[PATCH] get/set FAT filesystem attribute bits

From: H. Peter Anvin
Date: Mon Jan 03 2005 - 15:59:24 EST

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This patch adds a set of ioctls to get and set the FAT filesystem native attribute bits, including the unused bits (6 and 7.)

It also includes some very minor code cleanups; mostly by macroizing a few idioms.

-hpa

Signed-Off-By: H. Peter Anvin <hpa@xxxxxxxxx> Index: linux-2.5/fs/fat/dir.c
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/fs/fat/dir.c,v
retrieving revision 1.28
diff -u -r1.28 dir.c
--- linux-2.5/fs/fat/dir.c 1 Nov 2004 00:18:37 -0000 1.28
+++ linux-2.5/fs/fat/dir.c 3 Jan 2005 15:06:16 -0000
@@ -663,7 +663,7 @@
both = 1;
break;
default:
- return -EINVAL;
+ return fat_generic_ioctl(inode, filp, cmd, arg);
}

d1 = (struct dirent __user *)arg;
Index: linux-2.5/fs/fat/file.c
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/fs/fat/file.c,v
retrieving revision 1.26
diff -u -r1.26 file.c
--- linux-2.5/fs/fat/file.c 24 Aug 2004 18:43:21 -0000 1.26
+++ linux-2.5/fs/fat/file.c 3 Jan 2005 15:06:41 -0000
@@ -19,6 +19,7 @@
.read = generic_file_read,
.write = fat_file_write,
.mmap = generic_file_mmap,
+ .ioctl = fat_generic_ioctl,
.fsync = file_fsync,
.readv = generic_file_readv,
.writev = generic_file_writev,
Index: linux-2.5/fs/fat/inode.c
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/fs/fat/inode.c,v
retrieving revision 1.108
diff -u -r1.108 inode.c
--- linux-2.5/fs/fat/inode.c 20 Oct 2004 15:16:56 -0000 1.108
+++ linux-2.5/fs/fat/inode.c 3 Jan 2005 20:50:25 -0000
@@ -562,7 +562,6 @@
MSDOS_I(inode)->i_attrs = 0;
inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
- MSDOS_I(inode)->i_ctime_ms = 0;
inode->i_nlink = fat_subdirs(inode)+2;

return 0;
@@ -1218,8 +1217,7 @@
MSDOS_SB(sb)->options.isvfat
? date_dos2unix(le16_to_cpu(de->ctime), le16_to_cpu(de->cdate))
: inode->i_mtime.tv_sec;
- inode->i_ctime.tv_nsec = de->ctime_ms * 1000000;
- MSDOS_I(inode)->i_ctime_ms = de->ctime_ms;
+ inode->i_ctime.tv_nsec = de->ctime_ms * 1000000U;

return 0;
}
@@ -1255,21 +1253,18 @@
raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
[i_pos & (sbi->dir_per_block - 1)];
if (S_ISDIR(inode->i_mode)) {
- raw_entry->attr = ATTR_DIR;
raw_entry->size = 0;
}
else {
- raw_entry->attr = ATTR_NONE;
raw_entry->size = cpu_to_le32(inode->i_size);
}
- raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
- MSDOS_I(inode)->i_attrs;
+ raw_entry->attr = msdos_attr(inode);
raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
if (sbi->options.isvfat) {
fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
- raw_entry->ctime_ms = MSDOS_I(inode)->i_ctime_ms; /* use i_ctime.tv_nsec? */
+ raw_entry->ctime_ms = inode->i_ctime.tv_nsec / 1000000U;
}
spin_unlock(&sbi->inode_hash_lock);
mark_buffer_dirty(bh);
@@ -1328,4 +1323,105 @@
unlock_kernel();
return error;
}
+
+int fat_generic_ioctl(struct inode * inode, struct file * filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ switch (cmd) {
+ case FAT_IOCTL_GET_ATTRIBUTES:
+ {
+ u8 attr;
+
+ /* msdos_attr() isn't atomic */
+ down(&inode->i_sem);
+
+ if ( inode->i_ino == MSDOS_ROOT_INO )
+ attr = ATTR_DIR;
+ else
+ attr = msdos_attr(inode);
+
+ up(&inode->i_sem);
+
+ return put_user(attr, (u8 __user *)arg);
+ }
+ case FAT_IOCTL_SET_ATTRIBUTES:
+ {
+ u8 attr, oldattr;
+ int err;
+ int is_dir;
+ struct iattr ia;
+
+ if ( (err = get_user(attr, (u8 __user *)arg)) )
+ return err;
+
+ if (IS_RDONLY(inode))
+ return -EROFS;
+
+ /* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
+ prevents the user from turning us into a VFAT
+ longname entry. */
+ attr &= ~(ATTR_VOLUME|ATTR_DIR);
+
+ down(&inode->i_sem);
+
+ /* This is equivalent to an fchmod */
+ ia.ia_valid = ATTR_MODE|ATTR_CTIME;
+ ia.ia_ctime = CURRENT_TIME;
+
+ is_dir = S_ISDIR(inode->i_mode);
+
+ /* Merge in ATTR_VOLUME and ATTR_DIR */
+ attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
+ (is_dir ? ATTR_DIR : 0);
+
+ if (is_dir) {
+ ia.ia_mode = MSDOS_MKMODE(attr,
+ S_IRWXUGO & ~sbi->options.fs_dmask)
+ | S_IFDIR;
+ } else {
+ ia.ia_mode = MSDOS_MKMODE(attr,
+ (S_IRUGO|S_IWUGO|(inode->i_mode & S_IXUGO))
+ & ~sbi->options.fs_fmask)
+ | S_IFREG;
+ }
+
+ if ( (err = inode_change_ok(inode, &ia)) )
+ goto out;
+
+ /* The root directory has no attributes */
+ if ( inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR ) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ oldattr = msdos_attr(inode);
+ if (sbi->options.sys_immutable) {
+ if ((attr^oldattr) & ATTR_SYS) {
+ if (!capable(CAP_LINUX_IMMUTABLE)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ if ( attr & ATTR_SYS )
+ inode->i_flags |= S_IMMUTABLE;
+ else
+ inode->i_flags &= S_IMMUTABLE;
+ }
+ }
+
+ MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
+
+ err = inode_setattr(inode, &ia);
+ out:
+ up(&inode->i_sem);
+ return err;
+ }
+ default:
+ return -ENOTTY; /* Inappropriate ioctl for device */
+ }
+}
+
MODULE_LICENSE("GPL");
Index: linux-2.5/include/linux/compat_ioctl.h
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/include/linux/compat_ioctl.h,v
retrieving revision 1.35
diff -u -r1.35 compat_ioctl.h
--- linux-2.5/include/linux/compat_ioctl.h 16 Nov 2004 04:09:40 -0000 1.35
+++ linux-2.5/include/linux/compat_ioctl.h 3 Jan 2005 19:15:21 -0000
@@ -571,6 +571,9 @@
COMPATIBLE_IOCTL(DEVFSDIOC_SET_EVENT_MASK)
COMPATIBLE_IOCTL(DEVFSDIOC_RELEASE_EVENT_QUEUE)
COMPATIBLE_IOCTL(DEVFSDIOC_SET_DEBUG_MASK)
+/* FAT */
+COMPATIBLE_IOCTL(FAT_IOCTL_GET_ATTRIBUTES)
+COMPATIBLE_IOCTL(FAT_IOCTL_SET_ATTRIBUTES)
/* Raw devices */
COMPATIBLE_IOCTL(RAW_SETBIND)
COMPATIBLE_IOCTL(RAW_GETBIND)
Index: linux-2.5/include/linux/msdos_fs.h
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/include/linux/msdos_fs.h,v
retrieving revision 1.41
diff -u -r1.41 msdos_fs.h
--- linux-2.5/include/linux/msdos_fs.h 20 Oct 2004 15:16:45 -0000 1.41
+++ linux-2.5/include/linux/msdos_fs.h 3 Jan 2005 20:35:36 -0000
@@ -95,6 +95,9 @@
*/
#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct dirent [2])
#define VFAT_IOCTL_READDIR_SHORT _IOR('r', 2, struct dirent [2])
+/* Badness: 1..6 conflict with linux/videotext.h, despite ioctl-numbers.txt */
+#define FAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u8)
+#define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u8)

/*
* vfat shortname flags
@@ -202,6 +205,13 @@
return container_of(inode, struct msdos_inode_info, vfs_inode);
}

+static inline u8 msdos_attr(struct inode *inode)
+{
+ return MSDOS_MKATTR(inode->i_mode) |
+ MSDOS_I(inode)->i_attrs |
+ (S_ISDIR(inode->i_mode) ? ATTR_DIR : 0);
+}
+
static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
{
#ifdef __BIG_ENDIAN
@@ -267,6 +277,8 @@
int fat_fill_super(struct super_block *sb, void *data, int silent,
struct inode_operations *fs_dir_inode_ops, int isvfat);
extern int fat_notify_change(struct dentry * dentry, struct iattr * attr);
+extern int fat_generic_ioctl(struct inode * inode, struct file * filp,
+ unsigned int cmd, unsigned long arg);

/* fat/misc.c */
extern void fat_fs_panic(struct super_block *s, const char *fmt, ...);
Index: linux-2.5/include/linux/msdos_fs_i.h
===================================================================
RCS file: /home/hpa/kernel/bkcvs/linux-2.5/include/linux/msdos_fs_i.h,v
retrieving revision 1.11
diff -u -r1.11 msdos_fs_i.h
--- linux-2.5/include/linux/msdos_fs_i.h 20 Oct 2004 15:15:45 -0000 1.11
+++ linux-2.5/include/linux/msdos_fs_i.h 3 Jan 2005 20:37:05 -0000
@@ -20,7 +20,6 @@
int i_start; /* first cluster or 0 */
int i_logstart; /* logical first cluster */
int i_attrs; /* unused attribute bits */
- int i_ctime_ms; /* unused change time in milliseconds */
loff_t i_pos; /* on-disk position of directory entry or 0 */
struct hlist_node i_fat_hash; /* hash by i_location */
struct inode vfs_inode;

Next message: Peter Osterlund: "[PATCH] pktcdvd: make two functions static"
Previous message: Andreas Dilger: "Re: Ticket #1851 - PATCH (take 2) for adm1026.c, kernel 2.6.10-bk6"
Next in thread: Nicholas Miell: "Re: [PATCH] get/set FAT filesystem attribute bits"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]