Commit 2a4c8994eeef50796015f8a2005e4a75c1929166
1 parent
39a50b42f7
Exists in
smarc-l5.0.0_1.0.0-ga
and in
5 other branches
NFSv4.1: Fix umount when filelayout DS is also the MDS
Currently there is a 'chicken and egg' issue when the DS is also the mounted MDS. The nfs_match_client() reference from nfs4_set_ds_client bumps the cl_count, the nfs_client is not freed at umount, and nfs4_deviceid_purge_client is not called to dereference the MDS usage of a deviceid which holds a reference to the DS nfs_client. The result is the umount program returns, but the nfs_client is not freed, and the cl_session hearbeat continues. The MDS (and all other nfs mounts) lose their last nfs_client reference in nfs_free_server when the last nfs_server (fsid) is umounted. The file layout DS lose their last nfs_client reference in destroy_ds when the last deviceid referencing the data server is put and destroy_ds is called. This is triggered by a call to nfs4_deviceid_purge_client which removes references to a pNFS deviceid used by an MDS mount. The fix is to track how many pnfs enabled filesystems are mounted from this server, and then to purge the device id cache once that count reaches zero. Reported-by: Jorge Mora <Jorge.Mora@netapp.com> Reported-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Showing 3 changed files with 6 additions and 1 deletions Side-by-side Diff
fs/nfs/client.c
fs/nfs/pnfs.c
| ... | ... | @@ -80,6 +80,9 @@ |
| 80 | 80 | if (nfss->pnfs_curr_ld) { |
| 81 | 81 | if (nfss->pnfs_curr_ld->clear_layoutdriver) |
| 82 | 82 | nfss->pnfs_curr_ld->clear_layoutdriver(nfss); |
| 83 | + /* Decrement the MDS count. Purge the deviceid cache if zero */ | |
| 84 | + if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count)) | |
| 85 | + nfs4_deviceid_purge_client(nfss->nfs_client); | |
| 83 | 86 | module_put(nfss->pnfs_curr_ld->owner); |
| 84 | 87 | } |
| 85 | 88 | nfss->pnfs_curr_ld = NULL; |
| ... | ... | @@ -127,6 +130,8 @@ |
| 127 | 130 | module_put(ld_type->owner); |
| 128 | 131 | goto out_no_driver; |
| 129 | 132 | } |
| 133 | + /* Bump the MDS count */ | |
| 134 | + atomic_inc(&server->nfs_client->cl_mds_count); | |
| 130 | 135 | |
| 131 | 136 | dprintk("%s: pNFS module for %u set\n", __func__, id); |
| 132 | 137 | return; |
include/linux/nfs_fs_sb.h