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From: Al Viro <viro@zeniv.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
Cc: agruenba@redhat.com, amir73il@gmail.com, brauner@kernel.org,
	ceph-devel@vger.kernel.org, dhowells@redhat.com,
	hubcap@omnibond.com, jack@suse.cz, krisman@kernel.org,
	linux-nfs@vger.kernel.org, miklos@szeredi.hu,
	torvalds@linux-foundation.org
Subject: [PATCH 01/20] make sure that DNAME_INLINE_LEN is a multiple of word size
Date: Fri, 10 Jan 2025 02:42:44 +0000	[thread overview]
Message-ID: <20250110024303.4157645-1-viro@zeniv.linux.org.uk> (raw)
In-Reply-To: <20250110023854.GS1977892@ZenIV>

... calling the number of words DNAME_INLINE_WORDS.

The next step will be to have a structure to hold inline name arrays
(both in dentry and in name_snapshot) and use that to alias the
existing arrays of unsigned char there.  That will allow both
full-structure copies and convenient word-by-word accesses.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/dcache.c            | 4 +---
 include/linux/dcache.h | 8 +++++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index b4d5e9e1e43d..ea0f0bea511b 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2748,9 +2748,7 @@ static void swap_names(struct dentry *dentry, struct dentry *target)
 			/*
 			 * Both are internal.
 			 */
-			unsigned int i;
-			BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
-			for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
+			for (int i = 0; i < DNAME_INLINE_WORDS; i++) {
 				swap(((long *) &dentry->d_iname)[i],
 				     ((long *) &target->d_iname)[i]);
 			}
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index bff956f7b2b9..42dd89beaf4e 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -68,15 +68,17 @@ extern const struct qstr dotdot_name;
  * large memory footprint increase).
  */
 #ifdef CONFIG_64BIT
-# define DNAME_INLINE_LEN 40 /* 192 bytes */
+# define DNAME_INLINE_WORDS 5 /* 192 bytes */
 #else
 # ifdef CONFIG_SMP
-#  define DNAME_INLINE_LEN 36 /* 128 bytes */
+#  define DNAME_INLINE_WORDS 9 /* 128 bytes */
 # else
-#  define DNAME_INLINE_LEN 44 /* 128 bytes */
+#  define DNAME_INLINE_WORDS 11 /* 128 bytes */
 # endif
 #endif
 
+#define DNAME_INLINE_LEN (DNAME_INLINE_WORDS*sizeof(unsigned long))
+
 #define d_lock	d_lockref.lock
 
 struct dentry {
-- 
2.39.5


  reply	other threads:[~2025-01-10  2:43 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-10  2:38 [PATCHES][RFC][CFT] ->d_revalidate() calling conventions changes (->d_parent/->d_name stability problems) Al Viro
2025-01-10  2:42 ` Al Viro [this message]
2025-01-10  2:42   ` [PATCH 02/20] dcache: back inline names with a struct-wrapped array of unsigned long Al Viro
2025-01-10  9:35     ` Jan Kara
2025-01-10 16:24       ` Al Viro
2025-01-10  2:42   ` [PATCH 03/20] make take_dentry_name_snapshot() lockless Al Viro
2025-01-10  9:45     ` Jan Kara
2025-01-10  2:42   ` [PATCH 04/20] dissolve external_name.u into separate members Al Viro
2025-01-10  7:34     ` David Howells
2025-01-10 16:46       ` Al Viro
2025-01-10  2:42   ` [PATCH 05/20] ext4 fast_commit: make use of name_snapshot primitives Al Viro
2025-01-10  9:15     ` Jan Kara
2025-01-10  2:42   ` [PATCH 06/20] generic_ci_d_compare(): use shortname_storage Al Viro
2025-01-10  2:42   ` [PATCH 07/20] Pass parent directory inode and expected name to ->d_revalidate() Al Viro
2025-01-10  2:42   ` [PATCH 08/20] afs_d_revalidate(): use stable name and parent inode passed by caller Al Viro
2025-01-10  2:42   ` [PATCH 09/20] ceph_d_revalidate(): use stable " Al Viro
2025-01-10 19:45     ` Viacheslav Dubeyko
2025-01-10  2:42   ` [PATCH 10/20] ceph_d_revalidate(): propagate stable name down into request enconding Al Viro
2025-01-10  2:42   ` [PATCH 11/20] fscrypt_d_revalidate(): use stable parent inode passed by caller Al Viro
2025-01-10  2:42   ` [PATCH 12/20] exfat_d_revalidate(): " Al Viro
2025-01-10  2:42   ` [PATCH 13/20] vfat_revalidate{,_ci}(): " Al Viro
2025-01-10  2:42   ` [PATCH 14/20] fuse_dentry_revalidate(): use stable parent inode and name " Al Viro
2025-01-10  2:42   ` [PATCH 15/20] gfs2_drevalidate(): " Al Viro
2025-01-10 19:20     ` Andreas Grünbacher
2025-01-10  2:42   ` [PATCH 16/20] nfs{,4}_lookup_validate(): use stable parent inode " Al Viro
2025-01-10  2:43   ` [PATCH 17/20] nfs: fix ->d_revalidate() UAF on ->d_name accesses Al Viro
2025-01-10  2:43   ` [PATCH 18/20] ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller Al Viro
2025-01-10  9:54     ` Jan Kara
2025-01-10  2:43   ` [PATCH 19/20] orangefs_d_revalidate(): " Al Viro
2025-01-10  3:06     ` Linus Torvalds
2025-01-10  2:43   ` [PATCH 20/20] 9p: fix ->rename_sem exclusion Al Viro
2025-01-10  3:11     ` Linus Torvalds
2025-01-10  5:53       ` Al Viro
2025-01-10  9:21   ` [PATCH 01/20] make sure that DNAME_INLINE_LEN is a multiple of word size Jan Kara
2025-01-16  5:21 ` [PATCHES v2][RFC][CFT] ->d_revalidate() calling conventions changes (->d_parent/->d_name stability problems) Al Viro
2025-01-16  5:22   ` [PATCH v2 01/20] make sure that DNAME_INLINE_LEN is a multiple of word size Al Viro
2025-01-16  5:22     ` [PATCH v2 02/20] dcache: back inline names with a struct-wrapped array of unsigned long Al Viro
2025-01-16  5:23     ` [PATCH v2 03/20] make take_dentry_name_snapshot() lockless Al Viro
2025-01-16  5:23     ` [PATCH v2 04/20] dissolve external_name.u into separate members Al Viro
2025-01-16 10:06       ` Jan Kara
2025-01-16  5:23     ` [PATCH v2 05/20] ext4 fast_commit: make use of name_snapshot primitives Al Viro
2025-01-16  5:23     ` [PATCH v2 06/20] generic_ci_d_compare(): use shortname_storage Al Viro
2025-01-16 15:38       ` Gabriel Krisman Bertazi
2025-01-16 15:46         ` Al Viro
2025-01-16 15:53           ` Gabriel Krisman Bertazi
2025-01-16  5:23     ` [PATCH v2 07/20] Pass parent directory inode and expected name to ->d_revalidate() Al Viro
2025-01-16 15:15       ` Gabriel Krisman Bertazi
2025-01-17 18:55       ` Jeff Layton
2025-01-17 19:00         ` Al Viro
2025-01-16  5:23     ` [PATCH v2 08/20] afs_d_revalidate(): use stable name and parent inode passed by caller Al Viro
2025-01-22 20:27       ` David Howells
2025-01-22 21:01         ` Al Viro
2025-01-22 21:24           ` Al Viro
2025-01-22 21:55             ` David Howells
2025-01-16  5:23     ` [PATCH v2 09/20] ceph_d_revalidate(): use stable " Al Viro
2025-01-17 18:35       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 10/20] ceph_d_revalidate(): propagate stable name down into request enconding Al Viro
2025-01-17 18:35       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 11/20] fscrypt_d_revalidate(): use stable parent inode passed by caller Al Viro
2025-01-17 15:20       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 12/20] exfat_d_revalidate(): " Al Viro
2025-01-16  5:23     ` [PATCH v2 13/20] vfat_revalidate{,_ci}(): " Al Viro
2025-01-17 15:22       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 14/20] fuse_dentry_revalidate(): use stable parent inode and name " Al Viro
2025-01-17 15:18       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 15/20] gfs2_drevalidate(): " Al Viro
2025-01-16  5:23     ` [PATCH v2 16/20] nfs{,4}_lookup_validate(): use stable parent inode " Al Viro
2025-01-17 14:05       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 17/20] nfs: fix ->d_revalidate() UAF on ->d_name accesses Al Viro
2025-01-17 15:12       ` Jeff Layton
2025-01-16  5:23     ` [PATCH v2 18/20] ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller Al Viro
2025-01-16  5:23     ` [PATCH v2 19/20] orangefs_d_revalidate(): " Al Viro
2025-01-16  5:23     ` [PATCH v2 20/20] 9p: fix ->rename_sem exclusion Al Viro
2025-01-23  1:45   ` [PATCHES v3][RFC][CFT] ->d_revalidate() calling conventions changes (->d_parent/->d_name stability problems) Al Viro
2025-01-23  1:46     ` [PATCH v3 01/20] make sure that DNAME_INLINE_LEN is a multiple of word size Al Viro
2025-01-23  1:46       ` [PATCH v3 02/20] dcache: back inline names with a struct-wrapped array of unsigned long Al Viro
2025-01-23  1:46       ` [PATCH v3 03/20] make take_dentry_name_snapshot() lockless Al Viro
2025-01-23  1:46       ` [PATCH v3 04/20] dissolve external_name.u into separate members Al Viro
2025-01-23  1:46       ` [PATCH v3 05/20] ext4 fast_commit: make use of name_snapshot primitives Al Viro
2025-01-23  1:46       ` [PATCH v3 06/20] generic_ci_d_compare(): use shortname_storage Al Viro
2025-01-23  1:46       ` [PATCH v3 07/20] Pass parent directory inode and expected name to ->d_revalidate() Al Viro
2025-01-23  1:46       ` [PATCH v3 08/20] afs_d_revalidate(): use stable name and parent inode passed by caller Al Viro
2025-01-23  1:46       ` [PATCH v3 09/20] ceph_d_revalidate(): use stable " Al Viro
2025-01-23  1:46       ` [PATCH v3 10/20] ceph_d_revalidate(): propagate stable name down into request encoding Al Viro
2025-01-23  1:46       ` [PATCH v3 11/20] fscrypt_d_revalidate(): use stable parent inode passed by caller Al Viro
2025-01-23  1:46       ` [PATCH v3 12/20] exfat_d_revalidate(): " Al Viro
2025-01-23  1:46       ` [PATCH v3 13/20] vfat_revalidate{,_ci}(): " Al Viro
2025-01-23  1:46       ` [PATCH v3 14/20] fuse_dentry_revalidate(): use stable parent inode and name " Al Viro
2025-01-23 10:51         ` Miklos Szeredi
2025-01-23  1:46       ` [PATCH v3 15/20] gfs2_drevalidate(): " Al Viro
2025-01-23  1:46       ` [PATCH v3 16/20] nfs{,4}_lookup_validate(): use stable parent inode " Al Viro
2025-01-23  1:46       ` [PATCH v3 17/20] nfs: fix ->d_revalidate() UAF on ->d_name accesses Al Viro
2025-01-23  1:46       ` [PATCH v3 18/20] ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller Al Viro
2025-01-23  1:46       ` [PATCH v3 19/20] orangefs_d_revalidate(): " Al Viro
2025-01-25 16:25         ` Mike Marshall
2025-01-23  1:46       ` [PATCH v3 20/20] 9p: fix ->rename_sem exclusion Al Viro

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