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As the Reddit post linked in the article mentions, the photos that reappeared were manually saved as files by the user, e.g. via the share button. In fact, I b

As the Reddit post linked in the article mentions, the photos that reappeared were manually saved as files by the user, e.g. via the share button. In fact, I believe iOS uses hardlinks for this, as it is possible to save a 40GB video on a device with 64GB storage instantly - while logged out of iCloud and without an Internet connection. Since hardlinks are used, there is likely no way to tell the original and copy apart except by their paths. The photo-rescuing algorithm that shipped in 17.5 probably wandered around the filesystem farther than intended, possibly via mds. So Apple is probably not stealing your photos. If it is, this bug is not evidence of it.

steve1977 2y ago
> In fact, I believe iOS uses hardlinks for this, as it is possible to save a 40GB video on a device with 64GB storage instantly - while logged out of iCloud and without an Internet connection. How is this an indication of hardlinks being used?
- worstspotgain 2y ago
  40GB (movie in Photos) + 40GB (saved file) = 80GB > 64GB total storage space on device. Hardlinks are the most straightforward way of accomplishing this. It could be something more complex like APFS container trickery or masqueraded softlinks or some such, but they may lead to the same bug anyways.
  - steve1977 2y ago
    Ah I thought "save a 40GB video on a device" meant saving it once (not in Photos and somewhere else)
    - ianburrell 2y ago
      "Save to Files" on iPhone doesn't mean download but to save outside of Photos in Files. It makes sense to do hardlink since that doesn't duplicate storage, but deletion in Photos or Files leaves the other alone. I'm not sure if sharing to other places also makes a hardlink copy, but that would make sense.
ysleepy 2y ago
I assume it's apfs copy-on-write file clones not technically hard links. Hard links have the same inode and changes would be reflected by either path. https://eclecticlight.co/2020/04/14/copy-move-and-clone-files-in-apfs-a-primer/ https://eclecticlight.co/2020/04/14/copy-move-and-clone-file...

steve1977 2y ago

> In fact, I believe iOS uses hardlinks for this, as it is possible to save a 40GB video on a device with 64GB storage instantly - while logged out of iCloud and without an Internet connection. How is this an indication of hardlinks being used?

worstspotgain 2y ago
40GB (movie in Photos) + 40GB (saved file) = 80GB > 64GB total storage space on device. Hardlinks are the most straightforward way of accomplishing this. It could be something more complex like APFS container trickery or masqueraded softlinks or some such, but they may lead to the same bug anyways.
- steve1977 2y ago
  Ah I thought "save a 40GB video on a device" meant saving it once (not in Photos and somewhere else)
  - ianburrell 2y ago
    "Save to Files" on iPhone doesn't mean download but to save outside of Photos in Files. It makes sense to do hardlink since that doesn't duplicate storage, but deletion in Photos or Files leaves the other alone. I'm not sure if sharing to other places also makes a hardlink copy, but that would make sense.

ysleepy 2y ago

I assume it's apfs copy-on-write file clones not technically hard links. Hard links have the same inode and changes would be reflected by either path. https://eclecticlight.co/2020/04/14/copy-move-and-clone-files-in-apfs-a-primer/ https://eclecticlight.co/2020/04/14/copy-move-and-clone-file...