diff options
| author | Jens Axboe <jens.axboe@oracle.com> | 2006-10-17 19:50:36 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@nelson.home.kernel.dk> | 2006-10-19 20:53:08 +0200 |
| commit | 01de85e057328ecbef36e108673b1e81059d54c1 (patch) | |
| tree | 0dbac62e48b2a2fa3f4ec4dea9b340ff31892a8c | |
| parent | 6da61809822c22634a3de2dcb3c60283b836a88a (diff) | |
[PATCH] Add lockless helpers for remove_suid()
Right now users have to grab i_mutex before calling remove_suid(), in the
unlikely event that a call to ->setattr() may be needed. Split up the
function in two parts:
- One to check if we need to remove suid
- One to actually remove it
The first we can call lockless.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | include/linux/fs.h | 2 | ||||
| -rw-r--r-- | mm/filemap.c | 30 |
2 files changed, 24 insertions, 8 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index d695ba2346a..2fe6e3f900b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1712,6 +1712,8 @@ extern void __iget(struct inode * inode); extern void clear_inode(struct inode *); extern void destroy_inode(struct inode *); extern struct inode *new_inode(struct super_block *); +extern int __remove_suid(struct dentry *, int); +extern int should_remove_suid(struct dentry *); extern int remove_suid(struct dentry *); extern void remove_dquot_ref(struct super_block *, int, struct list_head *); diff --git a/mm/filemap.c b/mm/filemap.c index 3464b681f84..7c7addb9333 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1884,11 +1884,10 @@ repeat: * if suid or (sgid and xgrp) * remove privs */ -int remove_suid(struct dentry *dentry) +int should_remove_suid(struct dentry *dentry) { mode_t mode = dentry->d_inode->i_mode; int kill = 0; - int result = 0; /* suid always must be killed */ if (unlikely(mode & S_ISUID)) @@ -1901,13 +1900,28 @@ int remove_suid(struct dentry *dentry) if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; - if (unlikely(kill && !capable(CAP_FSETID))) { - struct iattr newattrs; + if (unlikely(kill && !capable(CAP_FSETID))) + return kill; - newattrs.ia_valid = ATTR_FORCE | kill; - result = notify_change(dentry, &newattrs); - } - return result; + return 0; +} + +int __remove_suid(struct dentry *dentry, int kill) +{ + struct iattr newattrs; + + newattrs.ia_valid = ATTR_FORCE | kill; + return notify_change(dentry, &newattrs); +} + +int remove_suid(struct dentry *dentry) +{ + int kill = should_remove_suid(dentry); + + if (unlikely(kill)) + return __remove_suid(dentry, kill); + + return 0; } EXPORT_SYMBOL(remove_suid); |