swapon over NFS does not go through generic_swapfile_activate
code path when setting up extents. This makes holes in NFS
swapfiles possible which is not expected for swapon.
Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
---
fs/nfs/file.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 8eb731d..ccd9bc0 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -489,7 +489,19 @@ static int nfs_launder_page(struct page *page)
static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
sector_t *span)
{
+ unsigned long blocks;
+ long long isize;
struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
+ struct inode *inode = file->f_mapping->host;
+
+ spin_lock(&inode->i_lock);
+ blocks = inode->i_blocks;
+ isize = inode->i_size;
+ spin_unlock(&inode->i_lock);
+ if (blocks*512 < isize) {
+ pr_warn("swap activate: swapfile has holes\n");
+ return -EINVAL;
+ }
*span = sis->pages;
--
1.8.3.1
