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authorEric W. Biederman <ebiederm@aristanetworks.com>2009-02-11 16:20:23 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-24 19:38:25 -0400
commit04256b4a8fc73f54cd14f20867882c299728a446 (patch)
tree16267f6c77e0fa9f7229a30f66343289b6d1108a /fs/sysfs
parent425cb02912d1095febfeaf8d379af7b2ac9e4a89 (diff)
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>
Diffstat (limited to 'fs/sysfs')
-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 dfa3d94cfc74..555f0ff988df 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)
147{ 147{
148 struct bin_attribute *bin_attr; 148 struct bin_attribute *bin_attr;
149 149
150 inode->i_private = sysfs_get(sd);
150 inode->i_mapping->a_ops = &sysfs_aops; 151 inode->i_mapping->a_ops = &sysfs_aops;
151 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; 152 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
152 inode->i_op = &sysfs_inode_operations; 153 inode->i_op = &sysfs_inode_operations;
@@ -214,6 +215,22 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
214 return inode; 215 return inode;
215} 216}
216 217
218/*
219 * The sysfs_dirent serves as both an inode and a directory entry for sysfs.
220 * To prevent the sysfs inode numbers from being freed prematurely we take a
221 * reference to sysfs_dirent from the sysfs inode. A
222 * super_operations.delete_inode() implementation is needed to drop that
223 * reference upon inode destruction.
224 */
225void sysfs_delete_inode(struct inode *inode)
226{
227 struct sysfs_dirent *sd = inode->i_private;
228
229 truncate_inode_pages(&inode->i_data, 0);
230 clear_inode(inode);
231 sysfs_put(sd);
232}
233
217int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name) 234int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
218{ 235{
219 struct sysfs_addrm_cxt acxt; 236 struct sysfs_addrm_cxt acxt;
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 84ef378673a8..49749955ccaf 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -29,6 +29,7 @@ struct kmem_cache *sysfs_dir_cachep;
29static const struct super_operations sysfs_ops = { 29static const struct super_operations sysfs_ops = {
30 .statfs = simple_statfs, 30 .statfs = simple_statfs,
31 .drop_inode = generic_delete_inode, 31 .drop_inode = generic_delete_inode,
32 .delete_inode = sysfs_delete_inode,
32}; 33};
33 34
34struct sysfs_dirent sysfs_root = { 35struct sysfs_dirent sysfs_root = {
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 93c6d6b27c4d..9055d04e4ab0 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -145,6 +145,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
145 * inode.c 145 * inode.c
146 */ 146 */
147struct inode *sysfs_get_inode(struct sysfs_dirent *sd); 147struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
148void sysfs_delete_inode(struct inode *inode);
148int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); 149int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
149int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name); 150int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
150int sysfs_inode_init(void); 151int sysfs_inode_init(void);