/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
struct page **prepared_pages,
const char __user * buf)
{
long page_fault = 0;
int i;
int offset = pos & (PAGE_CACHE_SIZE - 1);
for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
size_t count = min_t(size_t,
PAGE_CACHE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[i];
fault_in_pages_readable(buf, count);
/* Copy data from userspace to the current page */
kmap(page);
page_fault = __copy_from_user(page_address(page) + offset,
buf, count);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
kunmap(page);
buf += count;
write_bytes -= count;
if (page_fault)
break;
}
return page_fault ? -EFAULT : 0;
}
static void btrfs_drop_pages(struct page **pages, size_t num_pages)
{
size_t i;
for (i = 0; i < num_pages; i++) {
if (!pages[i])
break;
unlock_page(pages[i]);
mark_page_accessed(pages[i]);
page_cache_release(pages[i]);
}
}
static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct file *file,
struct page **pages,
size_t num_pages,
loff_t pos,
size_t write_bytes)
{
int i;
int offset;
int err = 0;
int ret;
int this_write;
struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh;
struct btrfs_file_extent_item *ei;
for (i = 0; i < num_pages; i++) {
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
/* FIXME, one block at a time */
bh = page_buffers(pages[i]);
if (buffer_mapped(bh) && bh->b_blocknr == 0) {
struct btrfs_key key;
struct btrfs_path *path;
char *ptr, *kaddr;
u32 datasize;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
/* create an inline extent, and copy the data in */
path = btrfs_alloc_path();
BUG_ON(!path);
key.objectid = inode->i_ino;
key.offset = pages[i]->index << PAGE_CACHE_SHIFT;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
BUG_ON(write_bytes >= PAGE_CACHE_SIZE);
datasize = offset +
btrfs_file_extent_calc_inline_size(write_bytes);
ret = btrfs_insert_empty_item(trans, root, path, &key,
datasize);
BUG_ON(ret);
ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
path->slots[0], struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(ei, trans->transid);
btrfs_set_file_extent_type(ei,
BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei);
kaddr = kmap_atomic(bh->b_page, KM_USER0);
btrfs_memcpy(root, path->nodes[0]->b_data,
ptr, kaddr + bh_offset(bh),
offset + write_bytes);
kunmap_atomic(kaddr, KM_USER0);
mark_buffer_dirty(path->nodes[0]);
btrfs_free_path(path);
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
mutex_unlock(&root->fs_info->fs_mutex);
}
ret = btrfs_commit_write(file, pages[i], offset,
offset + this_write);
pos += this_write;
if (ret) {
err = ret;
goto failed;
}
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
}
failed:
return err;
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
* that would be a good hint to the block allocator for this file.
*
* If an extent intersects the range but is not entirely inside the range
* it is either truncated or split. Anything entirely inside the range
* is deleted from the tree.
*/
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
u64 start, u64 end, u64 *hint_block)
{
int ret;
struct btrfs_key key;
struct btrfs_leaf *leaf;
int slot;
struct btrfs_file_extent_item *extent;
u64 extent_end = 0;
int keep;
struct btrfs_file_extent_item old;
struct btrfs_path *path;
u64 search_start = start;
int bookend;
int found_type;
int found_extent;
int found_inline;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
btrfs_release_path(root, path);
ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
search_start, -1);
if (ret < 0)
goto out;
if (ret > 0) {
if (path->slots[0] == 0) {
ret = 0;
goto out;
}
path->slots[0]--;
}
keep = 0;
bookend = 0;
found_extent = 0;
found_inline = 0;
extent = NULL;
leaf = btrfs_buffer_leaf(path->nodes[0]);
slot = path->slots[0];
btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
if (key.offset >= end || key.objectid != inode->i_ino) {
ret = 0;
goto out;
}
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY) {
ret = 0;
goto out;
}
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(extent);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = key.offset +
(btrfs_file_extent_num_blocks(extent) <<
inode->i_blkbits);
found_extent = 1;
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
found_inline = 1;
extent_end = key.offset +
btrfs_file_extent_inline_len(leaf->items + slot);
}
/* we found nothing we can drop */
if (!found_extent && !found_inline) {
ret = 0;
goto out;
}
/* we found nothing inside the range */
if (search_start >= extent_end) {
ret = 0;
goto out;
}
/* FIXME, there's only one inline extent allowed right now */
if (found_inline) {
u64 mask = root->blocksize - 1;
search_start = (extent_end + mask) & ~mask;
} else
search_start = extent_end;
if (end < extent_end && end >= key.offset) {
if (found_extent) {
u64 disk_blocknr =
btrfs_file_extent_disk_blocknr(extent);
u64 disk_num_blocks =
btrfs_file_extent_disk_num_blocks(extent);
memcpy(&old, extent, sizeof(old));
if (disk_blocknr != 0) {
ret = btrfs_inc_extent_ref(trans, root,
disk_blocknr, disk_num_blocks);
BUG_ON(ret);
}
}
WARN_ON(found_inline);
bookend = 1;
}
/* truncate existing extent */
if (start > key.offset) {
u64 new_num;
u64 old_num;
keep = 1;
WARN_ON(start & (root->blocksize - 1));
if (found_extent) {
new_num = (start - key.offset) >>
inode->i_blkbits;
old_num = btrfs_file_extent_num_blocks(extent);
*hint_block =
btrfs_file_extent_disk_blocknr(extent);
if (btrfs_file_extent_disk_blocknr(extent)) {
inode->i_blocks -=
(old_num - new_num) << 3;
}
btrfs_set_file_extent_num_blocks(extent,
new_num);
mark_buffer_dirty(path->nodes[0]);
} else {
WARN_ON(1);
}
}
/* delete the entire extent */
if (!keep) {
u64 disk_blocknr = 0;
u64 disk_num_blocks = 0;
u64 extent_num_blocks = 0;
if (found_extent) {
disk_blocknr =
btrfs_file_extent_disk_blocknr(extent);
disk_num_blocks =
btrfs_file_extent_disk_num_blocks(extent);
extent_num_blocks =
btrfs_file_extent_num_blocks(extent);
*hint_block =
btrfs_file_extent_disk_blocknr(extent);
}
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
btrfs_release_path(root, path);
extent = NULL;
if (found_extent && disk_blocknr != 0) {
inode->i_blocks -= extent_num_blocks << 3;
ret = btrfs_free_extent(trans, root,
disk_blocknr,
disk_num_blocks, 0);
}
BUG_ON(ret);
if (!bookend && search_start >= end) {
ret = 0;
goto out;
}
if (!bookend)
continue;
}
/* create bookend, splitting the extent in two */
if (bookend && found_extent) {
struct btrfs_key ins;
ins.objectid = inode->i_ino;
ins.offset = end;
ins.flags = 0;
btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
btrfs_release_path(root, path);
ret = btrfs_insert_empty_item(trans, root, path, &ins,
sizeof(*extent));
BUG_ON(ret);
extent = btrfs_item_ptr(
btrfs_buffer_leaf(path->nodes[0]),
path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_disk_blocknr(extent,
btrfs_file_extent_disk_blocknr(&old));
btrfs_set_file_extent_disk_num_blocks(extent,
btrfs_file_extent_disk_num_blocks(&old));
btrfs_set_file_extent_offset(extent,
btrfs_file_extent_offset(&old) +
((end - key.offset) >> inode->i_blkbits));
WARN_ON(btrfs_file_extent_num_blocks(&old) <
(extent_end - end) >> inode->i_blkbits);
btrfs_set_file_extent_num_blocks(extent,
(extent_end - end) >> inode->i_blkbits);
btrfs_set_file_extent_type(extent,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(extent,
btrfs_file_extent_generation(&old));
btrfs_mark_buffer_dirty(path->nodes[0]);
if (btrfs_file_extent_disk_blocknr(&old) != 0) {
inode->i_blocks +=
btrfs_file_extent_num_blocks(extent) << 3;
}
ret = 0;
goto out;
}
}
out:
btrfs_free_path(path);
return ret;
}
/*
* this gets pages into the page cache and locks them down
*/
static int prepare_pages(struct btrfs_root *root,
struct file *file,
struct page **pages,
size_t num_pages,
loff_t pos,
unsigned long first_index,
unsigned long last_index,
size_t write_bytes,
u64 alloc_extent_start)
{
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file->f_path.dentry->d_inode;
int offset;
int err = 0;
int this_write;
struct buffer_head *bh;
struct buffer_head *head;
loff_t isize = i_size_read(inode);
memset(pages, 0, num_pages * sizeof(struct page *));
for (i = 0; i < num_pages; i++) {
pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) {
err = -ENOMEM;
goto failed_release;
}
cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
wait_on_page_writeback(pages[i]);
offset = pos & (PAGE_CACHE_SIZE -1);
this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
if (!page_has_buffers(pages[i])) {
create_empty_buffers(pages[i],
root->fs_info->sb->s_blocksize,
(1 << BH_Uptodate));
}
head = page_buffers(pages[i]);
bh = head;
do {
err = btrfs_map_bh_to_logical(root, bh,
alloc_extent_start);
BUG_ON(err);
if (err)
goto failed_truncate;
bh = bh->b_this_page;
if (alloc_extent_start)
alloc_extent_start++;
} while (bh != head);
pos += this_write;
WARN_ON(this_write > write_bytes);
write_bytes -= this_write;
}
return 0;
failed_release:
btrfs_drop_pages(pages, num_pages);
return err;
failed_truncate:
btrfs_drop_pages(pages, num_pages);
if (pos > isize)
vmtruncate(inode, isize);
return err;
}
static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
loff_t pos;
size_t num_written = 0;
int err = 0;
int ret = 0;
struct inode *inode = file->f_path.dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page *pages[8];
struct page *pinned[2];
unsigned long first_index;
unsigned long last_index;
u64 start_pos;
u64 num_blocks;
u64 alloc_extent_start;
u64 hint_block;
struct btrfs_trans_handle *trans;
struct btrfs_key ins;
pinned[0] = NULL;
pinned[1] = NULL;
if (file->f_flags & O_DIRECT)
return -EINVAL;
pos = *ppos;
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
if (count == 0)
goto out;
err = remove_suid(file->f_path.dentry);
if (err)
goto out;
file_update_time(file);
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
num_blocks = (count + pos - start_pos + root->blocksize - 1) >>
inode->i_blkbits;
mutex_lock(&inode->i_mutex);
first_index = pos >> PAGE_CACHE_SHIFT;
last_index = (pos + count) >> PAGE_CACHE_SHIFT;
/*
* there are lots of better ways to do this, but this code
* makes sure the first and last page in the file range are
* up to date and ready for cow
*/
if ((pos & (PAGE_CACHE_SIZE - 1))) {
pinned[0] = grab_cache_page(inode->i_mapping, first_index);
if (!PageUptodate(pinned[0])) {
ret = btrfs_readpage(NULL, pinned[0]);
BUG_ON(ret);
wait_on_page_locked(pinned[0]);
} else {
unlock_page(pinned[0]);
}
}
if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
pinned[1] = grab_cache_page(inode->i_mapping, last_index);
if (!PageUptodate(pinned[1])) {
ret = btrfs_readpage(NULL, pinned[1]);
BUG_ON(ret);
wait_on_page_locked(pinned[1]);
} else {
unlock_page(pinned[1]);
}
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
mutex_unlock(&root->fs_info->fs_mutex);
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
/* FIXME blocksize != 4096 */
inode->i_blocks += num_blocks << 3;
hint_block = 0;
/* FIXME...EIEIO, ENOSPC and more */
/* step one, delete the existing extents in this range */
if (start_pos < inode->i_size) {
/* FIXME blocksize != pagesize */
ret = btrfs_drop_extents(trans, root, inode,
start_pos,
(pos + count + root->blocksize -1) &
~((u64)root->blocksize - 1),
&hint_block);
BUG_ON(ret);
}
/* insert any holes we need to create */
if (inode->i_size < start_pos) {
u64 last_pos_in_file;
u64 hole_size;
u64 mask = root->blocksize - 1;
last_pos_in_file = (inode->i_size + mask) & ~mask;
hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
hole_size >>= inode->i_blkbits;
if (last_pos_in_file < start_pos) {
ret = btrfs_insert_file_extent(trans, root,
inode->i_ino,
last_pos_in_file,
0, 0, hole_size);
}
BUG_ON(ret);
}
/*
* either allocate an extent for the new bytes or setup the key
* to show we are doing inline data in the extent
*/
if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size ||
pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
ret = btrfs_alloc_extent(trans, root, inode->i_ino,
num_blocks, hint_block, (u64)-1,
&ins, 1);
BUG_ON(ret);
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
start_pos, ins.objectid, ins.offset,
ins.offset);
BUG_ON(ret);
} else {
ins.offset = 0;
ins.objectid = 0;
}
BUG_ON(ret);
alloc_extent_start = ins.objectid;
ret = btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
while(count > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
size_t write_bytes = min(count,
(size_t)PAGE_CACHE_SIZE - offset);
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
memset(pages, 0, sizeof(pages));
ret = prepare_pages(root, file, pages, num_pages,
pos, first_index, last_index,
write_bytes, alloc_extent_start);
BUG_ON(ret);
/* FIXME blocks != pagesize */
if (alloc_extent_start)
alloc_extent_start += num_pages;
ret = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, buf);
BUG_ON(ret);
ret = dirty_and_release_pages(NULL, root, file, pages,
num_pages, pos, write_bytes);
BUG_ON(ret);
btrfs_drop_pages(pages, num_pages);
buf += write_bytes;
count -= write_bytes;
pos += write_bytes;
num_written += write_bytes;
balance_dirty_pages_ratelimited(inode->i_mapping);
btrfs_btree_balance_dirty(root);
cond_resched();
}
out_unlock:
mutex_unlock(&inode->i_mutex);
out:
if (pinned[0])
page_cache_release(pinned[0]);
if (pinned[1])
page_cache_release(pinned[1]);
*ppos = pos;
current->backing_dev_info = NULL;
mark_inode_dirty(inode);
return num_written ? num_written : err;
}
static int btrfs_sync_file(struct file *file,
struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
struct btrfs_trans_handle *trans;
/*
* FIXME, use inode generation number to check if we can skip the
* commit
*/
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_commit_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
out:
return ret > 0 ? EIO : ret;
}
static struct vm_operations_struct btrfs_file_vm_ops = {
.nopage = filemap_nopage,
.populate = filemap_populate,
.page_mkwrite = btrfs_page_mkwrite,
};
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
vma->vm_ops = &btrfs_file_vm_ops;
file_accessed(filp);
return 0;
}
struct file_operations btrfs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.write = btrfs_file_write,
.mmap = btrfs_file_mmap,
.open = generic_file_open,
.ioctl = btrfs_ioctl,
.fsync = btrfs_sync_file,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_compat_ioctl,
#endif
};
