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| author | David Howells <dhowells@redhat.com> | 2009-11-19 18:11:32 +0000 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2009-11-19 18:11:32 +0000 |
| commit | e3d4d28b1c8cc7c26536a50b43d86ccd39878550 (patch) | |
| tree | 23f6dacd5ffdf6c6d01c411517855a41405381b9 /fs/fscache/stats.c | |
| parent | 285e728b0ac55b53a673114096168d6f74930167 (diff) | |
| download | linux-e3d4d28b1c8cc7c26536a50b43d86ccd39878550.tar.bz2 | |
FS-Cache: Handle read request vs lookup, creation or other cache failure
FS-Cache doesn't correctly handle the netfs requesting a read from the cache
on an object that failed or was withdrawn by the cache. A trace similar to
the following might be seen:
CacheFiles: Lookup failed error -105
[exe ] unexpected submission OP165afe [OBJ6cac OBJECT_LC_DYING]
[exe ] objstate=OBJECT_LC_DYING [OBJECT_LC_DYING]
[exe ] objflags=0
[exe ] objevent=9 [fffffffffffffffb]
[exe ] ops=0 inp=0 exc=0
Pid: 6970, comm: exe Not tainted 2.6.32-rc6-cachefs #50
Call Trace:
[<ffffffffa0076477>] fscache_submit_op+0x3ff/0x45a [fscache]
[<ffffffffa0077997>] __fscache_read_or_alloc_pages+0x187/0x3c4 [fscache]
[<ffffffffa00b6480>] ? nfs_readpage_from_fscache_complete+0x0/0x66 [nfs]
[<ffffffffa00b6388>] __nfs_readpages_from_fscache+0x7e/0x176 [nfs]
[<ffffffff8108e483>] ? __alloc_pages_nodemask+0x11c/0x5cf
[<ffffffffa009d796>] nfs_readpages+0x114/0x1d7 [nfs]
[<ffffffff81090314>] __do_page_cache_readahead+0x15f/0x1ec
[<ffffffff81090228>] ? __do_page_cache_readahead+0x73/0x1ec
[<ffffffff810903bd>] ra_submit+0x1c/0x20
[<ffffffff810906bb>] ondemand_readahead+0x227/0x23a
[<ffffffff81090762>] page_cache_sync_readahead+0x17/0x19
[<ffffffff8108a99e>] generic_file_aio_read+0x236/0x5a0
[<ffffffffa00937bd>] nfs_file_read+0xe4/0xf3 [nfs]
[<ffffffff810b2fa2>] do_sync_read+0xe3/0x120
[<ffffffff81354cc3>] ? _spin_unlock_irq+0x2b/0x31
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffff811848e5>] ? selinux_file_permission+0x5d/0x10f
[<ffffffff81352bdb>] ? thread_return+0x3e/0x101
[<ffffffff8117d7b0>] ? security_file_permission+0x11/0x13
[<ffffffff810b3b06>] vfs_read+0xaa/0x16f
[<ffffffff81058df0>] ? trace_hardirqs_on_caller+0x10c/0x130
[<ffffffff810b3c84>] sys_read+0x45/0x6c
[<ffffffff8100ae2b>] system_call_fastpath+0x16/0x1b
The object state might also be OBJECT_DYING or OBJECT_WITHDRAWING.
This should be handled by simply rejecting the new operation with ENOBUFS.
There's no need to log an error for it. Events of this type now appear in the
stats file under Ops:rej.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/fscache/stats.c')
| -rw-r--r-- | fs/fscache/stats.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index 1d53ea68409e..045ba396dbf2 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -26,6 +26,7 @@ atomic_t fscache_n_op_deferred_release; atomic_t fscache_n_op_release; atomic_t fscache_n_op_gc; atomic_t fscache_n_op_cancelled; +atomic_t fscache_n_op_rejected; atomic_t fscache_n_attr_changed; atomic_t fscache_n_attr_changed_ok; @@ -210,11 +211,12 @@ static int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_store_radix_deletes), atomic_read(&fscache_n_store_pages_over_limit)); - seq_printf(m, "Ops : pend=%u run=%u enq=%u can=%u\n", + seq_printf(m, "Ops : pend=%u run=%u enq=%u can=%u rej=%u\n", atomic_read(&fscache_n_op_pend), atomic_read(&fscache_n_op_run), atomic_read(&fscache_n_op_enqueue), - atomic_read(&fscache_n_op_cancelled)); + atomic_read(&fscache_n_op_cancelled), + atomic_read(&fscache_n_op_rejected)); seq_printf(m, "Ops : dfr=%u rel=%u gc=%u\n", atomic_read(&fscache_n_op_deferred_release), atomic_read(&fscache_n_op_release), |