Fix stat to use the fd instead of the path #649
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glommer
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Apr 12, 2024
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tnx. Will merge, but format tests failing |
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Has a race condition fix for async APIs. Not sure if this actually impacts us but sounds like a worthwhile upgrade.
Attempting to stat on an unlinked file will error with NotFound when it shouldn't since we still have the fd. Similarly, invoking stat on a tempfile will stat the parent directory instead of the file itself.
This fixes the broken test cases - unlinked files will still stat successfully and temporary files will return stat for the file rather than the parent directory. There's probably a negligible performance boost since we don't need to do anything with the path (I believe it saves a memory allocation + some other cycles) + the kernel might have to do less work handling the syscall. Of course, stat should never be in the hot path so it's largely an academic difference.
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What does this PR do?
Fixes #648. Noticed that the reported inode for two sibling O_TMPFILE was identical because the stat was being invoked on the parent directory (i.e. stat never worked for temporary files). Similarly, you can now remove the path backing a file and stat continues to work.
Motivation
2 sibling O_TMPFILE files having the same inode & being unable to get the size of a temporary file.
Related issues
Additional Notes
Checklist
[X] I have added unit tests to the code I am submitting
[X] My unit tests cover both failure and success scenarios
[] If applicable, I have discussed my architecture