From 6e9918b7b3924f7a4cc3faa73c6e15d709ac239f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 5 May 2015 09:26:05 -0400 Subject: [PATCH] namei: explicitly pass seq number to unlazy_walk() when dentry != NULL Signed-off-by: Al Viro --- fs/namei.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 756e150c28fc..97315dfcf464 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -567,13 +567,14 @@ static inline int nd_alloc_stack(struct nameidata *nd) * unlazy_walk - try to switch to ref-walk mode. * @nd: nameidata pathwalk data * @dentry: child of nd->path.dentry or NULL + * @seq: seq number to check dentry against * Returns: 0 on success, -ECHILD on failure * * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry * for ref-walk mode. @dentry must be a path found by a do_lookup call on * @nd or NULL. Must be called from rcu-walk context. */ -static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) +static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq) { struct fs_struct *fs = current->fs; struct dentry *parent = nd->path.dentry; @@ -615,7 +616,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) } else { if (!lockref_get_not_dead(&dentry->d_lockref)) goto out; - if (read_seqcount_retry(&dentry->d_seq, nd->seq)) + if (read_seqcount_retry(&dentry->d_seq, seq)) goto drop_dentry; } @@ -671,7 +672,7 @@ static int complete_walk(struct nameidata *nd) if (nd->flags & LOOKUP_RCU) { if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - if (unlikely(unlazy_walk(nd, NULL))) + if (unlikely(unlazy_walk(nd, NULL, 0))) return -ECHILD; } @@ -1451,7 +1452,7 @@ static int lookup_fast(struct nameidata *nd, if (likely(__follow_mount_rcu(nd, path, inode))) return 0; unlazy: - if (unlazy_walk(nd, dentry)) + if (unlazy_walk(nd, dentry, nd->seq)) return -ECHILD; } else { dentry = __d_lookup(parent, &nd->last); @@ -1511,7 +1512,7 @@ static inline int may_lookup(struct nameidata *nd) int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); if (err != -ECHILD) return err; - if (unlazy_walk(nd, NULL)) + if (unlazy_walk(nd, NULL, 0)) return -ECHILD; } return inode_permission(nd->inode, MAY_EXEC); @@ -1552,7 +1553,7 @@ static int pick_link(struct nameidata *nd, struct path *link) } if (nd->flags & LOOKUP_RCU) { if (unlikely(nd->path.mnt != link->mnt || - unlazy_walk(nd, link->dentry))) { + unlazy_walk(nd, link->dentry, nd->seq))) { return -ECHILD; } } @@ -2297,7 +2298,7 @@ mountpoint_last(struct nameidata *nd, struct path *path) /* If we're in rcuwalk, drop out of it to handle last component */ if (nd->flags & LOOKUP_RCU) { - if (unlazy_walk(nd, NULL)) + if (unlazy_walk(nd, NULL, 0)) return -ECHILD; }