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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2008-11-06 15:53:54 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-06 18:41:21 -0500
commit9183482f5d4a2de00f66641b974e7f351d41b675 (patch)
treecc23af150f0aab03b29704eb461dac98b6c1f0cf
parent9c0aa1b87bf541affef519eb4879ce7c5a5941ae (diff)
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>
-rw-r--r--fs/fat/fat.h33
-rw-r--r--fs/fat/file.c7
2 files changed, 35 insertions, 5 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 3b4753a024e3..313b645b8126 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)
117 return container_of(inode, struct msdos_inode_info, vfs_inode); 117 return container_of(inode, struct msdos_inode_info, vfs_inode);
118} 118}
119 119
120/*
121 * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
122 * save ATTR_RO instead of ->i_mode.
123 */
124static inline int fat_mode_can_hold_ro(struct inode *inode)
125{
126 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
127 mode_t mask;
128
129 if (S_ISDIR(inode->i_mode))
130 mask = ~sbi->options.fs_dmask;
131 else
132 mask = ~sbi->options.fs_fmask;
133
134 if (!(mask & S_IWUGO))
135 return 0;
136 return 1;
137}
138
120/* Convert attribute bits and a mask to the UNIX mode. */ 139/* Convert attribute bits and a mask to the UNIX mode. */
121static inline mode_t fat_make_mode(struct msdos_sb_info *sbi, 140static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
122 u8 attrs, mode_t mode) 141 u8 attrs, mode_t mode)
@@ -133,14 +152,20 @@ static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
133/* Return the FAT attribute byte for this inode */ 152/* Return the FAT attribute byte for this inode */
134static inline u8 fat_make_attrs(struct inode *inode) 153static inline u8 fat_make_attrs(struct inode *inode)
135{ 154{
136 return ((inode->i_mode & S_IWUGO) ? ATTR_NONE : ATTR_RO) | 155 u8 attrs = MSDOS_I(inode)->i_attrs;
137 (S_ISDIR(inode->i_mode) ? ATTR_DIR : ATTR_NONE) | 156 if (S_ISDIR(inode->i_mode))
138 MSDOS_I(inode)->i_attrs; 157 attrs |= ATTR_DIR;
158 if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
159 attrs |= ATTR_RO;
160 return attrs;
139} 161}
140 162
141static inline void fat_save_attrs(struct inode *inode, u8 attrs) 163static inline void fat_save_attrs(struct inode *inode, u8 attrs)
142{ 164{
143 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED; 165 if (fat_mode_can_hold_ro(inode))
166 MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
167 else
168 MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
144} 169}
145 170
146static inline unsigned char fat_checksum(const __u8 *name) 171static inline unsigned char fat_checksum(const __u8 *name)
diff --git a/fs/fat/file.c b/fs/fat/file.c
index f5a7e907a8fa..81b15c623803 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,
27 switch (cmd) { 27 switch (cmd) {
28 case FAT_IOCTL_GET_ATTRIBUTES: 28 case FAT_IOCTL_GET_ATTRIBUTES:
29 { 29 {
30 u32 attr = fat_make_attrs(inode); 30 u32 attr;
31
32 mutex_lock(&inode->i_mutex);
33 attr = fat_make_attrs(inode);
34 mutex_unlock(&inode->i_mutex);
35
31 return put_user(attr, user_attr); 36 return put_user(attr, user_attr);
32 } 37 }
33 case FAT_IOCTL_SET_ATTRIBUTES: 38 case FAT_IOCTL_SET_ATTRIBUTES: