Messages in this thread | | | Date | Mon, 11 Jun 2001 22:45:11 +1000 | From | Andrew Morton <> | Subject | Re: [patch] truncate_inode_pages |
| |
Daniel Phillips wrote: > > On Sunday 10 June 2001 03:31, Andrew Morton wrote: > > Daniel Phillips wrote: > > > This is easy, just set the list head to the page about to be truncated. > > > > Works for me. > > It looks good, but it's black magic
No, it's wrong. I'm getting BUG()s in clear_inode():
485 if (inode->i_data.nrpages) 486 BUG();
(gdb) p inode->i_data $5 = {clean_pages = {next = 0xd7423ae4, prev = 0xc1628280}, dirty_pages = {next = 0xd7423aec, prev = 0xd7423aec}, locked_pages = {next = 0xd7423af4, prev = 0xd7423af4}, nrpages = 0x1, a_ops = 0xc02e4940, host = 0xd7423a40, i_mmap = 0x0, i_mmap_shared = 0x0, i_shared_lock = {lock = 0x1}, gfp_mask = 0x5}
(gdb) p *(struct page *)0xd7423ae4 $6 = {list = {next = 0xd7423ae4, prev = 0xc1628280}, mapping = 0xd7423aec, index = 0xd7423aec, next_hash = 0xd7423af4, count = {counter = 0xd7423af4}, flags = 0x1, lru = {next = 0xc02e4940, prev = 0xd7423a40}, age = 0x0, wait = {lock = {lock = 0x0}, task_list = {next = 0x1, prev = 0x5}}, pprev_hash = 0x0, buffers = 0x0, virtual = 0x0, zone = 0x0} (gdb) p &inode->i_data
The lists are mangled.
I think what's happening is:
curr = curr->next; offset = page->index;
/* Is one of the pages to truncate? */ if ((offset >= start) || (*partial && (offset + 1) == start)) { list_del(head); list_add_tail(head, curr);
`curr' can point to `head' when we get inside the `if'. So we do, effectively,
list_del(head); list_add_tail(head, head);
Which turns mapping->clean_pages into an empty list, and the target page.list thinks it's on a list, but really isn't. A subsequent list_del() on the page screws things up somehow.
Ho-hum. I'll have another go tomorrow. Probably a simple `if (curr != head)' will cure it.
- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |