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authorEric W. Biederman <ebiederm@aristanetworks.com>2009-02-11 13:20:23 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-24 16:38:25 -0700
commit04256b4a8fc73f54cd14f20867882c299728a446 (patch)
tree16267f6c77e0fa9f7229a30f66343289b6d1108a
parent425cb02912d1095febfeaf8d379af7b2ac9e4a89 (diff)
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sysfs: reference sysfs_dirent from sysfs inodes
The sysfs_dirent serves as both an inode and a directory entry for sysfs. To prevent the sysfs inode numbers from being freed prematurely hold a reference to sysfs_dirent from the sysfs inode. [akpm@linux-foundation.org: add comment] Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com> Cc: Tejun Heo <tj@kernel.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/sysfs/inode.c17
-rw-r--r--fs/sysfs/mount.c1
-rw-r--r--fs/sysfs/sysfs.h1
3 files changed, 19 insertions, 0 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index dfa3d94cfc7..555f0ff988d 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -147,6 +147,7 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
{
struct bin_attribute *bin_attr;
+ inode->i_private = sysfs_get(sd);
inode->i_mapping->a_ops = &sysfs_aops;
inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
inode->i_op = &sysfs_inode_operations;
@@ -214,6 +215,22 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
return inode;
}
+/*
+ * The sysfs_dirent serves as both an inode and a directory entry for sysfs.
+ * To prevent the sysfs inode numbers from being freed prematurely we take a
+ * reference to sysfs_dirent from the sysfs inode. A
+ * super_operations.delete_inode() implementation is needed to drop that
+ * reference upon inode destruction.
+ */
+void sysfs_delete_inode(struct inode *inode)
+{
+ struct sysfs_dirent *sd = inode->i_private;
+
+ truncate_inode_pages(&inode->i_data, 0);
+ clear_inode(inode);
+ sysfs_put(sd);
+}
+
int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
{
struct sysfs_addrm_cxt acxt;
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 84ef378673a..49749955cca 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -29,6 +29,7 @@ struct kmem_cache *sysfs_dir_cachep;
static const struct super_operations sysfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
+ .delete_inode = sysfs_delete_inode,
};
struct sysfs_dirent sysfs_root = {
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 93c6d6b27c4..9055d04e4ab 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -145,6 +145,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
* inode.c
*/
struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
+void sysfs_delete_inode(struct inode *inode);
int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
int sysfs_inode_init(void);