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introduce __block_write_begin

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Split up the block_write_begin implementation - __block_write_begin is a new
trivial wrapper for block_prepare_write that always takes an already
allocated page and can be either called from block_write_begin or filesystem
code that already has a page allocated.  Remove the handling of already
allocated pages from block_write_begin after switching all callers that
do it to __block_write_begin.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig 2010-06-04 11:29:57 +02:00 committed by Al Viro
parent f4e420dc42
commit 6e1db88d53
10 changed files with 39 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
fs/buffer.c
View File

@ -1833,9 +1833,10 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to)
}
EXPORT_SYMBOL(page_zero_new_buffers);
static int __block_prepare_write(struct inode *inode, struct page *page,
unsigned from, unsigned to, get_block_t *get_block)
int block_prepare_write(struct page *page, unsigned from, unsigned to,
get_block_t *get_block)
{
struct inode *inode = page->mapping->host;
unsigned block_start, block_end;
sector_t block;
int err = 0;
@ -1908,10 +1909,13 @@ static int __block_prepare_write(struct inode *inode, struct page *page,
if (!buffer_uptodate(*wait_bh))
err = -EIO;
}
if (unlikely(err))
if (unlikely(err)) {
page_zero_new_buffers(page, from, to);
ClearPageUptodate(page);
}
return err;
}
EXPORT_SYMBOL(block_prepare_write);
static int __block_commit_write(struct inode *inode, struct page *page,
unsigned from, unsigned to)
@ -1948,6 +1952,15 @@ static int __block_commit_write(struct inode *inode, struct page *page,
return 0;
}
int __block_write_begin(struct page *page, loff_t pos, unsigned len,
get_block_t *get_block)
{
unsigned start = pos & (PAGE_CACHE_SIZE - 1);
return block_prepare_write(page, start, start + len, get_block);
}
EXPORT_SYMBOL(__block_write_begin);
/*
* Filesystems implementing the new truncate sequence should use the
* _newtrunc postfix variant which won't incorrectly call vmtruncate.
@ -1958,41 +1971,22 @@ int block_write_begin_newtrunc(struct file *file, struct address_space *mapping,
struct page **pagep, void **fsdata,
get_block_t *get_block)
{
struct inode *inode = mapping->host;
int status = 0;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
struct page *page;
pgoff_t index;
unsigned start, end;
int ownpage = 0;
int status;
index = pos >> PAGE_CACHE_SHIFT;
start = pos & (PAGE_CACHE_SIZE - 1);
end = start + len;
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
page = *pagep;
if (page == NULL) {
ownpage = 1;
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {
status = -ENOMEM;
goto out;
}
*pagep = page;
} else
BUG_ON(!PageLocked(page));
status = __block_prepare_write(inode, page, start, end, get_block);
status = __block_write_begin(page, pos, len, get_block);
if (unlikely(status)) {
ClearPageUptodate(page);
if (ownpage) {
unlock_page(page);
page_cache_release(page);
*pagep = NULL;
}
unlock_page(page);
page_cache_release(page);
page = NULL;
}
out:
*pagep = page;
return status;
}
EXPORT_SYMBOL(block_write_begin_newtrunc);
@ -2379,17 +2373,6 @@ int cont_write_begin(struct file *file, struct address_space *mapping,
}
EXPORT_SYMBOL(cont_write_begin);
int block_prepare_write(struct page *page, unsigned from, unsigned to,
get_block_t *get_block)
{
struct inode *inode = page->mapping->host;
int err = __block_prepare_write(inode, page, from, to, get_block);
if (err)
ClearPageUptodate(page);
return err;
}
EXPORT_SYMBOL(block_prepare_write);
int block_commit_write(struct page *page, unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;

3
fs/ext2/dir.c
View File

@ -450,8 +450,7 @@ ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, ext2_get_block);
return __block_write_begin(page, pos, len, ext2_get_block);
}
/* Releases the page */

3
fs/ext3/inode.c
View File

@ -1196,8 +1196,7 @@ static int ext3_write_begin(struct file *file, struct address_space *mapping,
ret = PTR_ERR(handle);
goto out;
}
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
ext3_get_block);
ret = __block_write_begin(page, pos, len, ext3_get_block);
if (ret)
goto write_begin_failed;

11
fs/ext4/inode.c
View File

@ -1578,11 +1578,9 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
*pagep = page;
if (ext4_should_dioread_nolock(inode))
ret = block_write_begin(file, mapping, pos, len, flags, pagep,
fsdata, ext4_get_block_write);
ret = __block_write_begin(page, pos, len, ext4_get_block_write);
else
ret = block_write_begin(file, mapping, pos, len, flags, pagep,
fsdata, ext4_get_block);
ret = __block_write_begin(page, pos, len, ext4_get_block);
if (!ret && ext4_should_journal_data(inode)) {
ret = walk_page_buffers(handle, page_buffers(page),
@ -1593,7 +1591,7 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
unlock_page(page);
page_cache_release(page);
/*
* block_write_begin may have instantiated a few blocks
* __block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold i_mutex.
*
@ -3185,8 +3183,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
}
*pagep = page;
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
ext4_da_get_block_prep);
ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
if (ret < 0) {
unlock_page(page);
ext4_journal_stop(handle);

3
fs/minix/inode.c
View File

@ -359,8 +359,7 @@ static int minix_readpage(struct file *file, struct page *page)
int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, minix_get_block);
return __block_write_begin(page, pos, len, minix_get_block);
}
static int minix_write_begin(struct file *file, struct address_space *mapping,

3
fs/nilfs2/dir.c
View File

@ -83,8 +83,7 @@ static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
{
loff_t pos = page_offset(page) + from;
return block_write_begin_newtrunc(NULL, page->mapping, pos, to - from,
0, &page, NULL, nilfs_get_block);
return __block_write_begin(page, pos, to - from, nilfs_get_block);
}
static void nilfs_commit_chunk(struct page *page,

3
fs/reiserfs/inode.c
View File

@ -2585,8 +2585,7 @@ static int reiserfs_write_begin(struct file *file,
old_ref = th->t_refcount;
th->t_refcount++;
}
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
reiserfs_get_block);
ret = __block_write_begin(page, pos, len, reiserfs_get_block);
if (ret && reiserfs_transaction_running(inode->i_sb)) {
struct reiserfs_transaction_handle *th = current->journal_info;
/* this gets a little ugly. If reiserfs_get_block returned an

3
fs/sysv/itree.c
View File

@ -461,8 +461,7 @@ static int sysv_readpage(struct file *file, struct page *page)
int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, get_block);
return __block_write_begin(page, pos, len, get_block);
}
static int sysv_write_begin(struct file *file, struct address_space *mapping,

3
fs/ufs/inode.c
View File

@ -560,8 +560,7 @@ static int ufs_readpage(struct file *file, struct page *page)
int ufs_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, ufs_getfrag_block);
return __block_write_begin(page, pos, len, ufs_getfrag_block);
}
static int ufs_write_begin(struct file *file, struct address_space *mapping,

2
include/linux/buffer_head.h
View File

@ -209,6 +209,8 @@ int block_write_begin_newtrunc(struct file *, struct address_space *,
int block_write_begin(struct file *, struct address_space *,
loff_t, unsigned, unsigned,
struct page **, void **, get_block_t*);
int __block_write_begin(struct page *page, loff_t pos, unsigned len,
get_block_t *get_block);
int block_write_end(struct file *, struct address_space *,
loff_t, unsigned, unsigned,
struct page *, void *);