| [2414] | 1 | From eafc370c0eba7949d85547ebc27574aa106d3355 Mon Sep 17 00:00:00 2001 |
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| 2 | From: Anders Kaseorg <andersk@mit.edu> |
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| 3 | Date: Tue, 7 May 2013 00:27:33 -0400 |
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| 4 | Subject: [PATCH] =?UTF-8?q?Linux:=20osi=5FTryEvictVCache:=20Don=E2=80=99t?= |
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| 5 | =?UTF-8?q?=20skip=20the=20first=20dentry=20if=20D=5FALIAS=5FIS=5FHLIST?= |
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| 6 | MIME-Version: 1.0 |
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| 7 | Content-Type: text/plain; charset=UTF-8 |
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| 8 | Content-Transfer-Encoding: 8bit |
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| 9 | |
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| 10 | An hlist doesn’t begin with a sentinel like a list does, so the old |
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| 11 | code would skip the first dentry or crash with a NULL dereference if |
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| 12 | there wasn’t one. Use the kernel’s list_for_each_entry or |
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| 13 | hlist_for_each_entry macros instead of trying to do it manually. |
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| 14 | |
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| 15 | Should fix a crash observed by Alex Chernyakhovsky on kernel 3.6 and |
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| 16 | newer. |
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| 17 | |
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| 18 | Change-Id: I6d7bd190013a0250ca896af8d5182df55a3376b0 |
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| 19 | Signed-off-by: Anders Kaseorg <andersk@mit.edu> |
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| 20 | --- |
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| 21 | src/afs/LINUX/osi_vcache.c | 30 +++++++++--------------------- |
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| 22 | 1 file changed, 9 insertions(+), 21 deletions(-) |
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| 23 | |
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| 24 | diff --git a/src/afs/LINUX/osi_vcache.c b/src/afs/LINUX/osi_vcache.c |
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| 25 | index dc3685b..99aab91 100644 |
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| 26 | --- a/src/afs/LINUX/osi_vcache.c |
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| 27 | +++ b/src/afs/LINUX/osi_vcache.c |
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| 28 | @@ -19,10 +19,8 @@ osi_TryEvictVCache(struct vcache *avc, int *slept, int defersleep) { |
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| 29 | |
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| 30 | struct dentry *dentry; |
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| 31 | struct inode *inode = AFSTOV(avc); |
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| 32 | -#if defined(D_ALIAS_IS_HLIST) |
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| 33 | - struct hlist_node *cur, *head, *list_end; |
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| 34 | -#else |
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| 35 | - struct list_head *cur, *head, *list_end; |
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| 36 | +#if defined(D_ALIAS_IS_HLIST) && !defined(HLIST_ITERATOR_NO_NODE) |
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| 37 | + struct hlist_node *p; |
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| 38 | #endif |
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| 39 | |
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| 40 | /* First, see if we can evict the inode from the dcache */ |
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| 41 | @@ -33,13 +31,9 @@ osi_TryEvictVCache(struct vcache *avc, int *slept, int defersleep) { |
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| 42 | |
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| 43 | #if defined(HAVE_DCACHE_LOCK) |
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| 44 | spin_lock(&dcache_lock); |
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| 45 | - head = &inode->i_dentry; |
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| 46 | |
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| 47 | restart: |
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| 48 | - cur = head; |
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| 49 | - while ((cur = cur->next) != head) { |
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| 50 | - dentry = list_entry(cur, struct dentry, d_alias); |
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| 51 | - |
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| 52 | + list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
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| 53 | if (d_unhashed(dentry)) |
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| 54 | continue; |
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| 55 | dget_locked(dentry); |
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| 56 | @@ -57,23 +51,17 @@ restart: |
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| 57 | spin_unlock(&dcache_lock); |
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| 58 | #else /* HAVE_DCACHE_LOCK */ |
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| 59 | spin_lock(&inode->i_lock); |
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| 60 | -#if defined(D_ALIAS_IS_HLIST) |
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| 61 | - head = inode->i_dentry.first; |
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| 62 | - list_end = NULL; |
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| 63 | -#else |
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| 64 | - head = &inode->i_dentry; |
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| 65 | - list_end = head; |
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| 66 | -#endif |
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| 67 | |
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| 68 | restart: |
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| 69 | - cur = head; |
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| 70 | - while ((cur = cur->next) != list_end) { |
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| 71 | #if defined(D_ALIAS_IS_HLIST) |
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| 72 | - dentry = hlist_entry(cur, struct dentry, d_alias); |
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| 73 | +# if defined(HLIST_ITERATOR_NO_NODE) |
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| 74 | + hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
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| 75 | +# else |
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| 76 | + hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) { |
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| 77 | +# endif |
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| 78 | #else |
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| 79 | - dentry = list_entry(cur, struct dentry, d_alias); |
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| 80 | + list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
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| 81 | #endif |
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| 82 | - |
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| 83 | spin_lock(&dentry->d_lock); |
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| 84 | if (d_unhashed(dentry)) { |
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| 85 | spin_unlock(&dentry->d_lock); |
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| 86 | -- |
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| 87 | 1.8.3.rc1 |
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| 88 | |
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