Commit 4f6f0bd2 authored by Jens Axboe's avatar Jens Axboe
Browse files

[PATCH] splice: improve writeback and clean up page stealing



By cleaning up the writeback logic (killing write_one_page() and the manual
set_page_dirty()), we can get rid of ->stolen inside the pipe_buffer and
just keep it local in pipe_to_file().

This also adds dirty page balancing logic and O_SYNC handling.
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent 53cd9ae8
......@@ -124,7 +124,6 @@ static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer
static int anon_pipe_buf_steal(struct pipe_inode_info *info,
struct pipe_buffer *buf)
{
buf->stolen = 1;
return 0;
}
......
......@@ -22,7 +22,10 @@
#include <linux/pipe_fs_i.h>
#include <linux/mm_inline.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/module.h>
#include <linux/syscalls.h>
/*
* Passed to the actors
......@@ -38,11 +41,15 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
struct pipe_buffer *buf)
{
struct page *page = buf->page;
struct address_space *mapping = page_mapping(page);
WARN_ON(!PageLocked(page));
WARN_ON(!PageUptodate(page));
if (!remove_mapping(page_mapping(page), page))
if (PagePrivate(page))
try_to_release_page(page, mapping_gfp_mask(mapping));
if (!remove_mapping(mapping, page))
return 1;
if (PageLRU(page)) {
......@@ -55,7 +62,6 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info,
spin_unlock_irq(&zone->lru_lock);
}
buf->stolen = 1;
return 0;
}
......@@ -64,7 +70,6 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info,
{
page_cache_release(buf->page);
buf->page = NULL;
buf->stolen = 0;
}
static void *page_cache_pipe_buf_map(struct file *file,
......@@ -91,8 +96,7 @@ static void *page_cache_pipe_buf_map(struct file *file,
static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info,
struct pipe_buffer *buf)
{
if (!buf->stolen)
unlock_page(buf->page);
unlock_page(buf->page);
kunmap(buf->page);
}
......@@ -319,7 +323,8 @@ ssize_t generic_file_splice_read(struct file *in, struct inode *pipe,
}
/*
* Send 'len' bytes to socket from 'file' at position 'pos' using sendpage().
* Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
* using sendpage().
*/
static int pipe_to_sendpage(struct pipe_inode_info *info,
struct pipe_buffer *buf, struct splice_desc *sd)
......@@ -379,7 +384,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
struct page *page;
pgoff_t index;
char *src;
int ret;
int ret, stolen;
/*
* after this, page will be locked and unmapped
......@@ -390,6 +395,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
index = sd->pos >> PAGE_CACHE_SHIFT;
offset = sd->pos & ~PAGE_CACHE_MASK;
stolen = 0;
/*
* reuse buf page, if SPLICE_F_MOVE is set
......@@ -399,6 +405,7 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf,
goto find_page;
page = buf->page;
stolen = 1;
if (add_to_page_cache_lru(page, mapping, index,
mapping_gfp_mask(mapping)))
goto find_page;
......@@ -443,10 +450,13 @@ find_page:
}
ret = mapping->a_ops->prepare_write(file, page, 0, sd->len);
if (ret)
if (ret == AOP_TRUNCATED_PAGE) {
page_cache_release(page);
goto find_page;
} else if (ret)
goto out;
if (!buf->stolen) {
if (!stolen) {
char *dst = kmap_atomic(page, KM_USER0);
memcpy(dst + offset, src + buf->offset, sd->len);
......@@ -455,16 +465,18 @@ find_page:
}
ret = mapping->a_ops->commit_write(file, page, 0, sd->len);
if (ret < 0)
if (ret == AOP_TRUNCATED_PAGE) {
page_cache_release(page);
goto find_page;
} else if (ret)
goto out;
set_page_dirty(page);
ret = write_one_page(page, 0);
balance_dirty_pages_ratelimited(mapping);
out:
if (ret < 0)
unlock_page(page);
if (!buf->stolen)
if (!stolen) {
page_cache_release(page);
unlock_page(page);
}
buf->ops->unmap(info, buf);
return ret;
}
......@@ -576,7 +588,27 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out,
ssize_t generic_file_splice_write(struct inode *inode, struct file *out,
size_t len, unsigned int flags)
{
return move_from_pipe(inode, out, len, flags, pipe_to_file);
struct address_space *mapping = out->f_mapping;
ssize_t ret = move_from_pipe(inode, out, len, flags, pipe_to_file);
/*
* if file or inode is SYNC and we actually wrote some data, sync it
*/
if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(mapping->host))
&& ret > 0) {
struct inode *inode = mapping->host;
int err;
mutex_lock(&inode->i_mutex);
err = generic_osync_inode(mapping->host, mapping,
OSYNC_METADATA|OSYNC_DATA);
mutex_unlock(&inode->i_mutex);
if (err)
ret = err;
}
return ret;
}
ssize_t generic_splice_sendpage(struct inode *inode, struct file *out,
......
......@@ -9,7 +9,6 @@ struct pipe_buffer {
struct page *page;
unsigned int offset, len;
struct pipe_buf_operations *ops;
unsigned int stolen;
};
struct pipe_buf_operations {
......
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