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From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org
Cc: Takashi Iwai <tiwai@suse.de>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	dhowells@redhat.com, linux-afs@lists.infradead.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] cachefiles: Drop superfluous readpages aops NULL check
Date: Wed, 20 Jan 2021 16:11:12 +0000	[thread overview]
Message-ID: <161115907229.1175773.15191598530409204569.stgit@warthog.procyon.org.uk> (raw)

From: Takashi Iwai <tiwai@suse.de>

After the recent actions to convert readpages aops to readahead, the
NULL checks of readpages aops in cachefiles_read_or_alloc_page() may
hit falsely.  More badly, it's an ASSERT() call, and this panics.

Drop the superfluous NULL checks for fixing this regression.

[DH: Note that cachefiles never actually used readpages, so this check was
 never actually necessary]

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208883
BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1175245
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---

 fs/cachefiles/rdwr.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 8bda092e60c5..e027c718ca01 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -413,7 +413,6 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
 
 	inode = d_backing_inode(object->backer);
 	ASSERT(S_ISREG(inode->i_mode));
-	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
@@ -713,7 +712,6 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
 
 	inode = d_backing_inode(object->backer);
 	ASSERT(S_ISREG(inode->i_mode));
-	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;



             reply	other threads:[~2021-01-20 16:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20 16:11 David Howells [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-10-19 14:56 David Howells
2020-10-19 15:05 ` Matthew Wilcox
2020-10-20  7:53 ` Christoph Hellwig
2020-10-20 11:06   ` Matthew Wilcox
2021-01-20 16:12 ` David Howells

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