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 loff_t
dcache_dir_lseek(struct file
*file
, loff_t offset
, int whence
)
89 struct dentry
*dentry
= file
->f_path
.dentry
;
92 offset
+= file
->f_pos
;
99 if (offset
!= file
->f_pos
) {
100 file
->f_pos
= offset
;
101 if (file
->f_pos
>= 2) {
103 struct dentry
*cursor
= file
->private_data
;
104 loff_t n
= file
->f_pos
- 2;
106 spin_lock(&dentry
->d_lock
);
107 /* d_lock not required for cursor */
108 list_del(&cursor
->d_child
);
109 p
= dentry
->d_subdirs
.next
;
110 while (n
&& p
!= &dentry
->d_subdirs
) {
112 next
= list_entry(p
, struct dentry
, d_child
);
113 spin_lock_nested(&next
->d_lock
, DENTRY_D_LOCK_NESTED
);
114 if (simple_positive(next
))
116 spin_unlock(&next
->d_lock
);
119 list_add_tail(&cursor
->d_child
, p
);
120 spin_unlock(&dentry
->d_lock
);
125 EXPORT_SYMBOL(dcache_dir_lseek
);
127 /* Relationship between i_mode and the DT_xxx types */
128 static inline unsigned char dt_type(struct inode
*inode
)
130 return (inode
->i_mode
>> 12) & 15;
134 * Directory is locked and all positive dentries in it are safe, since
135 * for ramfs-type trees they can't go away without unlink() or rmdir(),
136 * both impossible due to the lock on directory.
139 int dcache_readdir(struct file
*file
, struct dir_context
*ctx
)
141 struct dentry
*dentry
= file
->f_path
.dentry
;
142 struct dentry
*cursor
= file
->private_data
;
143 struct list_head
*p
, *q
= &cursor
->d_child
;
145 if (!dir_emit_dots(file
, ctx
))
147 spin_lock(&dentry
->d_lock
);
149 list_move(q
, &dentry
->d_subdirs
);
151 for (p
= q
->next
; p
!= &dentry
->d_subdirs
; p
= p
->next
) {
152 struct dentry
*next
= list_entry(p
, struct dentry
, d_child
);
153 spin_lock_nested(&next
->d_lock
, DENTRY_D_LOCK_NESTED
);
154 if (!simple_positive(next
)) {
155 spin_unlock(&next
->d_lock
);
159 spin_unlock(&next
->d_lock
);
160 spin_unlock(&dentry
->d_lock
);
161 if (!dir_emit(ctx
, next
->d_name
.name
, next
->d_name
.len
,
162 d_inode(next
)->i_ino
, dt_type(d_inode(next
))))
164 spin_lock(&dentry
->d_lock
);
165 spin_lock_nested(&next
->d_lock
, DENTRY_D_LOCK_NESTED
);
166 /* next is still alive */
168 spin_unlock(&next
->d_lock
);
172 spin_unlock(&dentry
->d_lock
);
175 EXPORT_SYMBOL(dcache_readdir
);
177 ssize_t
generic_read_dir(struct file
*filp
, char __user
*buf
, size_t siz
, loff_t
*ppos
)
181 EXPORT_SYMBOL(generic_read_dir
);
183 const struct file_operations simple_dir_operations
= {
184 .open
= dcache_dir_open
,
185 .release
= dcache_dir_close
,
186 .llseek
= dcache_dir_lseek
,
187 .read
= generic_read_dir
,
188 .iterate_shared
= dcache_readdir
,
191 EXPORT_SYMBOL(simple_dir_operations
);
193 const struct inode_operations simple_dir_inode_operations
= {
194 .lookup
= simple_lookup
,
196 EXPORT_SYMBOL(simple_dir_inode_operations
);
198 static const struct super_operations simple_super_operations
= {
199 .statfs
= simple_statfs
,
203 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
204 * will never be mountable)
206 struct dentry
*mount_pseudo(struct file_system_type
*fs_type
, char *name
,
207 const struct super_operations
*ops
,
208 const struct dentry_operations
*dops
, unsigned long magic
)
210 struct super_block
*s
;
211 struct dentry
*dentry
;
213 struct qstr d_name
= QSTR_INIT(name
, strlen(name
));
215 s
= sget(fs_type
, NULL
, set_anon_super
, MS_NOUSER
, NULL
);
219 s
->s_maxbytes
= MAX_LFS_FILESIZE
;
220 s
->s_blocksize
= PAGE_SIZE
;
221 s
->s_blocksize_bits
= PAGE_SHIFT
;
223 s
->s_op
= ops
? ops
: &simple_super_operations
;
229 * since this is the first inode, make it number 1. New inodes created
230 * after this must take care not to collide with it (by passing
231 * max_reserved of 1 to iunique).
234 root
->i_mode
= S_IFDIR
| S_IRUSR
| S_IWUSR
;
235 root
->i_atime
= root
->i_mtime
= root
->i_ctime
= CURRENT_TIME
;
236 dentry
= __d_alloc(s
, &d_name
);
241 d_instantiate(dentry
, root
);
244 s
->s_flags
|= MS_ACTIVE
;
245 return dget(s
->s_root
);
248 deactivate_locked_super(s
);
249 return ERR_PTR(-ENOMEM
);
251 EXPORT_SYMBOL(mount_pseudo
);
253 int simple_open(struct inode
*inode
, struct file
*file
)
255 if (inode
->i_private
)
256 file
->private_data
= inode
->i_private
;
259 EXPORT_SYMBOL(simple_open
);
261 int simple_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
263 struct inode
*inode
= d_inode(old_dentry
);
265 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
269 d_instantiate(dentry
, inode
);
272 EXPORT_SYMBOL(simple_link
);
274 int simple_empty(struct dentry
*dentry
)
276 struct dentry
*child
;
279 spin_lock(&dentry
->d_lock
);
280 list_for_each_entry(child
, &dentry
->d_subdirs
, d_child
) {
281 spin_lock_nested(&child
->d_lock
, DENTRY_D_LOCK_NESTED
);
282 if (simple_positive(child
)) {
283 spin_unlock(&child
->d_lock
);
286 spin_unlock(&child
->d_lock
);
290 spin_unlock(&dentry
->d_lock
);
293 EXPORT_SYMBOL(simple_empty
);
295 int simple_unlink(struct inode
*dir
, struct dentry
*dentry
)
297 struct inode
*inode
= d_inode(dentry
);
299 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
304 EXPORT_SYMBOL(simple_unlink
);
306 int simple_rmdir(struct inode
*dir
, struct dentry
*dentry
)
308 if (!simple_empty(dentry
))
311 drop_nlink(d_inode(dentry
));
312 simple_unlink(dir
, dentry
);
316 EXPORT_SYMBOL(simple_rmdir
);
318 int simple_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
319 struct inode
*new_dir
, struct dentry
*new_dentry
)
321 struct inode
*inode
= d_inode(old_dentry
);
322 int they_are_dirs
= d_is_dir(old_dentry
);
324 if (!simple_empty(new_dentry
))
327 if (d_really_is_positive(new_dentry
)) {
328 simple_unlink(new_dir
, new_dentry
);
330 drop_nlink(d_inode(new_dentry
));
333 } else if (they_are_dirs
) {
338 old_dir
->i_ctime
= old_dir
->i_mtime
= new_dir
->i_ctime
=
339 new_dir
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
343 EXPORT_SYMBOL(simple_rename
);
346 * simple_setattr - setattr for simple filesystem
348 * @iattr: iattr structure
350 * Returns 0 on success, -error on failure.
352 * simple_setattr is a simple ->setattr implementation without a proper
353 * implementation of size changes.
355 * It can either be used for in-memory filesystems or special files
356 * on simple regular filesystems. Anything that needs to change on-disk
357 * or wire state on size changes needs its own setattr method.
359 int simple_setattr(struct dentry
*dentry
, struct iattr
*iattr
)
361 struct inode
*inode
= d_inode(dentry
);
364 error
= inode_change_ok(inode
, iattr
);
368 if (iattr
->ia_valid
& ATTR_SIZE
)
369 truncate_setsize(inode
, iattr
->ia_size
);
370 setattr_copy(inode
, iattr
);
371 mark_inode_dirty(inode
);
374 EXPORT_SYMBOL(simple_setattr
);
376 int simple_readpage(struct file
*file
, struct page
*page
)
378 clear_highpage(page
);
379 flush_dcache_page(page
);
380 SetPageUptodate(page
);
384 EXPORT_SYMBOL(simple_readpage
);
386 int simple_write_begin(struct file
*file
, struct address_space
*mapping
,
387 loff_t pos
, unsigned len
, unsigned flags
,
388 struct page
**pagep
, void **fsdata
)
393 index
= pos
>> PAGE_SHIFT
;
395 page
= grab_cache_page_write_begin(mapping
, index
, flags
);
401 if (!PageUptodate(page
) && (len
!= PAGE_SIZE
)) {
402 unsigned from
= pos
& (PAGE_SIZE
- 1);
404 zero_user_segments(page
, 0, from
, from
+ len
, PAGE_SIZE
);
408 EXPORT_SYMBOL(simple_write_begin
);
411 * simple_write_end - .write_end helper for non-block-device FSes
412 * @available: See .write_end of address_space_operations
421 * simple_write_end does the minimum needed for updating a page after writing is
422 * done. It has the same API signature as the .write_end of
423 * address_space_operations vector. So it can just be set onto .write_end for
424 * FSes that don't need any other processing. i_mutex is assumed to be held.
425 * Block based filesystems should use generic_write_end().
426 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
427 * is not called, so a filesystem that actually does store data in .write_inode
428 * should extend on what's done here with a call to mark_inode_dirty() in the
429 * case that i_size has changed.
431 int simple_write_end(struct file
*file
, struct address_space
*mapping
,
432 loff_t pos
, unsigned len
, unsigned copied
,
433 struct page
*page
, void *fsdata
)
435 struct inode
*inode
= page
->mapping
->host
;
436 loff_t last_pos
= pos
+ copied
;
438 /* zero the stale part of the page if we did a short copy */
440 unsigned from
= pos
& (PAGE_SIZE
- 1);
442 zero_user(page
, from
+ copied
, len
- copied
);
445 if (!PageUptodate(page
))
446 SetPageUptodate(page
);
448 * No need to use i_size_read() here, the i_size
449 * cannot change under us because we hold the i_mutex.
451 if (last_pos
> inode
->i_size
)
452 i_size_write(inode
, last_pos
);
454 set_page_dirty(page
);
460 EXPORT_SYMBOL(simple_write_end
);
463 * the inodes created here are not hashed. If you use iunique to generate
464 * unique inode values later for this filesystem, then you must take care
465 * to pass it an appropriate max_reserved value to avoid collisions.
467 int simple_fill_super(struct super_block
*s
, unsigned long magic
,
468 struct tree_descr
*files
)
472 struct dentry
*dentry
;
475 s
->s_blocksize
= PAGE_SIZE
;
476 s
->s_blocksize_bits
= PAGE_SHIFT
;
478 s
->s_op
= &simple_super_operations
;
481 inode
= new_inode(s
);
485 * because the root inode is 1, the files array must not contain an
489 inode
->i_mode
= S_IFDIR
| 0755;
490 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
491 inode
->i_op
= &simple_dir_inode_operations
;
492 inode
->i_fop
= &simple_dir_operations
;
494 root
= d_make_root(inode
);
497 for (i
= 0; !files
->name
|| files
->name
[0]; i
++, files
++) {
501 /* warn if it tries to conflict with the root inode */
502 if (unlikely(i
== 1))
503 printk(KERN_WARNING
"%s: %s passed in a files array"
504 "with an index of 1!\n", __func__
,
507 dentry
= d_alloc_name(root
, files
->name
);
510 inode
= new_inode(s
);
515 inode
->i_mode
= S_IFREG
| files
->mode
;
516 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
517 inode
->i_fop
= files
->ops
;
519 d_add(dentry
, inode
);
525 shrink_dcache_parent(root
);
529 EXPORT_SYMBOL(simple_fill_super
);
531 static DEFINE_SPINLOCK(pin_fs_lock
);
533 int simple_pin_fs(struct file_system_type
*type
, struct vfsmount
**mount
, int *count
)
535 struct vfsmount
*mnt
= NULL
;
536 spin_lock(&pin_fs_lock
);
537 if (unlikely(!*mount
)) {
538 spin_unlock(&pin_fs_lock
);
539 mnt
= vfs_kern_mount(type
, MS_KERNMOUNT
, type
->name
, NULL
);
542 spin_lock(&pin_fs_lock
);
548 spin_unlock(&pin_fs_lock
);
552 EXPORT_SYMBOL(simple_pin_fs
);
554 void simple_release_fs(struct vfsmount
**mount
, int *count
)
556 struct vfsmount
*mnt
;
557 spin_lock(&pin_fs_lock
);
561 spin_unlock(&pin_fs_lock
);
564 EXPORT_SYMBOL(simple_release_fs
);
567 * simple_read_from_buffer - copy data from the buffer to user space
568 * @to: the user space buffer to read to
569 * @count: the maximum number of bytes to read
570 * @ppos: the current position in the buffer
571 * @from: the buffer to read from
572 * @available: the size of the buffer
574 * The simple_read_from_buffer() function reads up to @count bytes from the
575 * buffer @from at offset @ppos into the user space address starting at @to.
577 * On success, the number of bytes read is returned and the offset @ppos is
578 * advanced by this number, or negative value is returned on error.
580 ssize_t
simple_read_from_buffer(void __user
*to
, size_t count
, loff_t
*ppos
,
581 const void *from
, size_t available
)
588 if (pos
>= available
|| !count
)
590 if (count
> available
- pos
)
591 count
= available
- pos
;
592 ret
= copy_to_user(to
, from
+ pos
, count
);
599 EXPORT_SYMBOL(simple_read_from_buffer
);
602 * simple_write_to_buffer - copy data from user space to the buffer
603 * @to: the buffer to write to
604 * @available: the size of the buffer
605 * @ppos: the current position in the buffer
606 * @from: the user space buffer to read from
607 * @count: the maximum number of bytes to read
609 * The simple_write_to_buffer() function reads up to @count bytes from the user
610 * space address starting at @from into the buffer @to at offset @ppos.
612 * On success, the number of bytes written is returned and the offset @ppos is
613 * advanced by this number, or negative value is returned on error.
615 ssize_t
simple_write_to_buffer(void *to
, size_t available
, loff_t
*ppos
,
616 const void __user
*from
, size_t count
)
623 if (pos
>= available
|| !count
)
625 if (count
> available
- pos
)
626 count
= available
- pos
;
627 res
= copy_from_user(to
+ pos
, from
, count
);
634 EXPORT_SYMBOL(simple_write_to_buffer
);
637 * memory_read_from_buffer - copy data from the buffer
638 * @to: the kernel space buffer to read to
639 * @count: the maximum number of bytes to read
640 * @ppos: the current position in the buffer
641 * @from: the buffer to read from
642 * @available: the size of the buffer
644 * The memory_read_from_buffer() function reads up to @count bytes from the
645 * buffer @from at offset @ppos into the kernel space address starting at @to.
647 * On success, the number of bytes read is returned and the offset @ppos is
648 * advanced by this number, or negative value is returned on error.
650 ssize_t
memory_read_from_buffer(void *to
, size_t count
, loff_t
*ppos
,
651 const void *from
, size_t available
)
657 if (pos
>= available
)
659 if (count
> available
- pos
)
660 count
= available
- pos
;
661 memcpy(to
, from
+ pos
, count
);
666 EXPORT_SYMBOL(memory_read_from_buffer
);
669 * Transaction based IO.
670 * The file expects a single write which triggers the transaction, and then
671 * possibly a read which collects the result - which is stored in a
675 void simple_transaction_set(struct file
*file
, size_t n
)
677 struct simple_transaction_argresp
*ar
= file
->private_data
;
679 BUG_ON(n
> SIMPLE_TRANSACTION_LIMIT
);
682 * The barrier ensures that ar->size will really remain zero until
683 * ar->data is ready for reading.
688 EXPORT_SYMBOL(simple_transaction_set
);
690 char *simple_transaction_get(struct file
*file
, const char __user
*buf
, size_t size
)
692 struct simple_transaction_argresp
*ar
;
693 static DEFINE_SPINLOCK(simple_transaction_lock
);
695 if (size
> SIMPLE_TRANSACTION_LIMIT
- 1)
696 return ERR_PTR(-EFBIG
);
698 ar
= (struct simple_transaction_argresp
*)get_zeroed_page(GFP_KERNEL
);
700 return ERR_PTR(-ENOMEM
);
702 spin_lock(&simple_transaction_lock
);
704 /* only one write allowed per open */
705 if (file
->private_data
) {
706 spin_unlock(&simple_transaction_lock
);
707 free_page((unsigned long)ar
);
708 return ERR_PTR(-EBUSY
);
711 file
->private_data
= ar
;
713 spin_unlock(&simple_transaction_lock
);
715 if (copy_from_user(ar
->data
, buf
, size
))
716 return ERR_PTR(-EFAULT
);
720 EXPORT_SYMBOL(simple_transaction_get
);
722 ssize_t
simple_transaction_read(struct file
*file
, char __user
*buf
, size_t size
, loff_t
*pos
)
724 struct simple_transaction_argresp
*ar
= file
->private_data
;
728 return simple_read_from_buffer(buf
, size
, pos
, ar
->data
, ar
->size
);
730 EXPORT_SYMBOL(simple_transaction_read
);
732 int simple_transaction_release(struct inode
*inode
, struct file
*file
)
734 free_page((unsigned long)file
->private_data
);
737 EXPORT_SYMBOL(simple_transaction_release
);
739 /* Simple attribute files */
742 int (*get
)(void *, u64
*);
743 int (*set
)(void *, u64
);
744 char get_buf
[24]; /* enough to store a u64 and "\n\0" */
747 const char *fmt
; /* format for read operation */
748 struct mutex mutex
; /* protects access to these buffers */
751 /* simple_attr_open is called by an actual attribute open file operation
752 * to set the attribute specific access operations. */
753 int simple_attr_open(struct inode
*inode
, struct file
*file
,
754 int (*get
)(void *, u64
*), int (*set
)(void *, u64
),
757 struct simple_attr
*attr
;
759 attr
= kmalloc(sizeof(*attr
), GFP_KERNEL
);
765 attr
->data
= inode
->i_private
;
767 mutex_init(&attr
->mutex
);
769 file
->private_data
= attr
;
771 return nonseekable_open(inode
, file
);
773 EXPORT_SYMBOL_GPL(simple_attr_open
);
775 int simple_attr_release(struct inode
*inode
, struct file
*file
)
777 kfree(file
->private_data
);
780 EXPORT_SYMBOL_GPL(simple_attr_release
); /* GPL-only? This? Really? */
782 /* read from the buffer that is filled with the get function */
783 ssize_t
simple_attr_read(struct file
*file
, char __user
*buf
,
784 size_t len
, loff_t
*ppos
)
786 struct simple_attr
*attr
;
790 attr
= file
->private_data
;
795 ret
= mutex_lock_interruptible(&attr
->mutex
);
799 if (*ppos
) { /* continued read */
800 size
= strlen(attr
->get_buf
);
801 } else { /* first read */
803 ret
= attr
->get(attr
->data
, &val
);
807 size
= scnprintf(attr
->get_buf
, sizeof(attr
->get_buf
),
808 attr
->fmt
, (unsigned long long)val
);
811 ret
= simple_read_from_buffer(buf
, len
, ppos
, attr
->get_buf
, size
);
813 mutex_unlock(&attr
->mutex
);
816 EXPORT_SYMBOL_GPL(simple_attr_read
);
818 /* interpret the buffer as a number to call the set function with */
819 ssize_t
simple_attr_write(struct file
*file
, const char __user
*buf
,
820 size_t len
, loff_t
*ppos
)
822 struct simple_attr
*attr
;
827 attr
= file
->private_data
;
831 ret
= mutex_lock_interruptible(&attr
->mutex
);
836 size
= min(sizeof(attr
->set_buf
) - 1, len
);
837 if (copy_from_user(attr
->set_buf
, buf
, size
))
840 attr
->set_buf
[size
] = '\0';
841 val
= simple_strtoll(attr
->set_buf
, NULL
, 0);
842 ret
= attr
->set(attr
->data
, val
);
844 ret
= len
; /* on success, claim we got the whole input */
846 mutex_unlock(&attr
->mutex
);
849 EXPORT_SYMBOL_GPL(simple_attr_write
);
852 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
853 * @sb: filesystem to do the file handle conversion on
854 * @fid: file handle to convert
855 * @fh_len: length of the file handle in bytes
856 * @fh_type: type of file handle
857 * @get_inode: filesystem callback to retrieve inode
859 * This function decodes @fid as long as it has one of the well-known
860 * Linux filehandle types and calls @get_inode on it to retrieve the
861 * inode for the object specified in the file handle.
863 struct dentry
*generic_fh_to_dentry(struct super_block
*sb
, struct fid
*fid
,
864 int fh_len
, int fh_type
, struct inode
*(*get_inode
)
865 (struct super_block
*sb
, u64 ino
, u32 gen
))
867 struct inode
*inode
= NULL
;
873 case FILEID_INO32_GEN
:
874 case FILEID_INO32_GEN_PARENT
:
875 inode
= get_inode(sb
, fid
->i32
.ino
, fid
->i32
.gen
);
879 return d_obtain_alias(inode
);
881 EXPORT_SYMBOL_GPL(generic_fh_to_dentry
);
884 * generic_fh_to_parent - generic helper for the fh_to_parent export operation
885 * @sb: filesystem to do the file handle conversion on
886 * @fid: file handle to convert
887 * @fh_len: length of the file handle in bytes
888 * @fh_type: type of file handle
889 * @get_inode: filesystem callback to retrieve inode
891 * This function decodes @fid as long as it has one of the well-known
892 * Linux filehandle types and calls @get_inode on it to retrieve the
893 * inode for the _parent_ object specified in the file handle if it
894 * is specified in the file handle, or NULL otherwise.
896 struct dentry
*generic_fh_to_parent(struct super_block
*sb
, struct fid
*fid
,
897 int fh_len
, int fh_type
, struct inode
*(*get_inode
)
898 (struct super_block
*sb
, u64 ino
, u32 gen
))
900 struct inode
*inode
= NULL
;
906 case FILEID_INO32_GEN_PARENT
:
907 inode
= get_inode(sb
, fid
->i32
.parent_ino
,
908 (fh_len
> 3 ? fid
->i32
.parent_gen
: 0));
912 return d_obtain_alias(inode
);
914 EXPORT_SYMBOL_GPL(generic_fh_to_parent
);
917 * __generic_file_fsync - generic fsync implementation for simple filesystems
919 * @file: file to synchronize
920 * @start: start offset in bytes
921 * @end: end offset in bytes (inclusive)
922 * @datasync: only synchronize essential metadata if true
924 * This is a generic implementation of the fsync method for simple
925 * filesystems which track all non-inode metadata in the buffers list
926 * hanging off the address_space structure.
928 int __generic_file_fsync(struct file
*file
, loff_t start
, loff_t end
,
931 struct inode
*inode
= file
->f_mapping
->host
;
935 err
= filemap_write_and_wait_range(inode
->i_mapping
, start
, end
);
940 ret
= sync_mapping_buffers(inode
->i_mapping
);
941 if (!(inode
->i_state
& I_DIRTY_ALL
))
943 if (datasync
&& !(inode
->i_state
& I_DIRTY_DATASYNC
))
946 err
= sync_inode_metadata(inode
, 1);
954 EXPORT_SYMBOL(__generic_file_fsync
);
957 * generic_file_fsync - generic fsync implementation for simple filesystems
959 * @file: file to synchronize
960 * @start: start offset in bytes
961 * @end: end offset in bytes (inclusive)
962 * @datasync: only synchronize essential metadata if true
966 int generic_file_fsync(struct file
*file
, loff_t start
, loff_t end
,
969 struct inode
*inode
= file
->f_mapping
->host
;
972 err
= __generic_file_fsync(file
, start
, end
, datasync
);
975 return blkdev_issue_flush(inode
->i_sb
->s_bdev
, GFP_KERNEL
, NULL
);
977 EXPORT_SYMBOL(generic_file_fsync
);
980 * generic_check_addressable - Check addressability of file system
981 * @blocksize_bits: log of file system block size
982 * @num_blocks: number of blocks in file system
984 * Determine whether a file system with @num_blocks blocks (and a
985 * block size of 2**@blocksize_bits) is addressable by the sector_t
986 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
988 int generic_check_addressable(unsigned blocksize_bits
, u64 num_blocks
)
990 u64 last_fs_block
= num_blocks
- 1;
992 last_fs_block
>> (PAGE_SHIFT
- blocksize_bits
);
994 if (unlikely(num_blocks
== 0))
997 if ((blocksize_bits
< 9) || (blocksize_bits
> PAGE_SHIFT
))
1000 if ((last_fs_block
> (sector_t
)(~0ULL) >> (blocksize_bits
- 9)) ||
1001 (last_fs_page
> (pgoff_t
)(~0ULL))) {
1006 EXPORT_SYMBOL(generic_check_addressable
);
1009 * No-op implementation of ->fsync for in-memory filesystems.
1011 int noop_fsync(struct file
*file
, loff_t start
, loff_t end
, int datasync
)
1015 EXPORT_SYMBOL(noop_fsync
);
1017 /* Because kfree isn't assignment-compatible with void(void*) ;-/ */
1018 void kfree_link(void *p
)
1022 EXPORT_SYMBOL(kfree_link
);
1025 * nop .set_page_dirty method so that people can use .page_mkwrite on
1028 static int anon_set_page_dirty(struct page
*page
)
1034 * A single inode exists for all anon_inode files. Contrary to pipes,
1035 * anon_inode inodes have no associated per-instance data, so we need
1036 * only allocate one of them.
1038 struct inode
*alloc_anon_inode(struct super_block
*s
)
1040 static const struct address_space_operations anon_aops
= {
1041 .set_page_dirty
= anon_set_page_dirty
,
1043 struct inode
*inode
= new_inode_pseudo(s
);
1046 return ERR_PTR(-ENOMEM
);
1048 inode
->i_ino
= get_next_ino();
1049 inode
->i_mapping
->a_ops
= &anon_aops
;
1052 * Mark the inode dirty from the very beginning,
1053 * that way it will never be moved to the dirty
1054 * list because mark_inode_dirty() will think
1055 * that it already _is_ on the dirty list.
1057 inode
->i_state
= I_DIRTY
;
1058 inode
->i_mode
= S_IRUSR
| S_IWUSR
;
1059 inode
->i_uid
= current_fsuid();
1060 inode
->i_gid
= current_fsgid();
1061 inode
->i_flags
|= S_PRIVATE
;
1062 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
1065 EXPORT_SYMBOL(alloc_anon_inode
);
1068 * simple_nosetlease - generic helper for prohibiting leases
1069 * @filp: file pointer
1070 * @arg: type of lease to obtain
1071 * @flp: new lease supplied for insertion
1072 * @priv: private data for lm_setup operation
1074 * Generic helper for filesystems that do not wish to allow leases to be set.
1075 * All arguments are ignored and it just returns -EINVAL.
1078 simple_nosetlease(struct file
*filp
, long arg
, struct file_lock
**flp
,
1083 EXPORT_SYMBOL(simple_nosetlease
);
1085 const char *simple_get_link(struct dentry
*dentry
, struct inode
*inode
,
1086 struct delayed_call
*done
)
1088 return inode
->i_link
;
1090 EXPORT_SYMBOL(simple_get_link
);
1092 const struct inode_operations simple_symlink_inode_operations
= {
1093 .get_link
= simple_get_link
,
1094 .readlink
= generic_readlink
1096 EXPORT_SYMBOL(simple_symlink_inode_operations
);
1099 * Operations for a permanently empty directory.
1101 static struct dentry
*empty_dir_lookup(struct inode
*dir
, struct dentry
*dentry
, unsigned int flags
)
1103 return ERR_PTR(-ENOENT
);
1106 static int empty_dir_getattr(struct vfsmount
*mnt
, struct dentry
*dentry
,
1109 struct inode
*inode
= d_inode(dentry
);
1110 generic_fillattr(inode
, stat
);
1114 static int empty_dir_setattr(struct dentry
*dentry
, struct iattr
*attr
)
1119 static int empty_dir_setxattr(struct dentry
*dentry
, struct inode
*inode
,
1120 const char *name
, const void *value
,
1121 size_t size
, int flags
)
1126 static ssize_t
empty_dir_getxattr(struct dentry
*dentry
, struct inode
*inode
,
1127 const char *name
, void *value
, size_t size
)
1132 static int empty_dir_removexattr(struct dentry
*dentry
, const char *name
)
1137 static ssize_t
empty_dir_listxattr(struct dentry
*dentry
, char *list
, size_t size
)
1142 static const struct inode_operations empty_dir_inode_operations
= {
1143 .lookup
= empty_dir_lookup
,
1144 .permission
= generic_permission
,
1145 .setattr
= empty_dir_setattr
,
1146 .getattr
= empty_dir_getattr
,
1147 .setxattr
= empty_dir_setxattr
,
1148 .getxattr
= empty_dir_getxattr
,
1149 .removexattr
= empty_dir_removexattr
,
1150 .listxattr
= empty_dir_listxattr
,
1153 static loff_t
empty_dir_llseek(struct file
*file
, loff_t offset
, int whence
)
1155 /* An empty directory has two entries . and .. at offsets 0 and 1 */
1156 return generic_file_llseek_size(file
, offset
, whence
, 2, 2);
1159 static int empty_dir_readdir(struct file
*file
, struct dir_context
*ctx
)
1161 dir_emit_dots(file
, ctx
);
1165 static const struct file_operations empty_dir_operations
= {
1166 .llseek
= empty_dir_llseek
,
1167 .read
= generic_read_dir
,
1168 .iterate_shared
= empty_dir_readdir
,
1169 .fsync
= noop_fsync
,
1173 void make_empty_dir_inode(struct inode
*inode
)
1175 set_nlink(inode
, 2);
1176 inode
->i_mode
= S_IFDIR
| S_IRUGO
| S_IXUGO
;
1177 inode
->i_uid
= GLOBAL_ROOT_UID
;
1178 inode
->i_gid
= GLOBAL_ROOT_GID
;
1181 inode
->i_blkbits
= PAGE_SHIFT
;
1182 inode
->i_blocks
= 0;
1184 inode
->i_op
= &empty_dir_inode_operations
;
1185 inode
->i_fop
= &empty_dir_operations
;
1188 bool is_empty_dir_inode(struct inode
*inode
)
1190 return (inode
->i_fop
== &empty_dir_operations
) &&
1191 (inode
->i_op
== &empty_dir_inode_operations
);