Open Radar

 
Summary:
OS X 10.10 Yosemite seems to have introduced a bug that causes corruption of the boot HFS+ filesystem. This behavior has occurred on both of my Macs: an iMac with Fusion drive, and a mid-2007 MBP with standard HDD.

Steps to Reproduce:
1. Boot to OS X Yosemite
2. Open Disk Utility and run a Verify Disk on the main boot drive. In my cases this is "Fusion" on my iMac and "Macintsoh HD" on my MBP.

You will receive a message about "Incorrect number of file hard links" and that a repair through recovery mode is required.

3. Boot into recovery mode with cmd+R and attempt a disk repair with Disk Utility.

Disk utility will be unable to repair disk however.

4. booted to single user mode and run "fsck -fy"

This will repair the disk. Run "fsck -fy" a second time and the disk will check out healthy

5. Boot into recovery mode again and run verify disk through Disk Utility. Disk utility will say that the disk is healthy.

6. Boot into OS X normally off the boot drive and run a verify disk with Disk Utility. You're now back at square one with "incorrect number of file hard links"

7. Boot into recovery mode and run verify disk through Disk Utility and you'll get the same error message.


Expected Results:
I expect the filesystem to remain healthy. I expect OS X 10.10 to not corrupt my filesystem. I expect Disk Utility and/or fsck to be able to correct the issue.

Actual Results:
Disk Utility reports "Incorrect number of file hard links" and then will exit with exit code 8. The full log is attached.

Rebooting into recovery mode and running repair disk with Disk Utility does not fix the problem. Booting into single user mode and running "fsck -fy" will fix the problem. Upon rebooting back into recovery mode Disk Utility will say that everything is healthy and good to go. However, immediately after booting off the drive to OS X normally and running Disk utility, the incorrect number of file hard links error comes back.

""
Error: This disk needs to be repaired using the Recovery HD. Restart your computer, holding down the Command key and the R key until you see the Apple logo. When the OS X Utilities window appears, choose Disk Utility.

Disk Utility stopped verifying “Fusion”: This disk needs to be repaired using the Recovery HD. Restart your computer, holding down the Command key and the R key until you see the Apple logo. When the OS X Utilities window appears, choose Disk Utility.
"""

Version:
10.10 (14A389)

Notes:
This bug was introduced with OS X Yosemite. It did not occur on Mavericks. Additionally, it is occurring on both of the Macs at my disposal and one does not have a Fusion drive, so this issue does not appear to be specific to Fusion drive and is a more widespread problem.

Configuration:
Mid 2007 17" Macbook Pro with stock HDD
Mid 2010 27" iMac with a DIY Fusion drive

Attachments:
'iMac.spx' and 'Disk Utility Log.rtf' were successfully uploaded.