Re: [PATCH v2] fadvise: introduce POSIX_FADV_DONTNEED_FS
flat view
From: Matthew Wilcox <hidden>
Date: 2011-04-27 18:33:08
Also in:
linux-fsdevel, lkml
On Wed, Apr 27, 2011 at 08:13:47PM +0200, Andrea Righi wrote:
quoted hunk
@@ -127,6 +128,12 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) invalidate_mapping_pages(mapping, start_index, end_index); break; + case POSIX_FADV_DONTNEED_FS: + if (capable(CAP_SYS_ADMIN)) + drop_pagecache_sb(file->f_dentry->d_sb, NULL); + else + ret = -EPERM; + break; default: ret = -EINVAL; }
Mmm ... what if I open /dev/sdxyz and call fadvise() on it? I think you end up flushing /dev's page cache entries, instead of the filesystem which is on /dev/sdxyz. If I understand correctly, you want mapping->host->i_sb instead of file->f_dentry->d_sb. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."