ceph: apply write checks in ceph_aio_write

copy write checks in __generic_file_aio_write to ceph_aio_write.
To make these checks cover sync write path.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>

fs/ceph/file.c

@@ -486,7 +486,7 @@ static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
  * objects, rollback on failure, etc.)
  */
 static ssize_t ceph_sync_write(struct file *file, const char __user *data,
-			       size_t left, loff_t *offset)
+			       size_t left, loff_t pos, loff_t *ppos)
 {
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
@@ -497,7 +497,6 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
 	int num_ops = 1;
 	struct page **pages;
 	int num_pages;
-	long long unsigned pos;
 	u64 len;
 	int written = 0;
 	int flags;
@@ -511,14 +510,9 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
 	if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
 		return -EROFS;
 
-	dout("sync_write on file %p %lld~%u %s\n", file, *offset,
+	dout("sync_write on file %p %lld~%u %s\n", file, pos,
 	     (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 
-	if (file->f_flags & O_APPEND)
-		pos = i_size_read(inode);
-	else
-		pos = *offset;
-
 	ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
 	if (ret < 0)
 		return ret;
@@ -617,7 +611,7 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
 			goto more;
 
 		ret = written;
-		*offset = pos;
+		*ppos = pos;
 		if (pos > i_size_read(inode))
 			check_caps = ceph_inode_set_size(inode, pos);
 		if (check_caps)
@@ -714,51 +708,75 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_osd_client *osdc =
 		&ceph_sb_to_client(inode->i_sb)->client->osdc;
-	loff_t endoff = pos + iov->iov_len;
-	int want, got = 0;
-	int ret, err;
+	ssize_t count, written = 0;
+	int err, want, got;
+	bool hold_mutex;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
 		return -EROFS;
 
 	sb_start_write(inode->i_sb);
+	mutex_lock(&inode->i_mutex);
+	hold_mutex = true;
+
+	err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
+	if (err)
+		goto out;
+
+	/* We can write back this queue in page reclaim */
+	current->backing_dev_info = file->f_mapping->backing_dev_info;
+
+	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+	if (err)
+		goto out;
+
+	if (count == 0)
+		goto out;
+
+	err = file_remove_suid(file);
+	if (err)
+		goto out;
+
+	err = file_update_time(file);
+	if (err)
+		goto out;
+
 retry_snap:
 	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
-		ret = -ENOSPC;
+		err = -ENOSPC;
 		goto out;
 	}
-	mutex_lock(&inode->i_mutex);
-	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);
+
+	dout("aio_write %p %llx.%llx %llu~%ld getting caps. i_size %llu\n",
+	     inode, ceph_vinop(inode), pos, count, 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) {
-		mutex_unlock(&inode->i_mutex);
+	got = 0;
+	err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos + count);
+	if (err < 0)
 		goto out;
-	}
 
-	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));
+	dout("aio_write %p %llx.%llx %llu~%ld got cap refs on %s\n",
+	     inode, ceph_vinop(inode), pos, count, 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)) {
 		mutex_unlock(&inode->i_mutex);
-		ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
-			&iocb->ki_pos);
+		written = ceph_sync_write(file, iov->iov_base, count,
+					  pos, &iocb->ki_pos);
 	} else {
-		ret = __generic_file_aio_write(iocb, iov, nr_segs,
-					       &iocb->ki_pos);
+		written = generic_file_buffered_write(iocb, iov, nr_segs,
+						      pos, &iocb->ki_pos,
+						      count, 0);
 		mutex_unlock(&inode->i_mutex);
 	}
+	hold_mutex = false;
 
-	if (ret >= 0) {
+	if (written >= 0) {
 		int dirty;
 		spin_lock(&ci->i_ceph_lock);
 		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
@@ -772,22 +790,28 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	     ceph_cap_string(got));
 	ceph_put_cap_refs(ci, got);
 
-	if (ret >= 0 &&
+	if (written >= 0 &&
 	    ((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 + ret - 1, 1);
+		err = vfs_fsync_range(file, pos, pos + written - 1, 1);
 		if (err < 0)
-			ret = err;
+			written = err;
 	}
-out:
-	if (ret == -EOLDSNAPC) {
+
+	if (written == -EOLDSNAPC) {
 		dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
 		     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
+		mutex_lock(&inode->i_mutex);
+		hold_mutex = true;
 		goto retry_snap;
 	}
+out:
+	if (hold_mutex)
+		mutex_unlock(&inode->i_mutex);
 	sb_end_write(inode->i_sb);
+	current->backing_dev_info = NULL;
 
-	return ret;
+	return written ? written : err;
 }
 
 /*