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| author | Al Viro <viro@zeniv.linux.org.uk> | 2015-08-02 02:59:28 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-08-02 03:18:38 +0300 |
| commit | 97242f99a013950af63effa0732f8ef7db4e31ec (patch) | |
| tree | 5cb822a4df9340f2b51a12a66d1653b0a6a1826e | |
| parent | cbfe8fa6cd672011c755c3cd85c9ffd4e2d10a6f (diff) | |
| download | linux-97242f99a013950af63effa0732f8ef7db4e31ec.tar.xz | |
link_path_walk(): be careful when failing with ENOTDIR
In RCU mode we might end up with dentry evicted just we check
that it's a directory. In such case we should return ECHILD
rather than ENOTDIR, so that pathwalk would be retries in non-RCU
mode.
Breakage had been introduced in commit b18825a - prior to that
we were looking at nd->inode, which had been fetched before
verifying that ->d_seq was still valid. That form of check
would only be satisfied if at some point the pathname prefix
would indeed have resolved to a non-directory. The fix consists
of checking ->d_seq after we'd run into a non-directory dentry,
and failing with ECHILD in case of mismatch.
Note that all branches since 3.12 have that problem...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/namei.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c index ae4e4c18b2ac..fbbcf0993312 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1954,8 +1954,13 @@ OK: continue; } } - if (unlikely(!d_can_lookup(nd->path.dentry))) + if (unlikely(!d_can_lookup(nd->path.dentry))) { + if (nd->flags & LOOKUP_RCU) { + if (unlazy_walk(nd, NULL, 0)) + return -ECHILD; + } return -ENOTDIR; + } } } |