Messages in this thread | | | Date | Wed, 7 Nov 2001 12:34:30 -0700 | From | Andreas Dilger <> | Subject | Re: [Ext2-devel] ext2/ialloc.c cleanup |
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On Nov 06, 2001 18:17 -0500, Alexander Viro wrote: > Folks, promised cleanup of ialloc.c is on > ftp.math.psu.edu:pub/viro/ialloc.c,v > > And yes, it's in RCS. The thing is split into _really_ small > steps (commented in the log). Each is a trivial transformation > and it should be very easy to verify correctness of any of > them. > > Please, review. IMO it's cut fine enough to make the gradual merge > possible for 2.4 - look and you'll see.
Minor nits, from my changes to this same function: 1) please replace use of "i" for best block group in find_cg_*, to something better like "group", just for clarity. 2) in find_cg_*, when you fail the quadratic search, the linear search should skip groups that were previously checked in the quadratic search, with slight changes to both loops:
start = dir->u.ext2_i.i_block_group;
/* Use quadratic hash to find group with a free inode */ for (j = 1; j < count; j <<= 1) { group = start + j; if (group >= count) group -= count; cg = ext2_get_group_desc(sb, group, &bh); if (cg && le16_to_cpu(cg->bg_free_inodes_count)) goto found; }
/* That failed: try linear search for a free inode * skipping groups we checked in the previous loop. */ for (j = 3; j < count; j++) { if ((j & (j - 1)) == 0) continue; group = start + j; if (group > count) group -= count; cg = ext2_get_group_desc(sb, group, &bh); if (cg && le16_to_cpu(cg->bg_free_inodes_count)) goto found; } 3) I know that "cylinder groups" were used in old FFS/whatever implementation, but all of the ext2 code/documentation refers to these as block groups. Can you stick with that for ext2 (e.g. gdp, not cg; bg_foo, not cg_foo)? 4) sbi can be gotten by "EXT2_SB(sb)".
Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/
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