NFSv4.1: Don't drop the pnfs_layout_hdr after a layoutget failure

We want to cache the pnfs_layout_hdr after a layoutget or i/o
failure so that pnfs_update_layout() can find it and know when
it is time to retry.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index d7a8f03..6834fa1 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -247,10 +247,28 @@ pnfs_iomode_to_fail_bit(u32 iomode)
 }
 
 static void
-pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
+pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 {
        lo->plh_retry_timestamp = jiffies;
-       set_bit(pnfs_iomode_to_fail_bit(iomode), &lo->plh_flags);
+       if (test_and_set_bit(fail_bit, &lo->plh_flags))
+               atomic_inc(&lo->plh_refcount);
+}
+
+static void
+pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
+{
+       if (test_and_clear_bit(fail_bit, &lo->plh_flags))
+               atomic_dec(&lo->plh_refcount);
+}
+
+static void
+pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
+{
+       struct inode *inode = lo->plh_inode;
+
+       spin_lock(&inode->i_lock);
+       pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
+       spin_unlock(&inode->i_lock);
        dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
                        iomode == IOMODE_RW ?  "RW" : "READ");
 }
@@ -259,14 +277,15 @@ static bool
 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 {
        unsigned long start, end;
-       if (test_bit(pnfs_iomode_to_fail_bit(iomode), &lo->plh_flags) == 0)
+       int fail_bit = pnfs_iomode_to_fail_bit(iomode);
+
+       if (test_bit(fail_bit, &lo->plh_flags) == 0)
                return false;
        end = jiffies;
        start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
        if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
                /* It is time to retry the failed layoutgets */
-               clear_bit(NFS_LAYOUT_RW_FAILED, &lo->plh_flags);
-               clear_bit(NFS_LAYOUT_RO_FAILED, &lo->plh_flags);
+               pnfs_layout_clear_fail_bit(lo, fail_bit);
                return false;
        }
        return true;
@@ -493,9 +512,14 @@ pnfs_destroy_layout(struct nfs_inode *nfsi)
        if (lo) {
                lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
                pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
-       }
-       spin_unlock(&nfsi->vfs_inode.i_lock);
-       pnfs_free_lseg_list(&tmp_list);
+               pnfs_get_layout_hdr(lo);
+               pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
+               pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
+               spin_unlock(&nfsi->vfs_inode.i_lock);
+               pnfs_free_lseg_list(&tmp_list);
+               pnfs_put_layout_hdr(lo);
+       } else
+               spin_unlock(&nfsi->vfs_inode.i_lock);
 }
 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);