3 From: Miklos Szeredi <mszeredi@redhat.com>
5 This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make
6 f_path always point to the overlay and f_inode to the underlay").
8 Regular files opened on overlayfs will result in the file being opened on
9 the underlying filesystem, while f_path points to the overlayfs
12 This confuses filesystems which get the dentry from struct file and assume
15 Add a new helper, file_dentry() [*], to get the filesystem's own dentry
16 from the file. This simply compares file_inode(file->f_path.dentry) to
17 file_inode(file) and if they are equal returns file->f_path.dentry (this is
18 the common, non-overlayfs case).
20 In the uncommon case (regular file on overlayfs) it will call into
21 overlayfs's ->d_native_dentry() to get the underlying dentry matching
24 [*] If possible, it's better simply to use file_inode() instead.
26 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
27 Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
28 Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com>
29 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
30 Cc: <stable@vger.kernel.org> # v4.2
31 Cc: David Howells <dhowells@redhat.com>
32 Cc: Al Viro <viro@zeniv.linux.org.uk>
33 Cc: Daniel Axtens <dja@axtens.net>
35 fs/open.c | 11 +++++++++++
36 fs/overlayfs/super.c | 16 ++++++++++++++++
37 include/linux/dcache.h | 1 +
38 include/linux/fs.h | 2 ++
39 4 files changed, 30 insertions(+)
41 diff --git a/fs/open.c b/fs/open.c
42 index 55bdc75..6326c11 100644
45 @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen)
47 EXPORT_SYMBOL(file_path);
49 +struct dentry *file_dentry(const struct file *file)
51 + struct dentry *dentry = file->f_path.dentry;
53 + if (likely(d_inode(dentry) == file_inode(file)))
56 + return dentry->d_op->d_native_dentry(dentry, file_inode(file));
58 +EXPORT_SYMBOL(file_dentry);
61 * vfs_open - open the file at the given path
63 diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
64 index 8d826bd..10dbdc7 100644
65 --- a/fs/overlayfs/super.c
66 +++ b/fs/overlayfs/super.c
67 @@ -334,13 +334,29 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
71 +static struct dentry *ovl_d_native_dentry(struct dentry *dentry,
72 + struct inode *inode)
74 + struct ovl_entry *oe = dentry->d_fsdata;
75 + struct dentry *realentry = ovl_upperdentry_dereference(oe);
77 + if (realentry && inode == d_inode(realentry))
79 + realentry = __ovl_dentry_lower(oe);
80 + if (realentry && inode == d_inode(realentry))
85 static const struct dentry_operations ovl_dentry_operations = {
86 .d_release = ovl_dentry_release,
87 .d_select_inode = ovl_d_select_inode,
88 + .d_native_dentry = ovl_d_native_dentry,
91 static const struct dentry_operations ovl_reval_dentry_operations = {
92 .d_release = ovl_dentry_release,
93 + .d_native_dentry = ovl_d_native_dentry,
94 .d_revalidate = ovl_dentry_revalidate,
95 .d_weak_revalidate = ovl_dentry_weak_revalidate,
97 diff --git a/include/linux/dcache.h b/include/linux/dcache.h
98 index 7781ce11..957dd36 100644
99 --- a/include/linux/dcache.h
100 +++ b/include/linux/dcache.h
101 @@ -161,6 +161,7 @@ struct dentry_operations {
102 struct vfsmount *(*d_automount)(struct path *);
103 int (*d_manage)(struct dentry *, bool);
104 struct inode *(*d_select_inode)(struct dentry *, unsigned);
105 + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *);
106 } ____cacheline_aligned;
109 diff --git a/include/linux/fs.h b/include/linux/fs.h
110 index 1a20462..e626ab6 100644
111 --- a/include/linux/fs.h
112 +++ b/include/linux/fs.h
113 @@ -1237,6 +1237,8 @@ static inline struct inode *file_inode(const struct file *f)
117 +extern struct dentry *file_dentry(const struct file *file);
119 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
121 return locks_lock_inode_wait(file_inode(filp), fl);