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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 16/20] VFS/namei: enable RCU-walk when following symlinks.
Date: Mon, 23 Mar 2015 13:37:40 +1100	[thread overview]
Message-ID: <20150323023740.8161.65198.stgit@notabene.brown> (raw)
In-Reply-To: <20150323023258.8161.32467.stgit@notabene.brown>

Now that follow_link handles LOOKUP_RCU, we do not need to
'unlazy_walk' when a symlink is found.

As we remain in RCU-walk mode, dentry->d_inode can change
so the BUG_ON() assertions are no longer appropriate.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 fs/namei.c |   21 +++------------------
 1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 40ff4cb04244..0f5b627bd78e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1636,16 +1636,9 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
 	if (!inode || d_is_negative(path->dentry))
 		goto out_path_put;
 
-	if (should_follow_link(path->dentry, follow)) {
-		if (nd->flags & LOOKUP_RCU) {
-			if (unlikely(unlazy_walk(nd, path->dentry))) {
-				err = -ECHILD;
-				goto out_err;
-			}
-		}
-		BUG_ON(inode != path->dentry->d_inode);
+	if (should_follow_link(path->dentry, follow))
 		return 1;
-	}
+
 	path_to_nameidata(path, nd);
 	nd->inode = inode;
 	return 0;
@@ -3102,16 +3095,8 @@ finish_lookup:
 		goto out;
 	}
 
-	if (should_follow_link(path->dentry, !symlink_ok)) {
-		if (nd->flags & LOOKUP_RCU) {
-			if (unlikely(unlazy_walk(nd, path->dentry))) {
-				error = -ECHILD;
-				goto out;
-			}
-		}
-		BUG_ON(inode != path->dentry->d_inode);
+	if (should_follow_link(path->dentry, !symlink_ok))
 		return 1;
-	}
 
 	if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
 		path_to_nameidata(path, nd);

  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 ` [PATCH 04/20] ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link NeilBrown
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 ` NeilBrown [this message]
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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