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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>
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Christoph Hellwig authored and Al Viro committed Aug 9, 2010
1 parent 282dc17 commit f4e420d
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Showing 13 changed files with 57 additions and 107 deletions.
24 changes: 12 additions & 12 deletions fs/ext2/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -576,8 +580,7 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
*/
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) +
Expand All @@ -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);
Expand All @@ -621,8 +623,7 @@ int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
*/
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;
Expand All @@ -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;
Expand Down
3 changes: 0 additions & 3 deletions fs/ext2/ext2.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
11 changes: 2 additions & 9 deletions fs/ext2/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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;
Expand Down
21 changes: 7 additions & 14 deletions fs/minix/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -271,8 +271,7 @@ int minix_add_link(struct dentry *dentry, struct inode *inode)

got_it:
pos = page_offset(page) + p - (char *)page_address(page);
err = __minix_write_begin(NULL, page->mapping, pos, sbi->s_dirsize,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
if (err)
goto out_unlock;
memcpy (namx, name, namelen);
Expand All @@ -297,17 +296,15 @@ int minix_add_link(struct dentry *dentry, struct inode *inode)

int minix_delete_entry(struct minix_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 = page_address(page);
loff_t pos = page_offset(page) + (char*)de - kaddr;
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
unsigned len = sbi->s_dirsize;
int err;

lock_page(page);
err = __minix_write_begin(NULL, mapping, pos, len,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = minix_prepare_chunk(page, pos, len);
if (err == 0) {
if (sbi->s_version == MINIX_V3)
((minix3_dirent *) de)->inode = 0;
Expand All @@ -325,16 +322,14 @@ int minix_delete_entry(struct minix_dir_entry *de, struct page *page)

int minix_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 minix_sb_info *sbi = minix_sb(inode->i_sb);
char *kaddr;
int err;

if (!page)
return -ENOMEM;
err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
if (err) {
unlock_page(page);
goto fail;
Expand Down Expand Up @@ -425,17 +420,15 @@ int minix_empty_dir(struct inode * inode)
void minix_set_link(struct minix_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;
struct minix_sb_info *sbi = minix_sb(dir->i_sb);
loff_t pos = page_offset(page) +
(char *)de-(char*)page_address(page);
int err;

lock_page(page);

err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize,
AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
if (err == 0) {
if (sbi->s_version == MINIX_V3)
((minix3_dirent *) de)->inode = inode->i_ino;
Expand Down
11 changes: 5 additions & 6 deletions fs/minix/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -357,20 +357,19 @@ static int minix_readpage(struct file *file, struct page *page)
return block_read_full_page(page,minix_get_block);
}

int __minix_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
minix_get_block);
return block_write_begin_newtrunc(NULL, page->mapping, pos, len, 0,
&page, NULL, minix_get_block);
}

static int minix_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
*pagep = NULL;
return __minix_write_begin(file, mapping, pos, len, flags, pagep, fsdata);
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
minix_get_block);
}

static sector_t minix_bmap(struct address_space *mapping, sector_t block)
Expand Down
4 changes: 1 addition & 3 deletions fs/minix/minix.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,9 +53,7 @@ extern int minix_new_block(struct inode * inode);
extern void minix_free_block(struct inode *inode, unsigned long block);
extern unsigned long minix_count_free_blocks(struct minix_sb_info *sbi);
extern int minix_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int __minix_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
extern int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len);

extern void V1_minix_truncate(struct inode *);
extern void V2_minix_truncate(struct inode *);
Expand Down
26 changes: 7 additions & 19 deletions fs/nilfs2/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -80,23 +80,11 @@ static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
return last_byte;
}

static int nilfs_prepare_chunk_uninterruptible(struct page *page,
struct address_space *mapping,
unsigned from, unsigned to)
static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
{
loff_t pos = page_offset(page) + from;
return block_write_begin(NULL, mapping, pos, to - from,
AOP_FLAG_UNINTERRUPTIBLE, &page,
NULL, nilfs_get_block);
}

static int nilfs_prepare_chunk(struct page *page,
struct address_space *mapping,
unsigned from, unsigned to)
{
loff_t pos = page_offset(page) + from;
return block_write_begin(NULL, mapping, pos, to - from, 0, &page,
NULL, nilfs_get_block);
return block_write_begin_newtrunc(NULL, page->mapping, pos, to - from,
0, &page, NULL, nilfs_get_block);
}

static void nilfs_commit_chunk(struct page *page,
Expand Down Expand Up @@ -449,7 +437,7 @@ void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
int err;

lock_page(page);
err = nilfs_prepare_chunk_uninterruptible(page, mapping, from, to);
err = nilfs_prepare_chunk(page, from, to);
BUG_ON(err);
de->inode = cpu_to_le64(inode->i_ino);
nilfs_set_de_type(de, inode);
Expand Down Expand Up @@ -530,7 +518,7 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
got_it:
from = (char *)de - (char *)page_address(page);
to = from + rec_len;
err = nilfs_prepare_chunk(page, page->mapping, from, to);
err = nilfs_prepare_chunk(page, from, to);
if (err)
goto out_unlock;
if (de->inode) {
Expand Down Expand Up @@ -587,7 +575,7 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
if (pde)
from = (char *)pde - (char *)page_address(page);
lock_page(page);
err = nilfs_prepare_chunk(page, mapping, from, to);
err = nilfs_prepare_chunk(page, from, to);
BUG_ON(err);
if (pde)
pde->rec_len = cpu_to_le16(to - from);
Expand Down Expand Up @@ -615,7 +603,7 @@ int nilfs_make_empty(struct inode *inode, struct inode *parent)
if (!page)
return -ENOMEM;

err = nilfs_prepare_chunk(page, mapping, 0, chunk_size);
err = nilfs_prepare_chunk(page, 0, chunk_size);
if (unlikely(err)) {
unlock_page(page);
goto fail;
Expand Down
21 changes: 7 additions & 14 deletions fs/sysv/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -218,8 +218,7 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
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);
Expand All @@ -239,15 +238,13 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)

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);
Expand All @@ -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;
Expand Down Expand Up @@ -341,15 +336,13 @@ int sysv_empty_dir(struct inode * inode)
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);
Expand Down
11 changes: 5 additions & 6 deletions fs/sysv/itree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -459,20 +459,19 @@ 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,
loff_t pos, unsigned len, unsigned flags,
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)
Expand Down
4 changes: 1 addition & 3 deletions fs/sysv/sysv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
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