[PATCH] clear PAGECACHE_TAG_DIRTY for truncated pages
DORMANTno replies
REVIEWED: 1 (0M)
From: Fengguang Wu <hidden>
Date: 2008-02-01 12:18:47
Also in:
linux-fsdevel
1 review trailer.
The `truncated' page in block_write_full_page()/nobh_writepage() may
stick for a long time. For example, ext2_rmdir() will set i_size to
0, and then the dir inode and its pages may hang around because of
being referenced by some process.
To produce this situation:
In terminal 1:
$ mkdir hi; cd hi
$ sleep 1h; cd ..
In terminal 2:
$ rmdir hi
The dir 'hi' is deleted in terminal 2 while still being referenced by
the shell(as working dir) in terminal 1. The deleted inode 'hi' with
its dirty-and-truncated page will stay for 1 hour, during which the
pdflush will retry the page _at least_ once every 5s.
So clear PAGECACHE_TAG_DIRTY to prevent pdflush from retrying on it.
Tested-by: Joerg Platte <redacted>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Rubin <redacted>
Signed-off-by: Fengguang Wu <redacted>
---
fs/buffer.c | 16 ++++++++++++++++
1 files changed, 16 insertions(+)
--- linux-mm.orig/fs/buffer.c
+++ linux-mm/fs/buffer.c@@ -2631,7 +2631,13 @@ int nobh_writepage(struct page *page, ge if (page->mapping->a_ops->invalidatepage) page->mapping->a_ops->invalidatepage(page, offset); #endif + /* + * Clear PAGECACHE_TAG_DIRTY to stop pdflush from retrying. + * Read block_write_full_page() for more details. + */ + set_page_writeback(page); unlock_page(page); + end_page_writeback(page); return 0; /* don't care */ }
@@ -2826,7 +2832,17 @@ int block_write_full_page(struct page *p * freeable here, so the page does not leak. */ do_invalidatepage(page, 0); + /* + * Clear PAGECACHE_TAG_DIRTY to stop pdflush from retrying. + * + * Some truncated pages may hang around for long time. + * For example, ext2_rmdir() will set i_size to 0, and then + * keep the pages as long as the dir is still referenced(as + * the working dir of some process). + */ + set_page_writeback(page); unlock_page(page); + end_page_writeback(page); return 0; /* don't care */ }