[PATCH 15/16] vfs: remove open intents from nameidata

From: Miklos Szeredi
Date: Wed Mar 28 2012 - 16:26:06 EST

From: Miklos Szeredi <mszeredi@xxxxxxx>

All users of open intents have been converted to use ->atomic_{open,create}.

This patch gets rid of nd->intent.open and related infrastructure.

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
fs/internal.h | 5 +--
fs/namei.c | 114 ++++++++++++++++++++++---------------------------
fs/open.c | 97 +++++------------------------------------
include/linux/namei.h | 11 -----
4 files changed, 64 insertions(+), 163 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 438fbd3..f99e89a 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -84,13 +84,10 @@ extern struct super_block *user_get_super(dev_t);
/*
* open.c
*/
-struct nameidata;
-extern struct file *nameidata_to_filp(struct nameidata *);
-extern void release_open_intent(struct nameidata *);
struct opendata {
struct dentry *dentry;
struct vfsmount *mnt;
- struct file **filp;
+ struct file *filp;
};
struct open_flags {
int open_flag;
diff --git a/fs/namei.c b/fs/namei.c
index f6dfd7c..66b26da 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -476,22 +476,6 @@ err_root:
return -ECHILD;
}

-/**
- * release_open_intent - free up open intent resources
- * @nd: pointer to nameidata
- */
-void release_open_intent(struct nameidata *nd)
-{
- struct file *file = nd->intent.open.file;
-
- if (file && !IS_ERR(file)) {
- if (file->f_path.dentry == NULL)
- put_filp(file);
- else
- fput(file);
- }
-}
-
static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
return dentry->d_op->d_revalidate(dentry, nd);
@@ -2109,7 +2093,8 @@ static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode)
}

static struct file *atomic_open(struct nameidata *nd, struct dentry *dentry,
- struct path *path, const struct open_flags *op,
+ struct path *path, struct opendata *od,
+ const struct open_flags *op,
int *want_write, bool need_lookup)
{
struct inode *dir = nd->path.dentry->d_inode;
@@ -2118,7 +2103,6 @@ static struct file *atomic_open(struct nameidata *nd, struct dentry *dentry,
int error;
bool created = false;
int acc_mode;
- struct opendata od;
struct file *filp;
int create_error = 0;
struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
@@ -2184,14 +2168,13 @@ static struct file *atomic_open(struct nameidata *nd, struct dentry *dentry,
if (nd->flags & LOOKUP_DIRECTORY)
open_flag |= O_DIRECTORY;

- od.dentry = DENTRY_NOT_SET;
- od.mnt = nd->path.mnt;
- od.filp = &nd->intent.open.file;
- filp = dir->i_op->atomic_open(dir, dentry, &od, open_flag, mode,
+ od->dentry = DENTRY_NOT_SET;
+ od->mnt = nd->path.mnt;
+ filp = dir->i_op->atomic_open(dir, dentry, od, open_flag, mode,
&created);
if (IS_ERR(filp)) {
- if (WARN_ON(od.dentry != DENTRY_NOT_SET))
- dput(od.dentry);
+ if (WARN_ON(od->dentry != DENTRY_NOT_SET))
+ dput(od->dentry);

if (create_error && PTR_ERR(filp) == -ENOENT)
filp = ERR_PTR(create_error);
@@ -2205,13 +2188,13 @@ static struct file *atomic_open(struct nameidata *nd, struct dentry *dentry,
}

if (!filp) {
- if (WARN_ON(od.dentry == DENTRY_NOT_SET)) {
+ if (WARN_ON(od->dentry == DENTRY_NOT_SET)) {
filp = ERR_PTR(-EIO);
goto out;
}
- if (od.dentry) {
+ if (od->dentry) {
dput(dentry);
- dentry = od.dentry;
+ dentry = od->dentry;
}
goto looked_up;
}
@@ -2271,6 +2254,7 @@ looked_up:
* was performed, only lookup.
*/
static struct file *lookup_open(struct nameidata *nd, struct path *path,
+ struct opendata *od,
const struct open_flags *op, int *want_write)
{
struct dentry *dir = nd->path.dentry;
@@ -2287,7 +2271,7 @@ static struct file *lookup_open(struct nameidata *nd, struct path *path,
goto out_no_open;

if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) {
- return atomic_open(nd, dentry, path, op, want_write,
+ return atomic_open(nd, dentry, path, od, op, want_write,
need_lookup);
}

@@ -2309,7 +2293,8 @@ out_no_open:
* Handle the last step of open()
*/
static struct file *do_last(struct nameidata *nd, struct path *path,
- const struct open_flags *op, const char *pathname)
+ struct opendata *od, const struct open_flags *op,
+ const char *pathname)
{
struct dentry *dir = nd->path.dentry;
struct dentry *dentry;
@@ -2385,7 +2370,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,

mutex_lock(&dir->d_inode->i_mutex);

- filp = lookup_open(nd, path, op, &want_write);
+ filp = lookup_open(nd, path, od, op, &want_write);
if (filp) {
mutex_unlock(&dir->d_inode->i_mutex);
if (IS_ERR(filp))
@@ -2411,7 +2396,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
* rw->ro transition does not occur between
* the time when the file is created and when
* a permanent write count is taken through
- * the 'struct file' in nameidata_to_filp().
+ * the 'struct file' in finish_open().
*/
if (!want_write) {
error = mnt_want_write(nd->path.mnt);
@@ -2505,23 +2490,22 @@ common:
error = may_open(&nd->path, acc_mode, open_flag);
if (error)
goto exit;
- filp = nameidata_to_filp(nd);
+ od->mnt = nd->path.mnt;
+ filp = finish_open(od, nd->path.dentry, NULL);
+ if (IS_ERR(filp))
+ goto out;
+ error = open_check_o_direct(filp);
+ if (error)
+ goto exit_fput;
opened:
- if (!IS_ERR(filp)) {
- error = ima_file_check(filp, op->acc_mode);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
- if (!IS_ERR(filp)) {
- if (will_truncate) {
- error = handle_truncate(filp);
- if (error) {
- fput(filp);
- filp = ERR_PTR(error);
- }
- }
+ error = ima_file_check(filp, op->acc_mode);
+ if (error)
+ goto exit_fput;
+
+ if (will_truncate) {
+ error = handle_truncate(filp);
+ if (error)
+ goto exit_fput;
}
out:
if (want_write)
@@ -2537,6 +2521,10 @@ exit:
filp = ERR_PTR(error);
goto out;

+exit_fput:
+ fput(filp);
+ goto exit;
+
terminate:
terminate_walk(nd);
return ERR_PTR(error);
@@ -2546,18 +2534,16 @@ static struct file *path_openat(int dfd, const char *pathname,
struct nameidata *nd, const struct open_flags *op, int flags)
{
struct file *base = NULL;
- struct file *filp;
+ struct opendata od;
+ struct file *res;
struct path path;
int error;

- filp = get_empty_filp();
- if (!filp)
+ od.filp = get_empty_filp();
+ if (!od.filp)
return ERR_PTR(-ENFILE);

- filp->f_flags = op->open_flag;
- nd->intent.open.file = filp;
- nd->intent.open.flags = open_to_namei_flags(op->open_flag);
- nd->intent.open.create_mode = op->mode;
+ od.filp->f_flags = op->open_flag;

error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
if (unlikely(error))
@@ -2568,23 +2554,23 @@ static struct file *path_openat(int dfd, const char *pathname,
if (unlikely(error))
goto out_filp;

- filp = do_last(nd, &path, op, pathname);
- while (unlikely(!filp)) { /* trailing symlink */
+ res = do_last(nd, &path, &od, op, pathname);
+ while (unlikely(!res)) { /* trailing symlink */
struct path link = path;
void *cookie;
if (!(nd->flags & LOOKUP_FOLLOW)) {
path_put_conditional(&path, nd);
path_put(&nd->path);
- filp = ERR_PTR(-ELOOP);
+ res = ERR_PTR(-ELOOP);
break;
}
nd->flags |= LOOKUP_PARENT;
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
error = follow_link(&link, nd, &cookie);
if (unlikely(error))
- filp = ERR_PTR(error);
+ res = ERR_PTR(error);
else
- filp = do_last(nd, &path, op, pathname);
+ res = do_last(nd, &path, &od, op, pathname);
put_link(nd, &link, cookie);
}
out:
@@ -2592,11 +2578,14 @@ out:
path_put(&nd->root);
if (base)
fput(base);
- release_open_intent(nd);
- return filp;
+ if (od.filp) {
+ BUG_ON(od.filp->f_path.dentry);
+ put_filp(od.filp);
+ }
+ return res;

out_filp:
- filp = ERR_PTR(error);
+ res = ERR_PTR(error);
goto out;
}

@@ -2652,7 +2641,6 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path
goto out;
nd.flags &= ~LOOKUP_PARENT;
nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL;
- nd.intent.open.flags = O_EXCL;

/*
* Do the final lookup.
diff --git a/fs/open.c b/fs/open.c
index cd73de1..a18e6bc 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -743,62 +743,6 @@ cleanup_file:
return ERR_PTR(error);
}

-static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
- struct file *f,
- int (*open)(struct inode *, struct file *),
- const struct cred *cred)
-{
- struct file *res = do_dentry_open(dentry, mnt, f, open, cred);
- if (!IS_ERR(res)) {
- int error = open_check_o_direct(f);
- if (error) {
- fput(res);
- res = ERR_PTR(error);
- }
- }
- return res;
-}
-
-/**
- * lookup_instantiate_filp - instantiates the open intent filp
- * @nd: pointer to nameidata
- * @dentry: pointer to dentry
- * @open: open callback
- *
- * Helper for filesystems that want to use lookup open intents and pass back
- * a fully instantiated struct file to the caller.
- * This function is meant to be called from within a filesystem's
- * lookup method.
- * Beware of calling it for non-regular files! Those ->open methods might block
- * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
- * leading to a deadlock, as nobody can open that fifo anymore, because
- * another process to open fifo will block on locked parent when doing lookup).
- * Note that in case of error, nd->intent.open.file is destroyed, but the
- * path information remains valid.
- * If the open callback is set to NULL, then the standard f_op->open()
- * filesystem callback is substituted.
- */
-struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
- int (*open)(struct inode *, struct file *))
-{
- const struct cred *cred = current_cred();
-
- if (IS_ERR(nd->intent.open.file))
- goto out;
- if (IS_ERR(dentry))
- goto out_err;
- nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
- nd->intent.open.file,
- open, cred);
-out:
- return nd->intent.open.file;
-out_err:
- release_open_intent(nd);
- nd->intent.open.file = ERR_CAST(dentry);
- goto out;
-}
-EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
-
/**
* finish_open - finish opening a file
* @od: opaque open data
@@ -815,8 +759,8 @@ struct file *finish_open(struct opendata *od, struct dentry *dentry,
{
struct file *filp;

- filp = *(od->filp);
- *(od->filp) = NULL;
+ filp = od->filp;
+ od->filp = NULL;

mntget(od->mnt);
dget(dentry);
@@ -840,31 +784,6 @@ void finish_no_open(struct opendata *od, struct dentry *dentry)
}
EXPORT_SYMBOL(finish_no_open);

-/**
- * nameidata_to_filp - convert a nameidata to an open filp.
- * @nd: pointer to nameidata
- * @flags: open flags
- *
- * Note that this function destroys the original nameidata
- */
-struct file *nameidata_to_filp(struct nameidata *nd)
-{
- const struct cred *cred = current_cred();
- struct file *filp;
-
- /* Pick up the filp from the open intent */
- filp = nd->intent.open.file;
- nd->intent.open.file = NULL;
-
- /* Has the filesystem initialised the file for us? */
- if (filp->f_path.dentry == NULL) {
- path_get(&nd->path);
- filp = __dentry_open(nd->path.dentry, nd->path.mnt, filp,
- NULL, cred);
- }
- return filp;
-}
-
/*
* dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
* error.
@@ -873,7 +792,7 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
const struct cred *cred)
{
int error;
- struct file *f;
+ struct file *f, *res;

validate_creds(cred);

@@ -889,7 +808,15 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
}

f->f_flags = flags;
- return __dentry_open(dentry, mnt, f, NULL, cred);
+ res = do_dentry_open(dentry, mnt, f, NULL, cred);
+ if (!IS_ERR(res)) {
+ int error = open_check_o_direct(f);
+ if (error) {
+ fput(res);
+ res = ERR_PTR(error);
+ }
+ }
+ return res;
}
EXPORT_SYMBOL(dentry_open);

diff --git a/include/linux/namei.h b/include/linux/namei.h
index ffc0213..54dadda 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -7,12 +7,6 @@

struct vfsmount;

-struct open_intent {
- int flags;
- int create_mode;
- struct file *file;
-};
-
enum { MAX_NESTED_LINKS = 8 };

struct nameidata {
@@ -25,11 +19,6 @@ struct nameidata {
int last_type;
unsigned depth;
char *saved_names[MAX_NESTED_LINKS + 1];
-
- /* Intent data */
- union {
- struct open_intent open;
- } intent;
};

/*
--
1.7.7

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