sdk/rust: Fix overlayfs whiteout for base files in promoted dirs#316
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broady wants to merge 1 commit intotursodatabase:mainfrom
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sdk/rust: Fix overlayfs whiteout for base files in promoted dirs#316broady wants to merge 1 commit intotursodatabase:mainfrom
broady wants to merge 1 commit intotursodatabase:mainfrom
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ah, the test is failing because of a separate fuse issue - cached directory entries, I'll try to address that issue separately (bug/PR) |
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FUSE cli integration test blocked on #317 |
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ready to review/merge @penberg |
When a base-layer file is unlinked or renamed inside a directory
that has been promoted from Base to Delta (via ensure_parent_dirs),
the old code walked the base HostFS to decide whether to create a
whiteout. For promoted directories the base inode mapping was
already removed by promote_to_delta(), so the walk silently
returned early -- skipping whiteout creation and leaving the base
file visible through the overlay.
This caused dpkg to fail with EEXIST during package installs:
unlink of /var/lib/dpkg/status-old succeeded in delta but never
created a whiteout, so the subsequent link("status", "status-old")
found the base-layer file and returned EEXIST.
Fix by:
1. Extracting resolve_delta_parent() that walks the delta layer
by path to find the parent inode, replacing 9 inline walk
patterns across lookup, mkdir, create_file, mknod, symlink,
unlink, rmdir, link, and rename. The walk validates that each
component is a directory to avoid shadowing by non-directory
entries (same class as tursodatabase#300).
2. Changing unlink/rmdir to remove from delta first, then use
self.lookup() to detect whether the file is still visible
-- if so, it must be from base and needs a whiteout.
3. Moving delta parent resolution in rename() after copy_up()
and ensure_parent_dirs() so the delta directories exist
before we try to resolve them.
Add 8 unit tests and extend the existing shell integration test
with base-file whiteout coverage.
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When a base-layer file is unlinked or renamed inside a directory that has been promoted from Base to Delta (via ensure_parent_dirs), the old code walked the base HostFS to decide whether to create a whiteout. For promoted directories the base inode mapping was already removed by promote_to_delta(), so the walk silently returned early -- skipping whiteout creation and leaving the base file visible through the overlay.
This caused dpkg to fail with EEXIST during package installs: unlink of /var/lib/dpkg/status-old succeeded in delta but never created a whiteout, so the subsequent link("status", "status-old") found the base-layer file and returned EEXIST.
Fix by:
Extracting resolve_delta_parent() that walks the delta layer by path to find the parent inode, replacing 9 inline walk patterns across lookup, mkdir, create_file, mknod, symlink, unlink, rmdir, link, and rename. The walk validates that each component is a directory to avoid shadowing by non-directory entries (same class as sdk/rust: Fix overlay lookup using wrong delta parent inode #300).
Changing unlink/rmdir to remove from delta first, then use self.lookup() to detect whether the file is still visible -- if so, it must be from base and needs a whiteout.
Moving delta parent resolution in rename() after copy_up() and ensure_parent_dirs() so the delta directories exist before we try to resolve them.
Add 8 unit tests and extend the existing shell integration test with base-file whiteout coverage.