zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/fs/libfs.c b/ap/os/linux/linux-3.4.x/fs/libfs.c
new file mode 100644
index 0000000..65c126f
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/libfs.c
@@ -0,0 +1,1016 @@
+/*
+ * fs/libfs.c
+ * Library for filesystems writers.
+ */
+
+#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/exportfs.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h> /* sync_mapping_buffers */
+
+#include <asm/uaccess.h>
+
+#include "internal.h"
+
+static inline int simple_positive(struct dentry *dentry)
+{
+ return dentry->d_inode && !d_unhashed(dentry);
+}
+
+int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct inode *inode = dentry->d_inode;
+ generic_fillattr(inode, stat);
+ stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
+ return 0;
+}
+
+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;
+}
+
+/*
+ * Retaining negative dentries for an in-memory filesystem just wastes
+ * memory and lookup time: arrange for them to be deleted immediately.
+ */
+static int simple_delete_dentry(const struct dentry *dentry)
+{
+ return 1;
+}
+
+/*
+ * 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, struct nameidata *nd)
+{
+ static const struct dentry_operations simple_dentry_operations = {
+ .d_delete = simple_delete_dentry,
+ };
+
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+ d_set_d_op(dentry, &simple_dentry_operations);
+ d_add(dentry, NULL);
+ return NULL;
+}
+
+int dcache_dir_open(struct inode *inode, struct file *file)
+{
+ static struct qstr cursor_name = {.len = 1, .name = "."};
+
+ file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
+
+ return file->private_data ? 0 : -ENOMEM;
+}
+
+int dcache_dir_close(struct inode *inode, struct file *file)
+{
+ dput(file->private_data);
+ return 0;
+}
+
+loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ mutex_lock(&dentry->d_inode->i_mutex);
+ switch (origin) {
+ case 1:
+ offset += file->f_pos;
+ case 0:
+ if (offset >= 0)
+ break;
+ default:
+ mutex_unlock(&dentry->d_inode->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(&dentry->d_inode->i_mutex);
+ return offset;
+}
+
+/* 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 * filp, void * dirent, filldir_t filldir)
+{
+ struct dentry *dentry = filp->f_path.dentry;
+ struct dentry *cursor = filp->private_data;
+ struct list_head *p, *q = &cursor->d_child;
+ ino_t ino;
+ int i = filp->f_pos;
+
+ switch (i) {
+ case 0:
+ ino = dentry->d_inode->i_ino;
+ if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+ break;
+ filp->f_pos++;
+ i++;
+ /* fallthrough */
+ case 1:
+ ino = parent_ino(dentry);
+ if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
+ break;
+ filp->f_pos++;
+ i++;
+ /* fallthrough */
+ default:
+ spin_lock(&dentry->d_lock);
+ if (filp->f_pos == 2)
+ list_move(q, &dentry->d_subdirs);
+
+ for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
+ 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)) {
+ spin_unlock(&next->d_lock);
+ continue;
+ }
+
+ spin_unlock(&next->d_lock);
+ spin_unlock(&dentry->d_lock);
+ if (filldir(dirent, next->d_name.name,
+ next->d_name.len, filp->f_pos,
+ next->d_inode->i_ino,
+ dt_type(next->d_inode)) < 0)
+ 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;
+ filp->f_pos++;
+ }
+ spin_unlock(&dentry->d_lock);
+ }
+ return 0;
+}
+
+ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
+{
+ return -EISDIR;
+}
+
+const struct file_operations simple_dir_operations = {
+ .open = dcache_dir_open,
+ .release = dcache_dir_close,
+ .llseek = dcache_dir_lseek,
+ .read = generic_read_dir,
+ .readdir = dcache_readdir,
+ .fsync = noop_fsync,
+};
+
+const struct inode_operations simple_dir_inode_operations = {
+ .lookup = simple_lookup,
+};
+
+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 = sget(fs_type, NULL, set_anon_super, NULL);
+ struct dentry *dentry;
+ struct inode *root;
+ struct qstr d_name = {.name = name, .len = strlen(name)};
+
+ if (IS_ERR(s))
+ return ERR_CAST(s);
+
+ s->s_flags = MS_NOUSER;
+ 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);
+}
+
+int simple_open(struct inode *inode, struct file *file)
+{
+ if (inode->i_private)
+ file->private_data = inode->i_private;
+ return 0;
+}
+
+int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = old_dentry->d_inode;
+
+ inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+ inc_nlink(inode);
+ ihold(inode);
+ dget(dentry);
+ d_instantiate(dentry, inode);
+ return 0;
+}
+
+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;
+}
+
+int simple_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+ drop_nlink(inode);
+ dput(dentry);
+ return 0;
+}
+
+int simple_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ if (!simple_empty(dentry))
+ return -ENOTEMPTY;
+
+ drop_nlink(dentry->d_inode);
+ simple_unlink(dir, dentry);
+ drop_nlink(dir);
+ return 0;
+}
+
+int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ struct inode *inode = old_dentry->d_inode;
+ int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode);
+
+ if (!simple_empty(new_dentry))
+ return -ENOTEMPTY;
+
+ if (new_dentry->d_inode) {
+ simple_unlink(new_dir, new_dentry);
+ if (they_are_dirs) {
+ drop_nlink(new_dentry->d_inode);
+ 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;
+}
+
+/**
+ * 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 = dentry->d_inode;
+ int error;
+
+ WARN_ON_ONCE(inode->i_op->truncate);
+
+ 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;
+}
+
+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;
+}
+
+/**
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+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;
+}
+
+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);
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+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;
+}
+
+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);
+}
+
+int simple_transaction_release(struct inode *inode, struct file *file)
+{
+ free_page((unsigned long)file->private_data);
+ return 0;
+}
+
+/* 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);
+}
+
+int simple_attr_release(struct inode *inode, struct file *file)
+{
+ kfree(file->private_data);
+ return 0;
+}
+
+/* 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;
+}
+
+/* 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;
+}
+
+/**
+ * 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_dentry - 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
+ * @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))
+ 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_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(dcache_dir_close);
+EXPORT_SYMBOL(dcache_dir_lseek);
+EXPORT_SYMBOL(dcache_dir_open);
+EXPORT_SYMBOL(dcache_readdir);
+EXPORT_SYMBOL(generic_read_dir);
+EXPORT_SYMBOL(mount_pseudo);
+EXPORT_SYMBOL(simple_write_begin);
+EXPORT_SYMBOL(simple_write_end);
+EXPORT_SYMBOL(simple_dir_inode_operations);
+EXPORT_SYMBOL(simple_dir_operations);
+EXPORT_SYMBOL(simple_empty);
+EXPORT_SYMBOL(simple_fill_super);
+EXPORT_SYMBOL(simple_getattr);
+EXPORT_SYMBOL(simple_open);
+EXPORT_SYMBOL(simple_link);
+EXPORT_SYMBOL(simple_lookup);
+EXPORT_SYMBOL(simple_pin_fs);
+EXPORT_SYMBOL(simple_readpage);
+EXPORT_SYMBOL(simple_release_fs);
+EXPORT_SYMBOL(simple_rename);
+EXPORT_SYMBOL(simple_rmdir);
+EXPORT_SYMBOL(simple_statfs);
+EXPORT_SYMBOL(noop_fsync);
+EXPORT_SYMBOL(simple_unlink);
+EXPORT_SYMBOL(simple_read_from_buffer);
+EXPORT_SYMBOL(simple_write_to_buffer);
+EXPORT_SYMBOL(memory_read_from_buffer);
+EXPORT_SYMBOL(simple_transaction_set);
+EXPORT_SYMBOL(simple_transaction_get);
+EXPORT_SYMBOL(simple_transaction_read);
+EXPORT_SYMBOL(simple_transaction_release);
+EXPORT_SYMBOL_GPL(simple_attr_open);
+EXPORT_SYMBOL_GPL(simple_attr_release);
+EXPORT_SYMBOL_GPL(simple_attr_read);
+EXPORT_SYMBOL_GPL(simple_attr_write);