[PATCH 1/5] Use existing macros for distinguishing mandatory locks

From: Pavel Emelyanov
Date: Wed Sep 12 2007 - 07:20:45 EST


The combination of S_ISGID bit set and S_IXGRP bit unset is
used to mark the inode as "mandatory lockable" and there's a
macro for this check called MANDATORY_LOCK(inode). However,
fs/locks.c and some filesystems still perform the explicit
i_mode checking.

Switch the fs/locks.c to macro making the code shorter and
more readable.

The __MANDATORY_LOCK() macro is to be used in places where
the IS_MANDLOCK() for superblock is already known to be true.

Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>

---

fs/locks.c | 14 ++++----------
include/linux/fs.h | 4 ++--
2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 291d40b..035ffda 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1488,8 +1488,8 @@ extern int locks_mandatory_area(int, str
* Candidates for mandatory locking have the setgid bit set
* but no group execute bit - an otherwise meaningless combination.
*/
-#define MANDATORY_LOCK(inode) \
- (IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+#define __MANDATORY_LOCK(ino) (((ino)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+#define MANDATORY_LOCK(inode) (IS_MANDLOCK(inode) && __MANDATORY_LOCK(inode))

static inline int locks_verify_locked(struct inode *inode)
{
diff --git a/fs/locks.c b/fs/locks.c
index 0db1a14..f90fe6d 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1112,7 +1112,7 @@ int locks_mandatory_area(int read_write,
* If we've been sleeping someone might have
* changed the permissions behind our back.
*/
- if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__MANDATORY_LOCK(inode))
continue;
}

@@ -1751,9 +1751,7 @@ int fcntl_setlk(unsigned int fd, struct
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (MANDATORY_LOCK(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
@@ -1877,9 +1875,7 @@ int fcntl_setlk64(unsigned int fd, struc
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (MANDATORY_LOCK(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
@@ -2073,9 +2069,7 @@ static void lock_get_status(char* out, s
out += sprintf(out, "%6s %s ",
(fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
(inode == NULL) ? "*NOINODE*" :
- (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ?
- "MANDATORY" : "ADVISORY ");
+ MANDATORY_LOCK(inode) ? "MANDATORY" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
if (fl->fl_type & LOCK_MAND) {
out += sprintf(out, "FLOCK MSNFS ");

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