From d5e66348bbe39dc78509e7561f7252aa443df8c0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 23 Sep 2008 17:28:35 -0400 Subject: [PATCH] NFS: Fix nfs_file_llseek() After the BKL removal patches were applied to the rest of the NFS code, the BKL protection in nfs_file_llseek() is no longer sufficient to ensure that inode->i_size is read safely in generic_file_llseek_unlocked(). In order to fix the situation, we either have to replace the naked read of inode->i_size in generic_file_llseek_unlocked() with i_size_read(), or the whole thing needs to be executed under the inode->i_lock; In order to avoid disrupting other filesystems, avoid touching generic_file_llseek_unlocked() for now... Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 78460657f5cb..3ddb00433f4f 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -188,13 +188,16 @@ static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin) /* origin == SEEK_END => we must revalidate the cached file length */ if (origin == SEEK_END) { struct inode *inode = filp->f_mapping->host; + int retval = nfs_revalidate_file_size(inode, filp); if (retval < 0) return (loff_t)retval; - } - lock_kernel(); /* BKL needed? */ - loff = generic_file_llseek_unlocked(filp, offset, origin); - unlock_kernel(); + + spin_lock(&inode->i_lock); + loff = generic_file_llseek_unlocked(filp, offset, origin); + spin_unlock(&inode->i_lock); + } else + loff = generic_file_llseek_unlocked(filp, offset, origin); return loff; } -- GitLab