[PATCH v7 17/49] vfs: make path_openat take a getname_info pointer

Jeff Layton
2012-10-02T00:17:30Z

...and fix up the callers. For do_file_open_root, just declare a
getname_info on the stack and fill out the .name field. For
do_filp_open, make it also take a getname_info pointer, and fix up its
callers to call it appropriately.

For filp_open, add a variant that takes a getname_info pointer and turn
filp_open into a wrapper around it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/exec.c | 5 +++--
fs/internal.h | 4 ++--
fs/namei.c | 28 +++++++++++++++-------------
fs/open.c | 33 +++++++++++++++++++++++++++++----
include/linux/fs.h | 1 +
kernel/acct.c | 6 +++---
mm/swapfile.c | 4 ++--
7 files changed, 55 insertions(+), 26 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 222e282..77ea602 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -126,7 +126,7 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
if (IS_ERR(tmp))
goto out;

- file = do_filp_open(AT_FDCWD, tmp->name, &uselib_flags, LOOKUP_FOLLOW);
+ file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW);
putname(tmp);
error = PTR_ERR(file);
if (IS_ERR(file))
@@ -761,13 +761,14 @@ struct file *open_exec(const char *name)
{
struct file *file;
int err;
+ struct getname_info tmp = { .name = name };
static const struct open_flags open_exec_flags = {
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
.acc_mode = MAY_EXEC | MAY_OPEN,
.intent = LOOKUP_OPEN
};

- file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW);
+ file = do_filp_open(AT_FDCWD, &tmp, &open_exec_flags, LOOKUP_FOLLOW);
if (IS_ERR(file))
goto out;

diff --git a/fs/internal.h b/fs/internal.h
index 371bcc4..ddc0d2c 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -97,8 +97,8 @@ struct open_flags {
int acc_mode;
int intent;
};
-extern struct file *do_filp_open(int dfd, const char *pathname,
- const struct open_flags *op, int lookup_flags);
+extern struct file *do_filp_open(int dfd, struct getname_info *ginfo,
+ const struct open_flags *op, int flags);
extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
const char *, const struct open_flags *, int lookup_flags);

diff --git a/fs/namei.c b/fs/namei.c
index 5e31fbb..048373c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2667,7 +2667,7 @@ out_dput:
*/
static int do_last(struct nameidata *nd, struct path *path,
struct file *file, const struct open_flags *op,
- int *opened, const char *pathname)
+ int *opened, struct getname_info *ginfo)
{
struct dentry *dir = nd->path.dentry;
int open_flag = op->open_flag;
@@ -2679,6 +2679,7 @@ static int do_last(struct nameidata *nd, struct path *path,
struct path save_parent = { .dentry = NULL, .mnt = NULL };
bool retried = false;
int error;
+ const char *pathname = ginfo->name;

nd->flags &= ~LOOKUP_PARENT;
nd->flags |= op->intent;
@@ -2913,7 +2914,7 @@ stale_open:
goto retry_lookup;
}

-static struct file *path_openat(int dfd, const char *pathname,
+static struct file *path_openat(int dfd, struct getname_info *ginfo,
struct nameidata *nd, const struct open_flags *op, int flags)
{
struct file *base = NULL;
@@ -2928,16 +2929,16 @@ static struct file *path_openat(int dfd, const char *pathname,

file->f_flags = op->open_flag;

- error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
+ error = path_init(dfd, ginfo->name, flags | LOOKUP_PARENT, nd, &base);
if (unlikely(error))
goto out;

current->total_link_count = 0;
- error = link_path_walk(pathname, nd);
+ error = link_path_walk(ginfo->name, nd);
if (unlikely(error))
goto out;

- error = do_last(nd, &path, file, op, &opened, pathname);
+ error = do_last(nd, &path, file, op, &opened, ginfo);
while (unlikely(error > 0)) { /* trailing symlink */
struct path link = path;
void *cookie;
@@ -2955,7 +2956,7 @@ static struct file *path_openat(int dfd, const char *pathname,
error = follow_link(&link, nd, &cookie);
if (unlikely(error))
break;
- error = do_last(nd, &path, file, op, &opened, pathname);
+ error = do_last(nd, &path, file, op, &opened, ginfo);
put_link(nd, &link, cookie);
}
out:
@@ -2979,17 +2980,17 @@ out:
return file;
}

-struct file *do_filp_open(int dfd, const char *pathname,
+struct file *do_filp_open(int dfd, struct getname_info *ginfo,
const struct open_flags *op, int flags)
{
struct nameidata nd;
struct file *filp;

- filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU);
+ filp = path_openat(dfd, ginfo, &nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
- filp = path_openat(dfd, pathname, &nd, op, flags);
+ filp = path_openat(dfd, ginfo, &nd, op, flags);
if (unlikely(filp == ERR_PTR(-ESTALE)))
- filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL);
+ filp = path_openat(dfd, ginfo, &nd, op, flags | LOOKUP_REVAL);
return filp;
}

@@ -2998,6 +2999,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
{
struct nameidata nd;
struct file *file;
+ struct getname_info ginfo = { .name = name };

nd.root.mnt = mnt;
nd.root.dentry = dentry;
@@ -3007,11 +3009,11 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
return ERR_PTR(-ELOOP);

- file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU);
+ file = path_openat(-1, &ginfo, &nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
- file = path_openat(-1, name, &nd, op, flags);
+ file = path_openat(-1, &ginfo, &nd, op, flags);
if (unlikely(file == ERR_PTR(-ESTALE)))
- file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL);
+ file = path_openat(-1, &ginfo, &nd, op, flags | LOOKUP_REVAL);
return file;
}

diff --git a/fs/open.c b/fs/open.c
index 3796d0c..d0f225e 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -909,6 +909,24 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
}

/**
+ * filp_open_ginfo - open file and return file pointer
+ *
+ * @ginfo: getname_info containing path to open
+ * @flags: open flags as per the open(2) second argument
+ * @mode: mode for the new file if O_CREAT is set, else ignored
+ *
+ * This is the helper to open a file from kernelspace if you really
+ * have to. But in generally you should not do this, so please move
+ * along, nothing to see here..
+ */
+struct file *filp_open_ginfo(struct getname_info *ginfo, int flags, umode_t mode)
+{
+ struct open_flags op;
+ int lookup = build_open_flags(flags, mode, &op);
+ return do_filp_open(AT_FDCWD, ginfo, &op, lookup);
+}
+
+/**
* filp_open - open file and return file pointer
*
* @filename: path to open
@@ -921,9 +939,16 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
*/
struct file *filp_open(const char *filename, int flags, umode_t mode)
{
- struct open_flags op;
- int lookup = build_open_flags(flags, mode, &op);
- return do_filp_open(AT_FDCWD, filename, &op, lookup);
+ struct file *filp;
+ struct getname_info *ginfo = kzalloc(sizeof(*ginfo), GFP_KERNEL);
+
+ if (!ginfo)
+ return ERR_PTR(-ENOMEM);
+
+ ginfo->name = filename;
+ filp = filp_open_ginfo(ginfo, flags, mode);
+ putname(ginfo);
+ return filp;
}
EXPORT_SYMBOL(filp_open);

@@ -951,7 +976,7 @@ long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
if (!IS_ERR(tmp)) {
fd = get_unused_fd_flags(flags);
if (fd >= 0) {
- struct file *f = do_filp_open(dfd, tmp->name, &op, lookup);
+ struct file *f = do_filp_open(dfd, tmp, &op, lookup);
if (IS_ERR(f)) {
put_unused_fd(fd);
fd = PTR_ERR(f);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1b0d0fb..a37b0c1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2200,6 +2200,7 @@ extern int do_fallocate(struct file *file, int mode, loff_t offset,
loff_t len);
extern long do_sys_open(int dfd, const char __user *filename, int flags,
umode_t mode);
+extern struct file *filp_open_ginfo(struct getname_info *, int, umode_t);
extern struct file *filp_open(const char *, int, umode_t);
extern struct file *file_open_root(struct dentry *, struct vfsmount *,
const char *, int);
diff --git a/kernel/acct.c b/kernel/acct.c
index 3943608..a6b3e14 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -193,7 +193,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
}
}

-static int acct_on(const char *name)
+static int acct_on(struct getname_info *pathname)
{
struct file *file;
struct vfsmount *mnt;
@@ -201,7 +201,7 @@ static int acct_on(const char *name)
struct bsd_acct_struct *acct = NULL;

/* Difference from BSD - they don't do O_APPEND */
- file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
+ file = filp_open_ginfo(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
if (IS_ERR(file))
return PTR_ERR(file);

@@ -263,7 +263,7 @@ SYSCALL_DEFINE1(acct, const char __user *, name)
struct getname_info *tmp = getname(name);
if (IS_ERR(tmp))
return (PTR_ERR(tmp));
- error = acct_on(tmp->name);
+ error = acct_on(tmp);
putname(tmp);
} else {
struct bsd_acct_struct *acct;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8dbf46d..0f8b1a4 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1498,7 +1498,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
if (IS_ERR(pathname))
goto out;

- victim = filp_open(pathname->name, O_RDWR|O_LARGEFILE, 0);
+ victim = filp_open_ginfo(pathname, O_RDWR|O_LARGEFILE, 0);
err = PTR_ERR(victim);
if (IS_ERR(victim))
goto out;
@@ -1966,7 +1966,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
name = NULL;
goto bad_swap;
}
- swap_file = filp_open(name->name, O_RDWR|O_LARGEFILE, 0);
+ swap_file = filp_open_ginfo(name, O_RDWR|O_LARGEFILE, 0);
if (IS_ERR(swap_file)) {
error = PTR_ERR(swap_file);
swap_file = NULL;
--
1.7.11.4