ocfs2: rework ocfs2_buffered_write_cluster()
Use some ideas from the new-aops patch series and turn
ocfs2_buffered_write_cluster() into a 2 stage operation with the caller
copying data in between. The code now understands multiple cluster writes as
a result of having to deal with a full page write for greater than 4k pages.
This sets us up to easily call into the write path during ->page_mkwrite().
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 566f9b7..4c850d0 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1335,15 +1335,16 @@
*basep = base;
}
-static struct page * ocfs2_get_write_source(struct ocfs2_buffered_write_priv *bp,
+static struct page * ocfs2_get_write_source(char **ret_src_buf,
const struct iovec *cur_iov,
size_t iov_offset)
{
int ret;
- char *buf;
+ char *buf = cur_iov->iov_base + iov_offset;
struct page *src_page = NULL;
+ unsigned long off;
- buf = cur_iov->iov_base + iov_offset;
+ off = (unsigned long)(buf) & ~PAGE_CACHE_MASK;
if (!segment_eq(get_fs(), KERNEL_DS)) {
/*
@@ -1355,18 +1356,17 @@
(unsigned long)buf & PAGE_CACHE_MASK, 1,
0, 0, &src_page, NULL);
if (ret == 1)
- bp->b_src_buf = kmap(src_page);
+ *ret_src_buf = kmap(src_page) + off;
else
src_page = ERR_PTR(-EFAULT);
} else {
- bp->b_src_buf = buf;
+ *ret_src_buf = buf;
}
return src_page;
}
-static void ocfs2_put_write_source(struct ocfs2_buffered_write_priv *bp,
- struct page *page)
+static void ocfs2_put_write_source(struct page *page)
{
if (page) {
kunmap(page);
@@ -1382,10 +1382,12 @@
{
int ret = 0;
ssize_t copied, total = 0;
- size_t iov_offset = 0;
+ size_t iov_offset = 0, bytes;
+ loff_t pos;
const struct iovec *cur_iov = iov;
- struct ocfs2_buffered_write_priv bp;
- struct page *page;
+ struct page *user_page, *page;
+ char *buf, *dst;
+ void *fsdata;
/*
* handle partial DIO write. Adjust cur_iov if needed.
@@ -1393,21 +1395,38 @@
ocfs2_set_next_iovec(&cur_iov, &iov_offset, o_direct_written);
do {
- bp.b_cur_off = iov_offset;
- bp.b_cur_iov = cur_iov;
+ pos = *ppos;
- page = ocfs2_get_write_source(&bp, cur_iov, iov_offset);
- if (IS_ERR(page)) {
- ret = PTR_ERR(page);
+ user_page = ocfs2_get_write_source(&buf, cur_iov, iov_offset);
+ if (IS_ERR(user_page)) {
+ ret = PTR_ERR(user_page);
goto out;
}
- copied = ocfs2_buffered_write_cluster(file, *ppos, count,
- ocfs2_map_and_write_user_data,
- &bp);
+ /* Stay within our page boundaries */
+ bytes = min((PAGE_CACHE_SIZE - ((unsigned long)pos & ~PAGE_CACHE_MASK)),
+ (PAGE_CACHE_SIZE - ((unsigned long)buf & ~PAGE_CACHE_MASK)));
+ /* Stay within the vector boundary */
+ bytes = min_t(size_t, bytes, cur_iov->iov_len - iov_offset);
+ /* Stay within count */
+ bytes = min(bytes, count);
- ocfs2_put_write_source(&bp, page);
+ page = NULL;
+ ret = ocfs2_write_begin(file, file->f_mapping, pos, bytes, 0,
+ &page, &fsdata);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ dst = kmap_atomic(page, KM_USER0);
+ memcpy(dst + (pos & (PAGE_CACHE_SIZE - 1)), buf, bytes);
+ kunmap_atomic(dst, KM_USER0);
+ flush_dcache_page(page);
+ ocfs2_put_write_source(user_page);
+
+ copied = ocfs2_write_end(file, file->f_mapping, pos, bytes,
+ bytes, page, fsdata);
if (copied < 0) {
mlog_errno(copied);
ret = copied;
@@ -1415,7 +1434,7 @@
}
total += copied;
- *ppos = *ppos + copied;
+ *ppos = pos + copied;
count -= copied;
ocfs2_set_next_iovec(&cur_iov, &iov_offset, copied);
@@ -1585,52 +1604,46 @@
struct pipe_buffer *buf,
struct splice_desc *sd)
{
- int ret, count, total = 0;
+ int ret, count;
ssize_t copied = 0;
- struct ocfs2_splice_write_priv sp;
+ struct file *file = sd->u.file;
+ unsigned int offset;
+ struct page *page = NULL;
+ void *fsdata;
+ char *src, *dst;
ret = buf->ops->confirm(pipe, buf);
if (ret)
goto out;
- sp.s_sd = sd;
- sp.s_buf = buf;
- sp.s_pipe = pipe;
- sp.s_offset = sd->pos & ~PAGE_CACHE_MASK;
- sp.s_buf_offset = buf->offset;
-
+ offset = sd->pos & ~PAGE_CACHE_MASK;
count = sd->len;
- if (count + sp.s_offset > PAGE_CACHE_SIZE)
- count = PAGE_CACHE_SIZE - sp.s_offset;
+ if (count + offset > PAGE_CACHE_SIZE)
+ count = PAGE_CACHE_SIZE - offset;
- do {
- /*
- * splice wants us to copy up to one page at a
- * time. For pagesize > cluster size, this means we
- * might enter ocfs2_buffered_write_cluster() more
- * than once, so keep track of our progress here.
- */
- copied = ocfs2_buffered_write_cluster(sd->u.file,
- (loff_t)sd->pos + total,
- count,
- ocfs2_map_and_write_splice_data,
- &sp);
- if (copied < 0) {
- mlog_errno(copied);
- ret = copied;
- goto out;
- }
+ ret = ocfs2_write_begin(file, file->f_mapping, sd->pos, count, 0,
+ &page, &fsdata);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
- count -= copied;
- sp.s_offset += copied;
- sp.s_buf_offset += copied;
- total += copied;
- } while (count);
+ src = buf->ops->map(pipe, buf, 1);
+ dst = kmap_atomic(page, KM_USER1);
+ memcpy(dst + offset, src + buf->offset, count);
+ kunmap_atomic(page, KM_USER1);
+ buf->ops->unmap(pipe, buf, src);
- ret = 0;
+ copied = ocfs2_write_end(file, file->f_mapping, sd->pos, count, count,
+ page, fsdata);
+ if (copied < 0) {
+ mlog_errno(copied);
+ ret = copied;
+ goto out;
+ }
out:
- return total ? total : ret;
+ return copied ? copied : ret;
}
static ssize_t __ocfs2_file_splice_write(struct pipe_inode_info *pipe,