perhaps running out of inodes could be taken "more seriously"?

Posted Jun 5, 2017 16:15 UTC (Mon) by nybble41 (subscriber, #55106)
In reply to: perhaps running out of inodes could be taken "more seriously"? by nix
Parent article: Improved block-layer error handling

> So adding more errors is not only not noncompliant, it is both explicitly permitted and very common.

Yes, for *new* error conditions not specified by POSIX. However:

> Implementations shall not generate a different error number from one required by this volume of POSIX.1-2008 for an error condition described in this volume of POSIX.1-2008, ...

The error list for the open() and openat() system calls specifies ENOSPC as follows:

> [ENOSPC]
> The directory or file system that would contain the new file cannot be expanded, the file does not exist, and O_CREAT is specified.

So if "the filesystem ... cannot be expanded" is read to include the "out of inodes" condition (a reasonable interpretation IMHO) then POSIX requires open() to return ENOSPC for this condition, and not some other error code.