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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-11-08 22:08:29 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-21 10:40:47 +0100 |
| commit | b7436698bf7406b2943e8d7ac95b9f0f38c141b1 (patch) | |
| tree | 8f3dc83ded9b0da327a447d655914dc350f6692a | |
| parent | a4623faa5e79b6f0df92fdbdb67c30bdaec3d516 (diff) | |
| download | linux-stable-b7436698bf7406b2943e8d7ac95b9f0f38c141b1.tar.gz linux-stable-b7436698bf7406b2943e8d7ac95b9f0f38c141b1.tar.bz2 linux-stable-b7436698bf7406b2943e8d7ac95b9f0f38c141b1.zip | |
exportfs_decode_fh(): negative pinned may become positive without the parent locked
[ Upstream commit a2ece088882666e1dc7113744ac912eb161e3f87 ]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/exportfs/expfs.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 7a7bba7c2328..3706939e5dd5 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -506,26 +506,33 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, * inode is actually connected to the parent. */ err = exportfs_get_name(mnt, target_dir, nbuf, result); - if (!err) { - inode_lock(target_dir->d_inode); - nresult = lookup_one_len(nbuf, target_dir, - strlen(nbuf)); - inode_unlock(target_dir->d_inode); - if (!IS_ERR(nresult)) { - if (nresult->d_inode) { - dput(result); - result = nresult; - } else - dput(nresult); - } + if (err) { + dput(target_dir); + goto err_result; } + inode_lock(target_dir->d_inode); + nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf)); + if (!IS_ERR(nresult)) { + if (unlikely(nresult->d_inode != result->d_inode)) { + dput(nresult); + nresult = ERR_PTR(-ESTALE); + } + } + inode_unlock(target_dir->d_inode); /* * At this point we are done with the parent, but it's pinned * by the child dentry anyway. */ dput(target_dir); + if (IS_ERR(nresult)) { + err = PTR_ERR(nresult); + goto err_result; + } + dput(result); + result = nresult; + /* * And finally make sure the dentry is actually acceptable * to NFSD. |