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authorYan, Zheng <zyan@redhat.com>2018-09-29 16:02:19 +0800
committerIlya Dryomov <idryomov@gmail.com>2018-10-22 10:28:20 +0200
commitfce7a9744bdf3baa9d08c52d2c78f53ab49918a4 (patch)
tree790648e3726259f60619a8a8b455f86cef9c37b0 /fs/ceph
parent74c9e6bf4c888e41bc7db340fb94fade96394038 (diff)
ceph: refactor ceph_sync_read()
Avoid allocating memory for the entire user request: striped_read() does a synchronous OSD request per object, so it doesn't need more than object size worth of pages at a time. [ Preserve the comment, changelog. ] Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/file.c219
1 files changed, 106 insertions, 113 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 92ab20433682..846997481674 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -557,90 +557,26 @@ enum {
};
/*
- * Read a range of bytes striped over one or more objects. Iterate over
- * objects we stripe over. (That's not atomic, but good enough for now.)
- *
- * If we get a short result from the OSD, check against i_size; we need to
- * only return a short read to the caller if we hit EOF.
- */
-static int striped_read(struct inode *inode,
- u64 pos, u64 len,
- struct page **pages, int num_pages,
- int page_align, int *checkeof)
-{
- struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
- struct ceph_inode_info *ci = ceph_inode(inode);
- u64 this_len;
- loff_t i_size;
- int page_idx;
- int ret, read = 0;
- bool hit_stripe, was_short;
-
- /*
- * we may need to do multiple reads. not atomic, unfortunately.
- */
-more:
- this_len = len;
- page_idx = (page_align + read) >> PAGE_SHIFT;
- ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
- &ci->i_layout, pos, &this_len,
- ci->i_truncate_seq, ci->i_truncate_size,
- pages + page_idx, num_pages - page_idx,
- ((page_align + read) & ~PAGE_MASK));
- if (ret == -ENOENT)
- ret = 0;
- hit_stripe = this_len < len;
- was_short = ret >= 0 && ret < this_len;
- dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, len, read,
- ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
-
- i_size = i_size_read(inode);
- if (ret >= 0) {
- if (was_short && (pos + ret < i_size)) {
- int zlen = min(this_len - ret, i_size - pos - ret);
- int zoff = page_align + read + ret;
- dout(" zero gap %llu to %llu\n",
- pos + ret, pos + ret + zlen);
- ceph_zero_page_vector_range(zoff, zlen, pages);
- ret += zlen;
- }
-
- read += ret;
- pos += ret;
- len -= ret;
-
- /* hit stripe and need continue*/
- if (len && hit_stripe && pos < i_size)
- goto more;
- }
-
- if (read > 0) {
- ret = read;
- /* did we bounce off eof? */
- if (pos + len > i_size)
- *checkeof = CHECK_EOF;
- }
-
- dout("striped_read returns %d\n", ret);
- return ret;
-}
-
-/*
* Completely synchronous read and write methods. Direct from __user
* buffer to osd, or directly to user pages (if O_DIRECT).
*
- * If the read spans object boundary, just do multiple reads.
+ * If the read spans object boundary, just do multiple reads. (That's not
+ * atomic, but good enough for now.)
+ *
+ * If we get a short result from the OSD, check against i_size; we need to
+ * only return a short read to the caller if we hit EOF.
*/
static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
- int *checkeof)
+ int *retry_op)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
- struct page **pages;
- u64 off = iocb->ki_pos;
- int num_pages;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+ struct ceph_osd_client *osdc = &fsc->client->osdc;
ssize_t ret;
- size_t len = iov_iter_count(to);
+ u64 off = iocb->ki_pos;
+ u64 len = iov_iter_count(to);
dout("sync_read on file %p %llu~%u %s\n", file, off, (unsigned)len,
(file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
@@ -653,61 +589,118 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
* but it will at least behave sensibly when they are
* in sequence.
*/
- ret = filemap_write_and_wait_range(inode->i_mapping, off,
- off + len);
+ ret = filemap_write_and_wait_range(inode->i_mapping, off, off + len);
if (ret < 0)
return ret;
- if (unlikely(to->type & ITER_PIPE)) {
+ ret = 0;
+ while ((len = iov_iter_count(to)) > 0) {
+ struct ceph_osd_request *req;
+ struct page **pages;
+ int num_pages;
size_t page_off;
- ret = iov_iter_get_pages_alloc(to, &pages, len,
- &page_off);
- if (ret <= 0)
- return -ENOMEM;
- num_pages = DIV_ROUND_UP(ret + page_off, PAGE_SIZE);
+ u64 i_size;
+ bool more;
+
+ req = ceph_osdc_new_request(osdc, &ci->i_layout,
+ ci->i_vino, off, &len, 0, 1,
+ CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
+ NULL, ci->i_truncate_seq,
+ ci->i_truncate_size, false);
+ if (IS_ERR(req)) {
+ ret = PTR_ERR(req);
+ break;
+ }
+
+ more = len < iov_iter_count(to);
- ret = striped_read(inode, off, ret, pages, num_pages,
- page_off, checkeof);
- if (ret > 0) {
- iov_iter_advance(to, ret);
- off += ret;
+ if (unlikely(to->type & ITER_PIPE)) {
+ ret = iov_iter_get_pages_alloc(to, &pages, len,
+ &page_off);
+ if (ret <= 0) {
+ ceph_osdc_put_request(req);
+ ret = -ENOMEM;
+ break;
+ }
+ num_pages = DIV_ROUND_UP(ret + page_off, PAGE_SIZE);
+ if (ret < len) {
+ len = ret;
+ osd_req_op_extent_update(req, 0, len);
+ more = false;
+ }
} else {
- iov_iter_advance(to, 0);
+ num_pages = calc_pages_for(off, len);
+ page_off = off & ~PAGE_MASK;
+ pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
+ if (IS_ERR(pages)) {
+ ceph_osdc_put_request(req);
+ ret = PTR_ERR(pages);
+ break;
+ }
}
- ceph_put_page_vector(pages, num_pages, false);
- } else {
- num_pages = calc_pages_for(off, len);
- pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
- if (IS_ERR(pages))
- return PTR_ERR(pages);
-
- ret = striped_read(inode, off, len, pages, num_pages,
- (off & ~PAGE_MASK), checkeof);
- if (ret > 0) {
- int l, k = 0;
- size_t left = ret;
-
- while (left) {
- size_t page_off = off & ~PAGE_MASK;
- size_t copy = min_t(size_t, left,
- PAGE_SIZE - page_off);
- l = copy_page_to_iter(pages[k++], page_off,
- copy, to);
- off += l;
- left -= l;
- if (l < copy)
+
+ osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_off,
+ false, false);
+ ret = ceph_osdc_start_request(osdc, req, false);
+ if (!ret)
+ ret = ceph_osdc_wait_request(osdc, req);
+ ceph_osdc_put_request(req);
+
+ i_size = i_size_read(inode);
+ dout("sync_read %llu~%llu got %zd i_size %llu%s\n",
+ off, len, ret, i_size, (more ? " MORE" : ""));
+
+ if (ret == -ENOENT)
+ ret = 0;
+ if (ret >= 0 && ret < len && (off + ret < i_size)) {
+ int zlen = min(len - ret, i_size - off - ret);
+ int zoff = page_off + ret;
+ dout("sync_read zero gap %llu~%llu\n",
+ off + ret, off + ret + zlen);
+ ceph_zero_page_vector_range(zoff, zlen, pages);
+ ret += zlen;
+ }
+
+ if (unlikely(to->type & ITER_PIPE)) {
+ if (ret > 0) {
+ iov_iter_advance(to, ret);
+ off += ret;
+ } else {
+ iov_iter_advance(to, 0);
+ }
+ ceph_put_page_vector(pages, num_pages, false);
+ } else {
+ int idx = 0;
+ size_t left = ret > 0 ? ret : 0;
+ while (left > 0) {
+ size_t len, copied;
+ page_off = off & ~PAGE_MASK;
+ len = min_t(size_t, left, PAGE_SIZE - page_off);
+ copied = copy_page_to_iter(pages[idx++],
+ page_off, len, to);
+ off += copied;
+ left -= copied;
+ if (copied < len) {
+ ret = -EFAULT;
break;
+ }
}
+ ceph_release_page_vector(pages, num_pages);
}
- ceph_release_page_vector(pages, num_pages);
+
+ if (ret <= 0 || off >= i_size || !more)
+ break;
}
if (off > iocb->ki_pos) {
+ if (ret >= 0 &&
+ iov_iter_count(to) > 0 && off >= i_size_read(inode))
+ *retry_op = CHECK_EOF;
ret = off - iocb->ki_pos;
iocb->ki_pos = off;
}
- dout("sync_read result %zd\n", ret);
+ dout("sync_read result %zd retry_op %d\n", ret, *retry_op);
return ret;
}