>>>>> " " == Andrea Arcangeli <[EMAIL PROTECTED]> writes:

     > On Thu, Jan 11, 2001 at 07:30:49PM +0100, Trond Myklebust
     > wrote:
    >> OK. In that case my patch, would just be amended to eliminate
    >> the redundant comparison as is the case below.

     > This patch looks fine w.r.t. alignment but given the below
     > seems called at runtime (not just at mount time) for
     > performance and to save a dozen of bytes of kernel stack it
     > would probably better to use the nfs_fh structure in 2.2.19pre7
     > for the in-kernel representation and to define a new structure
     > for userspace message passing (defined as the nfs_fh in
     > 2.2.19pre6). But at least now we see _why_ it broke ;)

I'm not at all convinced that saving us a copy of 66 bytes in NLM is
really worth the effort. It certainly isn't worth the ugliness of
living with arrays of (void *) in order to match the alignment of a
fake pointer. I'd rather we make them integers.
If we really are to change struct nfs_fh, I therefore propose that we
also make struct nfs_fhbase reflect the fact that fb_dentry is a
32-bit cookie. That means that both nfs_fh and knfs_fh would be
integer-aligned.

The following is untested, but should be correct.

Cheers,
  Trond

diff -u --recursive --new-file linux-2.2.18/fs/lockd/svcsubs.c 
linux-2.2.18-fix_ppc/fs/lockd/svcsubs.c
--- linux-2.2.18/fs/lockd/svcsubs.c     Mon Dec 11 01:49:44 2000
+++ linux-2.2.18-fix_ppc/fs/lockd/svcsubs.c     Thu Jan 11 20:37:37 2001
@@ -44,6 +44,10 @@
  * Note that we open the file O_RDONLY even when creating write locks.
  * This is not quite right, but for now, we assume the client performs
  * the proper R/W checking.
+ *
+ * BEWARE:
+ * The cast to struct knfs_fh in this routine, imposes an alignment
+ * requirement on (struct nfs_fh)->data for some platforms.
  */
 u32
 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
@@ -63,8 +67,7 @@
        down(&nlm_file_sema);
 
        for (file = nlm_files[hash]; file; file = file->f_next) {
-               if (file->f_handle.fh_dcookie == fh->fh_dcookie &&
-                   !memcmp(&file->f_handle, fh, sizeof(*fh)))
+               if (!memcmp(&file->f_handle, fh, sizeof(*fh)))
                        goto found;
        }
 
diff -u --recursive --new-file linux-2.2.18/fs/nfs/inode.c 
linux-2.2.18-fix_ppc/fs/nfs/inode.c
--- linux-2.2.18/fs/nfs/inode.c Mon Dec 11 01:49:44 2000
+++ linux-2.2.18-fix_ppc/fs/nfs/inode.c Thu Jan 11 21:13:04 2001
@@ -273,9 +273,8 @@
        struct nfs_server       *server;
        struct rpc_xprt         *xprt = 0;
        struct rpc_clnt         *clnt = 0;
-       struct nfs_fh           *root_fh = NULL,
-                               *root = &data->root,
-                               fh;
+       struct nfs_fh           fh,
+                               *root_fh = NULL;
        struct inode            *root_inode = NULL;
        unsigned int            authflavor;
        struct sockaddr_in      srvaddr;
@@ -290,7 +289,6 @@
                goto failure;
        }
 
-       memset(&fh, 0, sizeof(fh));
        if (data->version != NFS_MOUNT_VERSION) {
                printk(KERN_WARNING "nfs warning: mount version %s than kernel\n",
                        data->version < NFS_MOUNT_VERSION ? "older" : "newer");
@@ -298,12 +296,21 @@
                        data->namlen = 0;
                if (data->version < 3)
                        data->bsize  = 0;
-               if (data->version < 4) {
+               if (data->version < 4)
                        data->flags &= ~NFS_MOUNT_VER3;
-                       root = &fh;
-                       root->size = NFS2_FHSIZE;
-                       memcpy(root->data, data->old_root.data, NFS2_FHSIZE);
+       }
+
+       memset(&fh, 0, sizeof(fh));
+       if (data->version < 4) {
+               fh.size = NFS2_FHSIZE;
+               memcpy(fh.data, data->old_root.data, NFS2_FHSIZE);
+       } else {
+               fh.size = (data->flags & NFS_MOUNT_VER3) ? data->root.size : 
+NFS2_FHSIZE;
+               if (fh.size > sizeof(fh.data)) {
+                       printk(KERN_WARNING "NFS: mount program passes invalid 
+filehandle!\n");
+                       goto failure;
                }
+               memcpy(fh.data, data->root.data, fh.size);
        }
 
        /* We now require that the mount process passes the remote address */
@@ -351,19 +358,15 @@
        if (data->flags & NFS_MOUNT_VER3) {
 #ifdef CONFIG_NFS_V3
                server->rpc_ops = &nfs_v3_clientops;
-               NFS_SB_FHSIZE(sb) = sizeof(unsigned short) + NFS3_FHSIZE;
+               NFS_SB_FHSIZE(sb) = NFS3_FHSIZE;
                version = 3;
-               if (data->version < 4) {
-                       printk(KERN_NOTICE "NFS: NFSv3 not supported by mount 
program.\n");
-                       goto failure_unlock;
-               }
 #else
                printk(KERN_NOTICE "NFS: NFSv3 not supported.\n");
                goto failure_unlock;
 #endif
        } else {
                server->rpc_ops = &nfs_v2_clientops;
-               NFS_SB_FHSIZE(sb) = sizeof(unsigned short) + NFS2_FHSIZE;
+               NFS_SB_FHSIZE(sb) = NFS2_FHSIZE;
                version = 2;
        }
 
@@ -422,13 +425,14 @@
        root_fh = nfs_fh_alloc();
        if (!root_fh)
                goto out_no_fh;
-       memcpy((u8*)root_fh, (u8*)root, sizeof(*root_fh));
+       memcpy((u8*)root_fh, (u8*)&fh, sizeof(*root_fh));
 
        /* Did getting the root inode fail? */
-       if ((root->size > NFS_SB_FHSIZE(sb)
-            || ! (root_inode = nfs_get_root(sb, root)))
+       if ((fh.size > NFS_SB_FHSIZE(sb)
+            || ! (root_inode = nfs_get_root(sb, &fh)))
            && (data->flags & NFS_MOUNT_VER3)) {
                data->flags &= ~NFS_MOUNT_VER3;
+               fh.size = NFS2_FHSIZE;
                nfs_fh_free(root_fh);
                rpciod_down();
                rpc_shutdown_client(server->client);
@@ -445,7 +449,7 @@
        sb->u.nfs_sb.s_root = root_fh;
 
        /* Get some general file system info */
-       if (server->rpc_ops->statfs(server, root, &fsinfo) >= 0) {
+       if (server->rpc_ops->statfs(server, &fh, &fsinfo) >= 0) {
                if (server->namelen == 0)
                        server->namelen = fsinfo.namelen;
        } else {
diff -u --recursive --new-file linux-2.2.18/fs/nfsd/nfsfh.c 
linux-2.2.18-fix_ppc/fs/nfsd/nfsfh.c
--- linux-2.2.18/fs/nfsd/nfsfh.c        Mon Dec 11 01:49:44 2000
+++ linux-2.2.18-fix_ppc/fs/nfsd/nfsfh.c        Thu Jan 11 20:10:09 2001
@@ -690,7 +690,7 @@
        fhp->fh_handle.fh_dev    = kdev_t_to_u32(parent->d_inode->i_dev);
        fhp->fh_handle.fh_xdev   = kdev_t_to_u32(exp->ex_dev);
        fhp->fh_handle.fh_xino   = ino_t_to_u32(exp->ex_ino);
-       fhp->fh_handle.fh_dcookie = (struct dentry *)0xfeebbaca;
+       fhp->fh_handle.fh_dcookie = 0xfeebbaca;
        if (inode) {
                fhp->fh_handle.fh_ino = ino_t_to_u32(inode->i_ino);
                fhp->fh_handle.fh_generation = inode->i_generation;
diff -u --recursive --new-file linux-2.2.18/include/linux/nfs.h 
linux-2.2.18-fix_ppc/include/linux/nfs.h
--- linux-2.2.18/include/linux/nfs.h    Mon Dec 11 01:49:44 2000
+++ linux-2.2.18-fix_ppc/include/linux/nfs.h    Thu Jan 11 20:55:26 2001
@@ -94,8 +94,8 @@
  */
 #define NFS_MAXFHSIZE          64
 struct nfs_fh {
-       unsigned short          size;
-       unsigned char           data[NFS_MAXFHSIZE];
+       unsigned int            size;
+       unsigned int            data[NFS_MAXFHSIZE / sizeof(unsigned int)];
 };
 
 enum nfs3_stable_how {
diff -u --recursive --new-file linux-2.2.18/include/linux/nfs3.h 
linux-2.2.18-fix_ppc/include/linux/nfs3.h
--- linux-2.2.18/include/linux/nfs3.h   Mon Dec 11 01:49:44 2000
+++ linux-2.2.18-fix_ppc/include/linux/nfs3.h   Thu Jan 11 20:06:50 2001
@@ -58,6 +58,11 @@
        NF3BAD  = 8
 };
 
+struct nfs3_fh {
+       unsigned short          size;
+       unsigned char           data[NFS3_FHSIZE];
+};
+
 #define NFS3_VERSION           3
 #define NFS3PROC_NULL          0
 #define NFS3PROC_GETATTR       1
diff -u --recursive --new-file linux-2.2.18/include/linux/nfs_mount.h 
linux-2.2.18-fix_ppc/include/linux/nfs_mount.h
--- linux-2.2.18/include/linux/nfs_mount.h      Thu Dec 14 12:30:13 2000
+++ linux-2.2.18-fix_ppc/include/linux/nfs_mount.h      Thu Jan 11 21:21:09 2001
@@ -8,9 +8,9 @@
  *
  *  structure passed from user-space to kernel-space during an nfs mount
  */
-#include <linux/nfs.h>
+#include <linux/in.h>
 #include <linux/nfs2.h>
-#include <linux/nfs_fs.h>
+#include <linux/nfs3.h>
 
 /*
  * WARNING!  Do not delete or change the order of these fields.  If
@@ -42,7 +42,7 @@
        char            hostname[256];          /* 1 */
        int             namlen;                 /* 2 */
        unsigned int    bsize;                  /* 3 */
-       struct nfs_fh   root;                   /* 4 */
+       struct nfs3_fh  root;                   /* 4 */
 };
 
 /* bits in the flags field */
diff -u --recursive --new-file linux-2.2.18/include/linux/nfsd/nfsfh.h 
linux-2.2.18-fix_ppc/include/linux/nfsd/nfsfh.h
--- linux-2.2.18/include/linux/nfsd/nfsfh.h     Thu Dec 14 12:30:28 2000
+++ linux-2.2.18-fix_ppc/include/linux/nfsd/nfsfh.h     Thu Jan 11 20:09:31 2001
@@ -30,7 +30,7 @@
  * ino/dev of the exported inode.
  */
 struct nfs_fhbase {
-       struct dentry * fb_dentry;      /* dentry cookie */
+       __u32           fb_dcookie;     /* dentry cookie */
        __u32           fb_ino;         /* our inode number */
        __u32           fb_dirino;      /* dir inode number */
        __u32           fb_dev;         /* our device */
@@ -45,7 +45,7 @@
        __u8                    fh_cookie[NFS_FH_PADDING];
 };
 
-#define fh_dcookie             fh_base.fb_dentry
+#define fh_dcookie             fh_base.fb_dcookie
 #define fh_ino                 fh_base.fb_ino
 #define fh_dirino              fh_base.fb_dirino
 #define fh_dev                 fh_base.fb_dev
-
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