2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-14 00:04:00 +08:00

ceph: make readpages fully async

When we get a ->readpages() aop, submit async reads for all page ranges
in the provided page list.  Lock the pages immediately, so that VFS/MM
will block until the reads complete.

Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2011-08-03 09:58:09 -07:00
parent c3b92c8787
commit 7c272194e6

View File

@ -228,36 +228,128 @@ static int ceph_readpage(struct file *filp, struct page *page)
}
/*
* Build a vector of contiguous pages from the provided page list.
* Finish an async read(ahead) op.
*/
static struct page **page_vector_from_list(struct list_head *page_list,
unsigned *nr_pages)
static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
{
struct inode *inode = req->r_inode;
struct ceph_osd_reply_head *replyhead;
int rc, bytes;
int i;
/* parse reply */
replyhead = msg->front.iov_base;
WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
rc = le32_to_cpu(replyhead->result);
bytes = le32_to_cpu(msg->hdr.data_len);
dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
/* unlock all pages, zeroing any data we didn't read */
for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) {
struct page *page = req->r_pages[i];
if (bytes < (int)PAGE_CACHE_SIZE) {
/* zero (remainder of) page */
int s = bytes < 0 ? 0 : bytes;
zero_user_segment(page, s, PAGE_CACHE_SIZE);
}
dout("finish_read %p uptodate %p idx %lu\n", inode, page,
page->index);
flush_dcache_page(page);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
}
kfree(req->r_pages);
}
/*
* start an async read(ahead) operation. return nr_pages we submitted
* a read for on success, or negative error code.
*/
static int start_read(struct inode *inode, struct list_head *page_list)
{
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
struct ceph_inode_info *ci = ceph_inode(inode);
struct page *page = list_entry(page_list->prev, struct page, lru);
struct ceph_osd_request *req;
u64 off;
u64 len;
int i;
struct page **pages;
struct page *page;
int next_index, contig_pages = 0;
pgoff_t next_index;
int nr_pages = 0;
int ret;
off = page->index << PAGE_CACHE_SHIFT;
/* count pages */
next_index = page->index;
list_for_each_entry_reverse(page, page_list, lru) {
if (page->index != next_index)
break;
nr_pages++;
next_index++;
}
len = nr_pages << PAGE_CACHE_SHIFT;
dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
off, len);
req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode),
off, &len,
CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
NULL, 0,
ci->i_truncate_seq, ci->i_truncate_size,
NULL, false, 1, 0);
if (!req)
return -ENOMEM;
/* build page vector */
pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
nr_pages = len >> PAGE_CACHE_SHIFT;
pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
ret = -ENOMEM;
if (!pages)
return ERR_PTR(-ENOMEM);
BUG_ON(list_empty(page_list));
next_index = list_entry(page_list->prev, struct page, lru)->index;
list_for_each_entry_reverse(page, page_list, lru) {
if (page->index == next_index) {
dout("readpages page %d %p\n", contig_pages, page);
pages[contig_pages] = page;
contig_pages++;
next_index++;
} else {
break;
goto out;
for (i = 0; i < nr_pages; ++i) {
page = list_entry(page_list->prev, struct page, lru);
BUG_ON(PageLocked(page));
list_del(&page->lru);
dout("start_read %p adding %p idx %lu\n", inode, page,
page->index);
if (add_to_page_cache_lru(page, &inode->i_data, page->index,
GFP_NOFS)) {
page_cache_release(page);
dout("start_read %p add_to_page_cache failed %p\n",
inode, page);
nr_pages = i;
goto out_pages;
}
pages[i] = page;
}
*nr_pages = contig_pages;
return pages;
req->r_pages = pages;
req->r_num_pages = nr_pages;
req->r_callback = finish_read;
req->r_inode = inode;
dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
ret = ceph_osdc_start_request(osdc, req, false);
if (ret < 0)
goto out_pages;
ceph_osdc_put_request(req);
return nr_pages;
out_pages:
ceph_release_page_vector(pages, nr_pages);
kfree(pages);
out:
ceph_osdc_put_request(req);
return ret;
}
/*
* Read multiple pages. Leave pages we don't read + unlock in page_list;
* the caller (VM) cleans them up.
@ -266,64 +358,17 @@ static int ceph_readpages(struct file *file, struct address_space *mapping,
struct list_head *page_list, unsigned nr_pages)
{
struct inode *inode = file->f_dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
int rc = 0;
struct page **pages;
loff_t offset;
u64 len;
dout("readpages %p file %p nr_pages %d\n",
inode, file, nr_pages);
pages = page_vector_from_list(page_list, &nr_pages);
if (IS_ERR(pages))
return PTR_ERR(pages);
/* guess read extent */
offset = pages[0]->index << PAGE_CACHE_SHIFT;
len = nr_pages << PAGE_CACHE_SHIFT;
rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
offset, &len,
ci->i_truncate_seq, ci->i_truncate_size,
pages, nr_pages, 0);
if (rc == -ENOENT)
rc = 0;
if (rc < 0)
goto out;
for (; !list_empty(page_list) && len > 0;
rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
struct page *page =
list_entry(page_list->prev, struct page, lru);
list_del(&page->lru);
if (rc < (int)PAGE_CACHE_SIZE) {
/* zero (remainder of) page */
int s = rc < 0 ? 0 : rc;
zero_user_segment(page, s, PAGE_CACHE_SIZE);
}
if (add_to_page_cache_lru(page, mapping, page->index,
GFP_NOFS)) {
page_cache_release(page);
dout("readpages %p add_to_page_cache failed %p\n",
inode, page);
continue;
}
dout("readpages %p adding %p idx %lu\n", inode, page,
page->index);
flush_dcache_page(page);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
dout("readpages %p file %p nr_pages %d\n", inode, file, nr_pages);
while (!list_empty(page_list)) {
rc = start_read(inode, page_list);
if (rc < 0)
goto out;
BUG_ON(rc == 0);
}
rc = 0;
out:
kfree(pages);
dout("readpages %p file %p ret %d\n", inode, file, rc);
return rc;
}