From: NeilBrown <neilb@suse.de>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 04/20] ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link
Date: Mon, 23 Mar 2015 13:37:39 +1100 [thread overview]
Message-ID: <20150323023738.8161.18618.stgit@notabene.brown> (raw)
In-Reply-To: <20150323023258.8161.32467.stgit@notabene.brown>
ovl_follow_link current calls ->put_link on an error path.
However ->put_link is about to change in a way that it will be
impossible to call it from ovl_follow_link.
So rearrange the code to avoid the need for that error path.
Specifically: move the kmalloc() call before the ->follow_link()
call to the subordinate filesystem.
Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/overlayfs/inode.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 04f124884687..1b4b9c5e51b7 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -145,6 +145,7 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd)
void *ret;
struct dentry *realdentry;
struct inode *realinode;
+ struct ovl_link_data *data = NULL;
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;
@@ -152,25 +153,23 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd)
if (WARN_ON(!realinode->i_op->follow_link))
return ERR_PTR(-EPERM);
- ret = realinode->i_op->follow_link(realdentry, nd);
- if (IS_ERR(ret))
- return ret;
-
if (realinode->i_op->put_link) {
- struct ovl_link_data *data;
-
data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
- if (!data) {
- realinode->i_op->put_link(realdentry, nd, ret);
+ if (!data)
return ERR_PTR(-ENOMEM);
- }
data->realdentry = realdentry;
- data->cookie = ret;
+ }
- return data;
- } else {
- return NULL;
+ ret = realinode->i_op->follow_link(realdentry, nd);
+ if (IS_ERR(ret)) {
+ kfree(data);
+ return ret;
}
+
+ if (data)
+ data->cookie = ret;
+
+ return data;
}
static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
next prev parent reply other threads:[~2015-03-23 2:37 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 2:37 [PATCH 00/20] Support follow_link in RCU-walk - V3 NeilBrown
2015-03-23 2:37 ` [PATCH 02/20] STAGING/lustre: limit follow_link recursion using stack space NeilBrown
2015-04-18 3:01 ` Al Viro
2015-04-19 20:57 ` Andreas Dilger
2015-04-19 21:33 ` Al Viro
2015-04-20 2:29 ` Al Viro
2015-03-23 2:37 ` [PATCH 03/20] VFS: replace {, total_}link_count in task_struct with pointer to nameidata NeilBrown
2015-03-23 2:37 ` [PATCH 01/20] Documentation: remove outdated information from automount-support.txt NeilBrown
2015-03-23 2:37 ` [PATCH 10/20] security: make inode_follow_link RCU-walk aware NeilBrown
2015-03-23 2:37 ` NeilBrown [this message]
2015-03-23 2:37 ` [PATCH 07/20] VFS: remove nameidata args from ->follow_link NeilBrown
2015-03-23 2:37 ` [PATCH 06/20] SECURITY: remove nameidata arg from inode_follow_link NeilBrown
2015-03-23 2:37 ` [PATCH 05/20] VFS: replace nameidata arg to ->put_link with a char* NeilBrown
2015-03-23 2:37 ` [PATCH 09/20] security/selinux: pass 'flags' arg to avc_audit() and avc_has_perm_flags() NeilBrown
2015-03-23 2:37 ` [PATCH 11/20] VFS/namei: use terminate_walk when symlink lookup fails NeilBrown
2015-03-23 2:37 ` [PATCH 08/20] VFS: make all ->follow_link handlers aware for LOOKUP_RCU NeilBrown
2015-03-23 2:37 ` [PATCH 13/20] VFS/namei: abort RCU-walk on symlink if atime needs updating NeilBrown
2015-03-23 2:37 ` [PATCH 14/20] VFS/namei: add 'inode' arg to put_link() NeilBrown
2015-04-17 16:25 ` Al Viro
2015-04-17 19:09 ` Al Viro
2015-04-18 8:09 ` Al Viro
2015-03-23 2:37 ` [PATCH 16/20] VFS/namei: enable RCU-walk when following symlinks NeilBrown
2015-03-23 2:37 ` [PATCH 19/20] XFS: allow follow_link to often succeed in RCU-walk NeilBrown
2015-03-23 2:37 ` [PATCH 20/20] NFS: support LOOKUP_RCU in nfs_follow_link NeilBrown
2015-03-23 2:37 ` [PATCH 18/20] xfs: use RCU to free 'struct xfs_mount' NeilBrown
2015-03-23 2:37 ` [PATCH 17/20] VFS/namei: handle LOOKUP_RCU in page_follow_link_light NeilBrown
2015-03-23 2:37 ` [PATCH 12/20] VFS/namei: new flag to support RCU symlinks: LOOKUP_LINK_RCU NeilBrown
2015-03-23 2:37 ` [PATCH 15/20] VFS/namei: enhance follow_link to support RCU-walk NeilBrown
2015-03-25 23:23 ` [PATCH 00/20] Support follow_link in RCU-walk - V3 NeilBrown
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