V2->V3:
- alloc_page_buffers(): Add comment to explain use of page->mapping
- Consistently determine mapping if there is a reference chain
page->mapping->host to determine the inode.
Use page_cache_xxx in fs/buffer.c.
Reviewed-by: Dave Chinner <dgc@xxxxxxx>
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
---
fs/buffer.c | 112 ++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 65 insertions(+), 47 deletions(-)
Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c 2008-02-15 16:11:18.567307640 -0800
+++ linux-2.6/fs/buffer.c 2008-02-15 16:14:54.753021832 -0800
@@ -270,7 +270,7 @@ __find_get_block_slow(struct block_devic
struct page *page;
int all_mapped = 1;
- index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
+ index = block >> (page_cache_shift(bd_mapping) - bd_inode->i_blkbits);
page = find_get_page(bd_mapping, index);
if (!page)
goto out;
@@ -712,7 +712,7 @@ static int __set_page_dirty(struct page
__inc_zone_page_state(page, NR_FILE_DIRTY);
__inc_bdi_stat(mapping->backing_dev_info,
BDI_RECLAIMABLE);
- task_io_account_write(PAGE_CACHE_SIZE);
+ task_io_account_write(page_cache_size(mapping));
}
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
@@ -924,7 +924,13 @@ struct buffer_head *alloc_page_buffers(s
try_again:
head = NULL;
- offset = PAGE_SIZE;
+
+ /*
+ * Page is locked to serialize alloc_page_buffers()
+ * so we can use page->mapping here.
+ */
+ offset = page_cache_size(page->mapping);
+
while ((offset -= size) >= 0) {
bh = alloc_buffer_head(GFP_NOFS);
if (!bh)
@@ -1636,6 +1642,7 @@ static int __block_write_full_page(struc
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
+ struct address_space *mapping = inode->i_mapping;
BUG_ON(!PageLocked(page));
@@ -1656,7 +1663,8 @@ static int __block_write_full_page(struc
* handle that here by just cleaning them.
*/
- block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ block = (sector_t)page->index <<
+ (page_cache_shift(mapping) - inode->i_blkbits);
head = page_buffers(page);
bh = head;
@@ -1772,7 +1780,7 @@ recover:
} while ((bh = bh->b_this_page) != head);
SetPageError(page);
BUG_ON(PageWriteback(page));
- mapping_set_error(page->mapping, err);
+ mapping_set_error(mapping, err);
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
@@ -1839,8 +1847,8 @@ static int __block_prepare_write(struct
struct buffer_head *bh, *head, *wait[2], **wait_bh=wait;
BUG_ON(!PageLocked(page));
- BUG_ON(from > PAGE_CACHE_SIZE);
- BUG_ON(to > PAGE_CACHE_SIZE);
+ BUG_ON(from > page_cache_size(inode->i_mapping));
+ BUG_ON(to > page_cache_size(inode->i_mapping));
BUG_ON(from > to);
blocksize = 1 << inode->i_blkbits;
@@ -1849,7 +1857,8 @@ static int __block_prepare_write(struct
head = page_buffers(page);
bbits = inode->i_blkbits;
- block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
+ block = (sector_t)page->index <<
+ (page_cache_shift(inode->i_mapping) - bbits);
for(bh = head, block_start = 0; bh != head || !block_start;
block++, block_start=block_end, bh = bh->b_this_page) {
@@ -1964,8 +1973,8 @@ int block_write_begin(struct file *file,
unsigned start, end;
int ownpage = 0;
- index = pos >> PAGE_CACHE_SHIFT;
- start = pos & (PAGE_CACHE_SIZE - 1);
+ index = page_cache_index(mapping, pos);
+ start = page_cache_offset(mapping, pos);
end = start + len;
page = *pagep;
@@ -2012,7 +2021,7 @@ int block_write_end(struct file *file, s
struct inode *inode = mapping->host;
unsigned start;
- start = pos & (PAGE_CACHE_SIZE - 1);
+ start = page_cache_offset(mapping, pos);
if (unlikely(copied < len)) {
/*
@@ -2077,7 +2086,8 @@ EXPORT_SYMBOL(generic_write_end);
*/
int block_read_full_page(struct page *page, get_block_t *get_block)
{
- struct inode *inode = page->mapping->host;
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
sector_t iblock, lblock;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
unsigned int blocksize;
@@ -2090,7 +2100,8 @@ int block_read_full_page(struct page *pa
create_empty_buffers(page, blocksize, 0);
head = page_buffers(page);
- iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ iblock = (sector_t)page->index <<
+ (page_cache_shift(mapping) - inode->i_blkbits);
lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits;
bh = head;
nr = 0;
@@ -2208,16 +2219,17 @@ int cont_expand_zero(struct file *file,
unsigned zerofrom, offset, len;
int err = 0;
- index = pos >> PAGE_CACHE_SHIFT;
- offset = pos & ~PAGE_CACHE_MASK;
+ index = page_cache_index(mapping, pos);
+ offset = page_cache_offset(mapping, pos);
- while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) {
- zerofrom = curpos & ~PAGE_CACHE_MASK;
+ while (curpos = *bytes, curidx = page_cache_index(mapping, curpos),
+ index > curidx) {
+ zerofrom = page_cache_offset(mapping, curpos);
if (zerofrom & (blocksize-1)) {
*bytes |= (blocksize-1);
(*bytes)++;
}
- len = PAGE_CACHE_SIZE - zerofrom;
+ len = page_cache_size(mapping) - zerofrom;
err = pagecache_write_begin(file, mapping, curpos, len,
AOP_FLAG_UNINTERRUPTIBLE,
@@ -2235,7 +2247,7 @@ int cont_expand_zero(struct file *file,
/* page covers the boundary, find the boundary offset */
if (index == curidx) {
- zerofrom = curpos & ~PAGE_CACHE_MASK;
+ zerofrom = page_cache_offset(mapping, curpos);
/* if we will expand the thing last block will be filled */
if (offset <= zerofrom) {
goto out;
@@ -2281,7 +2293,7 @@ int cont_write_begin(struct file *file,
if (err)
goto out;
- zerofrom = *bytes & ~PAGE_CACHE_MASK;
+ zerofrom = page_cache_offset(mapping, *bytes);
if (pos+len > *bytes && zerofrom & (blocksize-1)) {
*bytes |= (blocksize-1);
(*bytes)++;
@@ -2314,8 +2326,9 @@ int block_commit_write(struct page *page
int generic_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
- struct inode *inode = page->mapping->host;
- loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ loff_t pos = page_cache_pos(mapping, page->index, to);
__block_commit_write(inode,page,from,to);
/*
* No need to use i_size_read() here, the i_size
@@ -2351,20 +2364,22 @@ block_page_mkwrite(struct vm_area_struct
unsigned long end;
loff_t size;
int ret = -EINVAL;
+ struct address_space *mapping;
lock_page(page);
+ mapping = page->mapping;
size = i_size_read(inode);
- if ((page->mapping != inode->i_mapping) ||
- (page_offset(page) > size)) {
+ if ((mapping != inode->i_mapping) ||
+ (page_cache_pos(mapping, page->index, 0) > size)) {
/* page got truncated out from underneath us */
goto out_unlock;
}
/* page is wholly or partially inside EOF */
- if (((page->index + 1) << PAGE_CACHE_SHIFT) > size)
- end = size & ~PAGE_CACHE_MASK;
+ if (page_cache_pos(mapping, page->index + 1, 0) > size)
+ end = page_cache_offset(mapping, size);
else
- end = PAGE_CACHE_SIZE;
+ end = page_cache_size(mapping);
ret = block_prepare_write(page, 0, end, get_block);
if (!ret)
@@ -2432,8 +2447,8 @@ int nobh_write_begin(struct file *file,
int ret = 0;
int is_mapped_to_disk = 1;
- index = pos >> PAGE_CACHE_SHIFT;
- from = pos & (PAGE_CACHE_SIZE - 1);
+ index = page_cache_index(mapping, pos);
+ from = page_cache_offset(mapping, pos);
to = from + len;
page = __grab_cache_page(mapping, index);
@@ -2468,7 +2483,8 @@ int nobh_write_begin(struct file *file,
goto out_release;
}
- block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
+ block_in_file = (sector_t)page->index <<
+ (page_cache_shift(mapping) - blkbits);
/*
* We loop across all blocks in the page, whether or not they are
@@ -2476,7 +2492,7 @@ int nobh_write_begin(struct file *file,
* page is fully mapped-to-disk.
*/
for (block_start = 0, block_in_page = 0, bh = head;
- block_start < PAGE_CACHE_SIZE;
+ block_start < page_cache_size(mapping);
block_in_page++, block_start += blocksize, bh = bh->b_this_page) {
int create;
@@ -2602,9 +2618,10 @@ EXPORT_SYMBOL(nobh_write_end);
int nobh_writepage(struct page *page, get_block_t *get_block,
struct writeback_control *wbc)
{
- struct inode * const inode = page->mapping->host;
+ struct address_space *mapping = page->mapping;
+ struct inode * const inode = mapping->host;
loff_t i_size = i_size_read(inode);
- const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+ const pgoff_t end_index = page_cache_index(mapping, i_size);
unsigned offset;
int ret;
@@ -2613,7 +2630,7 @@ int nobh_writepage(struct page *page, ge
goto out;
/* Is the page fully outside i_size? (truncate in progress) */
- offset = i_size & (PAGE_CACHE_SIZE-1);
+ offset = page_cache_offset(mapping, i_size);
if (page->index >= end_index+1 || !offset) {
/*
* The page may have dirty, unmapped buffers. For example,
@@ -2636,7 +2653,7 @@ int nobh_writepage(struct page *page, ge
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
- zero_user_segment(page, offset, PAGE_CACHE_SIZE);
+ zero_user_segment(page, offset, page_cache_size(mapping));
out:
ret = mpage_writepage(page, get_block, wbc);
if (ret == -EAGAIN)
@@ -2648,8 +2665,8 @@ EXPORT_SYMBOL(nobh_writepage);
int nobh_truncate_page(struct address_space *mapping,
loff_t from, get_block_t *get_block)
{
- pgoff_t index = from >> PAGE_CACHE_SHIFT;
- unsigned offset = from & (PAGE_CACHE_SIZE-1);
+ pgoff_t index = page_cache_index(mapping, from);
+ unsigned offset = page_cache_offset(mapping, from);
unsigned blocksize;
sector_t iblock;
unsigned length, pos;
@@ -2666,7 +2683,7 @@ int nobh_truncate_page(struct address_sp
return 0;
length = blocksize - length;
- iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ iblock = (sector_t)index << (page_cache_shift(mapping) - inode->i_blkbits);
page = grab_cache_page(mapping, index);
err = -ENOMEM;
@@ -2724,8 +2741,8 @@ EXPORT_SYMBOL(nobh_truncate_page);
int block_truncate_page(struct address_space *mapping,
loff_t from, get_block_t *get_block)
{
- pgoff_t index = from >> PAGE_CACHE_SHIFT;
- unsigned offset = from & (PAGE_CACHE_SIZE-1);
+ pgoff_t index = page_cache_index(mapping, from);
+ unsigned offset = page_cache_offset(mapping, from);
unsigned blocksize;
sector_t iblock;
unsigned length, pos;
@@ -2742,8 +2759,8 @@ int block_truncate_page(struct address_s
return 0;
length = blocksize - length;
- iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
-
+ iblock = (sector_t)index <<
+ (page_cache_shift(mapping) - inode->i_blkbits);
page = grab_cache_page(mapping, index);
err = -ENOMEM;
if (!page)
@@ -2802,9 +2819,10 @@ out:
int block_write_full_page(struct page *page, get_block_t *get_block,
struct writeback_control *wbc)
{
- struct inode * const inode = page->mapping->host;
+ struct address_space *mapping = page->mapping;
+ struct inode * const inode = mapping->host;
loff_t i_size = i_size_read(inode);
- const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+ const pgoff_t end_index = page_cache_index(mapping, i_size);
unsigned offset;
/* Is the page fully inside i_size? */
@@ -2812,7 +2830,7 @@ int block_write_full_page(struct page *p
return __block_write_full_page(inode, page, get_block, wbc);
/* Is the page fully outside i_size? (truncate in progress) */
- offset = i_size & (PAGE_CACHE_SIZE-1);
+ offset = page_cache_offset(mapping, i_size);
if (page->index >= end_index+1 || !offset) {
/*
* The page may have dirty, unmapped buffers. For example,
@@ -2831,7 +2849,7 @@ int block_write_full_page(struct page *p
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
- zero_user_segment(page, offset, PAGE_CACHE_SIZE);
+ zero_user_segment(page, offset, page_cache_size(mapping));
return __block_write_full_page(inode, page, get_block, wbc);
}
@@ -3081,7 +3099,7 @@ int try_to_free_buffers(struct page *pag
* dirty bit from being lost.
*/
if (ret)
- cancel_dirty_page(page, PAGE_CACHE_SIZE);
+ cancel_dirty_page(page, page_cache_size(mapping));
spin_unlock(&mapping->private_lock);
out:
if (buffers_to_free) {
--
-
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