This is a note to let you know that I've just added the patch titled
dlmfs_file_write(): fix the bogosity in handling non-zero *ppos
to the 5.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dlmfs_file_write-fix-the-bogosity-in-handling-non-zero-ppos.patch
and it can be found in the queue-5.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3815f1be546e752327b5868af103ccdddcc4db77 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Thu, 23 Apr 2020 13:45:27 -0400
Subject: dlmfs_file_write(): fix the bogosity in handling non-zero *ppos
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
commit 3815f1be546e752327b5868af103ccdddcc4db77 upstream.
'count' is how much you want written, not the final position.
Moreover, it can legitimately be less than the current position...
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlmfs/dlmfs.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -275,7 +275,6 @@ static ssize_t dlmfs_file_write(struct f
loff_t *ppos)
{
int bytes_left;
- ssize_t writelen;
char *lvb_buf;
struct inode *inode = file_inode(filp);
@@ -285,32 +284,30 @@ static ssize_t dlmfs_file_write(struct f
if (*ppos >= i_size_read(inode))
return -ENOSPC;
+ /* don't write past the lvb */
+ if (count > i_size_read(inode) - *ppos)
+ count = i_size_read(inode) - *ppos;
+
if (!count)
return 0;
if (!access_ok(buf, count))
return -EFAULT;
- /* don't write past the lvb */
- if ((count + *ppos) > i_size_read(inode))
- writelen = i_size_read(inode) - *ppos;
- else
- writelen = count - *ppos;
-
- lvb_buf = kmalloc(writelen, GFP_NOFS);
+ lvb_buf = kmalloc(count, GFP_NOFS);
if (!lvb_buf)
return -ENOMEM;
- bytes_left = copy_from_user(lvb_buf, buf, writelen);
- writelen -= bytes_left;
- if (writelen)
- user_dlm_write_lvb(inode, lvb_buf, writelen);
+ bytes_left = copy_from_user(lvb_buf, buf, count);
+ count -= bytes_left;
+ if (count)
+ user_dlm_write_lvb(inode, lvb_buf, count);
kfree(lvb_buf);
- *ppos = *ppos + writelen;
- mlog(0, "wrote %zd bytes\n", writelen);
- return writelen;
+ *ppos = *ppos + count;
+ mlog(0, "wrote %zu bytes\n", count);
+ return count;
}
static void dlmfs_init_once(void *foo)
Patches currently in stable-queue which might be from viro@xxxxxxxxxxxxxxxxxx are
queue-5.6/dlmfs_file_write-fix-the-bogosity-in-handling-non-zero-ppos.patch
