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authorJens Axboe <jens.axboe@oracle.com>2006-10-17 19:50:36 +0200
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-10-19 20:53:08 +0200
commit01de85e057328ecbef36e108673b1e81059d54c1 (patch)
tree0dbac62e48b2a2fa3f4ec4dea9b340ff31892a8c /mm
parent6da61809822c22634a3de2dcb3c60283b836a88a (diff)
downloadlinux-2.6.34-ux500-01de85e057328ecbef36e108673b1e81059d54c1.tar.gz
[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>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c30
1 files changed, 22 insertions, 8 deletions
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);