fs: new cont helpers
Rework the generic block "cont" routines to handle the new aops. Supporting cont_prepare_write would take quite a lot of code to support, so remove it instead (and we later convert all filesystems to use it). write_begin gets passed AOP_FLAG_CONT_EXPAND when called from generic_cont_expand, so filesystems can avoid the old hacks they used. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin
Linus Torvalds
parent
7765ec26ae
commit
89e107877b
202
fs/buffer.c
202
fs/buffer.c
|
|
@ -2156,14 +2156,14 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
|
|||
}
|
||||
|
||||
/* utility function for filesystems that need to do work on expanding
|
||||
* truncates. Uses prepare/commit_write to allow the filesystem to
|
||||
* truncates. Uses filesystem pagecache writes to allow the filesystem to
|
||||
* deal with the hole.
|
||||
*/
|
||||
static int __generic_cont_expand(struct inode *inode, loff_t size,
|
||||
pgoff_t index, unsigned int offset)
|
||||
int generic_cont_expand_simple(struct inode *inode, loff_t size)
|
||||
{
|
||||
struct address_space *mapping = inode->i_mapping;
|
||||
struct page *page;
|
||||
void *fsdata;
|
||||
unsigned long limit;
|
||||
int err;
|
||||
|
||||
|
|
@ -2176,140 +2176,134 @@ static int __generic_cont_expand(struct inode *inode, loff_t size,
|
|||
if (size > inode->i_sb->s_maxbytes)
|
||||
goto out;
|
||||
|
||||
err = -ENOMEM;
|
||||
page = grab_cache_page(mapping, index);
|
||||
if (!page)
|
||||
err = pagecache_write_begin(NULL, mapping, size, 0,
|
||||
AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND,
|
||||
&page, &fsdata);
|
||||
if (err)
|
||||
goto out;
|
||||
err = mapping->a_ops->prepare_write(NULL, page, offset, offset);
|
||||
if (err) {
|
||||
/*
|
||||
* ->prepare_write() may have instantiated a few blocks
|
||||
* outside i_size. Trim these off again.
|
||||
*/
|
||||
unlock_page(page);
|
||||
page_cache_release(page);
|
||||
vmtruncate(inode, inode->i_size);
|
||||
goto out;
|
||||
}
|
||||
|
||||
err = mapping->a_ops->commit_write(NULL, page, offset, offset);
|
||||
err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata);
|
||||
BUG_ON(err > 0);
|
||||
|
||||
unlock_page(page);
|
||||
page_cache_release(page);
|
||||
if (err > 0)
|
||||
err = 0;
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
int generic_cont_expand(struct inode *inode, loff_t size)
|
||||
{
|
||||
pgoff_t index;
|
||||
unsigned int offset;
|
||||
|
||||
offset = (size & (PAGE_CACHE_SIZE - 1)); /* Within page */
|
||||
|
||||
/* ugh. in prepare/commit_write, if from==to==start of block, we
|
||||
** skip the prepare. make sure we never send an offset for the start
|
||||
** of a block
|
||||
*/
|
||||
* skip the prepare. make sure we never send an offset for the start
|
||||
* of a block.
|
||||
* XXX: actually, this should be handled in those filesystems by
|
||||
* checking for the AOP_FLAG_CONT_EXPAND flag.
|
||||
*/
|
||||
if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
|
||||
/* caller must handle this extra byte. */
|
||||
offset++;
|
||||
size++;
|
||||
}
|
||||
index = size >> PAGE_CACHE_SHIFT;
|
||||
|
||||
return __generic_cont_expand(inode, size, index, offset);
|
||||
return generic_cont_expand_simple(inode, size);
|
||||
}
|
||||
|
||||
int generic_cont_expand_simple(struct inode *inode, loff_t size)
|
||||
int cont_expand_zero(struct file *file, struct address_space *mapping,
|
||||
loff_t pos, loff_t *bytes)
|
||||
{
|
||||
loff_t pos = size - 1;
|
||||
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
|
||||
unsigned int offset = (pos & (PAGE_CACHE_SIZE - 1)) + 1;
|
||||
struct inode *inode = mapping->host;
|
||||
unsigned blocksize = 1 << inode->i_blkbits;
|
||||
struct page *page;
|
||||
void *fsdata;
|
||||
pgoff_t index, curidx;
|
||||
loff_t curpos;
|
||||
unsigned zerofrom, offset, len;
|
||||
int err = 0;
|
||||
|
||||
/* prepare/commit_write can handle even if from==to==start of block. */
|
||||
return __generic_cont_expand(inode, size, index, offset);
|
||||
index = pos >> PAGE_CACHE_SHIFT;
|
||||
offset = pos & ~PAGE_CACHE_MASK;
|
||||
|
||||
while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) {
|
||||
zerofrom = curpos & ~PAGE_CACHE_MASK;
|
||||
if (zerofrom & (blocksize-1)) {
|
||||
*bytes |= (blocksize-1);
|
||||
(*bytes)++;
|
||||
}
|
||||
len = PAGE_CACHE_SIZE - zerofrom;
|
||||
|
||||
err = pagecache_write_begin(file, mapping, curpos, len,
|
||||
AOP_FLAG_UNINTERRUPTIBLE,
|
||||
&page, &fsdata);
|
||||
if (err)
|
||||
goto out;
|
||||
zero_user_page(page, zerofrom, len, KM_USER0);
|
||||
err = pagecache_write_end(file, mapping, curpos, len, len,
|
||||
page, fsdata);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
BUG_ON(err != len);
|
||||
err = 0;
|
||||
}
|
||||
|
||||
/* page covers the boundary, find the boundary offset */
|
||||
if (index == curidx) {
|
||||
zerofrom = curpos & ~PAGE_CACHE_MASK;
|
||||
/* if we will expand the thing last block will be filled */
|
||||
if (offset <= zerofrom) {
|
||||
goto out;
|
||||
}
|
||||
if (zerofrom & (blocksize-1)) {
|
||||
*bytes |= (blocksize-1);
|
||||
(*bytes)++;
|
||||
}
|
||||
len = offset - zerofrom;
|
||||
|
||||
err = pagecache_write_begin(file, mapping, curpos, len,
|
||||
AOP_FLAG_UNINTERRUPTIBLE,
|
||||
&page, &fsdata);
|
||||
if (err)
|
||||
goto out;
|
||||
zero_user_page(page, zerofrom, len, KM_USER0);
|
||||
err = pagecache_write_end(file, mapping, curpos, len, len,
|
||||
page, fsdata);
|
||||
if (err < 0)
|
||||
goto out;
|
||||
BUG_ON(err != len);
|
||||
err = 0;
|
||||
}
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
/*
|
||||
* For moronic filesystems that do not allow holes in file.
|
||||
* We may have to extend the file.
|
||||
*/
|
||||
|
||||
int cont_prepare_write(struct page *page, unsigned offset,
|
||||
unsigned to, get_block_t *get_block, loff_t *bytes)
|
||||
int cont_write_begin(struct file *file, struct address_space *mapping,
|
||||
loff_t pos, unsigned len, unsigned flags,
|
||||
struct page **pagep, void **fsdata,
|
||||
get_block_t *get_block, loff_t *bytes)
|
||||
{
|
||||
struct address_space *mapping = page->mapping;
|
||||
struct inode *inode = mapping->host;
|
||||
struct page *new_page;
|
||||
pgoff_t pgpos;
|
||||
long status;
|
||||
unsigned zerofrom;
|
||||
unsigned blocksize = 1 << inode->i_blkbits;
|
||||
unsigned zerofrom;
|
||||
int err;
|
||||
|
||||
while(page->index > (pgpos = *bytes>>PAGE_CACHE_SHIFT)) {
|
||||
status = -ENOMEM;
|
||||
new_page = grab_cache_page(mapping, pgpos);
|
||||
if (!new_page)
|
||||
goto out;
|
||||
/* we might sleep */
|
||||
if (*bytes>>PAGE_CACHE_SHIFT != pgpos) {
|
||||
unlock_page(new_page);
|
||||
page_cache_release(new_page);
|
||||
continue;
|
||||
}
|
||||
zerofrom = *bytes & ~PAGE_CACHE_MASK;
|
||||
if (zerofrom & (blocksize-1)) {
|
||||
*bytes |= (blocksize-1);
|
||||
(*bytes)++;
|
||||
}
|
||||
status = __block_prepare_write(inode, new_page, zerofrom,
|
||||
PAGE_CACHE_SIZE, get_block);
|
||||
if (status)
|
||||
goto out_unmap;
|
||||
zero_user_page(new_page, zerofrom, PAGE_CACHE_SIZE - zerofrom,
|
||||
KM_USER0);
|
||||
generic_commit_write(NULL, new_page, zerofrom, PAGE_CACHE_SIZE);
|
||||
unlock_page(new_page);
|
||||
page_cache_release(new_page);
|
||||
err = cont_expand_zero(file, mapping, pos, bytes);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
zerofrom = *bytes & ~PAGE_CACHE_MASK;
|
||||
if (pos+len > *bytes && zerofrom & (blocksize-1)) {
|
||||
*bytes |= (blocksize-1);
|
||||
(*bytes)++;
|
||||
}
|
||||
|
||||
if (page->index < pgpos) {
|
||||
/* completely inside the area */
|
||||
zerofrom = offset;
|
||||
} else {
|
||||
/* page covers the boundary, find the boundary offset */
|
||||
zerofrom = *bytes & ~PAGE_CACHE_MASK;
|
||||
|
||||
/* if we will expand the thing last block will be filled */
|
||||
if (to > zerofrom && (zerofrom & (blocksize-1))) {
|
||||
*bytes |= (blocksize-1);
|
||||
(*bytes)++;
|
||||
}
|
||||
|
||||
/* starting below the boundary? Nothing to zero out */
|
||||
if (offset <= zerofrom)
|
||||
zerofrom = offset;
|
||||
}
|
||||
status = __block_prepare_write(inode, page, zerofrom, to, get_block);
|
||||
if (status)
|
||||
goto out1;
|
||||
if (zerofrom < offset) {
|
||||
zero_user_page(page, zerofrom, offset - zerofrom, KM_USER0);
|
||||
__block_commit_write(inode, page, zerofrom, offset);
|
||||
}
|
||||
return 0;
|
||||
out1:
|
||||
ClearPageUptodate(page);
|
||||
return status;
|
||||
|
||||
out_unmap:
|
||||
ClearPageUptodate(new_page);
|
||||
unlock_page(new_page);
|
||||
page_cache_release(new_page);
|
||||
*pagep = NULL;
|
||||
err = block_write_begin(file, mapping, pos, len,
|
||||
flags, pagep, fsdata, get_block);
|
||||
out:
|
||||
return status;
|
||||
return err;
|
||||
}
|
||||
|
||||
int block_prepare_write(struct page *page, unsigned from, unsigned to,
|
||||
|
|
@ -3191,7 +3185,7 @@ EXPORT_SYMBOL(block_read_full_page);
|
|||
EXPORT_SYMBOL(block_sync_page);
|
||||
EXPORT_SYMBOL(block_truncate_page);
|
||||
EXPORT_SYMBOL(block_write_full_page);
|
||||
EXPORT_SYMBOL(cont_prepare_write);
|
||||
EXPORT_SYMBOL(cont_write_begin);
|
||||
EXPORT_SYMBOL(end_buffer_read_sync);
|
||||
EXPORT_SYMBOL(end_buffer_write_sync);
|
||||
EXPORT_SYMBOL(file_fsync);
|
||||
|
|
|
|||
|
|
@ -214,8 +214,9 @@ int generic_write_end(struct file *, struct address_space *,
|
|||
struct page *, void *);
|
||||
void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
|
||||
int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
|
||||
int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*,
|
||||
loff_t *);
|
||||
int cont_write_begin(struct file *, struct address_space *, loff_t,
|
||||
unsigned, unsigned, struct page **, void **,
|
||||
get_block_t *, loff_t *);
|
||||
int generic_cont_expand(struct inode *inode, loff_t size);
|
||||
int generic_cont_expand_simple(struct inode *inode, loff_t size);
|
||||
int block_commit_write(struct page *page, unsigned from, unsigned to);
|
||||
|
|
|
|||
|
|
@ -395,6 +395,7 @@ enum positive_aop_returns {
|
|||
};
|
||||
|
||||
#define AOP_FLAG_UNINTERRUPTIBLE 0x0001 /* will not do a short write */
|
||||
#define AOP_FLAG_CONT_EXPAND 0x0002 /* called from cont_expand */
|
||||
|
||||
/*
|
||||
* oh the beauties of C type declarations.
|
||||
|
|
|
|||
|
|
@ -1684,6 +1684,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
|
|||
|
||||
return copied;
|
||||
}
|
||||
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
|
||||
|
||||
/*
|
||||
* This has the same sideeffects and return value as
|
||||
|
|
@ -1710,6 +1711,7 @@ size_t iov_iter_copy_from_user(struct page *page,
|
|||
kunmap(page);
|
||||
return copied;
|
||||
}
|
||||
EXPORT_SYMBOL(iov_iter_copy_from_user);
|
||||
|
||||
static void __iov_iter_advance_iov(struct iov_iter *i, size_t bytes)
|
||||
{
|
||||
|
|
@ -1741,6 +1743,7 @@ void iov_iter_advance(struct iov_iter *i, size_t bytes)
|
|||
__iov_iter_advance_iov(i, bytes);
|
||||
i->count -= bytes;
|
||||
}
|
||||
EXPORT_SYMBOL(iov_iter_advance);
|
||||
|
||||
/*
|
||||
* Fault in the first iovec of the given iov_iter, to a maximum length
|
||||
|
|
@ -1757,6 +1760,7 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
|
|||
bytes = min(bytes, i->iov->iov_len - i->iov_offset);
|
||||
return fault_in_pages_readable(buf, bytes);
|
||||
}
|
||||
EXPORT_SYMBOL(iov_iter_fault_in_readable);
|
||||
|
||||
/*
|
||||
* Return the count of just the current iov_iter segment.
|
||||
|
|
@ -1769,6 +1773,7 @@ size_t iov_iter_single_seg_count(struct iov_iter *i)
|
|||
else
|
||||
return min(i->count, iov->iov_len - i->iov_offset);
|
||||
}
|
||||
EXPORT_SYMBOL(iov_iter_single_seg_count);
|
||||
|
||||
/*
|
||||
* Performs necessary checks before doing a write
|
||||
|
|
|
|||
Reference in New Issue