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fat: Fix ATTR_RO in the case of (~umask & S_WUGO) == 0

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If inode->i_mode doesn't have S_WUGO, current code assumes it means
ATTR_RO.  However, if (~[ufd]mask & S_WUGO) == 0, inode->i_mode can't
hold S_WUGO. Therefore the updated directory entry will always have
ATTR_RO.

This adds fat_mode_can_hold_ro() to check it. And if inode->i_mode
can't hold, uses -i_attrs to hold ATTR_RO instead.

With this, we don't set ATTR_RO unless users change it via ioctl() if
(~[ufd]mask & S_WUGO) == 0.

And on FAT_IOCTL_GET_ATTRIBUTES path, this adds ->i_mutex to it for
not returning the partially updated attributes by FAT_IOCTL_SET_ATTRIBUTES
to userland.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
OGAWA Hirofumi
2008-11-06 12:53:54 -08:00
committed by Linus Torvalds
parent 9c0aa1b87b
commit 9183482f5d
2 changed files with 35 additions and 5 deletions
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7
fs/fat/file.c
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@@ -27,7 +27,12 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
switch (cmd) {
case FAT_IOCTL_GET_ATTRIBUTES:
{
u32 attr = fat_make_attrs(inode);
u32 attr;
mutex_lock(&inode->i_mutex);
attr = fat_make_attrs(inode);
mutex_unlock(&inode->i_mutex);
return put_user(attr, user_attr);
}
case FAT_IOCTL_SET_ATTRIBUTES: