zonefs: prevent use of seq files as swap file

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: 1ec48a99df3c ("fs: New zonefs file system")
Cc: <stable@vger.kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 0fe76f376dee2e2c6c3eaea45460fc5d28231afe..a3d074f9866042a4ed1c1a15e1dda4139298408c 100644 (file)
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -165,6 +165,21 @@ static int zonefs_writepages(struct address_space *mapping,
        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,
@@ -177,6 +192,7 @@ static const struct address_space_operations zonefs_file_aops = {
        .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)