Messages in this thread Patch in this message | | | Date | Mon, 24 Sep 2007 09:20:41 -0700 | From | Greg KH <> | Subject | [14/50] JFFS2: fix write deadlock regression |
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From: Jason Lunz <lunz@falooley.org>
Changeset fc0e01974ccccc7530b7634a63ee3fcc57b845ea from mainline.
I've bisected the deadlock when many small appends are done on jffs2 down to this commit:
commit 6fe6900e1e5b6fa9e5c59aa5061f244fe3f467e2 Author: Nick Piggin <npiggin@suse.de> Date: Sun May 6 14:49:04 2007 -0700
mm: make read_cache_page synchronous
Ensure pages are uptodate after returning from read_cache_page, which allows us to cut out most of the filesystem-internal PageUptodate calls.
I didn't have a great look down the call chains, but this appears to fixes 7 possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in block2mtd. All depending on whether the filler is async and/or can return with a !uptodate page.
It introduced a wait to read_cache_page, as well as a read_cache_page_async function equivalent to the old read_cache_page without any callers.
Switching jffs2_gc_fetch_page to read_cache_page_async for the old behavior makes the deadlocks go away, but maybe reintroduces the use-before-uptodate problem? I don't understand the mm/fs interaction well enough to say.
[It's fine. dwmw2.]
Signed-off-by: Jason Lunz <lunz@falooley.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/jffs2/fs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/jffs2/fs.c +++ b/fs/jffs2/fs.c @@ -627,7 +627,7 @@ unsigned char *jffs2_gc_fetch_page(struc struct inode *inode = OFNI_EDONI_2SFFJ(f); struct page *pg; - pg = read_cache_page(inode->i_mapping, offset >> PAGE_CACHE_SHIFT, + pg = read_cache_page_async(inode->i_mapping, offset >> PAGE_CACHE_SHIFT, (void *)jffs2_do_readpage_unlock, inode); if (IS_ERR(pg)) return (void *)pg; -- - 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/
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