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| author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2008-11-06 12:53:54 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-11-06 15:41:21 -0800 |
| commit | 9183482f5d4a2de00f66641b974e7f351d41b675 (patch) | |
| tree | cc23af150f0aab03b29704eb461dac98b6c1f0cf /fs/fat | |
| parent | 9c0aa1b87bf541affef519eb4879ce7c5a5941ae (diff) | |
| download | kernel-crypto-9183482f5d4a2de00f66641b974e7f351d41b675.tar.gz kernel-crypto-9183482f5d4a2de00f66641b974e7f351d41b675.tar.xz kernel-crypto-9183482f5d4a2de00f66641b974e7f351d41b675.zip | |
fat: Fix ATTR_RO in the case of (~umask & S_WUGO) == 0
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>
Diffstat (limited to 'fs/fat')
| -rw-r--r-- | fs/fat/fat.h | 33 | ||||
| -rw-r--r-- | fs/fat/file.c | 7 |
2 files changed, 35 insertions, 5 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 3b4753a024e..313b645b812 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -117,6 +117,25 @@ static inline struct msdos_inode_info *MSDOS_I(struct inode *inode) return container_of(inode, struct msdos_inode_info, vfs_inode); } +/* + * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to + * save ATTR_RO instead of ->i_mode. + */ +static inline int fat_mode_can_hold_ro(struct inode *inode) +{ + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + mode_t mask; + + if (S_ISDIR(inode->i_mode)) + mask = ~sbi->options.fs_dmask; + else + mask = ~sbi->options.fs_fmask; + + if (!(mask & S_IWUGO)) + return 0; + return 1; +} + /* Convert attribute bits and a mask to the UNIX mode. */ static inline mode_t fat_make_mode(struct msdos_sb_info *sbi, u8 attrs, mode_t mode) @@ -133,14 +152,20 @@ static inline mode_t fat_make_mode(struct msdos_sb_info *sbi, /* Return the FAT attribute byte for this inode */ static inline u8 fat_make_attrs(struct inode *inode) { - return ((inode->i_mode & S_IWUGO) ? ATTR_NONE : ATTR_RO) | - (S_ISDIR(inode->i_mode) ? ATTR_DIR : ATTR_NONE) | - MSDOS_I(inode)->i_attrs; + u8 attrs = MSDOS_I(inode)->i_attrs; + if (S_ISDIR(inode->i_mode)) + attrs |= ATTR_DIR; + if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO)) + attrs |= ATTR_RO; + return attrs; } static inline void fat_save_attrs(struct inode *inode, u8 attrs) { - MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; + if (fat_mode_can_hold_ro(inode)) + MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; + else + MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO); } static inline unsigned char fat_checksum(const __u8 *name) diff --git a/fs/fat/file.c b/fs/fat/file.c index f5a7e907a8f..81b15c62380 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -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: |