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namei: stash dfd and name into nameidata
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fewer arguments to pass around...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed May 15, 2015
1 parent 102b8af commit c8a53ee
Showing 1 changed file with 46 additions and 50 deletions.
96 changes: 46 additions & 50 deletions fs/namei.c
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Original file line number Diff line number Diff line change
Expand Up @@ -498,6 +498,8 @@ struct nameidata {
struct qstr last;
struct path root;
struct inode *inode; /* path.dentry.d_inode */
struct filename *name;
int dfd;
unsigned int flags;
unsigned seq, m_seq, root_seq;
int last_type;
Expand All @@ -512,10 +514,13 @@ struct nameidata {
} *stack, internal[EMBEDDED_LEVELS];
};

static struct nameidata *set_nameidata(struct nameidata *p)
static struct nameidata *set_nameidata(struct nameidata *p, int dfd,
struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
p->dfd = dfd;
p->name = name;
p->total_link_count = old ? old->total_link_count : 0;
current->nameidata = p;
return old;
Expand Down Expand Up @@ -1954,11 +1959,10 @@ static int link_path_walk(const char *name, struct nameidata *nd)
}
}

static const char *path_init(int dfd, const struct filename *name,
unsigned int flags, struct nameidata *nd)
static const char *path_init(struct nameidata *nd, unsigned flags)
{
int retval = 0;
const char *s = name->name;
const char *s = nd->name->name;

nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
Expand Down Expand Up @@ -1999,7 +2003,7 @@ static const char *path_init(int dfd, const struct filename *name,
path_get(&nd->root);
}
nd->path = nd->root;
} else if (dfd == AT_FDCWD) {
} else if (nd->dfd == AT_FDCWD) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
Expand All @@ -2016,7 +2020,7 @@ static const char *path_init(int dfd, const struct filename *name,
}
} else {
/* Caller must check execute permissions on the starting path component */
struct fd f = fdget_raw(dfd);
struct fd f = fdget_raw(nd->dfd);
struct dentry *dentry;

if (!f.file)
Expand Down Expand Up @@ -2082,10 +2086,9 @@ static inline int lookup_last(struct nameidata *nd)
}

/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
struct nameidata *nd, struct path *path)
static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path)
{
const char *s = path_init(dfd, name, flags, nd);
const char *s = path_init(nd, flags);
int err;

if (IS_ERR(s))
Expand Down Expand Up @@ -2120,17 +2123,16 @@ static int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct nameidata nd, *saved_nd;
if (IS_ERR(name))
return PTR_ERR(name);
saved_nd = set_nameidata(&nd);
saved_nd = set_nameidata(&nd, dfd, name);
if (unlikely(root)) {
nd.root = *root;
flags |= LOOKUP_ROOT;
}
retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, &nd, path);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(dfd, name, flags, &nd, path);
retval = path_lookupat(&nd, flags, path);
if (unlikely(retval == -ESTALE))
retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
&nd, path);
retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path);

if (likely(!retval))
audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
Expand All @@ -2140,11 +2142,10 @@ static int filename_lookup(int dfd, struct filename *name, unsigned flags,
}

/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_parentat(int dfd, const struct filename *name,
unsigned int flags, struct nameidata *nd,
static int path_parentat(struct nameidata *nd, unsigned flags,
struct path *parent)
{
const char *s = path_init(dfd, name, flags, nd);
const char *s = path_init(nd, flags);
int err;
if (IS_ERR(s))
return PTR_ERR(s);
Expand All @@ -2169,13 +2170,12 @@ static struct filename *filename_parentat(int dfd, struct filename *name,

if (IS_ERR(name))
return name;
saved_nd = set_nameidata(&nd);
retval = path_parentat(dfd, name, flags | LOOKUP_RCU, &nd, parent);
saved_nd = set_nameidata(&nd, dfd, name);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(dfd, name, flags, &nd, parent);
retval = path_parentat(&nd, flags, parent);
if (unlikely(retval == -ESTALE))
retval = path_parentat(dfd, name, flags | LOOKUP_REVAL,
&nd, parent);
retval = path_parentat(&nd, flags | LOOKUP_REVAL, parent);
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
Expand Down Expand Up @@ -2415,19 +2415,17 @@ mountpoint_last(struct nameidata *nd, struct path *path)

/**
* path_mountpoint - look up a path to be umounted
* @dfd: directory file descriptor to start walk from
* @name: full pathname to walk
* @path: pointer to container for result
* @nameidata: lookup context
* @flags: lookup flags
* @path: pointer to container for result
*
* Look up the given name, but don't attempt to revalidate the last component.
* Returns 0 and "path" will be valid on success; Returns error otherwise.
*/
static int
path_mountpoint(int dfd, const struct filename *name, struct path *path,
struct nameidata *nd, unsigned int flags)
path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path)
{
const char *s = path_init(dfd, name, flags, nd);
const char *s = path_init(nd, flags);
int err;
if (IS_ERR(s))
return PTR_ERR(s);
Expand All @@ -2451,12 +2449,12 @@ filename_mountpoint(int dfd, struct filename *name, struct path *path,
int error;
if (IS_ERR(name))
return PTR_ERR(name);
saved = set_nameidata(&nd);
error = path_mountpoint(dfd, name, path, &nd, flags | LOOKUP_RCU);
saved = set_nameidata(&nd, dfd, name);
error = path_mountpoint(&nd, flags | LOOKUP_RCU, path);
if (unlikely(error == -ECHILD))
error = path_mountpoint(dfd, name, path, &nd, flags);
error = path_mountpoint(&nd, flags, path);
if (unlikely(error == -ESTALE))
error = path_mountpoint(dfd, name, path, &nd, flags | LOOKUP_REVAL);
error = path_mountpoint(&nd, flags | LOOKUP_REVAL, path);
if (likely(!error))
audit_inode(name, path->dentry, 0);
restore_nameidata(saved);
Expand Down Expand Up @@ -3217,17 +3215,15 @@ static int do_last(struct nameidata *nd,
goto retry_lookup;
}

static int do_tmpfile(int dfd, struct filename *pathname,
struct nameidata *nd, int flags,
static int do_tmpfile(struct nameidata *nd, unsigned flags,
const struct open_flags *op,
struct file *file, int *opened)
{
static const struct qstr name = QSTR_INIT("/", 1);
struct dentry *child;
struct inode *dir;
struct path path;
int error = path_lookupat(dfd, pathname,
flags | LOOKUP_DIRECTORY, nd, &path);
int error = path_lookupat(nd, flags | LOOKUP_DIRECTORY, &path);
if (unlikely(error))
return error;
error = mnt_want_write(path.mnt);
Expand All @@ -3252,7 +3248,7 @@ static int do_tmpfile(int dfd, struct filename *pathname,
error = dir->i_op->tmpfile(dir, child, op->mode);
if (error)
goto out2;
audit_inode(pathname, child, 0);
audit_inode(nd->name, child, 0);
/* Don't check for other permissions, the inode was just created */
error = may_open(&path, MAY_OPEN, op->open_flag);
if (error)
Expand All @@ -3277,8 +3273,8 @@ static int do_tmpfile(int dfd, struct filename *pathname,
return error;
}

static struct file *path_openat(int dfd, struct filename *pathname,
struct nameidata *nd, const struct open_flags *op, int flags)
static struct file *path_openat(struct nameidata *nd,
const struct open_flags *op, unsigned flags)
{
const char *s;
struct file *file;
Expand All @@ -3292,17 +3288,17 @@ static struct file *path_openat(int dfd, struct filename *pathname,
file->f_flags = op->open_flag;

if (unlikely(file->f_flags & __O_TMPFILE)) {
error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened);
error = do_tmpfile(nd, flags, op, file, &opened);
goto out2;
}

s = path_init(dfd, pathname, flags, nd);
s = path_init(nd, flags);
if (IS_ERR(s)) {
put_filp(file);
return ERR_CAST(s);
}
while (!(error = link_path_walk(s, nd)) &&
(error = do_last(nd, file, op, &opened, pathname)) > 0) {
(error = do_last(nd, file, op, &opened, nd->name)) > 0) {
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
s = trailing_symlink(nd);
if (IS_ERR(s)) {
Expand Down Expand Up @@ -3331,15 +3327,15 @@ static struct file *path_openat(int dfd, struct filename *pathname,
struct file *do_filp_open(int dfd, struct filename *pathname,
const struct open_flags *op)
{
struct nameidata nd, *saved_nd = set_nameidata(&nd);
struct nameidata nd, *saved_nd = set_nameidata(&nd, dfd, pathname);
int flags = op->lookup_flags;
struct file *filp;

filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU);
filp = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
filp = path_openat(dfd, pathname, &nd, op, flags);
filp = path_openat(&nd, op, flags);
if (unlikely(filp == ERR_PTR(-ESTALE)))
filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL);
filp = path_openat(&nd, op, flags | LOOKUP_REVAL);
restore_nameidata(saved_nd);
return filp;
}
Expand All @@ -3362,12 +3358,12 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
if (unlikely(IS_ERR(filename)))
return ERR_CAST(filename);

saved_nd = set_nameidata(&nd);
file = path_openat(-1, filename, &nd, op, flags | LOOKUP_RCU);
saved_nd = set_nameidata(&nd, -1, filename);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(-1, filename, &nd, op, flags);
file = path_openat(&nd, op, flags);
if (unlikely(file == ERR_PTR(-ESTALE)))
file = path_openat(-1, filename, &nd, op, flags | LOOKUP_REVAL);
file = path_openat(&nd, op, flags | LOOKUP_REVAL);
restore_nameidata(saved_nd);
putname(filename);
return file;
Expand Down

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