Messages in this thread |  | | | From | Daniel Phillips <> | | Subject | Re: invalidate_inode_pages in 2.5.32/3 | | Date | Sat, 7 Sep 2002 12:01:23 +0200 |
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On Saturday 07 September 2002 10:01, Daniel Phillips wrote: > On Thursday 05 September 2002 20:27, Andrew Morton wrote: > > But be aware that invalidate_inode_pages has always been best-effort. > > If someone is reading, or writing one of those pages then it > > certainly will not be removed. If you need assurances that the > > pagecache has been taken down then we'll need something stronger > > in there. > > But what is stopping us now from removing a page from the page cache > even while IO is in progress? (Practical issue: the page lock, but > that's a self-fullfilling prophesy.)
Never mind, I can see that the main function of the page lock here is to allow the filesystem to know there's no IO in progress on a block and so the block can be recovered and used for something else. Leaving the page in the page cache during IO is a simple means of keeping track of this.
All the same, I have deep misgivings about the logic of the vfs truncate path in general, and given all the trouble it's caused historically, there's good reason to. I don't know, it may be perfect the way it is, but history would suggest otherwise.
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