diff options
Diffstat (limited to 'fs/nfs/filelayout/filelayout.c')
| -rw-r--r-- | fs/nfs/filelayout/filelayout.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c index 080fc6b278bd..508126eb49f9 100644 --- a/fs/nfs/filelayout/filelayout.c +++ b/fs/nfs/filelayout/filelayout.c @@ -542,6 +542,10 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo, struct nfs4_file_layout_dsaddr *dsaddr; int status = -EINVAL; + /* Is the deviceid already set? If so, we're good. */ + if (fl->dsaddr != NULL) + return 0; + /* find and reference the deviceid */ d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid, lo->plh_lc_cred, gfp_flags); @@ -553,8 +557,6 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo, if (filelayout_test_devid_unavailable(&dsaddr->id_node)) goto out_put; - fl->dsaddr = dsaddr; - if (fl->first_stripe_index >= dsaddr->stripe_count) { dprintk("%s Bad first_stripe_index %u\n", __func__, fl->first_stripe_index); @@ -570,6 +572,13 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo, goto out_put; } status = 0; + + /* + * Atomic compare and xchange to ensure we don't scribble + * over a non-NULL pointer. + */ + if (cmpxchg(&fl->dsaddr, NULL, dsaddr) != NULL) + goto out_put; out: return status; out_put: @@ -736,7 +745,8 @@ filelayout_free_lseg(struct pnfs_layout_segment *lseg) struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg); dprintk("--> %s\n", __func__); - nfs4_fl_put_deviceid(fl->dsaddr); + if (fl->dsaddr != NULL) + nfs4_fl_put_deviceid(fl->dsaddr); /* This assumes a single RW lseg */ if (lseg->pls_range.iomode == IOMODE_RW) { struct nfs4_filelayout *flo; |