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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
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24
fs/ext2/dir.c
View File

@@ -448,6 +448,12 @@ ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
return res;
}
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);
}
/* Releases the page */
void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
struct page *page, struct inode *inode, int update_times)
@@ -458,8 +464,7 @@ void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
int err;
lock_page(page);
err = __ext2_write_begin(NULL, page->mapping, pos, len,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = ext2_prepare_chunk(page, pos, len);
BUG_ON(err);
de->inode = cpu_to_le32(inode->i_ino);
ext2_set_de_type(de, inode);
@@ -542,8 +547,7 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
got_it:
pos = page_offset(page) +
(char*)de - (char*)page_address(page);
err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0,
&page, NULL);
err = ext2_prepare_chunk(page, pos, rec_len);
if (err)
goto out_unlock;
if (de->inode) {
@@ -576,8 +580,7 @@ out_unlock:
*/
int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct inode *inode = page->mapping->host;
char *kaddr = page_address(page);
unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
unsigned to = ((char *)dir - kaddr) +
@@ -601,8 +604,7 @@ int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
from = (char*)pde - (char*)page_address(page);
pos = page_offset(page) + from;
lock_page(page);
err = __ext2_write_begin(NULL, page->mapping, pos, to - from, 0,
&page, NULL);
err = ext2_prepare_chunk(page, pos, to - from);
BUG_ON(err);
if (pde)
pde->rec_len = ext2_rec_len_to_disk(to - from);
@@ -621,8 +623,7 @@ out:
*/
int ext2_make_empty(struct inode *inode, struct inode *parent)
{
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);
unsigned chunk_size = ext2_chunk_size(inode);
struct ext2_dir_entry_2 * de;
int err;
@@ -631,8 +632,7 @@ int ext2_make_empty(struct inode *inode, struct inode *parent)
if (!page)
return -ENOMEM;
err = __ext2_write_begin(NULL, page->mapping, 0, chunk_size, 0,
&page, NULL);
err = ext2_prepare_chunk(page, 0, chunk_size);
if (err) {
unlock_page(page);
goto fail;

3
fs/ext2/ext2.h
View File

@@ -127,9 +127,6 @@ extern void ext2_set_inode_flags(struct inode *inode);
extern void ext2_get_inode_flags(struct ext2_inode_info *);
extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len);
int __ext2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
/* ioctl.c */
extern long ext2_ioctl(struct file *, unsigned int, unsigned long);

11
fs/ext2/inode.c
View File

@@ -765,14 +765,6 @@ ext2_readpages(struct file *file, struct address_space *mapping,
return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
}
int __ext2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
return block_write_begin_newtrunc(file, mapping, pos, len, flags,
pagep, fsdata, ext2_get_block);
}
static int
ext2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
@@ -781,7 +773,8 @@ ext2_write_begin(struct file *file, struct address_space *mapping,
int ret;
*pagep = NULL;
ret = __ext2_write_begin(file, mapping, pos, len, flags, pagep, fsdata);
ret = block_write_begin_newtrunc(file, mapping, pos, len, flags,
pagep, fsdata, ext2_get_block);
if (ret < 0)
ext2_write_failed(mapping, pos + len);
return ret;