Fix FDT rollback to not overwrite unnecessary fields #17205
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amotin
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When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Signed-off-by: Paul Dagnelie <[email protected]> Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc.
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When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc. Signed-off-by: Paul Dagnelie <[email protected]> Co-authored-by: Paul Dagnelie <[email protected]> Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Tony Hutter <[email protected]>
fuporovvStack
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Apr 11, 2025
When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc. Signed-off-by: Paul Dagnelie <[email protected]> Co-authored-by: Paul Dagnelie <[email protected]> Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Tony Hutter <[email protected]>
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When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc. Signed-off-by: Paul Dagnelie <[email protected]> Co-authored-by: Paul Dagnelie <[email protected]> Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Tony Hutter <[email protected]>
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When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc. Signed-off-by: Paul Dagnelie <[email protected]> Co-authored-by: Paul Dagnelie <[email protected]> Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Tony Hutter <[email protected]>
snajpa
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When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in 17123). This PR prevents that from happening by only rolling back the parts of the DDT entry that have been updated by the write so far. Sponsored-by: iXsystems, Inc. Sponsored-by: Klara, Inc. Signed-off-by: Paul Dagnelie <[email protected]> Co-authored-by: Paul Dagnelie <[email protected]> Reviewed-by: Alexander Motin <[email protected]> Reviewed-by: Tony Hutter <[email protected]>
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Sponsored-by: iXsystems, Inc.
Sponsored-by: Klara, Inc.
Motivation and Context
When a dedup write fails, we try to roll the DDT entry back to a known good state. However, this also rolls the refcounts and the last-update time back to the state they were at when we started this write. This doesn't appear to be able to cause any refcount leaks (after the fix in #17123, see that PR for discussion of these issues). There's no guarantee it couldn't break in the future.
Description
This PR prevents the breakage from happening by only rolling back the parts of the DDT entry that have been updated by the write so far.
How Has This Been Tested?
Passes the ZFS test suite locally
Types of changes
Checklist:
Signed-off-by.