• David Howells's avatar
    FS-Cache: Clear remaining page count on retrieval cancellation · 91c7fbbf
    David Howells authored
    Provide fscache_cancel_op() with a pointer to a function it should invoke under
    lock if it cancels an operation.
    
    Use this to clear the remaining page count upon cancellation of a pending
    retrieval operation so that fscache_release_retrieval_op() doesn't get an
    assertion failure (see below).  This can happen when a signal occurs, say from
    CTRL-C being pressed during data retrieval.
    
    FS-Cache: Assertion failed
    3 == 0 is false
    ------------[ cut here ]------------
    kernel BUG at fs/fscache/page.c:237!
    invalid opcode: 0000 [#641] SMP
    Modules linked in: cachefiles(F) nfsv4(F) nfsv3(F) nfsv2(F) nfs(F) fscache(F) auth_rpcgss(F) nfs_acl(F) lockd(F) sunrpc(F)
    CPU 0
    Pid: 6075, comm: slurp-q Tainted: GF     D      3.7.0-rc8-fsdevel+ #411                  /DG965RY
    RIP: 0010:[<ffffffffa007f328>]  [<ffffffffa007f328>] fscache_release_retrieval_op+0x75/0xff [fscache]
    RSP: 0000:ffff88001c6d7988  EFLAGS: 00010296
    RAX: 000000000000000f RBX: ffff880014cdfe00 RCX: ffffffff6c102000
    RDX: ffffffff8102d1ad RSI: ffffffff6c102000 RDI: ffffffff8102d1d6
    RBP: ffff88001c6d7998 R08: 0000000000000002 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffe00
    R13: ffff88001c6d7ab4 R14: ffff88001a8638a0 R15: ffff88001552b190
    FS:  00007f877aaf0700(0000) GS:ffff88003bc00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
    CR2: 00007fff11378fd2 CR3: 000000001c6c6000 CR4: 00000000000007f0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Process slurp-q (pid: 6075, threadinfo ffff88001c6d6000, task ffff88001c6c4080)
    Stack:
     ffffffffa007ec07 ffff880014cdfe00 ffff88001c6d79c8 ffffffffa007db4d
     ffffffffa007ec07 ffff880014cdfe00 00000000fffffe00 ffff88001c6d7ab4
     ffff88001c6d7a38 ffffffffa008116d 0000000000000000 ffff88001c6c4080
    Call Trace:
     [<ffffffffa007ec07>] ? fscache_cancel_op+0x194/0x1cf [fscache]
     [<ffffffffa007db4d>] fscache_put_operation+0x135/0x2ed [fscache]
     [<ffffffffa007ec07>] ? fscache_cancel_op+0x194/0x1cf [fscache]
     [<ffffffffa008116d>] __fscache_read_or_alloc_pages+0x413/0x4bc [fscache]
     [<ffffffff810ac8ae>] ? __alloc_pages_nodemask+0x195/0x75c
     [<ffffffffa00aab0f>] __nfs_readpages_from_fscache+0x86/0x13d [nfs]
     [<ffffffffa00a5fe0>] nfs_readpages+0x186/0x1bd [nfs]
     [<ffffffff810d23c8>] ? alloc_pages_current+0xc7/0xe4
     [<ffffffff810a68b5>] ? __page_cache_alloc+0x84/0x91
     [<ffffffff810af912>] ? __do_page_cache_readahead+0xa6/0x2e0
     [<ffffffff810afaa3>] __do_page_cache_readahead+0x237/0x2e0
     [<ffffffff810af912>] ? __do_page_cache_readahead+0xa6/0x2e0
     [<ffffffff810afe3e>] ra_submit+0x1c/0x20
     [<ffffffff810b019b>] ondemand_readahead+0x359/0x382
     [<ffffffff810b0279>] page_cache_sync_readahead+0x38/0x3a
     [<ffffffff810a77b5>] generic_file_aio_read+0x26b/0x637
     [<ffffffffa00f1852>] ? nfs_mark_delegation_referenced+0xb/0xb [nfsv4]
     [<ffffffffa009cc85>] nfs_file_read+0xaa/0xcf [nfs]
     [<ffffffff810db5b3>] do_sync_read+0x91/0xd1
     [<ffffffff810dbb8b>] vfs_read+0x9b/0x144
     [<ffffffff810dbc78>] sys_read+0x44/0x75
     [<ffffffff81422892>] system_call_fastpath+0x16/0x1b
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    91c7fbbf
operation.c 14.1 KB