commit 578d0198968806db50885e8282da08946a3d1a7c Author: Chuck Lever Date: Thu, 11 Feb 2010 18:47:59 +0000 (13:47 -0500) [PATCH] NFS: Too many GETATTR and ACCESS calls after direct I/O The cached read and write paths initialize fattr->time_start in their setup procedures. The value of fattr->time_start is propagated to read_cache_jiffies by nfs_update_inode(). Subsequent calls to nfs_attribute_timeout() will then use a good time stamp when computing the attribute cache timeout, and squelch unneeded GETATTR calls. Since the direct I/O paths erroneously leave the inode's fattr->time_start field set to zero, read_cache_jiffies for that inode is set to zero after any direct read or write operation. This triggers an otw GETATTR or ACCESS call to update the file's attribute and access caches properly, even when the NFS READ or WRITE replies have usable post-op attributes. Make sure the direct read and write setup code performs the same fattr initialization as the cached I/O paths to prevent unnecessary GETATTR calls. This was likely introduced by commit 0e574af1 in 2.6.15, which appears to add new nfs_fattr_init() call sites in the cached read and write paths, but not in the equivalent places in fs/nfs/direct.c. A subsequent commit in the same series, 33801147, introduces the fattr->time_start field. Interestingly, the direct write reschedule path already has a call to nfs_fattr_init() in the right place. Reported-by: Quentin Barnes Signed-off-by: Chuck Lever Cc: stable@kernel.org Applied without changes to kernel-2.6.18-194.0.0.0.4.el5. Signed-off-by: Chuck Lever diff -Naurp linux-2.6.18.x86_64/fs/nfs/direct.c cel-2.6.18/fs/nfs/direct.c --- linux-2.6.18.x86_64/fs/nfs/direct.c 2010-05-03 10:49:12.000000000 -0400 +++ cel-2.6.18/fs/nfs/direct.c 2010-05-03 11:04:05.000000000 -0400 @@ -312,6 +312,7 @@ static ssize_t nfs_direct_read_schedule( data->args.pgbase = pgbase; data->args.pages = data->pagevec; data->args.count = bytes; + nfs_fattr_init(&data->fattr); data->res.fattr = &data->fattr; data->res.eof = 0; data->res.count = bytes; @@ -480,6 +481,7 @@ static void nfs_direct_commit_schedule(s data->res.count = 0; data->res.fattr = &data->fattr; data->res.verf = &data->verf; + nfs_fattr_init(&data->fattr); rpc_init_task_wq(&data->task, NFS_CLIENT(dreq->inode), RPC_TASK_ASYNC, &nfs_commit_direct_ops, data, nfsiod_workqueue); @@ -652,6 +654,7 @@ static ssize_t nfs_direct_write_schedule data->args.pgbase = pgbase; data->args.pages = data->pagevec; data->args.count = bytes; + nfs_fattr_init(&data->fattr); data->res.fattr = &data->fattr; data->res.count = bytes; data->res.verf = &data->verf;