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authorDavid Howells <dhowells@redhat.com>2015-02-24 11:05:29 +0100
committerDavid Howells <dhowells@redhat.com>2015-04-02 15:28:53 +0200
commitd3b97ca4a99e4e6c78f5a21c968eadf5c8ba9971 (patch)
treeceae1c413126e7dc02ff40836d779a0b3b28ae99 /fs/fscache/cookie.c
parentFS-Cache: Put an aborted initialised op so that it is accounted correctly (diff)
downloadlinux-d3b97ca4a99e4e6c78f5a21c968eadf5c8ba9971.tar.xz
linux-d3b97ca4a99e4e6c78f5a21c968eadf5c8ba9971.zip
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/cookie.c')
-rw-r--r--fs/fscache/cookie.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 8de22164f5fb..d403c69bee08 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -672,7 +672,7 @@ int __fscache_check_consistency(struct fscache_cookie *cookie)
if (!op)
return -ENOMEM;
- fscache_operation_init(op, NULL, NULL);
+ fscache_operation_init(op, NULL, NULL, NULL);
op->flags = FSCACHE_OP_MYTHREAD |
(1 << FSCACHE_OP_WAITING) |
(1 << FSCACHE_OP_UNUSE_COOKIE);
@@ -696,8 +696,7 @@ int __fscache_check_consistency(struct fscache_cookie *cookie)
/* the work queue now carries its own ref on the object */
spin_unlock(&cookie->lock);
- ret = fscache_wait_for_operation_activation(object, op,
- NULL, NULL, NULL);
+ ret = fscache_wait_for_operation_activation(object, op, NULL, NULL);
if (ret == 0) {
/* ask the cache to honour the operation */
ret = object->cache->ops->check_consistency(op);