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ocfs2: When zero extending, do it by page.
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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>
Cc: stable@kernel.org
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Joel Becker committed Jul 8, 2010
1 parent 1739da4 commit a4bfb4c
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Showing 2 changed files with 84 additions and 64 deletions.
30 changes: 0 additions & 30 deletions fs/ocfs2/aops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
118 changes: 84 additions & 34 deletions fs/ocfs2/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -724,28 +724,55 @@ static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
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 > (((u64)index + 1) << PAGE_CACHE_SHIFT));
BUG_ON(abs_from & (inode->i_blkbits - 1));

page = grab_cache_page(mapping, index);
if (!page) {
Expand All @@ -754,31 +781,51 @@ 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 < 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);
Expand All @@ -790,18 +837,21 @@ 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
Expand Down

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