On Fri 13-03-20 20:42:05, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>
> Fix a debug-only build error in ext2/xattr.c:
>
> When building without extra debugging, (and with another patch that uses
> no_printk() instead of <empty> for the ext2-xattr debug-print macros,
> this build error happens:
>
> ../fs/ext2/xattr.c: In function ‘ext2_xattr_cache_insert’:
> ../fs/ext2/xattr.c:869:18: error: ‘ext2_xattr_cache’ undeclared (first use in this function); did you mean ‘ext2_xattr_list’?
> atomic_read(&ext2_xattr_cache->c_entry_count));
>
> Fix by moving struct mb_cache from fs/mbcache.c to <linux/mbcache.h>,
> and then using the correct struct name in the debug-print macro.
>
> This wasn't converted when ext2 xattr cache was changed to use mbcache.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxxx>
> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: linux-ext4@xxxxxxxxxxxxxxx
> Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Thanks for the patch! I don't think exporting 'struct mb_cache' just for
this is reasonable. I've committed a patch which just removes the entry
count from the debug message (attached).
Honza
> ---
> This is ancient, from the beginning of git history.
>
> Or just kill of that print of c_entry_count...
>
> fs/ext2/xattr.c | 2 +-
> fs/mbcache.c | 34 ----------------------------------
> include/linux/mbcache.h | 35 ++++++++++++++++++++++++++++++++++-
> 3 files changed, 35 insertions(+), 36 deletions(-)
>
> --- linux-next-20200313.orig/fs/ext2/xattr.c
> +++ linux-next-20200313/fs/ext2/xattr.c
> @@ -873,7 +873,7 @@ ext2_xattr_cache_insert(struct mb_cache
> if (error) {
> if (error == -EBUSY) {
> ea_bdebug(bh, "already in cache (%d cache entries)",
> - atomic_read(&ext2_xattr_cache->c_entry_count));
> + atomic_read(&cache->c_entry_count));
> error = 0;
> }
> } else
> --- linux-next-20200313.orig/fs/mbcache.c
> +++ linux-next-20200313/fs/mbcache.c
> @@ -8,40 +8,6 @@
> #include <linux/workqueue.h>
> #include <linux/mbcache.h>
>
> -/*
> - * Mbcache is a simple key-value store. Keys need not be unique, however
> - * key-value pairs are expected to be unique (we use this fact in
> - * mb_cache_entry_delete()).
> - *
> - * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
> - * Ext4 also uses it for deduplication of xattr values stored in inodes.
> - * They use hash of data as a key and provide a value that may represent a
> - * block or inode number. That's why keys need not be unique (hash of different
> - * data may be the same). However user provided value always uniquely
> - * identifies a cache entry.
> - *
> - * We provide functions for creation and removal of entries, search by key,
> - * and a special "delete entry with given key-value pair" operation. Fixed
> - * size hash table is used for fast key lookups.
> - */
> -
> -struct mb_cache {
> - /* Hash table of entries */
> - struct hlist_bl_head *c_hash;
> - /* log2 of hash table size */
> - int c_bucket_bits;
> - /* Maximum entries in cache to avoid degrading hash too much */
> - unsigned long c_max_entries;
> - /* Protects c_list, c_entry_count */
> - spinlock_t c_list_lock;
> - struct list_head c_list;
> - /* Number of entries in cache */
> - unsigned long c_entry_count;
> - struct shrinker c_shrink;
> - /* Work for shrinking when the cache has too many entries */
> - struct work_struct c_shrink_work;
> -};
> -
> static struct kmem_cache *mb_entry_cache;
>
> static unsigned long mb_cache_shrink(struct mb_cache *cache,
> --- linux-next-20200313.orig/include/linux/mbcache.h
> +++ linux-next-20200313/include/linux/mbcache.h
> @@ -8,7 +8,40 @@
> #include <linux/atomic.h>
> #include <linux/fs.h>
>
> -struct mb_cache;
> +/*
> + * Mbcache is a simple key-value store. Keys need not be unique, however
> + * key-value pairs are expected to be unique (we use this fact in
> + * mb_cache_entry_delete()).
> + *
> + * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
> + * Ext4 also uses it for deduplication of xattr values stored in inodes.
> + * They use hash of data as a key and provide a value that may represent a
> + * block or inode number. That's why keys need not be unique (hash of different
> + * data may be the same). However user provided value always uniquely
> + * identifies a cache entry.
> + *
> + * We provide functions for creation and removal of entries, search by key,
> + * and a special "delete entry with given key-value pair" operation. Fixed
> + * size hash table is used for fast key lookups.
> + */
> +
> +struct mb_cache {
> + /* Hash table of entries */
> + struct hlist_bl_head *c_hash;
> + /* log2 of hash table size */
> + int c_bucket_bits;
> + /* Maximum entries in cache to avoid degrading hash too much */
> + unsigned long c_max_entries;
> + /* Protects c_list, c_entry_count */
> + spinlock_t c_list_lock;
> + struct list_head c_list;
> + /* Number of entries in cache */
> + unsigned long c_entry_count;
> + struct shrinker c_shrink;
> + /* Work for shrinking when the cache has too many entries */
> + struct work_struct c_shrink_work;
> +};
> +
>
> struct mb_cache_entry {
> /* List of entries in cache - protected by cache->c_list_lock */
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
>From 32302085a8d90859c40cf1a5e8313f575d06ec75 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Tue, 17 Mar 2020 12:40:02 +0100
Subject: [PATCH] ext2: fix debug reference to ext2_xattr_cache
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Fix a debug-only build error in ext2/xattr.c:
When building without extra debugging, (and with another patch that uses
no_printk() instead of <empty> for the ext2-xattr debug-print macros,
this build error happens:
../fs/ext2/xattr.c: In function ‘ext2_xattr_cache_insert’:
../fs/ext2/xattr.c:869:18: error: ‘ext2_xattr_cache’ undeclared (first use in
this function); did you mean ‘ext2_xattr_list’?
atomic_read(&ext2_xattr_cache->c_entry_count));
Fix the problem by removing cached entry count from the debug message
since otherwise we'd have to export the mbcache structure just for that.
Fixes: be0726d33cb8 ("ext2: convert to mbcache2")
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext2/xattr.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 9ad07c7ef0b3..6d9731b03715 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -872,8 +872,7 @@ ext2_xattr_cache_insert(struct mb_cache *cache, struct buffer_head *bh)
true);
if (error) {
if (error == -EBUSY) {
- ea_bdebug(bh, "already in cache (%d cache entries)",
- atomic_read(&ext2_xattr_cache->c_entry_count));
+ ea_bdebug(bh, "already in cache");
error = 0;
}
} else
--
2.16.4
