On Tue, May 16, 2017 at 08:57:03PM +0800, Gu Zheng wrote: > Hi all: > we have a test about nfs on linux 4.11. > the detailed process as follow: > server ip:9.81.231.141 client > mount -t ext4 /dev/vdb /home/nfs/aa > mount -t nfs -o sync,tcp,vers=3,noac,timeo=70,retrans=3 9.81.231.141:/home/nfs /tmp/aa/ > ls /tmp/aa > umount /home/nfs/aa This is as expected. There's actually no guarantee you'll be able to unmount the filesystem till nfsd is stopped (even unexporting won't always do the job). --b. > > the umount remind "target is busy". > so we analyze the code , a reference count which is named "mnt_count" add 1 in rqst_exp_get_by_name() after execute the "ls" order. > the detailed call is nfsd3_proc_lookup->nfsd_lookup->nfsd_lookup_dentry->nfsd_cross_mnt->rqst_exp_get_by_name->exp_get_by_name->svc_export_lookup->sunrpc_cache_lookup->svc_export_init->path_get > the reference count can't be subtracted untill we stop nfsd or tcp idle timeout on server. the system call the cache_flush() to subtract the count. > then we can umount successfully. > > do dou have some patches can umount immediately or some suggestions? -- 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
