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| author | Eric W. Biederman <ebiederm@aristanetworks.com> | 2009-02-11 13:20:23 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-03-24 16:38:25 -0700 |
| commit | 04256b4a8fc73f54cd14f20867882c299728a446 (patch) | |
| tree | 16267f6c77e0fa9f7229a30f66343289b6d1108a /fs/sysfs | |
| parent | 425cb02912d1095febfeaf8d379af7b2ac9e4a89 (diff) | |
| download | lwn-04256b4a8fc73f54cd14f20867882c299728a446.tar.gz lwn-04256b4a8fc73f54cd14f20867882c299728a446.zip | |
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.c | 17 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 1 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 1 |
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) { 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 84ef378673a8..49749955ccaf 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 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) * 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); |