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authorDavid Howells <dhowells@redhat.com>2015-02-24 10:05:29 +0000
committerDavid Howells <dhowells@redhat.com>2015-04-02 14:28:53 +0100
commitd3b97ca4a99e4e6c78f5a21c968eadf5c8ba9971 (patch)
treeceae1c413126e7dc02ff40836d779a0b3b28ae99 /fs/fscache/object.c
parenta39caadf06879017cb9a8c5c5cb4fc4ccb213275 (diff)
downloadlinux-d3b97ca4a99e4e6c78f5a21c968eadf5c8ba9971.tar.bz2
FS-Cache: The operation cancellation method needs calling in more places
Any time an incomplete operation is cancelled, the operation cancellation function needs to be called to clean up. This is currently being passed directly to some of the functions that might want to call it, but not all. Instead, pass the cancellation method pointer to the fscache_operation_init() and have that cache it in the operation struct. Further, plug in a dummy cancellation handler if the caller declines to set one as this allows us to call the function unconditionally (the extra overhead isn't worth bothering about as we don't expect to be calling this typically). The cancellation method must thence be called everywhere the CANCELLED state is set. Note that we call it *before* setting the CANCELLED state such that the method can use the old state value to guide its operation. fscache_do_cancel_retrieval() needs moving higher up in the sources so that the init function can use it now. Without this, the following oops may be seen: FS-Cache: Assertion failed FS-Cache: 3 == 0 is false ------------[ cut here ]------------ kernel BUG at ../fs/fscache/page.c:261! ... RIP: 0010:[<ffffffffa0089c1b>] fscache_release_retrieval_op+0x77/0x100 [<ffffffffa008853d>] fscache_put_operation+0x114/0x2da [<ffffffffa008b8c2>] __fscache_read_or_alloc_pages+0x358/0x3b3 [<ffffffffa00b761f>] __nfs_readpages_from_fscache+0x59/0xbf [nfs] [<ffffffffa00b06c5>] nfs_readpages+0x10c/0x185 [nfs] [<ffffffff81124925>] ? alloc_pages_current+0x119/0x13e [<ffffffff810ee5fd>] ? __page_cache_alloc+0xfb/0x10a [<ffffffff810f87f8>] __do_page_cache_readahead+0x188/0x22c [<ffffffff810f8b3a>] ondemand_readahead+0x29e/0x2af [<ffffffff810f8c92>] page_cache_sync_readahead+0x38/0x3a [<ffffffff810ef337>] generic_file_read_iter+0x1a2/0x55a [<ffffffffa00a9dff>] ? nfs_revalidate_mapping+0xd6/0x288 [nfs] [<ffffffffa00a6a23>] nfs_file_read+0x49/0x70 [nfs] [<ffffffff811363be>] new_sync_read+0x78/0x9c [<ffffffff81137164>] __vfs_read+0x13/0x38 [<ffffffff8113721e>] vfs_read+0x95/0x121 [<ffffffff811372f6>] SyS_read+0x4c/0x8a [<ffffffff81557a52>] system_call_fastpath+0x12/0x17 The assertion is showing that the remaining number of pages (n_pages) is not 0 when the operation is being released. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jeff.layton@primarydata.com>
Diffstat (limited to 'fs/fscache/object.c')
-rw-r--r--fs/fscache/object.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 40049f7505f0..9e792e30f4db 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -961,7 +961,8 @@ static const struct fscache_state *_fscache_invalidate_object(struct fscache_obj
if (!op)
goto nomem;
- fscache_operation_init(op, object->cache->ops->invalidate_object, NULL);
+ fscache_operation_init(op, object->cache->ops->invalidate_object,
+ NULL, NULL);
op->flags = FSCACHE_OP_ASYNC |
(1 << FSCACHE_OP_EXCLUSIVE) |
(1 << FSCACHE_OP_UNUSE_COOKIE);