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clean up write_begin usage for directories in pagecache

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For filesystem that implement directories in pagecache we call
block_write_begin with an already allocated page for this code, while the
normal regular file write path uses the default block_write_begin behaviour.

Get rid of the __foofs_write_begin helper and opencode the normal write_begin
call in foofs_write_begin, while adding a new foofs_prepare_chunk helper for
the directory code.  The added benefit is that foofs_prepare_chunk has
a much saner calling convention.

Note that the interruptible flag passed into block_write_begin is always
ignored if we already pass in a page (see next patch for details), and
we never were doing truncations of exessive blocks for this case either so we
can switch directly to block_write_begin_newtrunc.

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 11:29:56 +02:00 • committed by Al Viro
parent 282dc17884
commit f4e420dc42
13 changed files with 57 additions and 107 deletions
Download patch file Download diff file Expand all files Collapse all files

21
fs/sysv/dir.c
View file

@ -218,8 +218,7 @@ got_it:
pos = page_offset(page) +
(char*)de - (char*)page_address(page);
lock_page(page);
err = __sysv_write_begin(NULL, page->mapping, pos, SYSV_DIRSIZE,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
if (err)
goto out_unlock;
memcpy (de->name, name, namelen);
@ -239,15 +238,13 @@ out_unlock:
int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = (struct inode*)mapping->host;
struct inode *inode = page->mapping->host;
char *kaddr = (char*)page_address(page);
loff_t pos = page_offset(page) + (char *)de - kaddr;
int err;
lock_page(page);
err = __sysv_write_begin(NULL, mapping, pos, SYSV_DIRSIZE,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
BUG_ON(err);
de->inode = 0;
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
@ -259,16 +256,14 @@ int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
int sysv_make_empty(struct inode *inode, struct inode *dir)
{
struct address_space *mapping = inode->i_mapping;
struct page *page = grab_cache_page(mapping, 0);
struct page *page = grab_cache_page(inode->i_mapping, 0);
struct sysv_dir_entry * de;
char *base;
int err;
if (!page)
return -ENOMEM;
err = __sysv_write_begin(NULL, mapping, 0, 2 * SYSV_DIRSIZE,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = sysv_prepare_chunk(page, 0, 2 * SYSV_DIRSIZE);
if (err) {
unlock_page(page);
goto fail;
@ -341,15 +336,13 @@ not_empty:
void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
struct inode *inode)
{
struct address_space *mapping = page->mapping;
struct inode *dir = mapping->host;
struct inode *dir = page->mapping->host;
loff_t pos = page_offset(page) +
(char *)de-(char*)page_address(page);
int err;
lock_page(page);
err = __sysv_write_begin(NULL, mapping, pos, SYSV_DIRSIZE,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
BUG_ON(err);
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);

11
fs/sysv/itree.c
View file

@ -459,12 +459,10 @@ static int sysv_readpage(struct file *file, struct page *page)
return block_read_full_page(page,get_block);
}
int __sysv_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
get_block);
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, get_block);
}
static int sysv_write_begin(struct file *file, struct address_space *mapping,
@ -472,7 +470,8 @@ static int sysv_write_begin(struct file *file, struct address_space *mapping,
struct page **pagep, void **fsdata)
{
*pagep = NULL;
return __sysv_write_begin(file, mapping, pos, len, flags, pagep, fsdata);
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
get_block);
}
static sector_t sysv_bmap(struct address_space *mapping, sector_t block)

4
fs/sysv/sysv.h
View file

@ -136,9 +136,7 @@ extern unsigned long sysv_count_free_blocks(struct super_block *);
/* itree.c */
extern void sysv_truncate(struct inode *);
extern int __sysv_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
extern int sysv_prepare_chunk(struct page *page, loff_t pos, unsigned len);
/* inode.c */
extern struct inode *sysv_iget(struct super_block *, unsigned int);