On 2011-03-30 13:07, Jens Axboe wrote:
> On 2011-03-30 06:25, Ryusuke Konishi wrote:
>> diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
>> index 4d2a1ee..9d2dc6b 100644
>> --- a/fs/nilfs2/page.c
>> +++ b/fs/nilfs2/page.c
>> @@ -495,12 +495,14 @@ unsigned nilfs_page_count_clean_buffers(struct page
>> *page,
>> void nilfs_mapping_init(struct address_space *mapping,
>> struct backing_dev_info *bdi)
>> {
>> + static const struct address_space_operations empty_aops;
>> +
>> mapping->host = NULL;
>> mapping->flags = 0;
>> mapping_set_gfp_mask(mapping, GFP_NOFS);
>> mapping->assoc_mapping = NULL;
>> mapping->backing_dev_info = bdi;
>> - mapping->a_ops = NULL;
>> + mapping->a_ops = &empty_aops;
>> }
>
> Hmm wait, inode init should set the mapping aops to an empty type
> already. Does the OOPS go away if you just remove the mapping->a_ops =
> NULL assignment?
In any case, I think this is a better fix.
diff --git a/fs/inode.c b/fs/inode.c
index 5f4e11a..b818730 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -125,6 +125,13 @@ __cacheline_aligned_in_smp
DEFINE_SPINLOCK(inode_wb_list_lock);
static DECLARE_RWSEM(iprune_sem);
/*
+ * Empty aops. Can be used for the cases where the user does not
+ * define any of the address_space operations.
+ */
+const struct address_space_operations empty_aops = {
+};
+
+/*
* Statistics gathering..
*/
struct inodes_stat_t inodes_stat;
@@ -176,7 +183,6 @@ int proc_nr_inodes(ctl_table *table, int write,
*/
int inode_init_always(struct super_block *sb, struct inode *inode)
{
- static const struct address_space_operations empty_aops;
static const struct inode_operations empty_iops;
static const struct file_operations empty_fops;
struct address_space *const mapping = &inode->i_data;
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 4d2a1ee..1168059 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -500,7 +500,7 @@ void nilfs_mapping_init(struct address_space *mapping,
mapping_set_gfp_mask(mapping, GFP_NOFS);
mapping->assoc_mapping = NULL;
mapping->backing_dev_info = bdi;
- mapping->a_ops = NULL;
+ mapping->a_ops = &empty_aops;
}
/*
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index c74400f..403c192 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -80,7 +80,6 @@ enum {
};
static const struct inode_operations none_inode_operations;
-static const struct address_space_operations none_address_operations;
static const struct file_operations none_file_operations;
/**
@@ -130,7 +129,7 @@ static int create_xattr(struct ubifs_info *c, struct inode
*host,
}
/* Re-define all operations to be "nothing" */
- inode->i_mapping->a_ops = &none_address_operations;
+ inode->i_mapping->a_ops = &empty_aops;
inode->i_op = &none_inode_operations;
inode->i_fop = &none_file_operations;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 52f283c..1b95af3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -613,6 +613,8 @@ struct address_space_operations {
int (*error_remove_page)(struct address_space *, struct page *);
};
+extern const struct address_space_operations empty_aops;
+
/*
* pagecache_write_begin/pagecache_write_end must be used by general code
* to write into the pagecache.
--
Jens Axboe
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