Comment 39 for bug 63175

I suspect the problem does not relate to the filesystem check interval, but to one of the other timestamps, such as the last mount time. A discrepancy there will trigger a full filesystem check regardless of the checkinterval. For example:

potpal:[/tmp] dd if=/dev/zero bs=1M count=1 of=fs.ext3
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.00205541 seconds, 510 MB/s
potpal:[/tmp] mke2fs -j fs.ext3
mke2fs 1.40-WIP (14-Nov-2006)
fs.ext3 is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
128 inodes, 1024 blocks
51 blocks (4.98%) reserved for the super user
First data block=1
Maximum filesystem blocks=1048576
1 block group
8192 blocks per group, 8192 fragments per group
128 inodes per group

Writing inode tables: done

Filesystem too small for a journal
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 38 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
potpal:[/tmp] debugfs -w fs.ext3
debugfs 1.40-WIP (14-Nov-2006)
debugfs: ssv mtime 201001010000
debugfs: quit
potpal:[/tmp] fsck -n /tmp/fs.ext3
fsck 1.40-WIP (14-Nov-2006)
e2fsck 1.40-WIP (14-Nov-2006)
Superblock last mount time is in the future. Fix? no

/tmp/fs.ext3 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/tmp/fs.ext3: 11/128 files (9.1% non-contiguous), 38/1024 blocks