Alternate Patch: [PATCH] Don't include device number in cache invalidation when running on NFS

[Thomas Glanzmann <sithglan@stud.uni-erlangen.de>]

Hello,

* Thomas Glanzmann <sithglan@stud.uni-erlangen.de> [050522 23:24]:
> Hello,

> > Sorry, I meant "rename", not "link", and yes, it should be NFS-safe. It's 
> > how all the mailers do things too, afaik.

> okay. I will doublecheck that and come back.

yes, you're right.

While reading liblockfile I saw the following:

/*
 *      See if the directory where is certain file is in
 *      is located on an NFS mounted volume.
 */
static int is_nfs(const char *file)
{
        char dir[1024];
        char *s;
        struct stat st;

        strncpy(dir, file, sizeof(dir));
        if ((s = strrchr(dir, '/')) != NULL)
                *s = 0;
        else
                strcpy(dir, ".");

        if (stat(dir, &st) < 0)
                return 0;

        return ((st.st_dev & 0xFF00) == 0);
}

So here comes an alternate patch if you like to verify the st_dev for non
NFS stuff. Also tested.

[PATCH] Don't include device number in cache invalidation when running on NFS

This patches includes the device number only in the cache invalidation
process when not running on a NFS volume.

Signed-off-by: Thomas Glanzmann <sithglan@stud.uni-erlangen.de>

diff --git a/read-cache.c b/read-cache.c
--- a/read-cache.c
+++ b/read-cache.c
@@ -65,8 +65,11 @@ int ce_match_stat(struct cache_entry *ce
 	if (ce->ce_uid != htonl(st->st_uid) ||
 	    ce->ce_gid != htonl(st->st_gid))
 		changed |= OWNER_CHANGED;
-	if (ce->ce_dev != htonl(st->st_dev) ||
-	    ce->ce_ino != htonl(st->st_ino))
+	/* Only include device number if not running on NFS */
+	if (ce->ce_dev != htonl(st->st_dev) &&
+	    ((st->st_dev & 0xFF00) == 0))
+		changed |= INODE_CHANGED;
+	if (ce->ce_ino != htonl(st->st_ino))
 		changed |= INODE_CHANGED;
 	if (ce->ce_size != htonl(st->st_size))
 		changed |= DATA_CHANGED;