When looking at blkmap_next_off I was a little puzzled, so I started adding comments. Hopefully this helps. I also noticed that if you happen to pass in a "t" beyond the last map, it'll happily go read off the end of the array and return you something based on what it finds, seems better to catch that & return something obvious instead. Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> --- diff --git a/repair/bmap.c b/repair/bmap.c index c43ca7f..85d66dc 100644 --- a/repair/bmap.c +++ b/repair/bmap.c @@ -206,8 +206,25 @@ blkmap_last_off( return ext->startoff + ext->blockcount; } -/* - * Return the next offset in a block map. +/** + * blkmap_next_off - Return next logical block offset in a block map. + * @blkmap: blockmap to use + * @o: current file logical block number + * @t: current extent index into blockmap (in/out) + * + * Given a logical block offset in a file, return the next mapped logical offset + * The map index "t" tracks the current extent number in the block map, and + * is updated automatically if the returned offset resides within the next + * mapped extent. + * + * If the blockmap contains no extents, or no more logical offsets are mapped, + * or the extent index exceeds the number of extents in the map, + * return NULLDFILOFF. + * + * If offset o is beyond extent index t, the first offset in the next extent + * after extent t will be returned. + * + * Intended to be called starting with offset 0, index 0, and iterated. */ xfs_dfiloff_t blkmap_next_off( @@ -223,10 +240,12 @@ blkmap_next_off( *t = 0; return blkmap->exts[0].startoff; } + if (*t >= blkmap->nexts) + return NULLDFILOFF; ext = blkmap->exts + *t; if (o < ext->startoff + ext->blockcount - 1) return o + 1; - if (*t >= blkmap->nexts - 1) + if (*t == blkmap->nexts - 1) return NULLDFILOFF; (*t)++; return ext[1].startoff; _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
