ceph: revert commit 22cddde104

commit 22cddde104 breaks the atomicity of write operation, it also
introduces a deadlock between write and truncate.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Greg Farnum <greg@inktank.com>

Conflicts:
	fs/ceph/addr.c

1 files changed, 43 insertions, 30 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index bf338d9b67e3..b86d2a0eb145 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -718,53 +718,63 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	struct ceph_osd_client *osdc =
 		&ceph_sb_to_client(inode->i_sb)->client->osdc;
 	loff_t endoff = pos + iov->iov_len;
-	int got = 0;
-	int ret, err, written;
+	int want, got = 0;
+	int ret, err;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
 		return -EROFS;
 
 retry_snap:
-	written = 0;
 	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
 		return -ENOSPC;
 	__ceph_do_pending_vmtruncate(inode);
+	dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
+	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+	     inode->i_size);
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_BUFFER;
+	ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
+	if (ret < 0)
+		goto out_put;
 
-	/*
-	 * try to do a buffered write.  if we don't have sufficient
-	 * caps, we'll get -EAGAIN from generic_file_aio_write, or a
-	 * short write if we only get caps for some pages.
-	 */
-	if (!(iocb->ki_filp->f_flags & O_DIRECT) &&
-	    !(inode->i_sb->s_flags & MS_SYNCHRONOUS) &&
-	    !(fi->flags & CEPH_F_SYNC)) {
-		ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
-		if (ret >= 0)
-			written = ret;
+	dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
+	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+	     ceph_cap_string(got));
+
+	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
+	    (iocb->ki_filp->f_flags & O_DIRECT) ||
+	    (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
+	    (fi->flags & CEPH_F_SYNC)) {
+		ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
+			&iocb->ki_pos);
+	} else {
+		/*
+		 * buffered write; drop Fw early to avoid slow
+		 * revocation if we get stuck on balance_dirty_pages
+		 */
+		int dirty;
 
+		spin_lock(&ci->i_ceph_lock);
+		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+		spin_unlock(&ci->i_ceph_lock);
+		ceph_put_cap_refs(ci, got);
+
+		ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
 		if ((ret >= 0 || ret == -EIOCBQUEUED) &&
 		    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
 		     || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
-			err = vfs_fsync_range(file, pos, pos + written - 1, 1);
+			err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
 			if (err < 0)
 				ret = err;
 		}
-		if ((ret < 0 && ret != -EAGAIN) || pos + written >= endoff)
-			goto out;
-	}
 
-	dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
-	     inode, ceph_vinop(inode), pos + written,
-	     (unsigned)iov->iov_len - written, inode->i_size);
-	ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, 0, &got, endoff);
-	if (ret < 0)
+		if (dirty)
+			__mark_inode_dirty(inode, dirty);
 		goto out;
+	}
 
-	dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
-	     inode, ceph_vinop(inode), pos + written,
-	     (unsigned)iov->iov_len - written, ceph_cap_string(got));
-	ret = ceph_sync_write(file, iov->iov_base + written,
-			      iov->iov_len - written, &iocb->ki_pos);
 	if (ret >= 0) {
 		int dirty;
 		spin_lock(&ci->i_ceph_lock);
@@ -773,10 +783,13 @@ retry_snap:
 		if (dirty)
 			__mark_inode_dirty(inode, dirty);
 	}
+
+out_put:
 	dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
-	     inode, ceph_vinop(inode), pos + written,
-	     (unsigned)iov->iov_len - written, ceph_cap_string(got));
+	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+	     ceph_cap_string(got));
 	ceph_put_cap_refs(ci, got);
+
 out:
 	if (ret == -EOLDSNAPC) {
 		dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",