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authorSage Weil <sage@newdream.net>2011-08-03 09:58:09 -0700
committerSage Weil <sage@newdream.net>2011-10-25 16:10:14 -0700
commit7c272194e66e91830b90f6202e61c69f8590f1eb (patch)
tree9a899f357cbf005235fd80ab3b4a240e42498b54 /fs/ceph
parentc3b92c8787367a8bb53d57d9789b558f1295cc96 (diff)
downloadlinux-rt-7c272194e66e91830b90f6202e61c69f8590f1eb.tar.gz
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>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/addr.c185
1 files changed, 115 insertions, 70 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5a3953db8118..5bb39a50f904 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -228,102 +228,147 @@ 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 page **pages;
- struct page *page;
- int next_index, contig_pages = 0;
+ struct inode *inode = req->r_inode;
+ struct ceph_osd_reply_head *replyhead;
+ int rc, bytes;
+ int i;
- /* build page vector */
- pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
- if (!pages)
- return ERR_PTR(-ENOMEM);
+ /* 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);
- 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;
+ 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);
}
- *nr_pages = contig_pages;
- return pages;
+ kfree(req->r_pages);
}
/*
- * Read multiple pages. Leave pages we don't read + unlock in page_list;
- * the caller (VM) cleans them up.
+ * start an async read(ahead) operation. return nr_pages we submitted
+ * a read for on success, or negative error code.
*/
-static int ceph_readpages(struct file *file, struct address_space *mapping,
- struct list_head *page_list, unsigned nr_pages)
+static int start_read(struct inode *inode, struct list_head *page_list)
{
- 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;
+ 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;
+ pgoff_t next_index;
+ int nr_pages = 0;
+ int ret;
- 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);
+ off = page->index << PAGE_CACHE_SHIFT;
- /* guess read extent */
- offset = pages[0]->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;
- 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);
+ 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 */
+ nr_pages = len >> PAGE_CACHE_SHIFT;
+ pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
+ ret = -ENOMEM;
+ if (!pages)
+ 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);
-
- 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,
+
+ 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("readpages %p add_to_page_cache failed %p\n",
+ dout("start_read %p add_to_page_cache failed %p\n",
inode, page);
- continue;
+ nr_pages = i;
+ goto out_pages;
}
- 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);
+ pages[i] = page;
}
- rc = 0;
+ 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:
+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.
+ */
+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;
+ int rc = 0;
+
+ 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);
+ }
+out:
+ dout("readpages %p file %p ret %d\n", inode, file, rc);
return rc;
}