On 10/14/2015 18:53, Trond Myklebust wrote: > On Wed, Oct 14, 2015 at 3:18 AM, Kinglong Mee <kinglongmee@xxxxxxxxx> wrote: >> On 10/13/2015 21:45, Trond Myklebust wrote: >>> On Tue, Oct 13, 2015 at 8:45 AM, Kinglong Mee <kinglongmee@xxxxxxxxx> wrote: >>>> ping ... >>>> >>>> What's your opinion about this problem ? >>>> >>>> If read/write of block layout file with bad length (res.count != arg.count), >>>> should nfs retry? NFS try to call rpc_restart_call_prepare() right now, >>>> that cause a panic with uninitialized task. >>> >>> The client should not be attempting to read more data than what was >>> requested by the O_DIRECT read request. It should be strictly >>> respecting the boundaries of the user buffer that was supplied. >> >> Yes, that's right. >> >>> Any idea why this is happening? >> >> As post before, bl_read_pagelist() return a longer result that causes the panic. >> >>>>> [ 1004.001842] bl_read_pagelist enter nr_pages 1 offset 2048 count 2048 >>>>> [ 1004.002110] bl_read_pagelist: pg_offset 2048 >>>>> [ 1004.002370] bl_read_pagelist: pg_len 2048 is_dio >>>>> [ 1004.002617] bl_read_pagelist: pg_len 2048 after do_add_page_to_bio >>>>> [ 1004.002853] bl_read_pagelist: 2048 4096 "(isect << SECTOR_SHIFT) < header->inode->i_size" >>>>> [ 1004.003774] NFS: nfs_pgio_result: 0, (status 0), tk_ops (null) >>>>> [ 1004.003989] --> nfs4_read_done >>>>> [ 1004.004224] nfs_readpage_done: 0 >>>>> [ 1004.004459] nfs_pgio_result: 0 >>>>> [ 1004.004691] nfs_readpage_result: eof 0, res.count 4096, args.count 2048 >>>>> [ 1004.004926] nfs_readpage_retry: tk_ops (null) > > Right, but that means one of two things: Either we need to fix > bl_read_pagelist, or we need to fall back to read-through-MDS in this > case. I don't know the restrict of calling bl_read_pagelist, Should the offset or count be aligning to PAGE_SIZE or not? If not, there maybe some problem exist in bl_read_pagelist. Otherwise, if bl_read_pagelist success but with res.count that not equal to args.count, nfs should fall back to read-through-MDS. So, both need be fixed. thanks, Kinglong Mee -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
