diff options
| author | Tom Caputi <[email protected]> | 2019-08-27 12:55:51 -0400 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2019-08-27 09:55:51 -0700 |
| commit | e7a2fa70c3b0d8c8cee2b484038bb5623c7c1ea9 (patch) | |
| tree | a216b26e20a92c1cd0635a19ab9a285ce5e6fda0 /include/sys/zfs_znode.h | |
| parent | 142f84dd19f20b47157bbbf45aaba489b6577c88 (diff) | |
Fix deadlock in 'zfs rollback'
Currently, the 'zfs rollback' code can end up deadlocked due to
the way the kernel handles unreferenced inodes on a suspended fs.
Essentially, the zfs_resume_fs() code path may cause zfs to spawn
new threads as it reinstantiates the suspended fs's zil. When a
new thread is spawned, the kernel may attempt to free memory for
that thread by freeing some unreferenced inodes. If it happens to
select inodes that are a a part of the suspended fs a deadlock
will occur because freeing inodes requires holding the fs's
z_teardown_inactive_lock which is still held from the suspend.
This patch corrects this issue by adding an additional reference
to all inodes that are still present when a suspend is initiated.
This prevents them from being freed by the kernel for any reason.
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #9203
Diffstat (limited to 'include/sys/zfs_znode.h')
| -rw-r--r-- | include/sys/zfs_znode.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/sys/zfs_znode.h b/include/sys/zfs_znode.h index a0a3dd1ad..acaaf2884 100644 --- a/include/sys/zfs_znode.h +++ b/include/sys/zfs_znode.h @@ -200,6 +200,7 @@ typedef struct znode { boolean_t z_is_mapped; /* are we mmap'ed */ boolean_t z_is_ctldir; /* are we .zfs entry */ boolean_t z_is_stale; /* are we stale due to rollback? */ + boolean_t z_suspended; /* extra ref from a suspend? */ uint_t z_blksz; /* block size in bytes */ uint_t z_seq; /* modification sequence number */ uint64_t z_mapcnt; /* number of pages mapped to file */ |