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authorDarrick J. Wong <djwong@kernel.org>2023-09-11 18:39:03 +0300
committerDarrick J. Wong <djwong@kernel.org>2023-09-11 18:39:03 +0300
commit62334fab47621dd91ab30dd5bb6c43d78a8ec279 (patch)
tree76f83feb49fd1a2d9529f99b6225364be52d8dd7 /fs/xfs/xfs_mount.h
parentecd49f7a36fbccc884471f86fc43de6ca8d1f786 (diff)
downloadlinux-62334fab47621dd91ab30dd5bb6c43d78a8ec279.tar.xz
xfs: use per-mount cpumask to track nonempty percpu inodegc lists
Directly track which CPUs have contributed to the inodegc percpu lists instead of trusting the cpu online mask. This eliminates a theoretical problem where the inodegc flush functions might fail to flush a CPU's inodes if that CPU happened to be dying at exactly the same time. Most likely nobody's noticed this because the CPU dead hook moves the percpu inodegc list to another CPU and schedules that worker immediately. But it's quite possible that this is a subtle race leading to UAF if the inodegc flush were part of an unmount. Further benefits: This reduces the overhead of the inodegc flush code slightly by allowing us to ignore CPUs that have empty lists. Better yet, it reduces our dependence on the cpu online masks, which have been the cause of confusion and drama lately. Fixes: ab23a7768739 ("xfs: per-cpu deferred inode inactivation queues") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
Diffstat (limited to 'fs/xfs/xfs_mount.h')
-rw-r--r--fs/xfs/xfs_mount.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index a25eece3be2b..f4a8879ba0e9 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -60,6 +60,7 @@ struct xfs_error_cfg {
* Per-cpu deferred inode inactivation GC lists.
*/
struct xfs_inodegc {
+ struct xfs_mount *mp;
struct llist_head list;
struct delayed_work work;
int error;
@@ -67,9 +68,7 @@ struct xfs_inodegc {
/* approximate count of inodes in the list */
unsigned int items;
unsigned int shrinker_hits;
-#if defined(DEBUG) || defined(XFS_WARN)
unsigned int cpu;
-#endif
};
/*
@@ -249,6 +248,9 @@ typedef struct xfs_mount {
unsigned int *m_errortag;
struct xfs_kobj m_errortag_kobj;
#endif
+
+ /* cpus that have inodes queued for inactivation */
+ struct cpumask m_inodegc_cpumask;
} xfs_mount_t;
#define M_IGEO(mp) (&(mp)->m_ino_geo)