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| author | Al Viro <viro@zeniv.linux.org.uk> | 2011-02-15 01:32:55 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-02-15 02:26:54 -0500 |
| commit | f5e1c1c1afc1d979e2ac6a24cc99ba7143639f4d (patch) | |
| tree | 48dad00e6bead517191094c0c05ef7b01c226e25 | |
| parent | 24643087e748bf192f1182766716e522dc1c972f (diff) | |
| download | lwn-f5e1c1c1afc1d979e2ac6a24cc99ba7143639f4d.tar.gz lwn-f5e1c1c1afc1d979e2ac6a24cc99ba7143639f4d.zip | |
split do_revalidate() into RCU and non-RCU cases
fixing oopsen in lookup_one_len()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/namei.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/fs/namei.c b/fs/namei.c index 7609bacc7046..a98f7f141780 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -592,12 +592,10 @@ static int d_revalidate(struct dentry *dentry, struct nameidata *nd) return status; } -static inline struct dentry * +static struct dentry * do_revalidate(struct dentry *dentry, struct nameidata *nd) { - int status; - - status = d_revalidate(dentry, nd); + int status = d_revalidate(dentry, nd); if (unlikely(status <= 0)) { /* * The dentry failed validation. @@ -606,24 +604,39 @@ do_revalidate(struct dentry *dentry, struct nameidata *nd) * to return a fail status. */ if (status < 0) { - /* If we're in rcu-walk, we don't have a ref */ - if (!(nd->flags & LOOKUP_RCU)) - dput(dentry); + dput(dentry); dentry = ERR_PTR(status); - - } else { - /* Don't d_invalidate in rcu-walk mode */ - if (nameidata_dentry_drop_rcu_maybe(nd, dentry)) - return ERR_PTR(-ECHILD); - if (!d_invalidate(dentry)) { - dput(dentry); - dentry = NULL; - } + } else if (!d_invalidate(dentry)) { + dput(dentry); + dentry = NULL; } } return dentry; } +static inline struct dentry * +do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd) +{ + int status = dentry->d_op->d_revalidate(dentry, nd); + if (likely(status > 0)) + return dentry; + if (status == -ECHILD) { + if (nameidata_dentry_drop_rcu(nd, dentry)) + return ERR_PTR(-ECHILD); + return do_revalidate(dentry, nd); + } + if (status < 0) + return ERR_PTR(status); + /* Don't d_invalidate in rcu-walk mode */ + if (nameidata_dentry_drop_rcu(nd, dentry)) + return ERR_PTR(-ECHILD); + if (!d_invalidate(dentry)) { + dput(dentry); + dentry = NULL; + } + return dentry; +} + static inline int need_reval_dot(struct dentry *dentry) { if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE))) @@ -1260,7 +1273,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, nd->seq = seq; if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { - dentry = do_revalidate(dentry, nd); + dentry = do_revalidate_rcu(dentry, nd); if (!dentry) goto need_lookup; if (IS_ERR(dentry)) |