ReiserFS Maximum file size (in practice)

[Jeff Mahoney <jeffm@suse.com>]

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Hey all -

The ReiserFS FAQ that we quote and point people to when they ask 
questions about limits in ReiserFS states that the maxmimum file size 
for a reiserfs v3 filesystem is 2^60-1. However, the actual limits, in 
practice, are far less.

I tried to create a 3 TB sparse file, and ended up getting told it was 
too large. 2 TB was too large also, just under 2 TB was ok.

This is a result of super->s_maxbytes = (512LL << 32) - s->s_blocksize;, 
in fs/reiserfs/super.c, which is set so that i_blocks isn't overflowed.

Other filesystems that have the ability to cross the 2 TB limit on file 
sizes simply ignore the limit and allow i_blocks to wrap. There's really 
no reason we can't do the same.

The patch is attached.

-Jeff

-- 
Jeff Mahoney
SuSE Labs

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--- linux-2.6.5/fs/reiserfs/super.c	2004-05-14 15:32:49.000000000 -0400
+++ linux-2.6.5.fix/fs/reiserfs/super.c	2004-05-18 12:07:25.000000000 -0400
@@ -1204,7 +1204,7 @@
     /* new format is limited by the 32 bit wide i_blocks field, want to
     ** be one full block below that.
     */
-    s->s_maxbytes = (512LL << 32) - s->s_blocksize ;
+    s->s_maxbytes = MAX_LFS_FILESIZE;
     return 0;
 }