On Wed, Apr 16, 2014 at 12:09:37PM -0400, Paul Gortmaker wrote: > Hi Dave, > > Not sure if this has been reported yet, but this new failure showed > up in the xtensa link of today's linux-next builds. > > http://kisskb.ellerman.id.au/kisskb/buildresult/10938384/ fs/built-in.o: In function `__xfs_get_blocks': /home/dave/src/build/x86-64/xfsdev/fs/xfs/xfs_aops.c:1368: undefined reference to `__divdi3' Fmeh. The hunk that throws the error: @@ -1354,6 +1362,12 @@ __xfs_get_blocks( ASSERT(mapping_size > 0); if (mapping_size > size) mapping_size = size; + if (offset < i_size_read(inode) && + offset + mapping_size >= i_size_read(inode)) { + /* limit mapping to block that spans EOF */ + mapping_size = roundup(i_size_read(inode) - offset, + 1 << inode->i_blkbits); + } if (mapping_size > LONG_MAX) mapping_size = LONG_MAX; You'd think a generic function like roundup() would handle that sort of 64/32 bit type problem, yes? But it doesn't, despite what the comment implies: /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ #define roundup(x, y) ( \ { \ const typeof(y) __y = y; \ (((x) + (__y - 1)) / __y) * __y; \ } \ ) It doesn't even have type checking that might warn you of impending problems... <sigh> /me looks around in the XFS code for a bit ... and finds roundup_64() in fs/xfs/xfs_linux.h. That uses do_div() to avoid this problem. And it's a static inline function, so it has type checking, too. And so this hunk fixes the problem: @@ -1365,7 +1365,7 @@ __xfs_get_blocks( if (offset < i_size_read(inode) && offset + mapping_size >= i_size_read(inode)) { /* limit mapping to block that spans EOF */ - mapping_size = roundup(i_size_read(inode) - offset, + mapping_size = roundup_64(i_size_read(inode) - offset, 1 << inode->i_blkbits); } if (mapping_size > LONG_MAX) Can you test it, please, and I'll push out an updated branch hopefully in time for today's linux-next build.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
