diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/namei.c b/fs/namei.c index 709fb2c17b5..f9e883c1b85 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1144,12 +1144,25 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, */ if (nd->flags & LOOKUP_RCU) { unsigned seq; - *inode = nd->inode; - dentry = __d_lookup_rcu(parent, name, &seq, inode); + dentry = __d_lookup_rcu(parent, name, &seq, nd->inode); if (!dentry) goto unlazy; - /* Memory barrier in read_seqcount_begin of child is enough */ + /* + * This sequence count validates that the inode matches + * the dentry name information from lookup. + */ + *inode = dentry->d_inode; + if (read_seqcount_retry(&dentry->d_seq, seq)) + return -ECHILD; + + /* + * This sequence count validates that the parent had no + * changes while we did the lookup of the dentry above. + * + * The memory barrier in read_seqcount_begin of child is + * enough, we can use __read_seqcount_retry here. + */ if (__read_seqcount_retry(&parent->d_seq, nd->seq)) return -ECHILD; nd->seq = seq; |