From 04256b4a8fc73f54cd14f20867882c299728a446 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 11 Feb 2009 13:20:23 -0800 Subject: [PATCH] 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 Cc: Tejun Heo Cc: Al Viro Cc: Cornelia Huck Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/inode.c | 17 +++++++++++++++++ fs/sysfs/mount.c | 1 + fs/sysfs/sysfs.h | 1 + 3 files changed, 19 insertions(+) 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); -- 2.11.4.GIT