2020-01-02 08:04:57

by Murphy Zhou

Subject: [PATCH] fs/nfs, swapon: check holes in swapfile

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 <[email protected]>
---
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

2020-01-15 04:50:03

by Murphy Zhou

Subject: Re: [PATCH] fs/nfs, swapon: check holes in swapfile

On Thu, Jan 02, 2020 at 04:04:26PM +0800, Murphy Zhou wrote:
> 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.

Any review?

>
> Signed-off-by: Murphy Zhou <[email protected]>
> ---
> 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
>