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authorDave Chinner <dchinner@redhat.com>2022-07-18 18:20:37 -0700
committerDarrick J. Wong <djwong@kernel.org>2022-07-20 16:40:39 -0700
commit231f91ab504ecebcb88e942341b3d7dd91de45f1 (patch)
tree65c1e9844a43b5c0ebacacc45678bfcc9be2ee08 /fs/xfs
parent3f52e016af600982989b5dee958d313c52483c92 (diff)
xfs: xfs_buf cache destroy isn't RCU safe
Darrick and Sachin Sant reported that xfs/435 and xfs/436 would report an non-empty xfs_buf slab on module remove. This isn't easily to reproduce, but is clearly a side effect of converting the buffer caceh to RUC freeing and lockless lookups. Sachin bisected and Darrick hit it when testing the patchset directly. Turns out that the xfs_buf slab is not destroyed when all the other XFS slab caches are destroyed. Instead, it's got it's own little wrapper function that gets called separately, and so it doesn't have an rcu_barrier() call in it that is needed to drain all the rcu callbacks before the slab is destroyed. Fix it by removing the xfs_buf_init/terminate wrappers that just allocate and destroy the xfs_buf slab, and move them to the same place that all the other slab caches are set up and destroyed. Reported-and-tested-by: Sachin Sant <sachinp@linux.ibm.com> Fixes: 298f34224506 ("xfs: lockless buffer lookup") Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_buf.c25
-rw-r--r--fs/xfs/xfs_buf.h6
-rw-r--r--fs/xfs/xfs_super.c22
3 files changed, 16 insertions, 37 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 6dac5583977f..ecceef8b4af3 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -21,7 +21,7 @@
#include "xfs_error.h"
#include "xfs_ag.h"
-static struct kmem_cache *xfs_buf_cache;
+struct kmem_cache *xfs_buf_cache;
/*
* Locking orders
@@ -2308,29 +2308,6 @@ xfs_buf_delwri_pushbuf(
return error;
}
-int __init
-xfs_buf_init(void)
-{
- xfs_buf_cache = kmem_cache_create("xfs_buf", sizeof(struct xfs_buf), 0,
- SLAB_HWCACHE_ALIGN |
- SLAB_RECLAIM_ACCOUNT |
- SLAB_MEM_SPREAD,
- NULL);
- if (!xfs_buf_cache)
- goto out;
-
- return 0;
-
- out:
- return -ENOMEM;
-}
-
-void
-xfs_buf_terminate(void)
-{
- kmem_cache_destroy(xfs_buf_cache);
-}
-
void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
{
/*
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 02b3c1635ec3..549c60942208 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -15,6 +15,8 @@
#include <linux/uio.h>
#include <linux/list_lru.h>
+extern struct kmem_cache *xfs_buf_cache;
+
/*
* Base types
*/
@@ -307,10 +309,6 @@ extern int xfs_buf_delwri_submit(struct list_head *);
extern int xfs_buf_delwri_submit_nowait(struct list_head *);
extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
-/* Buffer Daemon Setup Routines */
-extern int xfs_buf_init(void);
-extern void xfs_buf_terminate(void);
-
static inline xfs_daddr_t xfs_buf_daddr(struct xfs_buf *bp)
{
return bp->b_maps[0].bm_bn;
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 4edee1d3784a..3d27ba1295c9 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1967,11 +1967,19 @@ xfs_init_caches(void)
{
int error;
+ xfs_buf_cache = kmem_cache_create("xfs_buf", sizeof(struct xfs_buf), 0,
+ SLAB_HWCACHE_ALIGN |
+ SLAB_RECLAIM_ACCOUNT |
+ SLAB_MEM_SPREAD,
+ NULL);
+ if (!xfs_buf_cache)
+ goto out;
+
xfs_log_ticket_cache = kmem_cache_create("xfs_log_ticket",
sizeof(struct xlog_ticket),
0, 0, NULL);
if (!xfs_log_ticket_cache)
- goto out;
+ goto out_destroy_buf_cache;
error = xfs_btree_init_cur_caches();
if (error)
@@ -2145,6 +2153,8 @@ xfs_init_caches(void)
xfs_btree_destroy_cur_caches();
out_destroy_log_ticket_cache:
kmem_cache_destroy(xfs_log_ticket_cache);
+ out_destroy_buf_cache:
+ kmem_cache_destroy(xfs_buf_cache);
out:
return -ENOMEM;
}
@@ -2178,6 +2188,7 @@ xfs_destroy_caches(void)
xfs_defer_destroy_item_caches();
xfs_btree_destroy_cur_caches();
kmem_cache_destroy(xfs_log_ticket_cache);
+ kmem_cache_destroy(xfs_buf_cache);
}
STATIC int __init
@@ -2283,13 +2294,9 @@ init_xfs_fs(void)
if (error)
goto out_destroy_wq;
- error = xfs_buf_init();
- if (error)
- goto out_mru_cache_uninit;
-
error = xfs_init_procfs();
if (error)
- goto out_buf_terminate;
+ goto out_mru_cache_uninit;
error = xfs_sysctl_register();
if (error)
@@ -2346,8 +2353,6 @@ init_xfs_fs(void)
xfs_sysctl_unregister();
out_cleanup_procfs:
xfs_cleanup_procfs();
- out_buf_terminate:
- xfs_buf_terminate();
out_mru_cache_uninit:
xfs_mru_cache_uninit();
out_destroy_wq:
@@ -2373,7 +2378,6 @@ exit_xfs_fs(void)
kset_unregister(xfs_kset);
xfs_sysctl_unregister();
xfs_cleanup_procfs();
- xfs_buf_terminate();
xfs_mru_cache_uninit();
xfs_destroy_workqueues();
xfs_destroy_caches();