[PATCH v3 101/110] namei: make put_link() RCU-safe

From: Al Viro
Date: Mon May 11 2015 - 14:13:10 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

very simple - just make path_put() conditional on !RCU.
Note that right now it doesn't get called in RCU mode -
we leave it before getting anything into stack.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index 4303404..998c3c2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -750,7 +750,8 @@ static inline void put_link(struct nameidata *nd)
struct inode *inode = last->inode;
if (last->cookie && inode->i_op->put_link)
inode->i_op->put_link(inode, last->cookie);
- path_put(&last->link);
+ if (!(nd->flags & LOOKUP_RCU))
+ path_put(&last->link);
}

int sysctl_protected_symlinks __read_mostly = 0;
--
2.1.4

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