Messages in this thread Patch in this message | | | From | ChenGuanqiao <> | Subject | [PATCH 3/3] fs: fat: add ioctl method in fat filesystem driver | Date | Wed, 17 Jan 2018 18:43:55 +0800 |
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Signed-off-by: ChenGuanqiao <chen.chenchacha@foxmail.com> --- fs/fat/file.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 insertions(+)
diff --git a/fs/fat/file.c b/fs/fat/file.c index 4724cc9ad650..a885f92df1eb 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -15,11 +15,33 @@ #include <linux/fsnotify.h> #include <linux/security.h> #include <linux/falloc.h> +#include <linux/ctype.h> #include "fat.h"
static long fat_fallocate(struct file *file, int mode, loff_t offset, loff_t len);
+static int fat_check_d_characters(char *label, unsigned long len) +{ + int i; + + for (i = 0; i < len; ++i) { + switch (label[i]) { + case 'a' ... 'z': + label[i] = __toupper(label[i]); + case 'A' ... 'Z': + case '0' ... '9': + case '_': + case 0x20: + continue; + default: + return -EINVAL; + } + } + + return 0; +} + static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) { u32 attr; @@ -121,10 +143,116 @@ static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr) return put_user(sbi->vol_id, user_attr); }
+static int fat_ioctl_get_volume_label(struct inode *inode, + u8 __user *vol_label) +{ + int err = 0; + struct buffer_head *bh; + struct msdos_dir_entry *de; + struct super_block *sb = inode->i_sb; + + inode = d_inode(sb->s_root); + inode_lock_shared(inode); + + err = fat_get_volume_label_entry(inode, &bh, &de); + if (err) + goto out; + + if (copy_to_user(vol_label, de->name, MSDOS_NAME)) + err = -EFAULT; + + brelse(bh); +out: + inode_unlock_shared(inode); + + return err; +} + +static int fat_ioctl_set_volume_label(struct file *file, + u8 __user *vol_label) +{ + int err = 0; + u8 label[MSDOS_NAME]; + struct timespec ts; + struct buffer_head *boot_bh; + struct buffer_head *vol_bh; + struct msdos_dir_entry *de; + struct fat_boot_sector *b; + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + + inode = d_inode(sb->s_root); + + if (copy_from_user(label, vol_label, sizeof(label))) { + err = -EFAULT; + goto out; + } + + err = fat_check_d_characters(label, sizeof(label)); + if (err) + goto out; + + err = mnt_want_write_file(file); + if (err) + goto out; + + down_write(&sb->s_umount); + + /* Updates root directory's vol_label */ + err = fat_get_volume_label_entry(inode, &vol_bh, &de); + ts = current_time(inode); + if (err) { + /* Create volume label entry */ + err = fat_add_volume_label_entry(inode, label, &ts); + if (err) + goto out_vol_brelse; + } else { + /* Write to root directory */ + memcpy(de->name, label, sizeof(de->name)); + inode->i_ctime = inode->i_mtime = inode->i_atime = ts; + + mark_buffer_dirty(vol_bh); + } + + /* Update sector's vol_label */ + boot_bh = sb_bread(sb, 0); + if (boot_bh == NULL) { + fat_msg(sb, KERN_ERR, + "unable to read boot sector to write volume label"); + err = -EIO; + goto out_boot_brelse; + } + + b = (struct fat_boot_sector *)boot_bh->b_data; + if (sbi->fat_bits == 32) + memcpy(b->fat32.vol_label, label, sizeof(label)); + else + memcpy(b->fat16.vol_label, label, sizeof(label)); + + mark_buffer_dirty(boot_bh); + + /* Synchronize the data together */ + err = sync_dirty_buffer(boot_bh); + if (err) + goto out_boot_brelse; + +out_boot_brelse: + brelse(boot_bh); +out_vol_brelse: + brelse(vol_bh); + + up_write(&sb->s_umount); + mnt_drop_write_file(file); +out: + return err; +} + long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); u32 __user *user_attr = (u32 __user *)arg; + u8 __user *user_vol_label = (u8 __user *)arg;
switch (cmd) { case FAT_IOCTL_GET_ATTRIBUTES: @@ -133,6 +261,10 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return fat_ioctl_set_attributes(filp, user_attr); case FAT_IOCTL_GET_VOLUME_ID: return fat_ioctl_get_volume_id(inode, user_attr); + case FAT_IOCTL_GET_VOLUME_LABEL: + return fat_ioctl_get_volume_label(inode, user_vol_label); + case FAT_IOCTL_SET_VOLUME_LABEL: + return fat_ioctl_set_volume_label(filp, user_vol_label); default: return -ENOTTY; /* Inappropriate ioctl for device */ } -- 2.11.0
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