Fix zrele race in zrele_async that can cause hang #11530
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ahrens
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ahrens
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ahrens
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Jan 27, 2021
behlendorf
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Jan 27, 2021
Signed-off-by: Paul Dagnelie <[email protected]>
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There is a race condition in zfs_zrele_async when we are checking if we would be the one to evict an inode. This can lead to a txg sync deadlock. Instead of calling into iput directly, we attempt to perform the atomic decrement ourselves, unless that would set the i_count value to zero. In that case, we dispatch a call to iput to run later, to prevent a deadlock from occurring. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes #11527 Closes #11530
jsai20
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There is a race condition in zfs_zrele_async when we are checking if we would be the one to evict an inode. This can lead to a txg sync deadlock. Instead of calling into iput directly, we attempt to perform the atomic decrement ourselves, unless that would set the i_count value to zero. In that case, we dispatch a call to iput to run later, to prevent a deadlock from occurring. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes openzfs#11527 Closes openzfs#11530
sempervictus
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May 31, 2021
There is a race condition in zfs_zrele_async when we are checking if we would be the one to evict an inode. This can lead to a txg sync deadlock. Instead of calling into iput directly, we attempt to perform the atomic decrement ourselves, unless that would set the i_count value to zero. In that case, we dispatch a call to iput to run later, to prevent a deadlock from occurring. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes openzfs#11527 Closes openzfs#11530
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Signed-off-by: Paul Dagnelie [email protected]
Motivation and Context
See #11527. Basically, there is a race condition in zfs_zrele_async when we are checking if we would be the one to evict an inode. This can lead to a txg sync deadlock.
Description
Instead of calling into iput directly, we attempt to perform the atomic decrement ourselves, unless that would set the i_count value to zero. In that case, we dispatch a call to iput to run later, to prevent a deadlock from occuring.
How Has This Been Tested?
ZFS test suite passes, along with some minor stress testing.
Types of changes
Checklist:
Signed-off-by.