| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20160517215326.GA1589@veci.piliscsaba.szeredi.hu>
Date: Tue, 17 May 2016 23:53:26 +0200
From: Miklos Szeredi <miklos@...redi.hu>
To: Al Viro <viro@...IV.linux.org.uk>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
David Howells <dhowells@...hat.com>
Subject: [PATCH 1/3] vfs: merge .d_select_inode() into .d_real()
The two methods essentially do the same: find the real dentry/inode
belonging to an overlay dentry. The difference is in the usage:
vfs_open() uses ->d_select_inode() and expects the function to perform
copy-up if necessary based on the open flags argument.
file_dentry() uses ->d_real() passing in the overlay dentry as well as the
underlying inode.
vfs_rename() uses ->d_select_inode() but passes zero flags. ->d_real()
with a zero inode would have worked just as well here.
This patch merges the functionality of ->d_select_inode() into ->d_real()
by adding an 'open_flags' argument to the latter.
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
---
fs/dcache.c | 3 ---
fs/namei.c | 2 +-
fs/open.c | 17 +++++++++++++----
fs/overlayfs/inode.c | 31 ++++++++++---------------------
fs/overlayfs/overlayfs.h | 2 +-
fs/overlayfs/super.c | 17 +++++++++++++----
include/linux/dcache.h | 22 ++++------------------
include/linux/fs.h | 2 +-
8 files changed, 43 insertions(+), 53 deletions(-)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1667,7 +1667,6 @@ void d_set_d_op(struct dentry *dentry, c
DCACHE_OP_REVALIDATE |
DCACHE_OP_WEAK_REVALIDATE |
DCACHE_OP_DELETE |
- DCACHE_OP_SELECT_INODE |
DCACHE_OP_REAL));
dentry->d_op = op;
if (!op)
@@ -1684,8 +1683,6 @@ void d_set_d_op(struct dentry *dentry, c
dentry->d_flags |= DCACHE_OP_DELETE;
if (op->d_prune)
dentry->d_flags |= DCACHE_OP_PRUNE;
- if (op->d_select_inode)
- dentry->d_flags |= DCACHE_OP_SELECT_INODE;
if (op->d_real)
dentry->d_flags |= DCACHE_OP_REAL;
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4247,7 +4247,7 @@ int vfs_rename(struct inode *old_dir, st
* Check source == target.
* On overlayfs need to look at underlying inodes.
*/
- if (vfs_select_inode(old_dentry, 0) == vfs_select_inode(new_dentry, 0))
+ if (d_inode(d_real(old_dentry)) == d_inode(d_real(new_dentry)))
return 0;
error = may_delete(old_dir, old_dentry, is_dir);
--- a/fs/open.c
+++ b/fs/open.c
@@ -831,6 +831,15 @@ char *file_path(struct file *filp, char
}
EXPORT_SYMBOL(file_path);
+static struct dentry *open_select_dentry(struct dentry *dentry,
+ unsigned int open_flags)
+{
+ if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
+ return dentry->d_op->d_real(dentry, NULL, open_flags);
+ else
+ return dentry;
+}
+
/**
* vfs_open - open the file at the given path
* @path: path to open
@@ -840,13 +849,13 @@ EXPORT_SYMBOL(file_path);
int vfs_open(const struct path *path, struct file *file,
const struct cred *cred)
{
- struct inode *inode = vfs_select_inode(path->dentry, file->f_flags);
+ struct dentry *dentry = open_select_dentry(path->dentry, file->f_flags);
- if (IS_ERR(inode))
- return PTR_ERR(inode);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
file->f_path = *path;
- return do_dentry_open(file, inode, NULL, cred);
+ return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
}
struct file *dentry_open(const struct path *path, int flags,
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -338,36 +338,25 @@ static bool ovl_open_need_copy_up(int fl
return true;
}
-struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
+int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
{
- int err;
+ int err = 0;
struct path realpath;
enum ovl_path_type type;
- if (d_is_dir(dentry))
- return d_backing_inode(dentry);
-
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
err = ovl_want_write(dentry);
- if (err)
- return ERR_PTR(err);
-
- if (file_flags & O_TRUNC)
- err = ovl_copy_up_truncate(dentry);
- else
- err = ovl_copy_up(dentry);
- ovl_drop_write(dentry);
- if (err)
- return ERR_PTR(err);
-
- ovl_path_upper(dentry, &realpath);
+ if (!err) {
+ if (file_flags & O_TRUNC)
+ err = ovl_copy_up_truncate(dentry);
+ else
+ err = ovl_copy_up(dentry);
+ ovl_drop_write(dentry);
+ }
}
- if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
- return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);
-
- return d_backing_inode(realpath.dentry);
+ return err;
}
static const struct inode_operations ovl_file_inode_operations = {
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -177,7 +177,7 @@ ssize_t ovl_getxattr(struct dentry *dent
void *value, size_t size);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
int ovl_removexattr(struct dentry *dentry, const char *name);
-struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags);
+int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
struct ovl_entry *oe);
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -295,7 +295,8 @@ static void ovl_dentry_release(struct de
}
}
-static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode)
+static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode,
+ unsigned int open_flags)
{
struct dentry *real;
@@ -305,6 +306,16 @@ static struct dentry *ovl_d_real(struct
goto bug;
}
+ if (d_is_negative(dentry))
+ return dentry;
+
+ if (open_flags) {
+ int err = ovl_open_maybe_copy_up(dentry, open_flags);
+
+ if (err)
+ return ERR_PTR(err);
+ }
+
real = ovl_dentry_upper(dentry);
if (real && (!inode || inode == d_inode(real)))
return real;
@@ -318,7 +329,7 @@ static struct dentry *ovl_d_real(struct
/* Handle recursion */
if (real->d_flags & DCACHE_OP_REAL)
- return real->d_op->d_real(real, inode);
+ return real->d_op->d_real(real, inode, open_flags);
bug:
WARN(1, "ovl_d_real(%pd4, %s:%lu\n): real dentry not found\n", dentry,
@@ -369,13 +380,11 @@ static int ovl_dentry_weak_revalidate(st
static const struct dentry_operations ovl_dentry_operations = {
.d_release = ovl_dentry_release,
- .d_select_inode = ovl_d_select_inode,
.d_real = ovl_d_real,
};
static const struct dentry_operations ovl_reval_dentry_operations = {
.d_release = ovl_dentry_release,
- .d_select_inode = ovl_d_select_inode,
.d_real = ovl_d_real,
.d_revalidate = ovl_dentry_revalidate,
.d_weak_revalidate = ovl_dentry_weak_revalidate,
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -160,8 +160,7 @@ struct dentry_operations {
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(struct dentry *, bool);
- struct inode *(*d_select_inode)(struct dentry *, unsigned);
- struct dentry *(*d_real)(struct dentry *, struct inode *);
+ struct dentry *(*d_real)(struct dentry *, struct inode *, unsigned int);
} ____cacheline_aligned;
/*
@@ -227,10 +226,8 @@ struct dentry_operations {
#define DCACHE_MAY_FREE 0x00800000
#define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */
-#define DCACHE_OP_SELECT_INODE 0x02000000 /* Unioned entry: dcache op selects inode */
-
-#define DCACHE_ENCRYPTED_WITH_KEY 0x04000000 /* dir is encrypted with a valid key */
-#define DCACHE_OP_REAL 0x08000000
+#define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */
+#define DCACHE_OP_REAL 0x04000000
extern seqlock_t rename_lock;
@@ -560,21 +557,10 @@ static inline struct dentry *d_backing_d
static inline struct dentry *d_real(struct dentry *dentry)
{
if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
- return dentry->d_op->d_real(dentry, NULL);
+ return dentry->d_op->d_real(dentry, NULL, 0);
else
return dentry;
}
-static inline struct inode *vfs_select_inode(struct dentry *dentry,
- unsigned open_flags)
-{
- struct inode *inode = d_inode(dentry);
-
- if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE))
- inode = dentry->d_op->d_select_inode(dentry, open_flags);
-
- return inode;
-}
-
#endif /* __LINUX_DCACHE_H */
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1246,7 +1246,7 @@ static inline struct dentry *file_dentry
struct dentry *dentry = file->f_path.dentry;
if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
- return dentry->d_op->d_real(dentry, file_inode(file));
+ return dentry->d_op->d_real(dentry, file_inode(file), 0);
else
return dentry;
}
Powered by blists - more mailing lists