[patch] make tmpfs_statfs more user friendly

[Christoph Rohland <cr@sap.com>]

Hi Alan,

The following patch make shmem_statfs report some sensible size
estimates in the case that the user does not give a size limit.

This should make it more error prone when used as /tmp

Greetings
                Christoph

diff -uNr 2.4.1-tmpfs/mm/shmem.c 2.4.1-tmpfs-fstat/mm/shmem.c
--- 2.4.1-tmpfs/mm/shmem.c	Sun Feb  4 16:08:57 2001
+++ 2.4.1-tmpfs-fstat/mm/shmem.c	Sun Feb  4 16:09:50 2001
@@ -696,13 +696,20 @@
 	buf->f_type = TMPFS_MAGIC;
 	buf->f_bsize = PAGE_CACHE_SIZE;
 	spin_lock (&sb->u.shmem_sb.stat_lock);
-	if (sb->u.shmem_sb.max_blocks != ULONG_MAX || 
-	    sb->u.shmem_sb.max_inodes != ULONG_MAX) {
+	if (sb->u.shmem_sb.max_blocks == ULONG_MAX) {
+		/*
+		 * This is only a guestimate and not honoured.
+		 * We need it to make some programs happy which like to
+		 * test the free space of a file system.
+		 */
+		buf->f_bavail = buf->f_bfree = nr_free_pages() + nr_swap_pages + atomic_read(&buffermem_pages);
+		buf->f_blocks = buf->f_bfree + ULONG_MAX - sb->u.shmem_sb.free_blocks;
+	} else {
 		buf->f_blocks = sb->u.shmem_sb.max_blocks;
 		buf->f_bavail = buf->f_bfree = sb->u.shmem_sb.free_blocks;
-		buf->f_files = sb->u.shmem_sb.max_inodes;
-		buf->f_ffree = sb->u.shmem_sb.free_inodes;
 	}
+	buf->f_files = sb->u.shmem_sb.max_inodes;
+	buf->f_ffree = sb->u.shmem_sb.free_inodes;
 	spin_unlock (&sb->u.shmem_sb.stat_lock);
 	buf->f_namelen = 255;
 	return 0;

-
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