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fs: remove prepare_write/commit_write

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Nothing uses prepare_write or commit_write. Remove them from the tree
completely.

[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
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
2008-10-29 14:00:55 -07:00
committed by Linus Torvalds
parent 9b913735e5
commit 4e02ed4b4a
9 changed files with 23 additions and 293 deletions
Download Patch File Download Diff File Expand all files Collapse all files

242
mm/filemap.c
View File

@@ -2029,48 +2029,8 @@ int pagecache_write_begin(struct file *file, struct address_space *mapping,
{
const struct address_space_operations *aops = mapping->a_ops;
if (aops->write_begin) {
return aops->write_begin(file, mapping, pos, len, flags,
return aops->write_begin(file, mapping, pos, len, flags,
pagep, fsdata);
} else {
int ret;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
struct inode *inode = mapping->host;
struct page *page;
again:
page = __grab_cache_page(mapping, index);
*pagep = page;
if (!page)
return -ENOMEM;
if (flags & AOP_FLAG_UNINTERRUPTIBLE && !PageUptodate(page)) {
/*
* There is no way to resolve a short write situation
* for a !Uptodate page (except by double copying in
* the caller done by generic_perform_write_2copy).
*
* Instead, we have to bring it uptodate here.
*/
ret = aops->readpage(file, page);
page_cache_release(page);
if (ret) {
if (ret == AOP_TRUNCATED_PAGE)
goto again;
return ret;
}
goto again;
}
ret = aops->prepare_write(file, page, offset, offset+len);
if (ret) {
unlock_page(page);
page_cache_release(page);
if (pos + len > inode->i_size)
vmtruncate(inode, inode->i_size);
}
return ret;
}
}
EXPORT_SYMBOL(pagecache_write_begin);
@@ -2079,32 +2039,9 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
struct page *page, void *fsdata)
{
const struct address_space_operations *aops = mapping->a_ops;
int ret;
if (aops->write_end) {
mark_page_accessed(page);
ret = aops->write_end(file, mapping, pos, len, copied,
page, fsdata);
} else {
unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
struct inode *inode = mapping->host;
flush_dcache_page(page);
ret = aops->commit_write(file, page, offset, offset+len);
unlock_page(page);
mark_page_accessed(page);
page_cache_release(page);
if (ret < 0) {
if (pos + len > inode->i_size)
vmtruncate(inode, inode->i_size);
} else if (ret > 0)
ret = min_t(size_t, copied, ret);
else
ret = copied;
}
return ret;
mark_page_accessed(page);
return aops->write_end(file, mapping, pos, len, copied, page, fsdata);
}
EXPORT_SYMBOL(pagecache_write_end);
@@ -2226,174 +2163,6 @@ repeat:
}
EXPORT_SYMBOL(__grab_cache_page);
static ssize_t generic_perform_write_2copy(struct file *file,
struct iov_iter *i, loff_t pos)
{
struct address_space *mapping = file->f_mapping;
const struct address_space_operations *a_ops = mapping->a_ops;
struct inode *inode = mapping->host;
long status = 0;
ssize_t written = 0;
do {
struct page *src_page;
struct page *page;
pgoff_t index; /* Pagecache index for current page */
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
size_t copied; /* Bytes copied from user */
offset = (pos & (PAGE_CACHE_SIZE - 1));
index = pos >> PAGE_CACHE_SHIFT;
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
iov_iter_count(i));
/*
* a non-NULL src_page indicates that we're doing the
* copy via get_user_pages and kmap.
*/
src_page = NULL;
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
* same page as we're writing to, without it being marked
* up-to-date.
*
* Not only is this an optimisation, but it is also required
* to check that the address is actually valid, when atomic
* usercopies are used, below.
*/
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
page = __grab_cache_page(mapping, index);
if (!page) {
status = -ENOMEM;
break;
}
/*
* non-uptodate pages cannot cope with short copies, and we
* cannot take a pagefault with the destination page locked.
* So pin the source page to copy it.
*/
if (!PageUptodate(page) && !segment_eq(get_fs(), KERNEL_DS)) {
unlock_page(page);
src_page = alloc_page(GFP_KERNEL);
if (!src_page) {
page_cache_release(page);
status = -ENOMEM;
break;
}
/*
* Cannot get_user_pages with a page locked for the
* same reason as we can't take a page fault with a
* page locked (as explained below).
*/
copied = iov_iter_copy_from_user(src_page, i,
offset, bytes);
if (unlikely(copied == 0)) {
status = -EFAULT;
page_cache_release(page);
page_cache_release(src_page);
break;
}
bytes = copied;
lock_page(page);
/*
* Can't handle the page going uptodate here, because
* that means we would use non-atomic usercopies, which
* zero out the tail of the page, which can cause
* zeroes to become transiently visible. We could just
* use a non-zeroing copy, but the APIs aren't too
* consistent.
*/
if (unlikely(!page->mapping || PageUptodate(page))) {
unlock_page(page);
page_cache_release(page);
page_cache_release(src_page);
continue;
}
}
status = a_ops->prepare_write(file, page, offset, offset+bytes);
if (unlikely(status))
goto fs_write_aop_error;
if (!src_page) {
/*
* Must not enter the pagefault handler here, because
* we hold the page lock, so we might recursively
* deadlock on the same lock, or get an ABBA deadlock
* against a different lock, or against the mmap_sem
* (which nests outside the page lock). So increment
* preempt count, and use _atomic usercopies.
*
* The page is uptodate so we are OK to encounter a
* short copy: if unmodified parts of the page are
* marked dirty and written out to disk, it doesn't
* really matter.
*/
pagefault_disable();
copied = iov_iter_copy_from_user_atomic(page, i,
offset, bytes);
pagefault_enable();
} else {
void *src, *dst;
src = kmap_atomic(src_page, KM_USER0);
dst = kmap_atomic(page, KM_USER1);
memcpy(dst + offset, src + offset, bytes);
kunmap_atomic(dst, KM_USER1);
kunmap_atomic(src, KM_USER0);
copied = bytes;
}
flush_dcache_page(page);
status = a_ops->commit_write(file, page, offset, offset+bytes);
if (unlikely(status < 0))
goto fs_write_aop_error;
if (unlikely(status > 0)) /* filesystem did partial write */
copied = min_t(size_t, copied, status);
unlock_page(page);
mark_page_accessed(page);
page_cache_release(page);
if (src_page)
page_cache_release(src_page);
iov_iter_advance(i, copied);
pos += copied;
written += copied;
balance_dirty_pages_ratelimited(mapping);
cond_resched();
continue;
fs_write_aop_error:
unlock_page(page);
page_cache_release(page);
if (src_page)
page_cache_release(src_page);
/*
* prepare_write() may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold i_mutex.
*/
if (pos + bytes > inode->i_size)
vmtruncate(inode, inode->i_size);
break;
} while (iov_iter_count(i));
return written ? written : status;
}
static ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
@@ -2494,10 +2263,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
struct iov_iter i;
iov_iter_init(&i, iov, nr_segs, count, written);
if (a_ops->write_begin)
status = generic_perform_write(file, &i, pos);
else
status = generic_perform_write_2copy(file, &i, pos);
status = generic_perform_write(file, &i, pos);
if (likely(status >= 0)) {
written += status;