From bc40aee053be1c2c443e812034f41e1a3cf34752 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 9 May 2015 13:04:24 -0400 Subject: [PATCH] namei: don't unlazy until get_link() Signed-off-by: Al Viro --- fs/namei.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index a64df4c4aaef..47b20086e9f3 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -536,10 +536,19 @@ static void restore_nameidata(struct nameidata *old) static int __nd_alloc_stack(struct nameidata *nd) { - struct saved *p = kmalloc(MAXSYMLINKS * sizeof(struct saved), + struct saved *p; + + if (nd->flags & LOOKUP_RCU) { + p= kmalloc(MAXSYMLINKS * sizeof(struct saved), + GFP_ATOMIC); + if (unlikely(!p)) + return -ECHILD; + } else { + p= kmalloc(MAXSYMLINKS * sizeof(struct saved), GFP_KERNEL); - if (unlikely(!p)) - return -ENOMEM; + if (unlikely(!p)) + return -ENOMEM; + } memcpy(p, nd->internal, sizeof(nd->internal)); nd->stack = p; return 0; @@ -957,8 +966,10 @@ const char *get_link(struct nameidata *nd) int error; const char *res; - BUG_ON(nd->flags & LOOKUP_RCU); - + if (nd->flags & LOOKUP_RCU) { + if (unlikely(unlazy_walk(nd, NULL, 0))) + return ERR_PTR(-ECHILD); + } cond_resched(); touch_atime(&last->link); @@ -1623,17 +1634,21 @@ static int pick_link(struct nameidata *nd, struct path *link, path_to_nameidata(link, nd); return -ELOOP; } - if (nd->flags & LOOKUP_RCU) { - if (unlikely(unlazy_link(nd, link, seq))) - return -ECHILD; - } else { + if (!(nd->flags & LOOKUP_RCU)) { if (link->mnt == nd->path.mnt) mntget(link->mnt); } error = nd_alloc_stack(nd); if (unlikely(error)) { - path_put(link); - return error; + if (error == -ECHILD) { + if (unlikely(unlazy_link(nd, link, seq))) + return -ECHILD; + error = nd_alloc_stack(nd); + } + if (error) { + path_put(link); + return error; + } } last = nd->stack + nd->depth++; -- 2.20.1