lkml.org 
[lkml]   [2010]   [Jul]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] ocfs2: When zero extending, do it by page.
Date
ocfs2_zero_extend() does its zeroing block by block, but it calls a
function named ocfs2_write_zero_page(). Let's have
ocfs2_write_zero_page() handle the page level. From
ocfs2_zero_extend()'s perspective, it is now page-at-a-time.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
---
fs/ocfs2/aops.c | 30 --------------
fs/ocfs2/file.c | 119 +++++++++++++++++++++++++++++++++++++++----------------
2 files changed, 85 insertions(+), 64 deletions(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 3623ca2..9a5c931 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -459,36 +459,6 @@ int walk_page_buffers( handle_t *handle,
return ret;
}

-handle_t *ocfs2_start_walk_page_trans(struct inode *inode,
- struct page *page,
- unsigned from,
- unsigned to)
-{
- struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
- handle_t *handle;
- int ret = 0;
-
- handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
- if (IS_ERR(handle)) {
- ret = -ENOMEM;
- mlog_errno(ret);
- goto out;
- }
-
- if (ocfs2_should_order_data(inode)) {
- ret = ocfs2_jbd2_file_inode(handle, inode);
- if (ret < 0)
- mlog_errno(ret);
- }
-out:
- if (ret) {
- if (!IS_ERR(handle))
- ocfs2_commit_trans(osb, handle);
- handle = ERR_PTR(ret);
- }
- return handle;
-}
-
static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
{
sector_t status;
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 6a13ea6..a6e0eb6 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -724,28 +724,55 @@ leave:
return status;
}

+/*
+ * While a write will already be ordering the data, a truncate will not.
+ * Thus, we need to explicitly order the zeroed pages.
+ */
+static handle_t *ocfs2_zero_start_ordered_transaction(struct inode *inode)
+{
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ handle_t *handle = NULL;
+ int ret = 0;
+
+ if (ocfs2_should_order_data(inode))
+ goto out;
+
+ handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+ if (IS_ERR(handle)) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_jbd2_file_inode(handle, inode);
+ if (ret < 0)
+ mlog_errno(ret);
+
+out:
+ if (ret) {
+ if (!IS_ERR(handle))
+ ocfs2_commit_trans(osb, handle);
+ handle = ERR_PTR(ret);
+ }
+ return handle;
+}
+
/* Some parts of this taken from generic_cont_expand, which turned out
* to be too fragile to do exactly what we need without us having to
* worry about recursive locking in ->write_begin() and ->write_end(). */
-static int ocfs2_write_zero_page(struct inode *inode,
- u64 size)
+static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from,
+ u64 abs_to)
{
struct address_space *mapping = inode->i_mapping;
struct page *page;
- unsigned long index;
- unsigned int offset;
+ unsigned long index = abs_from >> PAGE_CACHE_SHIFT;
handle_t *handle = NULL;
int ret;
+ unsigned zero_from, zero_to, block_start, block_end;

- 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
- */
- if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
- offset++;
- }
- index = size >> PAGE_CACHE_SHIFT;
+ BUG_ON(abs_from >= abs_to);
+ BUG_ON(abs_to > ((index + 1) << PAGE_CACHE_SHIFT));
+ BUG_ON(abs_from & (inode->i_blkbits - 1));

page = grab_cache_page(mapping, index);
if (!page) {
@@ -754,31 +781,52 @@ static int ocfs2_write_zero_page(struct inode *inode,
goto out;
}

- ret = ocfs2_prepare_write_nolock(inode, page, offset, offset);
- if (ret < 0) {
- mlog_errno(ret);
- goto out_unlock;
- }
+ /* Get the offsets within the page that we want to zero */
+ zero_from = abs_from & (PAGE_CACHE_SIZE - 1);
+ zero_to = abs_to & (PAGE_CACHE_SIZE - 1);
+ if (!zero_to)
+ zero_to = PAGE_CACHE_SIZE;

- if (ocfs2_should_order_data(inode)) {
- handle = ocfs2_start_walk_page_trans(inode, page, offset,
- offset);
- if (IS_ERR(handle)) {
- ret = PTR_ERR(handle);
- handle = NULL;
+ /* We know that zero_from is block aligned */
+ for (block_start = zero_from;
+ (block_start < PAGE_CACHE_SIZE) && (block_start < zero_to);
+ block_start = block_end) {
+ block_end = block_start + (1 << inode->i_blkbits);
+
+ /*
+ * block_start is block-aligned. Bump it by one to
+ * force ocfs2_{prepare,commit}_write() to zero the
+ * whole block.
+ */
+ ret = ocfs2_prepare_write_nolock(inode, page,
+ block_start + 1,
+ block_start + 1);
+ if (ret < 0) {
+ mlog_errno(ret);
goto out_unlock;
}
- }

- /* must not update i_size! */
- ret = block_commit_write(page, offset, offset);
- if (ret < 0)
- mlog_errno(ret);
- else
- ret = 0;
+ if (!handle) {
+ handle = ocfs2_zero_start_ordered_transaction(inode);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ handle = NULL;
+ break;
+ }
+ }
+
+ /* must not update i_size! */
+ ret = block_commit_write(page, block_start + 1,
+ block_start + 1);
+ if (ret < 0)
+ mlog_errno(ret);
+ else
+ ret = 0;
+ }

if (handle)
ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
+
out_unlock:
unlock_page(page);
page_cache_release(page);
@@ -790,18 +838,21 @@ static int ocfs2_zero_extend(struct inode *inode,
u64 zero_to_size)
{
int ret = 0;
- u64 start_off;
+ u64 start_off, next_off;
struct super_block *sb = inode->i_sb;

start_off = ocfs2_align_bytes_to_blocks(sb, i_size_read(inode));
while (start_off < zero_to_size) {
- ret = ocfs2_write_zero_page(inode, start_off);
+ next_off = (start_off & PAGE_CACHE_MASK) + PAGE_CACHE_SIZE;
+ if (next_off > zero_to_size)
+ next_off = zero_to_size;
+ ret = ocfs2_write_zero_page(inode, start_off, next_off);
if (ret < 0) {
mlog_errno(ret);
goto out;
}

- start_off += sb->s_blocksize;
+ start_off = next_off;

/*
* Very large extends have the potential to lock up
--
1.7.1


\
 
 \ /
  Last update: 2010-07-07 13:21    [from the cache]
©2003-2011 Jasper Spaans