#include <linux/module.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>
#include <asm/uaccess.h>
return NULL;
}
-int simple_sync_file(struct file * file, struct dentry *dentry, int datasync)
-{
- return 0;
-}
-
int dcache_dir_open(struct inode *inode, struct file *file)
{
static struct qstr cursor_name = {.len = 1, .name = "."};
.llseek = dcache_dir_lseek,
.read = generic_read_dir,
.readdir = dcache_readdir,
- .fsync = simple_sync_file,
+ .fsync = noop_fsync,
};
const struct inode_operations simple_dir_inode_operations = {
return PTR_ERR(s);
s->s_flags = MS_NOUSER;
- s->s_maxbytes = ~0ULL;
+ s->s_maxbytes = MAX_LFS_FILESIZE;
s->s_blocksize = PAGE_SIZE;
s->s_blocksize_bits = PAGE_SHIFT;
s->s_magic = magic;
return 0;
Enomem:
- up_write(&s->s_umount);
- deactivate_super(s);
+ deactivate_locked_super(s);
return -ENOMEM;
}
return 0;
}
+/**
+ * simple_setsize - handle core mm and vfs requirements for file size change
+ * @inode: inode
+ * @newsize: new file size
+ *
+ * Returns 0 on success, -error on failure.
+ *
+ * simple_setsize must be called with inode_mutex held.
+ *
+ * simple_setsize will check that the requested new size is OK (see
+ * inode_newsize_ok), and then will perform the necessary i_size update
+ * and pagecache truncation (if necessary). It will be typically be called
+ * from the filesystem's setattr function when ATTR_SIZE is passed in.
+ *
+ * The inode itself must have correct permissions and attributes to allow
+ * i_size to be changed, this function then just checks that the new size
+ * requested is valid.
+ *
+ * In the case of simple in-memory filesystems with inodes stored solely
+ * in the inode cache, and file data in the pagecache, nothing more needs
+ * to be done to satisfy a truncate request. Filesystems with on-disk
+ * blocks for example will need to free them in the case of truncate, in
+ * that case it may be easier not to use simple_setsize (but each of its
+ * components will likely be required at some point to update pagecache
+ * and inode etc).
+ */
+int simple_setsize(struct inode *inode, loff_t newsize)
+{
+ loff_t oldsize;
+ int error;
+
+ error = inode_newsize_ok(inode, newsize);
+ if (error)
+ return error;
+
+ oldsize = inode->i_size;
+ i_size_write(inode, newsize);
+ truncate_pagecache(inode, oldsize, newsize);
+
+ return error;
+}
+EXPORT_SYMBOL(simple_setsize);
+
+/**
+ * simple_setattr - setattr for simple in-memory filesystem
+ * @dentry: dentry
+ * @iattr: iattr structure
+ *
+ * Returns 0 on success, -error on failure.
+ *
+ * simple_setattr implements setattr for an in-memory filesystem which
+ * does not store its own file data or metadata (eg. uses the page cache
+ * and inode cache as its data store).
+ */
+int simple_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = dentry->d_inode;
+ int error;
+
+ error = inode_change_ok(inode, iattr);
+ if (error)
+ return error;
+
+ if (iattr->ia_valid & ATTR_SIZE) {
+ error = simple_setsize(inode, iattr->ia_size);
+ if (error)
+ return error;
+ }
+
+ generic_setattr(inode, iattr);
+
+ return error;
+}
+EXPORT_SYMBOL(simple_setattr);
+
int simple_readpage(struct file *file, struct page *page)
{
clear_highpage(page);
return 0;
}
-int simple_prepare_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
-{
- if (!PageUptodate(page)) {
- if (to - from != PAGE_CACHE_SIZE)
- zero_user_segments(page,
- 0, from,
- to, PAGE_CACHE_SIZE);
- }
- 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;
- unsigned from;
index = pos >> PAGE_CACHE_SHIFT;
- from = pos & (PAGE_CACHE_SIZE - 1);
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
*pagep = page;
- return simple_prepare_write(file, page, from, from+len);
-}
-
-static int simple_commit_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
-{
- struct inode *inode = page->mapping->host;
- loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+ if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
- 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 (pos > inode->i_size)
- i_size_write(inode, pos);
- set_page_dirty(page);
+ 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)
{
- unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ 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) {
- void *kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr + from + copied, 0, len - copied);
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+
+ zero_user(page, from + copied, len - copied);
}
- simple_commit_write(file, page, from, from+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);
* 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, int magic, struct tree_descr *files)
+int simple_fill_super(struct super_block *s, unsigned long magic,
+ struct tree_descr *files)
{
struct inode *inode;
struct dentry *root;
const void *from, size_t available)
{
loff_t pos = *ppos;
+ size_t ret;
+
if (pos < 0)
return -EINVAL;
- if (pos >= available)
+ if (pos >= available || !count)
return 0;
if (count > available - pos)
count = available - pos;
- if (copy_to_user(to, from + pos, count))
+ 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;
}
if (copy_from_user(attr->set_buf, buf, size))
goto out;
- ret = len; /* claim we got the whole input */
attr->set_buf[size] = '\0';
val = simple_strtol(attr->set_buf, NULL, 0);
- attr->set(attr->data, val);
+ 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(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, int datasync)
+{
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = 0, /* metadata-only; caller takes care of data */
+ };
+ struct inode *inode = file->f_mapping->host;
+ int err;
+ int ret;
+
+ ret = sync_mapping_buffers(inode->i_mapping);
+ if (!(inode->i_state & I_DIRTY))
+ return ret;
+ if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+ return ret;
+
+ err = sync_inode(inode, &wbc);
+ if (ret == 0)
+ ret = err;
+ return ret;
+}
+EXPORT_SYMBOL(generic_file_fsync);
+
+/*
+ * No-op implementation of ->fsync for in-memory filesystems.
+ */
+int noop_fsync(struct file *file, int datasync)
+{
+ return 0;
+}
+
EXPORT_SYMBOL(dcache_dir_close);
EXPORT_SYMBOL(dcache_dir_lseek);
EXPORT_SYMBOL(dcache_dir_open);
EXPORT_SYMBOL(simple_dir_inode_operations);
EXPORT_SYMBOL(simple_dir_operations);
EXPORT_SYMBOL(simple_empty);
-EXPORT_SYMBOL(d_alloc_name);
EXPORT_SYMBOL(simple_fill_super);
EXPORT_SYMBOL(simple_getattr);
EXPORT_SYMBOL(simple_link);
EXPORT_SYMBOL(simple_lookup);
EXPORT_SYMBOL(simple_pin_fs);
-EXPORT_UNUSED_SYMBOL(simple_prepare_write);
EXPORT_SYMBOL(simple_readpage);
EXPORT_SYMBOL(simple_release_fs);
EXPORT_SYMBOL(simple_rename);
EXPORT_SYMBOL(simple_rmdir);
EXPORT_SYMBOL(simple_statfs);
-EXPORT_SYMBOL(simple_sync_file);
+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);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff