[PATCH] Add nobh_writepage() support
Hi Andrew,
Here is the patch to add nobh_wripage() support for the filesystems
which uses nobh_prepare_write/nobh_commit_write().
Idea here is to reduce unnecessary bufferhead creation/attachment
to the page through block_write_full_page(). nobh_wripage() tries
to operate by directly creating bios, but it falls back to
__block_write_full_page() if it can't make progress.
Note that this is not really generic routine and can't be used
for filesystems which uses page->Private for anything other
than buffer heads.
BTW, my next set of patches are to add ext3_writepages() support
for writeback mode and to add "nobh" support for ext3 writeback
mode - which are based on some of this work (These are already
discussed on ext2-devel).
And also, this needs some airtime in -mm tree before hitting mainline.
Thanks,
Badari
Signed-off-by: Badari Pulavarty <[EMAIL PROTECTED]>
diff -Narup -X dontdiff linux-2.6.10/fs/buffer.c linux-2.6.10.nobh/fs/buffer.c
--- linux-2.6.10/fs/buffer.c2004-12-24 13:34:58.0 -0800
+++ linux-2.6.10.nobh/fs/buffer.c 2005-02-18 14:52:20.707345056 -0800
@@ -39,6 +39,7 @@
#include
#include
#include
+#include
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
static void invalidate_bh_lrus(void);
@@ -2492,6 +2493,62 @@ int nobh_commit_write(struct file *file,
EXPORT_SYMBOL(nobh_commit_write);
/*
+ * nobh_writepage() - based on block_full_write_page() except
+ * that it tries to operate without attaching bufferheads to
+ * the page.
+ */
+int nobh_writepage(struct page *page, get_block_t *get_block,
+ struct writeback_control *wbc)
+{
+ struct inode * const inode = page->mapping->host;
+ loff_t i_size = i_size_read(inode);
+ const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+ unsigned offset;
+ void *kaddr;
+ int ret;
+
+ /* Is the page fully inside i_size? */
+ if (page->index < end_index) {
+ goto out;
+ }
+
+ /* Is the page fully outside i_size? (truncate in progress) */
+ offset = i_size & (PAGE_CACHE_SIZE-1);
+ if (page->index >= end_index+1 || !offset) {
+ /*
+* The page may have dirty, unmapped buffers. For example,
+* they may have been added in ext3_writepage(). Make them
+* freeable here, so the page does not leak.
+*/
+#if 0
+ /* Not really sure about this - do we need this ? */
+ if (page->mapping->a_ops->invalidatepage)
+ page->mapping->a_ops->invalidatepage(page, offset);
+#endif
+ unlock_page(page);
+ return 0; /* don't care */
+ }
+
+ /*
+* The page straddles i_size. It must be zeroed out on each and every
+* writepage invocation because it may be mmapped. "A file is mapped
+* in multiples of the page size. For a file that is not a multiple of
+* the page size, the remaining memory is zeroed when mapped, and
+* writes to that region are not written out to the file."
+*/
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+out:
+ ret = mpage_writepage(page, get_block, wbc);
+ if (ret == -EAGAIN)
+ ret = __block_write_full_page(inode, page, get_block, wbc);
+ return ret;
+}
+EXPORT_SYMBOL(nobh_writepage);
+
+/*
* This function assumes that ->prepare_write() uses nobh_prepare_write().
*/
int nobh_truncate_page(struct address_space *mapping, loff_t from)
diff -Narup -X dontdiff linux-2.6.10/fs/ext2/inode.c
linux-2.6.10.nobh/fs/ext2/inode.c
--- linux-2.6.10/fs/ext2/inode.c2004-12-24 13:33:51.0 -0800
+++ linux-2.6.10.nobh/fs/ext2/inode.c 2005-02-16 16:27:32.0 -0800
@@ -626,6 +626,12 @@ ext2_nobh_prepare_write(struct file *fil
return nobh_prepare_write(page,from,to,ext2_get_block);
}
+static int ext2_nobh_writepage(struct page *page,
+ struct writeback_control *wbc)
+{
+ return nobh_writepage(page, ext2_get_block, wbc);
+}
+
static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping,block,ext2_get_block);
@@ -675,7 +681,7 @@ struct address_space_operations ext2_aop
struct address_space_operations ext2_nobh_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
- .writepage = ext2_writepage,
+ .writepage = ext2_nobh_writepage,
.sync_page = block_sync_page,
.prepare_write = ext2_nobh_prepare_write,
.commit_write = nobh_commit_write,
diff -Narup -X dontdiff linux-2.6.10/fs/jfs/inode.c
linux-2.6.10.nobh/fs/jfs/inode.c
--- linux-2.6.10/fs/jfs/inode.c 2004-12-24
[PATCH] Add nobh_writepage() support
Hi Andrew,
Here is the patch to add nobh_wripage() support for the filesystems
which uses nobh_prepare_write/nobh_commit_write().
Idea here is to reduce unnecessary bufferhead creation/attachment
to the page through block_write_full_page(). nobh_wripage() tries
to operate by directly creating bios, but it falls back to
__block_write_full_page() if it can't make progress.
Note that this is not really generic routine and can't be used
for filesystems which uses page-Private for anything other
than buffer heads.
BTW, my next set of patches are to add ext3_writepages() support
for writeback mode and to add nobh support for ext3 writeback
mode - which are based on some of this work (These are already
discussed on ext2-devel).
And also, this needs some airtime in -mm tree before hitting mainline.
Thanks,
Badari
Signed-off-by: Badari Pulavarty [EMAIL PROTECTED]
diff -Narup -X dontdiff linux-2.6.10/fs/buffer.c linux-2.6.10.nobh/fs/buffer.c
--- linux-2.6.10/fs/buffer.c2004-12-24 13:34:58.0 -0800
+++ linux-2.6.10.nobh/fs/buffer.c 2005-02-18 14:52:20.707345056 -0800
@@ -39,6 +39,7 @@
#include linux/notifier.h
#include linux/cpu.h
#include linux/bitops.h
+#include linux/mpage.h
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
static void invalidate_bh_lrus(void);
@@ -2492,6 +2493,62 @@ int nobh_commit_write(struct file *file,
EXPORT_SYMBOL(nobh_commit_write);
/*
+ * nobh_writepage() - based on block_full_write_page() except
+ * that it tries to operate without attaching bufferheads to
+ * the page.
+ */
+int nobh_writepage(struct page *page, get_block_t *get_block,
+ struct writeback_control *wbc)
+{
+ struct inode * const inode = page-mapping-host;
+ loff_t i_size = i_size_read(inode);
+ const pgoff_t end_index = i_size PAGE_CACHE_SHIFT;
+ unsigned offset;
+ void *kaddr;
+ int ret;
+
+ /* Is the page fully inside i_size? */
+ if (page-index end_index) {
+ goto out;
+ }
+
+ /* Is the page fully outside i_size? (truncate in progress) */
+ offset = i_size (PAGE_CACHE_SIZE-1);
+ if (page-index = end_index+1 || !offset) {
+ /*
+* The page may have dirty, unmapped buffers. For example,
+* they may have been added in ext3_writepage(). Make them
+* freeable here, so the page does not leak.
+*/
+#if 0
+ /* Not really sure about this - do we need this ? */
+ if (page-mapping-a_ops-invalidatepage)
+ page-mapping-a_ops-invalidatepage(page, offset);
+#endif
+ unlock_page(page);
+ return 0; /* don't care */
+ }
+
+ /*
+* The page straddles i_size. It must be zeroed out on each and every
+* writepage invocation because it may be mmapped. A file is mapped
+* in multiples of the page size. For a file that is not a multiple of
+* the page size, the remaining memory is zeroed when mapped, and
+* writes to that region are not written out to the file.
+*/
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+out:
+ ret = mpage_writepage(page, get_block, wbc);
+ if (ret == -EAGAIN)
+ ret = __block_write_full_page(inode, page, get_block, wbc);
+ return ret;
+}
+EXPORT_SYMBOL(nobh_writepage);
+
+/*
* This function assumes that -prepare_write() uses nobh_prepare_write().
*/
int nobh_truncate_page(struct address_space *mapping, loff_t from)
diff -Narup -X dontdiff linux-2.6.10/fs/ext2/inode.c
linux-2.6.10.nobh/fs/ext2/inode.c
--- linux-2.6.10/fs/ext2/inode.c2004-12-24 13:33:51.0 -0800
+++ linux-2.6.10.nobh/fs/ext2/inode.c 2005-02-16 16:27:32.0 -0800
@@ -626,6 +626,12 @@ ext2_nobh_prepare_write(struct file *fil
return nobh_prepare_write(page,from,to,ext2_get_block);
}
+static int ext2_nobh_writepage(struct page *page,
+ struct writeback_control *wbc)
+{
+ return nobh_writepage(page, ext2_get_block, wbc);
+}
+
static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping,block,ext2_get_block);
@@ -675,7 +681,7 @@ struct address_space_operations ext2_aop
struct address_space_operations ext2_nobh_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
- .writepage = ext2_writepage,
+ .writepage = ext2_nobh_writepage,
.sync_page = block_sync_page,
.prepare_write = ext2_nobh_prepare_write,
.commit_write = nobh_commit_write,
diff -Narup -X dontdiff linux-2.6.10/fs/jfs/inode.c
linux-2.6.10.nobh/fs/jfs/inode.c
---
