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Message-Id: <20190411013441.5415-14-tobin@kernel.org>
Date: Thu, 11 Apr 2019 11:34:39 +1000
From: "Tobin C. Harding" <tobin@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "Tobin C. Harding" <tobin@...nel.org>,
Roman Gushchin <guro@...com>,
Alexander Viro <viro@....linux.org.uk>,
Christoph Hellwig <hch@...radead.org>,
Pekka Enberg <penberg@...helsinki.fi>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Christopher Lameter <cl@...ux.com>,
Matthew Wilcox <willy@...radead.org>,
Miklos Szeredi <mszeredi@...hat.com>,
Andreas Dilger <adilger@...ger.ca>,
Waiman Long <longman@...hat.com>,
Tycho Andersen <tycho@...ho.ws>,
"Theodore Ts'o" <tytso@....edu>, Andi Kleen <ak@...ux.intel.com>,
David Chinner <david@...morbit.com>,
Nick Piggin <npiggin@...il.com>,
Rik van Riel <riel@...hat.com>,
Hugh Dickins <hughd@...gle.com>,
Jonathan Corbet <corbet@....net>, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH v3 13/15] dcache: Provide a dentry constructor
In order to support object migration on the dentry cache we need to have
a determined object state at all times. Without a constructor the object
would have a random state after allocation.
Provide a dentry constructor.
Signed-off-by: Tobin C. Harding <tobin@...nel.org>
---
fs/dcache.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index aac41adf4743..606cfca20d42 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1603,6 +1603,16 @@ void d_invalidate(struct dentry *dentry)
}
EXPORT_SYMBOL(d_invalidate);
+static void dcache_ctor(void *p)
+{
+ struct dentry *dentry = p;
+
+ /* Mimic lockref_mark_dead() */
+ dentry->d_lockref.count = -128;
+
+ spin_lock_init(&dentry->d_lock);
+}
+
/**
* __d_alloc - allocate a dcache entry
* @sb: filesystem it will belong to
@@ -1658,7 +1668,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
dentry->d_lockref.count = 1;
dentry->d_flags = 0;
- spin_lock_init(&dentry->d_lock);
+
seqcount_init(&dentry->d_seq);
dentry->d_inode = NULL;
dentry->d_parent = dentry;
@@ -3091,14 +3101,17 @@ static void __init dcache_init_early(void)
static void __init dcache_init(void)
{
- /*
- * A constructor could be added for stable state like the lists,
- * but it is probably not worth it because of the cache nature
- * of the dcache.
- */
- dentry_cache = KMEM_CACHE_USERCOPY(dentry,
- SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
- d_iname);
+ slab_flags_t flags =
+ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | SLAB_MEM_SPREAD | SLAB_ACCOUNT;
+
+ dentry_cache =
+ kmem_cache_create_usercopy("dentry",
+ sizeof(struct dentry),
+ __alignof__(struct dentry),
+ flags,
+ offsetof(struct dentry, d_iname),
+ sizeof_field(struct dentry, d_iname),
+ dcache_ctor);
/* Hash may have been set up in dcache_init_early */
if (!hashdist)
--
2.21.0
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