NFSv4.1: Replace dprintk() in pnfs_update_layout with something less buggy

Dereferencing nfsi->layout in order to read plh_flags without holding
a spin lock is bug prone. Furthermore, the dprintk() tells you nothing
about whether or not the call succeeded.
Replace it with something that tells you about whether or not a valid
layout segment was returned for the inode in question.

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

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 498af8779959dea0067ee1f8dafb079c0d07bca6..df45acaf91f710b8d22f573267d3b3b52b9f3dd3 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1027,17 +1027,15 @@ pnfs_update_layout(struct inode *ino,
        bool first = false;
 
        if (!pnfs_enabled_sb(NFS_SERVER(ino)))
-               return NULL;
+               goto out;
 
        if (pnfs_within_mdsthreshold(ctx, ino, iomode))
-               return NULL;
+               goto out;
 
        spin_lock(&ino->i_lock);
        lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
-       if (lo == NULL) {
-               dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__);
+       if (lo == NULL)
                goto out_unlock;
-       }
 
        /* Do we even need to bother with this? */
        if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
@@ -1093,8 +1091,14 @@ pnfs_update_layout(struct inode *ino,
        atomic_dec(&lo->plh_outstanding);
        pnfs_put_layout_hdr(lo);
 out:
-       dprintk("%s end, state 0x%lx lseg %p\n", __func__,
-               nfsi->layout ? nfsi->layout->plh_flags : -1, lseg);
+       dprintk("%s: inode %s/%llu pNFS layout segment %s for "
+                       "(%s, offset: %llu, length: %llu)\n",
+                       __func__, ino->i_sb->s_id,
+                       (unsigned long long)NFS_FILEID(ino),
+                       lseg == NULL ? "not found" : "found",
+                       iomode==IOMODE_RW ?  "read/write" : "read-only",
+                       (unsigned long long)pos,
+                       (unsigned long long)count);
        return lseg;
 out_unlock:
        spin_unlock(&ino->i_lock);