| /* |
| * fs/libfs.c |
| * Library for filesystems writers. |
| */ |
| |
| #include <linux/blkdev.h> |
| #include <linux/export.h> |
| #include <linux/pagemap.h> |
| #include <linux/slab.h> |
| #include <linux/mount.h> |
| #include <linux/vfs.h> |
| #include <linux/quotaops.h> |
| #include <linux/mutex.h> |
| #include <linux/namei.h> |
| #include <linux/exportfs.h> |
| #include <linux/writeback.h> |
| #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
| |
| #include <asm/uaccess.h> |
| |
| #include "internal.h" |
| |
| int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
| struct kstat *stat) |
| { |
| struct inode *inode = d_inode(dentry); |
| generic_fillattr(inode, stat); |
| stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_getattr); |
| |
| int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
| { |
| buf->f_type = dentry->d_sb->s_magic; |
| buf->f_bsize = PAGE_CACHE_SIZE; |
| buf->f_namelen = NAME_MAX; |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_statfs); |
| |
| /* |
| * Retaining negative dentries for an in-memory filesystem just wastes |
| * memory and lookup time: arrange for them to be deleted immediately. |
| */ |
| int always_delete_dentry(const struct dentry *dentry) |
| { |
| return 1; |
| } |
| EXPORT_SYMBOL(always_delete_dentry); |
| |
| const struct dentry_operations simple_dentry_operations = { |
| .d_delete = always_delete_dentry, |
| }; |
| EXPORT_SYMBOL(simple_dentry_operations); |
| |
| /* |
| * Lookup the data. This is trivial - if the dentry didn't already |
| * exist, we know it is negative. Set d_op to delete negative dentries. |
| */ |
| struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| { |
| if (dentry->d_name.len > NAME_MAX) |
| return ERR_PTR(-ENAMETOOLONG); |
| if (!dentry->d_sb->s_d_op) |
| d_set_d_op(dentry, &simple_dentry_operations); |
| d_add(dentry, NULL); |
| return NULL; |
| } |
| EXPORT_SYMBOL(simple_lookup); |
| |
| int dcache_dir_open(struct inode *inode, struct file *file) |
| { |
| static struct qstr cursor_name = QSTR_INIT(".", 1); |
| |
| file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
| |
| return file->private_data ? 0 : -ENOMEM; |
| } |
| EXPORT_SYMBOL(dcache_dir_open); |
| |
| int dcache_dir_close(struct inode *inode, struct file *file) |
| { |
| dput(file->private_data); |
| return 0; |
| } |
| EXPORT_SYMBOL(dcache_dir_close); |
| |
| loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
| { |
| struct dentry *dentry = file->f_path.dentry; |
| mutex_lock(&d_inode(dentry)->i_mutex); |
| switch (whence) { |
| case 1: |
| offset += file->f_pos; |
| case 0: |
| if (offset >= 0) |
| break; |
| default: |
| mutex_unlock(&d_inode(dentry)->i_mutex); |
| return -EINVAL; |
| } |
| if (offset != file->f_pos) { |
| file->f_pos = offset; |
| if (file->f_pos >= 2) { |
| struct list_head *p; |
| struct dentry *cursor = file->private_data; |
| loff_t n = file->f_pos - 2; |
| |
| spin_lock(&dentry->d_lock); |
| /* d_lock not required for cursor */ |
| list_del(&cursor->d_child); |
| p = dentry->d_subdirs.next; |
| while (n && p != &dentry->d_subdirs) { |
| struct dentry *next; |
| next = list_entry(p, struct dentry, d_child); |
| spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
| if (simple_positive(next)) |
| n--; |
| spin_unlock(&next->d_lock); |
| p = p->next; |
| } |
| list_add_tail(&cursor->d_child, p); |
| spin_unlock(&dentry->d_lock); |
| } |
| } |
| mutex_unlock(&d_inode(dentry)->i_mutex); |
| return offset; |
| } |
| EXPORT_SYMBOL(dcache_dir_lseek); |
| |
| /* Relationship between i_mode and the DT_xxx types */ |
| static inline unsigned char dt_type(struct inode *inode) |
| { |
| return (inode->i_mode >> 12) & 15; |
| } |
| |
| /* |
| * Directory is locked and all positive dentries in it are safe, since |
| * for ramfs-type trees they can't go away without unlink() or rmdir(), |
| * both impossible due to the lock on directory. |
| */ |
| |
| int dcache_readdir(struct file *file, struct dir_context *ctx) |
| { |
| struct dentry *dentry = file->f_path.dentry; |
| struct dentry *cursor = file->private_data; |
| struct list_head *p, *q = &cursor->d_child; |
| |
| if (!dir_emit_dots(file, ctx)) |
| return 0; |
| spin_lock(&dentry->d_lock); |
| if (ctx->pos == 2) |
| list_move(q, &dentry->d_subdirs); |
| |
| for (p = q->next; p != &dentry->d_subdirs; p = p->next) { |
| struct dentry *next = list_entry(p, struct dentry, d_child); |
| spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
| if (!simple_positive(next)) { |
| spin_unlock(&next->d_lock); |
| continue; |
| } |
| |
| spin_unlock(&next->d_lock); |
| spin_unlock(&dentry->d_lock); |
| if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
| d_inode(next)->i_ino, dt_type(d_inode(next)))) |
| return 0; |
| spin_lock(&dentry->d_lock); |
| spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
| /* next is still alive */ |
| list_move(q, p); |
| spin_unlock(&next->d_lock); |
| p = q; |
| ctx->pos++; |
| } |
| spin_unlock(&dentry->d_lock); |
| return 0; |
| } |
| EXPORT_SYMBOL(dcache_readdir); |
| |
| ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) |
| { |
| return -EISDIR; |
| } |
| EXPORT_SYMBOL(generic_read_dir); |
| |
| const struct file_operations simple_dir_operations = { |
| .open = dcache_dir_open, |
| .release = dcache_dir_close, |
| .llseek = dcache_dir_lseek, |
| .read = generic_read_dir, |
| .iterate = dcache_readdir, |
| .fsync = noop_fsync, |
| }; |
| EXPORT_SYMBOL(simple_dir_operations); |
| |
| const struct inode_operations simple_dir_inode_operations = { |
| .lookup = simple_lookup, |
| }; |
| EXPORT_SYMBOL(simple_dir_inode_operations); |
| |
| static const struct super_operations simple_super_operations = { |
| .statfs = simple_statfs, |
| }; |
| |
| /* |
| * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that |
| * will never be mountable) |
| */ |
| struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
| const struct super_operations *ops, |
| const struct dentry_operations *dops, unsigned long magic) |
| { |
| struct super_block *s; |
| struct dentry *dentry; |
| struct inode *root; |
| struct qstr d_name = QSTR_INIT(name, strlen(name)); |
| |
| s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); |
| if (IS_ERR(s)) |
| return ERR_CAST(s); |
| |
| s->s_maxbytes = MAX_LFS_FILESIZE; |
| s->s_blocksize = PAGE_SIZE; |
| s->s_blocksize_bits = PAGE_SHIFT; |
| s->s_magic = magic; |
| s->s_op = ops ? ops : &simple_super_operations; |
| s->s_time_gran = 1; |
| root = new_inode(s); |
| if (!root) |
| goto Enomem; |
| /* |
| * since this is the first inode, make it number 1. New inodes created |
| * after this must take care not to collide with it (by passing |
| * max_reserved of 1 to iunique). |
| */ |
| root->i_ino = 1; |
| root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
| root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
| dentry = __d_alloc(s, &d_name); |
| if (!dentry) { |
| iput(root); |
| goto Enomem; |
| } |
| d_instantiate(dentry, root); |
| s->s_root = dentry; |
| s->s_d_op = dops; |
| s->s_flags |= MS_ACTIVE; |
| return dget(s->s_root); |
| |
| Enomem: |
| deactivate_locked_super(s); |
| return ERR_PTR(-ENOMEM); |
| } |
| EXPORT_SYMBOL(mount_pseudo); |
| |
| int simple_open(struct inode *inode, struct file *file) |
| { |
| if (inode->i_private) |
| file->private_data = inode->i_private; |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_open); |
| |
| int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = d_inode(old_dentry); |
| |
| inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| inc_nlink(inode); |
| ihold(inode); |
| dget(dentry); |
| d_instantiate(dentry, inode); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_link); |
| |
| int simple_empty(struct dentry *dentry) |
| { |
| struct dentry *child; |
| int ret = 0; |
| |
| spin_lock(&dentry->d_lock); |
| list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
| spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
| if (simple_positive(child)) { |
| spin_unlock(&child->d_lock); |
| goto out; |
| } |
| spin_unlock(&child->d_lock); |
| } |
| ret = 1; |
| out: |
| spin_unlock(&dentry->d_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL(simple_empty); |
| |
| int simple_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = d_inode(dentry); |
| |
| inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| drop_nlink(inode); |
| dput(dentry); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_unlink); |
| |
| int simple_rmdir(struct inode *dir, struct dentry *dentry) |
| { |
| if (!simple_empty(dentry)) |
| return -ENOTEMPTY; |
| |
| drop_nlink(d_inode(dentry)); |
| simple_unlink(dir, dentry); |
| drop_nlink(dir); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_rmdir); |
| |
| int simple_rename(struct inode *old_dir, struct dentry *old_dentry, |
| struct inode *new_dir, struct dentry *new_dentry) |
| { |
| struct inode *inode = d_inode(old_dentry); |
| int they_are_dirs = d_is_dir(old_dentry); |
| |
| if (!simple_empty(new_dentry)) |
| return -ENOTEMPTY; |
| |
| if (d_really_is_positive(new_dentry)) { |
| simple_unlink(new_dir, new_dentry); |
| if (they_are_dirs) { |
| drop_nlink(d_inode(new_dentry)); |
| drop_nlink(old_dir); |
| } |
| } else if (they_are_dirs) { |
| drop_nlink(old_dir); |
| inc_nlink(new_dir); |
| } |
| |
| old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = |
| new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_rename); |
| |
| /** |
| * simple_setattr - setattr for simple filesystem |
| * @dentry: dentry |
| * @iattr: iattr structure |
| * |
| * Returns 0 on success, -error on failure. |
| * |
| * simple_setattr is a simple ->setattr implementation without a proper |
| * implementation of size changes. |
| * |
| * It can either be used for in-memory filesystems or special files |
| * on simple regular filesystems. Anything that needs to change on-disk |
| * or wire state on size changes needs its own setattr method. |
| */ |
| int simple_setattr(struct dentry *dentry, struct iattr *iattr) |
| { |
| struct inode *inode = d_inode(dentry); |
| int error; |
| |
| error = inode_change_ok(inode, iattr); |
| if (error) |
| return error; |
| |
| if (iattr->ia_valid & ATTR_SIZE) |
| truncate_setsize(inode, iattr->ia_size); |
| setattr_copy(inode, iattr); |
| mark_inode_dirty(inode); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_setattr); |
| |
| int simple_readpage(struct file *file, struct page *page) |
| { |
| clear_highpage(page); |
| flush_dcache_page(page); |
| SetPageUptodate(page); |
| unlock_page(page); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_readpage); |
| |
| int simple_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct page *page; |
| pgoff_t index; |
| |
| index = pos >> PAGE_CACHE_SHIFT; |
| |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (!page) |
| return -ENOMEM; |
| |
| *pagep = page; |
| |
| if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { |
| unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| |
| zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_write_begin); |
| |
| /** |
| * simple_write_end - .write_end helper for non-block-device FSes |
| * @available: See .write_end of address_space_operations |
| * @file: " |
| * @mapping: " |
| * @pos: " |
| * @len: " |
| * @copied: " |
| * @page: " |
| * @fsdata: " |
| * |
| * simple_write_end does the minimum needed for updating a page after writing is |
| * done. It has the same API signature as the .write_end of |
| * address_space_operations vector. So it can just be set onto .write_end for |
| * FSes that don't need any other processing. i_mutex is assumed to be held. |
| * Block based filesystems should use generic_write_end(). |
| * NOTE: Even though i_size might get updated by this function, mark_inode_dirty |
| * is not called, so a filesystem that actually does store data in .write_inode |
| * should extend on what's done here with a call to mark_inode_dirty() in the |
| * case that i_size has changed. |
| */ |
| int simple_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = page->mapping->host; |
| loff_t last_pos = pos + copied; |
| |
| /* zero the stale part of the page if we did a short copy */ |
| if (copied < len) { |
| unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| |
| zero_user(page, from + copied, len - copied); |
| } |
| |
| if (!PageUptodate(page)) |
| SetPageUptodate(page); |
| /* |
| * No need to use i_size_read() here, the i_size |
| * cannot change under us because we hold the i_mutex. |
| */ |
| if (last_pos > inode->i_size) |
| i_size_write(inode, last_pos); |
| |
| set_page_dirty(page); |
| unlock_page(page); |
| page_cache_release(page); |
| |
| return copied; |
| } |
| EXPORT_SYMBOL(simple_write_end); |
| |
| /* |
| * the inodes created here are not hashed. If you use iunique to generate |
| * unique inode values later for this filesystem, then you must take care |
| * to pass it an appropriate max_reserved value to avoid collisions. |
| */ |
| int simple_fill_super(struct super_block *s, unsigned long magic, |
| struct tree_descr *files) |
| { |
| struct inode *inode; |
| struct dentry *root; |
| struct dentry *dentry; |
| int i; |
| |
| s->s_blocksize = PAGE_CACHE_SIZE; |
| s->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| s->s_magic = magic; |
| s->s_op = &simple_super_operations; |
| s->s_time_gran = 1; |
| |
| inode = new_inode(s); |
| if (!inode) |
| return -ENOMEM; |
| /* |
| * because the root inode is 1, the files array must not contain an |
| * entry at index 1 |
| */ |
| inode->i_ino = 1; |
| inode->i_mode = S_IFDIR | 0755; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| inode->i_op = &simple_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| set_nlink(inode, 2); |
| root = d_make_root(inode); |
| if (!root) |
| return -ENOMEM; |
| for (i = 0; !files->name || files->name[0]; i++, files++) { |
| if (!files->name) |
| continue; |
| |
| /* warn if it tries to conflict with the root inode */ |
| if (unlikely(i == 1)) |
| printk(KERN_WARNING "%s: %s passed in a files array" |
| "with an index of 1!\n", __func__, |
| s->s_type->name); |
| |
| dentry = d_alloc_name(root, files->name); |
| if (!dentry) |
| goto out; |
| inode = new_inode(s); |
| if (!inode) { |
| dput(dentry); |
| goto out; |
| } |
| inode->i_mode = S_IFREG | files->mode; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| inode->i_fop = files->ops; |
| inode->i_ino = i; |
| d_add(dentry, inode); |
| } |
| s->s_root = root; |
| return 0; |
| out: |
| d_genocide(root); |
| shrink_dcache_parent(root); |
| dput(root); |
| return -ENOMEM; |
| } |
| EXPORT_SYMBOL(simple_fill_super); |
| |
| static DEFINE_SPINLOCK(pin_fs_lock); |
| |
| int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
| { |
| struct vfsmount *mnt = NULL; |
| spin_lock(&pin_fs_lock); |
| if (unlikely(!*mount)) { |
| spin_unlock(&pin_fs_lock); |
| mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
| if (IS_ERR(mnt)) |
| return PTR_ERR(mnt); |
| spin_lock(&pin_fs_lock); |
| if (!*mount) |
| *mount = mnt; |
| } |
| mntget(*mount); |
| ++*count; |
| spin_unlock(&pin_fs_lock); |
| mntput(mnt); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_pin_fs); |
| |
| void simple_release_fs(struct vfsmount **mount, int *count) |
| { |
| struct vfsmount *mnt; |
| spin_lock(&pin_fs_lock); |
| mnt = *mount; |
| if (!--*count) |
| *mount = NULL; |
| spin_unlock(&pin_fs_lock); |
| mntput(mnt); |
| } |
| EXPORT_SYMBOL(simple_release_fs); |
| |
| /** |
| * simple_read_from_buffer - copy data from the buffer to user space |
| * @to: the user space buffer to read to |
| * @count: the maximum number of bytes to read |
| * @ppos: the current position in the buffer |
| * @from: the buffer to read from |
| * @available: the size of the buffer |
| * |
| * The simple_read_from_buffer() function reads up to @count bytes from the |
| * buffer @from at offset @ppos into the user space address starting at @to. |
| * |
| * On success, the number of bytes read is returned and the offset @ppos is |
| * advanced by this number, or negative value is returned on error. |
| **/ |
| ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
| const void *from, size_t available) |
| { |
| loff_t pos = *ppos; |
| size_t ret; |
| |
| if (pos < 0) |
| return -EINVAL; |
| if (pos >= available || !count) |
| return 0; |
| if (count > available - pos) |
| count = available - pos; |
| ret = copy_to_user(to, from + pos, count); |
| if (ret == count) |
| return -EFAULT; |
| count -= ret; |
| *ppos = pos + count; |
| return count; |
| } |
| EXPORT_SYMBOL(simple_read_from_buffer); |
| |
| /** |
| * simple_write_to_buffer - copy data from user space to the buffer |
| * @to: the buffer to write to |
| * @available: the size of the buffer |
| * @ppos: the current position in the buffer |
| * @from: the user space buffer to read from |
| * @count: the maximum number of bytes to read |
| * |
| * The simple_write_to_buffer() function reads up to @count bytes from the user |
| * space address starting at @from into the buffer @to at offset @ppos. |
| * |
| * On success, the number of bytes written is returned and the offset @ppos is |
| * advanced by this number, or negative value is returned on error. |
| **/ |
| ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, |
| const void __user *from, size_t count) |
| { |
| loff_t pos = *ppos; |
| size_t res; |
| |
| if (pos < 0) |
| return -EINVAL; |
| if (pos >= available || !count) |
| return 0; |
| if (count > available - pos) |
| count = available - pos; |
| res = copy_from_user(to + pos, from, count); |
| if (res == count) |
| return -EFAULT; |
| count -= res; |
| *ppos = pos + count; |
| return count; |
| } |
| EXPORT_SYMBOL(simple_write_to_buffer); |
| |
| /** |
| * memory_read_from_buffer - copy data from the buffer |
| * @to: the kernel space buffer to read to |
| * @count: the maximum number of bytes to read |
| * @ppos: the current position in the buffer |
| * @from: the buffer to read from |
| * @available: the size of the buffer |
| * |
| * The memory_read_from_buffer() function reads up to @count bytes from the |
| * buffer @from at offset @ppos into the kernel space address starting at @to. |
| * |
| * On success, the number of bytes read is returned and the offset @ppos is |
| * advanced by this number, or negative value is returned on error. |
| **/ |
| ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
| const void *from, size_t available) |
| { |
| loff_t pos = *ppos; |
| |
| if (pos < 0) |
| return -EINVAL; |
| if (pos >= available) |
| return 0; |
| if (count > available - pos) |
| count = available - pos; |
| memcpy(to, from + pos, count); |
| *ppos = pos + count; |
| |
| return count; |
| } |
| EXPORT_SYMBOL(memory_read_from_buffer); |
| |
| /* |
| * Transaction based IO. |
| * The file expects a single write which triggers the transaction, and then |
| * possibly a read which collects the result - which is stored in a |
| * file-local buffer. |
| */ |
| |
| void simple_transaction_set(struct file *file, size_t n) |
| { |
| struct simple_transaction_argresp *ar = file->private_data; |
| |
| BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); |
| |
| /* |
| * The barrier ensures that ar->size will really remain zero until |
| * ar->data is ready for reading. |
| */ |
| smp_mb(); |
| ar->size = n; |
| } |
| EXPORT_SYMBOL(simple_transaction_set); |
| |
| char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
| { |
| struct simple_transaction_argresp *ar; |
| static DEFINE_SPINLOCK(simple_transaction_lock); |
| |
| if (size > SIMPLE_TRANSACTION_LIMIT - 1) |
| return ERR_PTR(-EFBIG); |
| |
| ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); |
| if (!ar) |
| return ERR_PTR(-ENOMEM); |
| |
| spin_lock(&simple_transaction_lock); |
| |
| /* only one write allowed per open */ |
| if (file->private_data) { |
| spin_unlock(&simple_transaction_lock); |
| free_page((unsigned long)ar); |
| return ERR_PTR(-EBUSY); |
| } |
| |
| file->private_data = ar; |
| |
| spin_unlock(&simple_transaction_lock); |
| |
| if (copy_from_user(ar->data, buf, size)) |
| return ERR_PTR(-EFAULT); |
| |
| return ar->data; |
| } |
| EXPORT_SYMBOL(simple_transaction_get); |
| |
| ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) |
| { |
| struct simple_transaction_argresp *ar = file->private_data; |
| |
| if (!ar) |
| return 0; |
| return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); |
| } |
| EXPORT_SYMBOL(simple_transaction_read); |
| |
| int simple_transaction_release(struct inode *inode, struct file *file) |
| { |
| free_page((unsigned long)file->private_data); |
| return 0; |
| } |
| EXPORT_SYMBOL(simple_transaction_release); |
| |
| /* Simple attribute files */ |
| |
| struct simple_attr { |
| int (*get)(void *, u64 *); |
| int (*set)(void *, u64); |
| char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
| char set_buf[24]; |
| void *data; |
| const char *fmt; /* format for read operation */ |
| struct mutex mutex; /* protects access to these buffers */ |
| }; |
| |
| /* simple_attr_open is called by an actual attribute open file operation |
| * to set the attribute specific access operations. */ |
| int simple_attr_open(struct inode *inode, struct file *file, |
| int (*get)(void *, u64 *), int (*set)(void *, u64), |
| const char *fmt) |
| { |
| struct simple_attr *attr; |
| |
| attr = kmalloc(sizeof(*attr), GFP_KERNEL); |
| if (!attr) |
| return -ENOMEM; |
| |
| attr->get = get; |
| attr->set = set; |
| attr->data = inode->i_private; |
| attr->fmt = fmt; |
| mutex_init(&attr->mutex); |
| |
| file->private_data = attr; |
| |
| return nonseekable_open(inode, file); |
| } |
| EXPORT_SYMBOL_GPL(simple_attr_open); |
| |
| int simple_attr_release(struct inode *inode, struct file *file) |
| { |
| kfree(file->private_data); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
| |
| /* read from the buffer that is filled with the get function */ |
| ssize_t simple_attr_read(struct file *file, char __user *buf, |
| size_t len, loff_t *ppos) |
| { |
| struct simple_attr *attr; |
| size_t size; |
| ssize_t ret; |
| |
| attr = file->private_data; |
| |
| if (!attr->get) |
| return -EACCES; |
| |
| ret = mutex_lock_interruptible(&attr->mutex); |
| if (ret) |
| return ret; |
| |
| if (*ppos) { /* continued read */ |
| size = strlen(attr->get_buf); |
| } else { /* first read */ |
| u64 val; |
| ret = attr->get(attr->data, &val); |
| if (ret) |
| goto out; |
| |
| size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
| attr->fmt, (unsigned long long)val); |
| } |
| |
| ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
| out: |
| mutex_unlock(&attr->mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(simple_attr_read); |
| |
| /* interpret the buffer as a number to call the set function with */ |
| ssize_t simple_attr_write(struct file *file, const char __user *buf, |
| size_t len, loff_t *ppos) |
| { |
| struct simple_attr *attr; |
| u64 val; |
| size_t size; |
| ssize_t ret; |
| |
| attr = file->private_data; |
| if (!attr->set) |
| return -EACCES; |
| |
| ret = mutex_lock_interruptible(&attr->mutex); |
| if (ret) |
| return ret; |
| |
| ret = -EFAULT; |
| size = min(sizeof(attr->set_buf) - 1, len); |
| if (copy_from_user(attr->set_buf, buf, size)) |
| goto out; |
| |
| attr->set_buf[size] = '\0'; |
| val = simple_strtoll(attr->set_buf, NULL, 0); |
| ret = attr->set(attr->data, val); |
| if (ret == 0) |
| ret = len; /* on success, claim we got the whole input */ |
| out: |
| mutex_unlock(&attr->mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(simple_attr_write); |
| |
| /** |
| * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation |
| * @sb: filesystem to do the file handle conversion on |
| * @fid: file handle to convert |
| * @fh_len: length of the file handle in bytes |
| * @fh_type: type of file handle |
| * @get_inode: filesystem callback to retrieve inode |
| * |
| * This function decodes @fid as long as it has one of the well-known |
| * Linux filehandle types and calls @get_inode on it to retrieve the |
| * inode for the object specified in the file handle. |
| */ |
| struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, |
| int fh_len, int fh_type, struct inode *(*get_inode) |
| (struct super_block *sb, u64 ino, u32 gen)) |
| { |
| struct inode *inode = NULL; |
| |
| if (fh_len < 2) |
| return NULL; |
| |
| switch (fh_type) { |
| case FILEID_INO32_GEN: |
| case FILEID_INO32_GEN_PARENT: |
| inode = get_inode(sb, fid->i32.ino, fid->i32.gen); |
| break; |
| } |
| |
| return d_obtain_alias(inode); |
| } |
| EXPORT_SYMBOL_GPL(generic_fh_to_dentry); |
| |
| /** |
| * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
| * @sb: filesystem to do the file handle conversion on |
| * @fid: file handle to convert |
| * @fh_len: length of the file handle in bytes |
| * @fh_type: type of file handle |
| * @get_inode: filesystem callback to retrieve inode |
| * |
| * This function decodes @fid as long as it has one of the well-known |
| * Linux filehandle types and calls @get_inode on it to retrieve the |
| * inode for the _parent_ object specified in the file handle if it |
| * is specified in the file handle, or NULL otherwise. |
| */ |
| struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, |
| int fh_len, int fh_type, struct inode *(*get_inode) |
| (struct super_block *sb, u64 ino, u32 gen)) |
| { |
| struct inode *inode = NULL; |
| |
| if (fh_len <= 2) |
| return NULL; |
| |
| switch (fh_type) { |
| case FILEID_INO32_GEN_PARENT: |
| inode = get_inode(sb, fid->i32.parent_ino, |
| (fh_len > 3 ? fid->i32.parent_gen : 0)); |
| break; |
| } |
| |
| return d_obtain_alias(inode); |
| } |
| EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
| |
| /** |
| * __generic_file_fsync - generic fsync implementation for simple filesystems |
| * |
| * @file: file to synchronize |
| * @start: start offset in bytes |
| * @end: end offset in bytes (inclusive) |
| * @datasync: only synchronize essential metadata if true |
| * |
| * This is a generic implementation of the fsync method for simple |
| * filesystems which track all non-inode metadata in the buffers list |
| * hanging off the address_space structure. |
| */ |
| int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| int datasync) |
| { |
| struct inode *inode = file->f_mapping->host; |
| int err; |
| int ret; |
| |
| err = filemap_write_and_wait_range(inode->i_mapping, start, end); |
| if (err) |
| return err; |
| |
| mutex_lock(&inode->i_mutex); |
| ret = sync_mapping_buffers(inode->i_mapping); |
| if (!(inode->i_state & I_DIRTY_ALL)) |
| goto out; |
| if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
| goto out; |
| |
| err = sync_inode_metadata(inode, 1); |
| if (ret == 0) |
| ret = err; |
| |
| out: |
| mutex_unlock(&inode->i_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL(__generic_file_fsync); |
| |
| /** |
| * generic_file_fsync - generic fsync implementation for simple filesystems |
| * with flush |
| * @file: file to synchronize |
| * @start: start offset in bytes |
| * @end: end offset in bytes (inclusive) |
| * @datasync: only synchronize essential metadata if true |
| * |
| */ |
| |
| int generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| int datasync) |
| { |
| struct inode *inode = file->f_mapping->host; |
| int err; |
| |
| err = __generic_file_fsync(file, start, end, datasync); |
| if (err) |
| return err; |
| return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); |
| } |
| EXPORT_SYMBOL(generic_file_fsync); |
| |
| /** |
| * generic_check_addressable - Check addressability of file system |
| * @blocksize_bits: log of file system block size |
| * @num_blocks: number of blocks in file system |
| * |
| * Determine whether a file system with @num_blocks blocks (and a |
| * block size of 2**@blocksize_bits) is addressable by the sector_t |
| * and page cache of the system. Return 0 if so and -EFBIG otherwise. |
| */ |
| int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) |
| { |
| u64 last_fs_block = num_blocks - 1; |
| u64 last_fs_page = |
| last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); |
| |
| if (unlikely(num_blocks == 0)) |
| return 0; |
| |
| if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) |
| return -EINVAL; |
| |
| if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
| (last_fs_page > (pgoff_t)(~0ULL))) { |
| return -EFBIG; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(generic_check_addressable); |
| |
| /* |
| * No-op implementation of ->fsync for in-memory filesystems. |
| */ |
| int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| { |
| return 0; |
| } |
| EXPORT_SYMBOL(noop_fsync); |
| |
| void kfree_put_link(struct inode *unused, void *cookie) |
| { |
| kfree(cookie); |
| } |
| EXPORT_SYMBOL(kfree_put_link); |
| |
| void free_page_put_link(struct inode *unused, void *cookie) |
| { |
| free_page((unsigned long) cookie); |
| } |
| EXPORT_SYMBOL(free_page_put_link); |
| |
| /* |
| * nop .set_page_dirty method so that people can use .page_mkwrite on |
| * anon inodes. |
| */ |
| static int anon_set_page_dirty(struct page *page) |
| { |
| return 0; |
| }; |
| |
| /* |
| * A single inode exists for all anon_inode files. Contrary to pipes, |
| * anon_inode inodes have no associated per-instance data, so we need |
| * only allocate one of them. |
| */ |
| struct inode *alloc_anon_inode(struct super_block *s) |
| { |
| static const struct address_space_operations anon_aops = { |
| .set_page_dirty = anon_set_page_dirty, |
| }; |
| struct inode *inode = new_inode_pseudo(s); |
| |
| if (!inode) |
| return ERR_PTR(-ENOMEM); |
| |
| inode->i_ino = get_next_ino(); |
| inode->i_mapping->a_ops = &anon_aops; |
| |
| /* |
| * Mark the inode dirty from the very beginning, |
| * that way it will never be moved to the dirty |
| * list because mark_inode_dirty() will think |
| * that it already _is_ on the dirty list. |
| */ |
| inode->i_state = I_DIRTY; |
| inode->i_mode = S_IRUSR | S_IWUSR; |
| inode->i_uid = current_fsuid(); |
| inode->i_gid = current_fsgid(); |
| inode->i_flags |= S_PRIVATE; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| return inode; |
| } |
| EXPORT_SYMBOL(alloc_anon_inode); |
| |
| /** |
| * simple_nosetlease - generic helper for prohibiting leases |
| * @filp: file pointer |
| * @arg: type of lease to obtain |
| * @flp: new lease supplied for insertion |
| * @priv: private data for lm_setup operation |
| * |
| * Generic helper for filesystems that do not wish to allow leases to be set. |
| * All arguments are ignored and it just returns -EINVAL. |
| */ |
| int |
| simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
| void **priv) |
| { |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(simple_nosetlease); |
| |
| const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
| void **cookie) |
| { |
| return inode->i_link; |
| } |
| EXPORT_SYMBOL(simple_get_link); |
| |
| const struct inode_operations simple_symlink_inode_operations = { |
| .get_link = simple_get_link, |
| .readlink = generic_readlink |
| }; |
| EXPORT_SYMBOL(simple_symlink_inode_operations); |
| |
| /* |
| * Operations for a permanently empty directory. |
| */ |
| static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| { |
| return ERR_PTR(-ENOENT); |
| } |
| |
| static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, |
| struct kstat *stat) |
| { |
| struct inode *inode = d_inode(dentry); |
| generic_fillattr(inode, stat); |
| return 0; |
| } |
| |
| static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| return -EPERM; |
| } |
| |
| static int empty_dir_setxattr(struct dentry *dentry, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| return -EOPNOTSUPP; |
| } |
| |
| static ssize_t empty_dir_getxattr(struct dentry *dentry, const char *name, |
| void *value, size_t size) |
| { |
| return -EOPNOTSUPP; |
| } |
| |
| static int empty_dir_removexattr(struct dentry *dentry, const char *name) |
| { |
| return -EOPNOTSUPP; |
| } |
| |
| static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
| { |
| return -EOPNOTSUPP; |
| } |
| |
| static const struct inode_operations empty_dir_inode_operations = { |
| .lookup = empty_dir_lookup, |
| .permission = generic_permission, |
| .setattr = empty_dir_setattr, |
| .getattr = empty_dir_getattr, |
| .setxattr = empty_dir_setxattr, |
| .getxattr = empty_dir_getxattr, |
| .removexattr = empty_dir_removexattr, |
| .listxattr = empty_dir_listxattr, |
| }; |
| |
| static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) |
| { |
| /* An empty directory has two entries . and .. at offsets 0 and 1 */ |
| return generic_file_llseek_size(file, offset, whence, 2, 2); |
| } |
| |
| static int empty_dir_readdir(struct file *file, struct dir_context *ctx) |
| { |
| dir_emit_dots(file, ctx); |
| return 0; |
| } |
| |
| static const struct file_operations empty_dir_operations = { |
| .llseek = empty_dir_llseek, |
| .read = generic_read_dir, |
| .iterate = empty_dir_readdir, |
| .fsync = noop_fsync, |
| }; |
| |
| |
| void make_empty_dir_inode(struct inode *inode) |
| { |
| set_nlink(inode, 2); |
| inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; |
| inode->i_uid = GLOBAL_ROOT_UID; |
| inode->i_gid = GLOBAL_ROOT_GID; |
| inode->i_rdev = 0; |
| inode->i_size = 0; |
| inode->i_blkbits = PAGE_SHIFT; |
| inode->i_blocks = 0; |
| |
| inode->i_op = &empty_dir_inode_operations; |
| inode->i_fop = &empty_dir_operations; |
| } |
| |
| bool is_empty_dir_inode(struct inode *inode) |
| { |
| return (inode->i_fop == &empty_dir_operations) && |
| (inode->i_op == &empty_dir_inode_operations); |
| } |