[PATCH 1/2] ceph: Implement readv/preadv for sync operation.

[majianpeng <majianpeng@gmail.com>]

For readv/preadv sync-operatoin, ceph only do the first iov.
It don't think other iovs.Now implement this.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
---
 fs/ceph/file.c | 175 ++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 123 insertions(+), 52 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 3de8982..7d6a3ee 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -408,51 +408,95 @@ more:
  *
  * If the read spans object boundary, just do multiple reads.
  */
-static ssize_t ceph_sync_read(struct file *file, char __user *data,
-			      unsigned len, loff_t *poff, int *checkeof)
+static ssize_t ceph_sync_read(struct kiocb *iocb, struct iovec *iov,
+			      unsigned long nr_segs, int *checkeof)
 {
+	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
 	struct page **pages;
-	u64 off = *poff;
-	int num_pages, ret;
+	u64 off = iocb->ki_pos;
+	int num_pages, ret, i;
 
-	dout("sync_read on file %p %llu~%u %s\n", file, off, len,
+	dout("sync_read on file %p %llu~%u %s\n", file, off,
+	     (unsigned)iocb->ki_left,
 	     (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
-
-	if (file->f_flags & O_DIRECT) {
-		num_pages = calc_pages_for((unsigned long)data, len);
-		pages = ceph_get_direct_page_vector(data, num_pages, true);
-	} else {
-		num_pages = calc_pages_for(off, len);
-		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
-	}
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
-
 	/*
 	 * flush any page cache pages in this range.  this
 	 * will make concurrent normal and sync io slow,
 	 * but it will at least behave sensibly when they are
 	 * in sequence.
 	 */
-	ret = filemap_write_and_wait(inode->i_mapping);
+	ret = filemap_write_and_wait_range(inode->i_mapping, off,
+						off + iocb->ki_left);
 	if (ret < 0)
-		goto done;
-
-	ret = striped_read(inode, off, len, pages, num_pages, checkeof,
-			   file->f_flags & O_DIRECT,
-			   (unsigned long)data & ~PAGE_MASK);
+		return ret;
 
-	if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
-		ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
-	if (ret >= 0)
-		*poff = off + ret;
+	if (file->f_flags & O_DIRECT) {
+		for (i = 0; i < nr_segs; i++) {
+			void __user *data = iov[i].iov_base;
+			size_t len = iov[i].iov_len;
+
+			num_pages = calc_pages_for((unsigned long)data, len);
+			pages = ceph_get_direct_page_vector(data,
+							    num_pages, true);
+			if (IS_ERR(pages))
+				return PTR_ERR(pages);
+
+			ret = striped_read(inode, off, len,
+					   pages, num_pages, checkeof,
+					   1, (unsigned long)data & ~PAGE_MASK);
+			ceph_put_page_vector(pages, num_pages, true);
+
+			if (ret <= 0)
+				break;
+			off += ret;
+			if (ret < len)
+				break;
+		}
+		if (off > iocb->ki_pos) {
+			ret = off - iocb->ki_pos;
+			iocb->ki_pos = off;
+			iocb->ki_left -= ret;
+		}
+	} else {
+		size_t len = iocb->ki_left;
 
-done:
-	if (file->f_flags & O_DIRECT)
-		ceph_put_page_vector(pages, num_pages, true);
-	else
+		num_pages = calc_pages_for(off, len);
+		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
+		if (IS_ERR(pages))
+			return PTR_ERR(pages);
+		ret = striped_read(inode, off, len, pages,
+					num_pages, checkeof, 0, 0);
+		len = ret;
+		if (len) {
+			int i, l, k = 0;
+			size_t left = len;
+
+			for (i = 0; i < nr_segs && left; i++) {
+				void __user *data = iov[i].iov_base;
+				l = min(left, iov[i].iov_len);
+				ret = ceph_copy_page_vector_to_user(&pages[k],
+								    data, off,
+								    l);
+				if (ret > 0) {
+					left -= ret;
+					off += ret;
+					k = calc_pages_for(iocb->ki_pos,
+							   len - left + 1) - 1;
+					BUG_ON(k >= num_pages && left);
+				} else
+					break;
+			}
+
+			if (left == 0) {
+				iocb->ki_pos += len;
+				iocb->ki_left -= len;
+				ret = len;
+			}
+		}
 		ceph_release_page_vector(pages, num_pages);
+	}
+
 	dout("sync_read result %d\n", ret);
 	return ret;
 }
@@ -647,55 +691,82 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
 {
 	struct file *filp = iocb->ki_filp;
 	struct ceph_file_info *fi = filp->private_data;
-	loff_t *ppos = &iocb->ki_pos;
-	size_t len = iov->iov_len;
+	size_t len = iocb->ki_left;
 	struct inode *inode = file_inode(filp);
 	struct ceph_inode_info *ci = ceph_inode(inode);
-	void __user *base = iov->iov_base;
 	ssize_t ret;
 	int want, got = 0;
 	int checkeof = 0, read = 0;
 
+
 	dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
 	     inode, ceph_vinop(inode), pos, (unsigned)len, inode);
-again:
+
 	if (fi->fmode & CEPH_FILE_MODE_LAZY)
 		want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
 	else
 		want = CEPH_CAP_FILE_CACHE;
 	ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
 	if (ret < 0)
-		goto out;
+		return ret;
+
 	dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
 	     inode, ceph_vinop(inode), pos, (unsigned)len,
 	     ceph_cap_string(got));
 
 	if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 	    (iocb->ki_filp->f_flags & O_DIRECT) ||
-	    (fi->flags & CEPH_F_SYNC))
+	    (fi->flags & CEPH_F_SYNC)) {
+		unsigned long curr_seg = 0;
+		struct iovec *iov_clone;
+
+		iov_clone = kmalloc(nr_segs * sizeof(struct iovec), GFP_KERNEL);
+		if (iov_clone == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		memcpy(iov_clone, iov, nr_segs * sizeof(struct iovec));
+again:
 		/* hmm, this isn't really async... */
-		ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
-	else
-		ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
+		ret = ceph_sync_read(iocb, &iov_clone[curr_seg],
+					nr_segs - curr_seg, &checkeof);
+
+		if (checkeof && ret >= 0) {
+			int statret = ceph_do_getattr(inode,
+						      CEPH_STAT_CAP_SIZE);
+
+			/* hit EOF or hole? */
+			if (statret == 0 && iocb->ki_pos < inode->i_size &&
+				iocb->ki_left) {
+				size_t tmp = 0;
+				dout("%s sync_read hit hole, ppos %lld < size %lld"
+				     ", reading more\n", __func__, iocb->ki_pos,
+				     inode->i_size);
+
+				read += ret;
+				for (; curr_seg < nr_segs; curr_seg++) {
+					if ((tmp + iov_clone[curr_seg].iov_len)
+						> ret)
+						break;
+					tmp += iov_clone[curr_seg].iov_len;
+				}
+
+				BUG_ON(curr_seg == nr_segs);
+				iov_clone[curr_seg].iov_base += ret - tmp;
+				iov_clone[curr_seg].iov_len -= ret - tmp;
+				checkeof = 0;
+				goto again;
+			}
+		}
+		kfree(iov_clone);
 
+	} else
+		ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
 out:
 	dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
 	     inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
 	ceph_put_cap_refs(ci, got);
 
-	if (checkeof && ret >= 0) {
-		int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
-
-		/* hit EOF or hole? */
-		if (statret == 0 && *ppos < inode->i_size) {
-			dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
-			read += ret;
-			base += ret;
-			len -= ret;
-			checkeof = 0;
-			goto again;
-		}
-	}
 	if (ret >= 0)
 		ret += read;
 
-- 
1.8.1.2