More aggressively assert that db_mtx protects db.db_data #17209
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db.db_mtx must be held any time that db.db_data is accessed. All of these functions do have the lock held by a parent; add assertions to ensure that it stays that way. Also, refactor dbuf_read_bonus to make it obvious why db_rwlock isn't required. See openzfs#17118 Sponsored by: ConnectWise Signed-off-by: Alan Somers <asomers@gmail.com>
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@pcd1193182 could you review, please? |
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From one of the test runs: it would seem that |
It looks like that's a Linux-only panic, which is why I didn't see it . I'll investigate. |
It's an error that nothing locks the mutex here. I'll fix it in my next PR. Signed-off-by: Alan Somers <asomers@gmail.com>
amotin
reviewed
Apr 30, 2025
Copy data into the newly allocated buffer before assigning it to the db. That way, there will be no need to take db->db_rwlock. Signed-off-by: Alan Somers <asomers@gmail.com>
In the case of an indirect hole, initialize the newly allocated buffer before assigning it to the dmu_buf_impl_t. Signed-off-by: Alan Somers <asomers@gmail.com>
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@amotin I applied your suggestions. |
amotin
reviewed
May 1, 2025
Signed-off-by: Alan Somers <asomers@gmail.com>
amotin
approved these changes
May 1, 2025
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db.db_mtx must be held any time that db.db_data is accessed. All of these functions do have the lock held by a parent; add assertions to ensure that it stays that way.
Also, refactor dbuf_read_bonus to make it obvious why db_rwlock isn't required.
See #17118
Sponsored by: ConnectWise
Signed-off-by: Alan Somers asomers@gmail.com
Motivation and Context
Bug #16626 probably results from improper locking around db.db_data. Any time that variable is accessed, db_mtx must be held.
Description
As a first step to fixing that bug, add some more assertions in places that already do have the lock, but don't currently assert that they do. This will make the problem more clear, and prevent regressions in those functions.
How Has This Been Tested?
I ran the ZFS test suite in FreeBSD 15.0-CURRENT.
Types of changes
Checklist:
Signed-off-by.