btrfs_file_write -- first pass
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
parent
30ae846748
commit
75dfe3960e
1 changed files with 213 additions and 9 deletions
222
fs/btrfs/super.c
222
fs/btrfs/super.c
|
|
@ -9,6 +9,8 @@
|
|||
#include <linux/smp_lock.h>
|
||||
#include <linux/backing-dev.h>
|
||||
#include <linux/mpage.h>
|
||||
#include <linux/swap.h>
|
||||
#include <linux/writeback.h>
|
||||
#include "ctree.h"
|
||||
#include "disk-io.h"
|
||||
#include "transaction.h"
|
||||
|
|
@ -755,7 +757,7 @@ printk("btrfs sync_fs\n");
|
|||
return 0;
|
||||
}
|
||||
|
||||
static int btrfs_get_block(struct inode *inode, sector_t iblock,
|
||||
static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
|
||||
struct buffer_head *result, int create)
|
||||
{
|
||||
int ret;
|
||||
|
|
@ -772,7 +774,6 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
|
|||
struct btrfs_disk_key *found_key;
|
||||
|
||||
btrfs_init_path(&path);
|
||||
mutex_lock(&root->fs_info->fs_mutex);
|
||||
if (create)
|
||||
trans = btrfs_start_transaction(root, 1);
|
||||
|
||||
|
|
@ -848,6 +849,16 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
|
|||
out:
|
||||
if (trans)
|
||||
btrfs_end_transaction(trans, root);
|
||||
return err;
|
||||
}
|
||||
|
||||
static int btrfs_get_block(struct inode *inode, sector_t iblock,
|
||||
struct buffer_head *result, int create)
|
||||
{
|
||||
int err;
|
||||
struct btrfs_root *root = btrfs_sb(inode->i_sb);
|
||||
mutex_lock(&root->fs_info->fs_mutex);
|
||||
err = btrfs_get_block_lock(inode, iblock, result, create);
|
||||
mutex_unlock(&root->fs_info->fs_mutex);
|
||||
return err;
|
||||
}
|
||||
|
|
@ -855,8 +866,15 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
|
|||
static int btrfs_prepare_write(struct file *file, struct page *page,
|
||||
unsigned from, unsigned to)
|
||||
{
|
||||
WARN_ON(1);
|
||||
return nobh_prepare_write(page, from, to, btrfs_get_block);
|
||||
}
|
||||
static int btrfs_commit_write(struct file *file, struct page *page,
|
||||
unsigned from, unsigned to)
|
||||
{
|
||||
WARN_ON(1);
|
||||
return nobh_commit_write(file, page, from, to);
|
||||
}
|
||||
|
||||
static void btrfs_write_super(struct super_block *sb)
|
||||
{
|
||||
|
|
@ -903,6 +921,196 @@ static void btrfs_truncate(struct inode *inode)
|
|||
mark_inode_dirty(inode);
|
||||
}
|
||||
|
||||
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;
|
||||
|
||||
for (i = 0; i < num_pages; i++) {
|
||||
offset = pos & (PAGE_CACHE_SIZE -1);
|
||||
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
|
||||
ret = nobh_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;
|
||||
}
|
||||
|
||||
static int prepare_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;
|
||||
unsigned long index = pos >> PAGE_CACHE_SHIFT;
|
||||
struct inode *inode = file->f_path.dentry->d_inode;
|
||||
int offset;
|
||||
int err = 0;
|
||||
int ret;
|
||||
int this_write;
|
||||
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;
|
||||
}
|
||||
offset = pos & (PAGE_CACHE_SIZE -1);
|
||||
this_write = min(PAGE_CACHE_SIZE - offset, write_bytes);
|
||||
ret = nobh_prepare_write(pages[i], offset,
|
||||
offset + this_write,
|
||||
btrfs_get_block_lock);
|
||||
pos += this_write;
|
||||
if (ret) {
|
||||
err = ret;
|
||||
goto failed_truncate;
|
||||
}
|
||||
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 btrfs_trans_handle *trans;
|
||||
struct inode *inode = file->f_path.dentry->d_inode;
|
||||
struct btrfs_root *root = btrfs_sb(inode->i_sb);
|
||||
struct page *pages[1];
|
||||
|
||||
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);
|
||||
mutex_lock(&inode->i_mutex);
|
||||
while(count > 0) {
|
||||
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
|
||||
size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
|
||||
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
|
||||
PAGE_CACHE_SHIFT;
|
||||
mutex_lock(&root->fs_info->fs_mutex);
|
||||
trans = btrfs_start_transaction(root, 1);
|
||||
|
||||
ret = prepare_pages(trans, root, file, pages, num_pages,
|
||||
pos, write_bytes);
|
||||
BUG_ON(ret);
|
||||
ret = btrfs_copy_from_user(pos, num_pages,
|
||||
write_bytes, pages, buf);
|
||||
BUG_ON(ret);
|
||||
|
||||
mutex_unlock(&root->fs_info->fs_mutex);
|
||||
|
||||
ret = dirty_and_release_pages(trans, root, file, pages,
|
||||
num_pages, pos, write_bytes);
|
||||
BUG_ON(ret);
|
||||
btrfs_drop_pages(pages, num_pages);
|
||||
|
||||
ret = btrfs_end_transaction(trans, root);
|
||||
|
||||
buf += write_bytes;
|
||||
count -= write_bytes;
|
||||
pos += write_bytes;
|
||||
num_written += write_bytes;
|
||||
|
||||
balance_dirty_pages_ratelimited(inode->i_mapping);
|
||||
cond_resched();
|
||||
}
|
||||
mutex_unlock(&inode->i_mutex);
|
||||
out:
|
||||
*ppos = pos;
|
||||
current->backing_dev_info = NULL;
|
||||
return num_written ? num_written : err;
|
||||
}
|
||||
|
||||
static int btrfs_get_sb(struct file_system_type *fs_type,
|
||||
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
|
||||
{
|
||||
|
|
@ -948,7 +1156,7 @@ static struct address_space_operations btrfs_aops = {
|
|||
.writepage = btrfs_writepage,
|
||||
.sync_page = block_sync_page,
|
||||
.prepare_write = btrfs_prepare_write,
|
||||
.commit_write = nobh_commit_write,
|
||||
.commit_write = btrfs_commit_write,
|
||||
};
|
||||
|
||||
static struct inode_operations btrfs_file_inode_operations = {
|
||||
|
|
@ -958,14 +1166,10 @@ static struct inode_operations btrfs_file_inode_operations = {
|
|||
static struct file_operations btrfs_file_operations = {
|
||||
.llseek = generic_file_llseek,
|
||||
.read = do_sync_read,
|
||||
.write = do_sync_write,
|
||||
.aio_read = generic_file_aio_read,
|
||||
.aio_write = generic_file_aio_write,
|
||||
.aio_read = generic_file_aio_read,
|
||||
.write = btrfs_file_write,
|
||||
.mmap = generic_file_mmap,
|
||||
.open = generic_file_open,
|
||||
.sendfile = generic_file_sendfile,
|
||||
.splice_read = generic_file_splice_read,
|
||||
.splice_write = generic_file_splice_write,
|
||||
};
|
||||
|
||||
static int __init init_btrfs_fs(void)
|
||||
|
|
|
|||
Loading…
Reference in a new issue