, int *count)
590 struct vfsmount *mnt;
591 spin_lock(&pin_fs_lock);
595 spin_unlock(&pin_fs_lock);
598 EXPORT_SYMBOL(simple_release_fs);
601 * simple_read_from_buffer - copy data from the buffer to user space
602 * @to: the user space buffer to read to
603 * @count: the maximum number of bytes to read
604 * @ppos: the current position in the buffer
605 * @from: the buffer to read from
606 * @available: the size of the buffer
608 * The simple_read_from_buffer() function reads up to @count bytes from the
609 * buffer @from at offset @ppos into the user space address starting at @to.
611 * On success, the number of bytes read is returned and the offset @ppos is
612 * advanced by this number, or negative value is returned on error.
614 ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
615 const void *from, size_t available)
622 if (pos >= available || !count)
624 if (count > available - pos)
625 count = available - pos;
626 ret = copy_to_user(to, from + pos, count);
633 EXPORT_SYMBOL(simple_read_from_buffer);
636 * simple_write_to_buffer - copy data from user space to the buffer
637 * @to: the buffer to write to
638 * @available: the size of the buffer
639 * @ppos: the current position in the buffer
640 * @from: the user space buffer to read from
641 * @count: the maximum number of bytes to read
643 * The simple_write_to_buffer() function reads up to @count bytes from the user
644 * space address starting at @from into the buffer @to at offset @ppos.
646 * On success, the number of bytes written is returned and the offset @ppos is
647 * advanced by this number, or negative value is returned on error.
649 ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
650 const void __user *from, size_t count)
657 if (pos >= available || !count)
659 if (count > available - pos)
660 count = available - pos;
661 res = copy_from_user(to + pos, from, count);
668 EXPORT_SYMBOL(simple_write_to_buffer);
671 * memory_read_from_buffer - copy data from the buffer
672 * @to: the kernel space buffer to read to
673 * @count: the maximum number of bytes to read
674 * @ppos: the current position in the buffer
675 * @from: the buffer to read from
676 * @available: the size of the buffer
678 * The memory_read_from_buffer() function reads up to @count bytes from the
679 * buffer @from at offset @ppos into the kernel space address starting at @to.
681 * On success, the number of bytes read is returned and the offset @ppos is
682 * advanced by this number, or negative value is returned on error.
684 ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
685 const void *from, size_t available)
691 if (pos >= available)
693 if (count > available - pos)
694 count = available - pos;
695 memcpy(to, from + pos, count);
700 EXPORT_SYMBOL(memory_read_from_buffer);
703 * Transaction based IO.
704 * The file expects a single write which triggers the transaction, and then
705 * possibly a read which collects the result - which is stored in a
709 void simple_transaction_set(struct file *file, size_t n)
711 struct simple_transaction_argresp *ar = file->private_data;
713 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
716 * The barrier ensures that ar->size will really remain zero until
717 * ar->data is ready for reading.
722 EXPORT_SYMBOL(simple_transaction_set);
724 char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
726 struct simple_transaction_argresp *ar;
727 static DEFINE_SPINLOCK(simple_transaction_lock);
729 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
730 return ERR_PTR(-EFBIG);
732 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
734 return ERR_PTR(-ENOMEM);
736 spin_lock(&simple_transaction_lock);
738 /* only one write allowed per open */
739 if (file->private_data) {
740 spin_unlock(&simple_transaction_lock);
741 free_page((unsigned long)ar);
742 return ERR_PTR(-EBUSY);
745 file->private_data = ar;
747 spin_unlock(&simple_transaction_lock);
749 if (copy_from_user(ar->data, buf, size))
750 return ERR_PTR(-EFAULT);
754 EXPORT_SYMBOL(simple_transaction_get);
756 ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
758 struct simple_transaction_argresp *ar = file->private_data;
762 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
764 EXPORT_SYMBOL(simple_transaction_read);
766 int simple_transaction_release(struct inode *inode, struct file *file)
768 free_page((unsigned long)file->private_data);
771 EXPORT_SYMBOL(simple_transaction_release);
773 /* Simple attribute files */
776 int (*get)(void *, u64 *);
777 int (*set)(void *, u64);
778 char get_buf[24]; /* enough to store a u64 and "\n\0" */
781 const char *fmt; /* format for read operation */
782 struct mutex mutex; /* protects access to these buffers */
785 /* simple_attr_open is called by an actual attribute open file operation
786 * to set the attribute specific access operations. */
787 int simple_attr_open(struct inode *inode, struct file *file,
788 int (*get)(void *, u64 *), int (*set)(void *, u64),
791 struct simple_attr *attr;
793 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
799 attr->data = inode->i_private;
801 mutex_init(&attr->mutex);
803 file->private_data = attr;
805 return nonseekable_open(inode, file);
807 EXPORT_SYMBOL_GPL(simple_attr_open);
809 int simple_attr_release(struct inode *inode, struct file *file)
811 kfree(file->private_data);
814 EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
816 /* read from the buffer that is filled with the get function */
817 ssize_t simple_attr_read(struct file *file, char __user *buf,
818 size_t len, loff_t *ppos)
820 struct simple_attr *attr;
824 attr = file->private_data;
829 ret = mutex_lock_interruptible(&attr->mutex);
833 if (*ppos) { /* continued read */
834 size = strlen(attr->get_buf);
835 } else { /* first read */
837 ret = attr->get(attr->data, &val);
841 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
842 attr->fmt, (unsigned long long)val);
845 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
847 mutex_unlock(&attr->mutex);
850 EXPORT_SYMBOL_GPL(simple_attr_read);
852 /* interpret the buffer as a number to call the set function with */
853 ssize_t simple_attr_write(struct file *file, const char __user *buf,
854 size_t len, loff_t *ppos)
856 struct simple_attr *attr;
861 attr = file->private_data;
865 ret = mutex_lock_interruptible(&attr->mutex);
870 size = min(sizeof(attr->set_buf) - 1, len);
871 if (copy_from_user(attr->set_buf, buf, size))
874 attr->set_buf[size] = '\0';
875 val = simple_strtoll(attr->set_buf, NULL, 0);
876 ret = attr->set(attr->data, val);
878 ret = len; /* on success, claim we got the whole input */
880 mutex_unlock(&attr->mutex);
883 EXPORT_SYMBOL_GPL(simple_attr_write);
886 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
887 * @sb: filesystem to do the file handle conversion on
888 * @fid: file handle to convert
889 * @fh_len: length of the file handle in bytes
890 * @fh_type: type of file handle
891 * @get_inode: filesystem callback to retrieve inode
893 * This function decodes @fid as long as it has one of the well-known
894 * Linux filehandle types and calls @get_inode on it to retrieve the
895 * inode for the object specified in the file handle.
897 struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
898 int fh_len, int fh_type, struct inode *(*get_inode)
899 (struct super_block *sb, u64 ino, u32 gen))
901 struct inode *inode = NULL;
907 case FILEID_INO32_GEN:
908 case FILEID_INO32_GEN_PARENT:
909 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
913 return d_obtain_alias(inode);
915 EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
918 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
919 * @sb: filesystem to do the file handle conversion on
920 * @fid: file handle to convert
921 * @fh_len: length of the file handle in bytes
922 * @fh_type: type of file handle
923 * @get_inode: filesystem callback to retrieve inode
925 * This function decodes @fid as long as it has one of the well-known
926 * Linux filehandle types and calls @get_inode on it to retrieve the
927 * inode for the _parent_ object specified in the file handle if it
928 * is specified in the file handle, or NULL otherwise.
930 struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
931 int fh_len, int fh_type, struct inode *(*get_inode)
932 (struct super_block *sb, u64 ino, u32 gen))
934 struct inode *inode = NULL;
940 case FILEID_INO32_GEN_PARENT:
941 inode = get_inode(sb, fid->i32.parent_ino,
942 (fh_len > 3 ? fid->i32.parent_gen : 0));
946 return d_obtain_alias(inode);
948 EXPORT_SYMBOL_GPL(generic_fh_to_parent);
951 * __generic_file_fsync - generic fsync implementation for simple filesystems
953 * @file: file to synchronize
954 * @start: start offset in bytes
955 * @end: end offset in bytes (inclusive)
956 * @datasync: only synchronize essential metadata if true
958 * This is a generic implementation of the fsync method for simple
959 * filesystems which track all non-inode metadata in the buffers list
960 * hanging off the address_space structure.
962 int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
965 struct inode *inode = file->f_mapping->host;
969 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
974 ret = sync_mapping_buffers(inode->i_mapping);
975 if (!(inode->i_state & I_DIRTY_ALL))
977 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
980 err = sync_inode_metadata(inode, 1);
988 EXPORT_SYMBOL(__generic_file_fsync);
991 * generic_file_fsync - generic fsync implementation for simple filesystems
993 * @file: file to synchronize
994 * @start: start offset in bytes
995 * @end: end offset in bytes (inclusive)
996 * @datasync: only synchronize essential metadata if true
1000 int generic_file_fsync(struct file *file, loff_t start, loff_t end,
1003 struct inode *inode = file->f_mapping->host;
1006 err = __generic_file_fsync(file, start, end, datasync);
1009 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
1011 EXPORT_SYMBOL(generic_file_fsync);
1014 * generic_check_addressable - Check addressability of file system
1015 * @blocksize_bits: log of file system block size
1016 * @num_blocks: number of blocks in file system
1018 * Determine whether a file system with @num_blocks blocks (and a
1019 * block size of 2**@blocksize_bits) is addressable by the sector_t
1020 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
1022 int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
1024 u64 last_fs_block = num_blocks - 1;
1026 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
1028 if (unlikely(num_blocks == 0))
1031 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
1034 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1035 (last_fs_page > (pgoff_t)(~0ULL))) {
1040 EXPORT_SYMBOL(generic_check_addressable);
1043 * No-op implementation of ->fsync for in-memory filesystems.
1045 int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
1049 EXPORT_SYMBOL(noop_fsync);
1051 /* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1052 void kfree_link(void *p)
1056 EXPORT_SYMBOL(kfree_link);
1059 * nop .set_page_dirty method so that people can use .page_mkwrite on
1062 static int anon_set_page_dirty(struct page *page)
1068 * A single inode exists for all anon_inode files. Contrary to pipes,
1069 * anon_inode inodes have no associated per-instance data, so we need
1070 * only allocate one of them.
1072 struct inode *alloc_anon_inode(struct super_block *s)
1074 static const struct address_space_operations anon_aops = {
1075 .set_page_dirty = anon_set_page_dirty,
1077 struct inode *inode = new_inode_pseudo(s);
1080 return ERR_PTR(-ENOMEM);
1082 inode->i_ino = get_next_ino();
1083 inode->i_mapping->a_ops = &anon_aops;
1086 * Mark the inode dirty from the very beginning,
1087 * that way it will never be moved to the dirty
1088 * list because mark_inode_dirty() will think
1089 * that it already _is_ on the dirty list.
1091 inode->i_state = I_DIRTY;
1092 inode->i_mode = S_IRUSR | S_IWUSR;
1093 inode->i_uid = current_fsuid();
1094 inode->i_gid = current_fsgid();
1095 inode->i_flags |= S_PRIVATE;
1096 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1099 EXPORT_SYMBOL(alloc_anon_inode);
1102 * simple_nosetlease - generic helper for prohibiting leases
1103 * @filp: file pointer
1104 * @arg: type of lease to obtain
1105 * @flp: new lease supplied for insertion
1106 * @priv: private data for lm_setup operation
1108 * Generic helper for filesystems that do not wish to allow leases to be set.
1109 * All arguments are ignored and it just returns -EINVAL.
1112 simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1117 EXPORT_SYMBOL(simple_nosetlease);
1119 const char *simple_get_link(struct dentry *dentry, struct inode *inode,
1120 struct delayed_call *done)
1122 return inode->i_link;
1124 EXPORT_SYMBOL(simple_get_link);
1126 const struct inode_operations simple_symlink_inode_operations = {
1127 .get_link = simple_get_link,
1128 .readlink = generic_readlink
1130 EXPORT_SYMBOL(simple_symlink_inode_operations);
1133 * Operations for a permanently empty directory.
1135 static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1137 return ERR_PTR(-ENOENT);
1140 static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
1143 struct inode *inode = d_inode(dentry);
1144 generic_fillattr(inode, stat);
1148 static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1153 static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
1154 const char *name, const void *value,
1155 size_t size, int flags)
1160 static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
1161 const char *name, void *value, size_t size)
1166 static int empty_dir_removexattr(struct dentry *dentry, const char *name)
1171 static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1176 static const struct inode_operations empty_dir_inode_operations = {
1177 .lookup = empty_dir_lookup,
1178 .permission = generic_permission,
1179 .setattr = empty_dir_setattr,
1180 .getattr = empty_dir_getattr,
1181 .setxattr = empty_dir_setxattr,
1182 .getxattr = empty_dir_getxattr,
1183 .removexattr = empty_dir_removexattr,
1184 .listxattr = empty_dir_listxattr,
1187 static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1189 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1190 return generic_file_llseek_size(file, offset, whence, 2, 2);
1193 static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1195 dir_emit_dots(file, ctx);
1199 static const struct file_operations empty_dir_operations = {
1200 .llseek = empty_dir_llseek,
1201 .read = generic_read_dir,
1202 .iterate_shared = empty_dir_readdir,
1203 .fsync = noop_fsync,
1207 void make_empty_dir_inode(struct inode *inode)
1209 set_nlink(inode, 2);
1210 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1211 inode->i_uid = GLOBAL_ROOT_UID;
1212 inode->i_gid = GLOBAL_ROOT_GID;
1215 inode->i_blkbits = PAGE_SHIFT;
1216 inode->i_blocks = 0;
1218 inode->i_op = &empty_dir_inode_operations;
1219 inode->i_fop = &empty_dir_operations;
1222 bool is_empty_dir_inode(struct inode *inode)
1224 return (inode->i_fop == &empty_dir_operations) &&
1225 (inode->i_op == &empty_dir_inode_operations);