2010/5/17 Boaz Harrosh <bharrosh@xxxxxxxxxxx>: > On 05/17/2010 12:59 PM, Zhang Jingwang wrote: >> These two functions mustn't be called from the same workqueue. Otherwise >> deadlock may occur. So we schedule the return_layout_barrier to nfsiod. >> nfsiod may not be a good choice, maybe we should setup a new workqueue >> to do the job. > > Please give more information. When does it happen that pnfs_XXX_done will > return -EAGAIN? network error or something else. > > What is the stack trace of the deadlock? > http://linux-nfs.org/pipermail/pnfs/2010-January/009939.html > And please rebase that patch on the latest changes to _pnfs_return_layout(). > but since in the new code _pnfs_return_layout() must be called with NO_WAIT > if called from the nfsiod then you cannot call pnfs_initiate_write/read() right > after. For writes you can get by with doing nothing because the write-back > thread will kick in soon enough. For reads I'm not sure, you'll need to send > me more information, stack trace. > > Or you can wait for the new state machine. I think the reason of this deadlock is that the put and the wait are in the same workqueue and run serially. So the state machine will not help. > > Boaz > >> >> Signed-off-by: Zhang Jingwang <zhangjingwang@xxxxxxxxxxxx> >> --- >> fs/nfs/pnfs.c | 58 +++++++++++++++++++++++++++++++++++++++----------------- >> 1 files changed, 40 insertions(+), 18 deletions(-) >> >> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c >> index 5ad7fc6..d2b72be 100644 >> --- a/fs/nfs/pnfs.c >> +++ b/fs/nfs/pnfs.c >> @@ -1655,6 +1655,24 @@ pnfs_call_done(struct pnfs_call_data *pdata, struct rpc_task *task, void *data) >> * cleanup. >> */ >> static void >> +pnfs_write_retry(struct work_struct *work) >> +{ >> + struct rpc_task *task; >> + struct nfs_write_data *wdata; >> + struct nfs4_pnfs_layout_segment range; >> + >> + dprintk("%s enter\n", __func__); >> + task = container_of(work, struct rpc_task, u.tk_work); >> + wdata = container_of(task, struct nfs_write_data, task); >> + range.iomode = IOMODE_RW; >> + range.offset = wdata->args.offset; >> + range.length = wdata->args.count; >> + _pnfs_return_layout(wdata->inode, &range, NULL, RETURN_FILE); >> + pnfs_initiate_write(wdata, NFS_CLIENT(wdata->inode), >> + wdata->pdata.call_ops, wdata->pdata.how); >> +} >> + >> +static void >> pnfs_writeback_done(struct nfs_write_data *data) >> { >> struct pnfs_call_data *pdata = &data->pdata; >> @@ -1674,15 +1692,8 @@ pnfs_writeback_done(struct nfs_write_data *data) >> } >> >> if (pnfs_call_done(pdata, &data->task, data) == -EAGAIN) { >> - struct nfs4_pnfs_layout_segment range = { >> - .iomode = IOMODE_RW, >> - .offset = data->args.offset, >> - .length = data->args.count, >> - }; >> - dprintk("%s: retrying\n", __func__); >> - _pnfs_return_layout(data->inode, &range, NULL, RETURN_FILE); >> - pnfs_initiate_write(data, NFS_CLIENT(data->inode), >> - pdata->call_ops, pdata->how); >> + INIT_WORK(&data->task.u.tk_work, pnfs_write_retry); >> + queue_work(nfsiod_workqueue, &data->task.u.tk_work); >> } >> } >> >> @@ -1798,6 +1809,24 @@ out: >> * read_pagelist is done >> */ >> static void >> +pnfs_read_retry(struct work_struct *work) >> +{ >> + struct rpc_task *task; >> + struct nfs_read_data *rdata; >> + struct nfs4_pnfs_layout_segment range; >> + >> + dprintk("%s enter\n", __func__); >> + task = container_of(work, struct rpc_task, u.tk_work); >> + rdata = container_of(task, struct nfs_read_data, task); >> + range.iomode = IOMODE_RW; >> + range.offset = rdata->args.offset; >> + range.length = rdata->args.count; >> + _pnfs_return_layout(rdata->inode, &range, NULL, RETURN_FILE); >> + pnfs_initiate_read(rdata, NFS_CLIENT(rdata->inode), >> + rdata->pdata.call_ops); >> +} >> + >> +static void >> pnfs_read_done(struct nfs_read_data *data) >> { >> struct pnfs_call_data *pdata = &data->pdata; >> @@ -1805,15 +1834,8 @@ pnfs_read_done(struct nfs_read_data *data) >> dprintk("%s: Begin (status %d)\n", __func__, data->task.tk_status); >> >> if (pnfs_call_done(pdata, &data->task, data) == -EAGAIN) { >> - struct nfs4_pnfs_layout_segment range = { >> - .iomode = IOMODE_ANY, >> - .offset = data->args.offset, >> - .length = data->args.count, >> - }; >> - dprintk("%s: retrying\n", __func__); >> - _pnfs_return_layout(data->inode, &range, NULL, RETURN_FILE); >> - pnfs_initiate_read(data, NFS_CLIENT(data->inode), >> - pdata->call_ops); >> + INIT_WORK(&data->task.u.tk_work, pnfs_read_retry); >> + queue_work(nfsiod_workqueue, &data->task.u.tk_work); >> } >> } >> > > -- > 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 > -- Zhang Jingwang National Research Centre for High Performance Computers Institute of Computing Technology, Chinese Academy of Sciences No. 6, South Kexueyuan Road, Haidian District Beijing, China -- 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
