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[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: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dave Hansen 2008-02-15 14:37:27 -08:00 committed by Al Viro
parent 3925e6fc1f
commit d57999e152
2 changed files with 36 additions and 29 deletions
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43
fs/namei.c
View File

@ -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 @@ do_last:
/* 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;

22
fs/open.c
View File

@ -796,31 +796,13 @@ cleanup_file:
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);