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> The proposed addition of case-insensitive file-name lookups to the ext4 filesystem... Ugh, why? I thought the general consensus was that case-insensitive fil

> The proposed addition of case-insensitive file-name lookups to the ext4 filesystem... Ugh, why? I thought the general consensus was that case-insensitive filesystems were a mistake. The article linked on that line is behind a paywall, can someone summarize the rationale for this change? Also, this article doesn't mention how the kernel developers plan to handle differences in case folding between locales (e.g. the infamous Turkish "dotted I"). I learned recently that NTFS actually stores a full case-folding table (from the current locale of the system formatting the volume) in the filesystem metadata specifically to ensure case-folding will remain consistent even if the volume is attached to a system with a different locale which seems like the only sane way to handle this.

bruce_one 8y ago
https://lwn.net/SubscriberLink/784041/06801df80bc16e10/ https://lwn.net/SubscriberLink/784041/06801df80bc16e10/ LWN is super great, consider subscribing :-) ;-) I remember finding the underlying reasoning fairly compelling for non-technical, or more Windows familiar, users - but my memory might be hazy...
saagarjha 8y ago
macOS's HFS+ and APFS are case-insensitive by default, which I feel is a bit less confusing to users ("What do you mean that 'document' and 'Document' are different things?! They're both 'document'!")
- legulere 8y ago
  On iOS they are both case-sensitive. My guess is that they didn't want to break compatibility.
- benj111 8y ago
  That's only a very small leap to 'documents' ("its obvious what I mean!") though. I don't think the kernel should start trying to handle that.
amelius 8y ago
Instead of worrying about such basic mechanisms, perhaps they should be thinking about bigger things, like adding Google-like search to the filesystem. User-mode approaches, such as mlocate/updatedb have not been very successful (imho).
- saagarjha 8y ago
  Metadata on macOS works pretty well, given that it drives Spotlight.
lisper 8y ago
> I thought the general consensus was that case-insensitive filesystems were a mistake. Where did you get that idea? Case-senstivity is NEVER the right answer. Never, never. NeVer.
- geofft 8y ago
  Can you expand on why it's not the right answer? (For what?) The following arguments for case-sensitivity come to mind: - Different locales treat uppercasing and lowercasing differently. In Turkish, for instance, the dotted and dotless letter I are two different letters, unlike languages where dotless uppercase I corresponds to dotted lowercase i. https://en.wikipedia.org/wiki/Dotted_and_dotless_I https://en.wikipedia.org/wiki/Dotted_and_dotless_I - There are common codebases that have files that differ only in case - for instance, the Linux kernel source tree itself has include/uapi/linux/netfilter/xt_rateest.h and include/uapi/linux/netfilter/xt_RATEEST.h with different contents. Can you supply some arguments against case-sensitivity?
  - lisper 8y ago
    Because you never want to distinguish between never and Never and NEVER and NeVer. They are all the same word. The only time that English is case-sensitive is when you want to distinguish between a proper noun and a similarly-spelled word, like rich and Rich. But that hardly ever matters for identifiers, which is what file names are.
    - geofft 8y ago
      Well, I think just about all of my filenames have personal names in them - they tend to start with /home/geofft. And "never," your original claim, is not "hardly ever," your revised claim. If there are valid use cases for case-sensitive filenames, it seems like it should be allowed on robustness-principle grounds, even if they are rare, unless they impose some disproportionate cost on users of the system. And filenames don't have to be in English, and usually aren't. "geofft" is not an English word; neither is "usr" or "etc" or "tmp," let alone "xt_RATEEST.h" or "/tmp/tmp.CGZ8Lq5f". And even for common nouns in English, case matters - the UCC for instance requires certain text to be "conspicuous," and gives one example as "a heading in capitals equal to or greater in size than the surrounding text." It's pretty common for lawyers to write "conspicuous" text in all caps to satisfy this requirement. In these cases, you do want to distinguish between "never," "Never," and "NEVER".
ploxiln 8y ago
I think the primary motivation is more efficient SMB and NFS serving to systems which prefer case-insensitivity - macOS and Windows. Samba doing this in userspace is less efficient (and maybe racy) since it has to list the whole directory to check for case-insensitive match. I'll agree though, having the filesystem do case folding according to some locale is ... bad in general. But as a rarely-enabled option on linux systems just for this purpose, maybe it's not that bad.
asveikau 8y ago
I came here also to say "why dear god whyyyy". Case insensitive compares differ by language. I don't want the filesystem to have to know this, and potentially see "file not found" if a user has a language different from me. (The kernel is multi-user anyway, so ... two processes on the same machine can rightfully disagree on what "lowercase" means.)
yellowapple 8y ago
As one example, a lot of Windows software assumes it's running on a case-insensitive filesystem, so projects like Wine would benefit from this quite a bit (historically, the only way to run case-insensitive-FS-assuming software on Linux is to either actually point that software to something case-insensitive like NTFS or use a FUSE-based userspace FS to add case-insensitivity to specific folders). This also applies to games where the modding community primarily uses Windows and thus has zero concept of case consistency (I recall this being a major issue at one point - if not still - for the Linux ports of the recent Civ games).

bruce_one 8y ago

https://lwn.net/SubscriberLink/784041/06801df80bc16e10/ https://lwn.net/SubscriberLink/784041/06801df80bc16e10/ LWN is super great, consider subscribing :-) ;-) I remember finding the underlying reasoning fairly compelling for non-technical, or more Windows familiar, users - but my memory might be hazy...

saagarjha 8y ago

macOS's HFS+ and APFS are case-insensitive by default, which I feel is a bit less confusing to users ("What do you mean that 'document' and 'Document' are different things?! They're both 'document'!")

legulere 8y ago
On iOS they are both case-sensitive. My guess is that they didn't want to break compatibility.
benj111 8y ago
That's only a very small leap to 'documents' ("its obvious what I mean!") though. I don't think the kernel should start trying to handle that.

amelius 8y ago

Instead of worrying about such basic mechanisms, perhaps they should be thinking about bigger things, like adding Google-like search to the filesystem. User-mode approaches, such as mlocate/updatedb have not been very successful (imho).

saagarjha 8y ago
Metadata on macOS works pretty well, given that it drives Spotlight.

lisper 8y ago

> I thought the general consensus was that case-insensitive filesystems were a mistake. Where did you get that idea? Case-senstivity is NEVER the right answer. Never, never. NeVer.

geofft 8y ago
Can you expand on why it's not the right answer? (For what?) The following arguments for case-sensitivity come to mind: - Different locales treat uppercasing and lowercasing differently. In Turkish, for instance, the dotted and dotless letter I are two different letters, unlike languages where dotless uppercase I corresponds to dotted lowercase i. https://en.wikipedia.org/wiki/Dotted_and_dotless_I https://en.wikipedia.org/wiki/Dotted_and_dotless_I - There are common codebases that have files that differ only in case - for instance, the Linux kernel source tree itself has include/uapi/linux/netfilter/xt_rateest.h and include/uapi/linux/netfilter/xt_RATEEST.h with different contents. Can you supply some arguments against case-sensitivity?
- lisper 8y ago
  Because you never want to distinguish between never and Never and NEVER and NeVer. They are all the same word. The only time that English is case-sensitive is when you want to distinguish between a proper noun and a similarly-spelled word, like rich and Rich. But that hardly ever matters for identifiers, which is what file names are.
  - geofft 8y ago
    Well, I think just about all of my filenames have personal names in them - they tend to start with /home/geofft. And "never," your original claim, is not "hardly ever," your revised claim. If there are valid use cases for case-sensitive filenames, it seems like it should be allowed on robustness-principle grounds, even if they are rare, unless they impose some disproportionate cost on users of the system. And filenames don't have to be in English, and usually aren't. "geofft" is not an English word; neither is "usr" or "etc" or "tmp," let alone "xt_RATEEST.h" or "/tmp/tmp.CGZ8Lq5f". And even for common nouns in English, case matters - the UCC for instance requires certain text to be "conspicuous," and gives one example as "a heading in capitals equal to or greater in size than the surrounding text." It's pretty common for lawyers to write "conspicuous" text in all caps to satisfy this requirement. In these cases, you do want to distinguish between "never," "Never," and "NEVER".

ploxiln 8y ago

I think the primary motivation is more efficient SMB and NFS serving to systems which prefer case-insensitivity - macOS and Windows. Samba doing this in userspace is less efficient (and maybe racy) since it has to list the whole directory to check for case-insensitive match. I'll agree though, having the filesystem do case folding according to some locale is ... bad in general. But as a rarely-enabled option on linux systems just for this purpose, maybe it's not that bad.

asveikau 8y ago

I came here also to say "why dear god whyyyy". Case insensitive compares differ by language. I don't want the filesystem to have to know this, and potentially see "file not found" if a user has a language different from me. (The kernel is multi-user anyway, so ... two processes on the same machine can rightfully disagree on what "lowercase" means.)

yellowapple 8y ago

As one example, a lot of Windows software assumes it's running on a case-insensitive filesystem, so projects like Wine would benefit from this quite a bit (historically, the only way to run case-insensitive-FS-assuming software on Linux is to either actually point that software to something case-insensitive like NTFS or use a FUSE-based userspace FS to add case-insensitivity to specific folders). This also applies to games where the modding community primarily uses Windows and thus has zero concept of case consistency (I recall this being a major issue at one point - if not still - for the Linux ports of the recent Civ games).