linux-kernel - [PATCH 5.11 017/120] zonefs: prevent use of seq files as swap file

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Date:   Mon, 22 Mar 2021 13:26:40 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Johannes Thumshirn <johannes.thumshirn@....com>,
        Damien Le Moal <damien.lemoal@....com>
Subject: [PATCH 5.11 017/120] zonefs: prevent use of seq files as swap file

From: Damien Le Moal <damien.lemoal@....com>

commit 1601ea068b886da1f8f8d4e18b9403e9e24adef6 upstream.

The sequential write constraint of sequential zone file prevent their
use as swap files. Only allow conventional zone files to be used as swap
files.

Fixes: 8dcc1a9d90c1 ("fs: New zonefs file system")
Cc: <stable@...r.kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@....com>
Signed-off-by: Damien Le Moal <damien.lemoal@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/zonefs/super.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -159,6 +159,21 @@ static int zonefs_writepages(struct addr
 	return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops);
 }
 
+static int zonefs_swap_activate(struct swap_info_struct *sis,
+				struct file *swap_file, sector_t *span)
+{
+	struct inode *inode = file_inode(swap_file);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+	if (zi->i_ztype != ZONEFS_ZTYPE_CNV) {
+		zonefs_err(inode->i_sb,
+			   "swap file: not a conventional zone file\n");
+		return -EINVAL;
+	}
+
+	return iomap_swapfile_activate(sis, swap_file, span, &zonefs_iomap_ops);
+}
+
 static const struct address_space_operations zonefs_file_aops = {
 	.readpage		= zonefs_readpage,
 	.readahead		= zonefs_readahead,
@@ -171,6 +186,7 @@ static const struct address_space_operat
 	.is_partially_uptodate	= iomap_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.direct_IO		= noop_direct_IO,
+	.swap_activate		= zonefs_swap_activate,
 };
 
 static void zonefs_update_stats(struct inode *inode, loff_t new_isize)