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authorAl Viro <viro@zeniv.linux.org.uk>2020-04-23 13:45:27 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2020-04-23 13:45:27 -0400
commit3815f1be546e752327b5868af103ccdddcc4db77 (patch)
tree1aa45836cbf25923241e5221d070af52edb36867 /fs/ocfs2
parent8f3d9f354286745c751374f5f1fcafee6b3f3136 (diff)
dlmfs_file_write(): fix the bogosity in handling non-zero *ppos
'count' is how much you want written, not the final position. Moreover, it can legitimately be less than the current position... Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/ocfs2')
-rw-r--r--fs/ocfs2/dlmfs/dlmfs.c27
1 files changed, 12 insertions, 15 deletions
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index 8e4f1ace467c..1de77f1a600b 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -275,7 +275,6 @@ static ssize_t dlmfs_file_write(struct file *filp,
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 file *filp,
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)