Commit d57999e1 authored by Dave Hansen's avatar Dave Hansen Committed by Al Viro
Browse files

[PATCH] do namei_flags calculation inside open_namei() 



My end goal here is to make sure all users of may_open()
return filps.  This will ensure that we properly release
mount write counts which were taken for the filp in
may_open().

This patch moves the sys_open flags to namei flags
calculation into fs/namei.c.  We'll shortly be moving
the nameidata_to_filp() calls into namei.c, and this
gets the sys_open flags to a place where we can get
at them when we need them.

Acked-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 3925e6fc

fs/namei.c

+34 −9
Original line number Diff line number Diff line
@@ -1677,7 +1677,12 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) 
	return 0;

}



static int open_namei_create(struct nameidata *nd, struct path *path,

/*

 * Be careful about ever adding any more callers of this

 * function.  Its flags must be in the namei format, not

 * what get passed to sys_open().

 */

static int __open_namei_create(struct nameidata *nd, struct path *path,

				int flag, int mode)

{

	int error;
@@ -1695,27 +1700,47 @@ static int open_namei_create(struct nameidata *nd, struct path *path, 
	return may_open(nd, 0, flag & ~O_TRUNC);

}



/*

 * Note that while the flag value (low two bits) for sys_open means:

 *	00 - read-only

 *	01 - write-only

 *	10 - read-write

 *	11 - special

 * it is changed into

 *	00 - no permissions needed

 *	01 - read-permission

 *	10 - write-permission

 *	11 - read-write

 * for the internal routines (ie open_namei()/follow_link() etc)

 * This is more logical, and also allows the 00 "no perm needed"

 * to be used for symlinks (where the permissions are checked

 * later).

 *

*/

static inline int open_to_namei_flags(int flag)

{

	if ((flag+1) & O_ACCMODE)

		flag++;

	return flag;

}



/*

 *	open_namei()

 *

 * namei for open - this is in fact almost the whole open-routine.

 *

 * Note that the low bits of "flag" aren't the same as in the open

 * system call - they are 00 - no permissions needed

 *			  01 - read permission needed

 *			  10 - write permission needed

 *			  11 - read/write permissions needed

 * which is a lot more logical, and also allows the "no perm" needed

 * for symlinks (where the permissions are checked later).

 * system call.  See open_to_namei_flags().

 * SMP-safe

 */

int open_namei(int dfd, const char *pathname, int flag,

int open_namei(int dfd, const char *pathname, int open_flag,

		int mode, struct nameidata *nd)

{

	int acc_mode, error;

	struct path path;

	struct dentry *dir;

	int count = 0;

	int flag = open_to_namei_flags(open_flag);



	acc_mode = ACC_MODE(flag);
@@ -1776,7 +1801,7 @@ int open_namei(int dfd, const char *pathname, int flag, 


	/* Negative dentry, just create the file */

	if (!path.dentry->d_inode) {

		error = open_namei_create(nd, &path, flag, mode);

		error = __open_namei_create(nd, &path, flag, mode);

		if (error)

			goto exit;

		return 0;

fs/open.c

+2 −20
Original line number Diff line number Diff line
@@ -796,31 +796,13 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, 
	return ERR_PTR(error);

}



/*

 * Note that while the flag value (low two bits) for sys_open means:

 *	00 - read-only

 *	01 - write-only

 *	10 - read-write

 *	11 - special

 * it is changed into

 *	00 - no permissions needed

 *	01 - read-permission

 *	10 - write-permission

 *	11 - read-write

 * for the internal routines (ie open_namei()/follow_link() etc). 00 is

 * used by symlinks.

 */

static struct file *do_filp_open(int dfd, const char *filename, int flags,

				 int mode)

{

	int namei_flags, error;

	int error;

	struct nameidata nd;



	namei_flags = flags;

	if ((namei_flags+1) & O_ACCMODE)

		namei_flags++;



	error = open_namei(dfd, filename, namei_flags, mode, &nd);

	error = open_namei(dfd, filename, flags, mode, &nd);

	if (!error)

		return nameidata_to_filp(&nd, flags);