Commit 6e1db88d authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

introduce __block_write_begin



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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f4e420dc
......@@ -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 = *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));
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
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;
......
......@@ -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 */
......
......@@ -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;
......
......@@ -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);
......
......@@ -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,
......
......@@ -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,
......
......@@ -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
......
......@@ -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,
......
......@@ -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,
......
......@@ -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 *);
......
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