#include "fsmap.h"
#include <trace/events/ext4.h>
+typedef void ext4_update_sb_callback(struct ext4_super_block *es,
+ const void *arg);
+
+/*
+ * Superblock modification callback function for changing file system
+ * label
+ */
+static void ext4_sb_setlabel(struct ext4_super_block *es, const void *arg)
+{
+ /* Sanity check, this should never happen */
+ BUILD_BUG_ON(sizeof(es->s_volume_name) < EXT4_LABEL_MAX);
+
+ memcpy(es->s_volume_name, (char *)arg, EXT4_LABEL_MAX);
+}
+
+static
+int ext4_update_primary_sb(struct super_block *sb, handle_t *handle,
+ ext4_update_sb_callback func,
+ const void *arg)
+{
+ int err = 0;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct buffer_head *bh = sbi->s_sbh;
+ struct ext4_super_block *es = sbi->s_es;
+
+ trace_ext4_update_sb(sb, bh->b_blocknr, 1);
+
+ BUFFER_TRACE(bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, sb,
+ bh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto out_err;
+
+ lock_buffer(bh);
+ func(es, arg);
+ ext4_superblock_csum_set(sb);
+ unlock_buffer(bh);
+
+ if (buffer_write_io_error(bh) || !buffer_uptodate(bh)) {
+ ext4_msg(sbi->s_sb, KERN_ERR, "previous I/O error to "
+ "superblock detected");
+ clear_buffer_write_io_error(bh);
+ set_buffer_uptodate(bh);
+ }
+
+ err = ext4_handle_dirty_metadata(handle, NULL, bh);
+ if (err)
+ goto out_err;
+ err = sync_dirty_buffer(bh);
+out_err:
+ ext4_std_error(sb, err);
+ return err;
+}
+
+/*
+ * Update one backup superblock in the group 'grp' using the callback
+ * function 'func' and argument 'arg'. If the handle is NULL the
+ * modification is not journalled.
+ *
+ * Returns: 0 when no modification was done (no superblock in the group)
+ * 1 when the modification was successful
+ * <0 on error
+ */
+static int ext4_update_backup_sb(struct super_block *sb,
+ handle_t *handle, ext4_group_t grp,
+ ext4_update_sb_callback func, const void *arg)
+{
+ int err = 0;
+ ext4_fsblk_t sb_block;
+ struct buffer_head *bh;
+ unsigned long offset = 0;
+ struct ext4_super_block *es;
+
+ if (!ext4_bg_has_super(sb, grp))
+ return 0;
+
+ /*
+ * For the group 0 there is always 1k padding, so we have
+ * either adjust offset, or sb_block depending on blocksize
+ */
+ if (grp == 0) {
+ sb_block = 1 * EXT4_MIN_BLOCK_SIZE;
+ offset = do_div(sb_block, sb->s_blocksize);
+ } else {
+ sb_block = ext4_group_first_block_no(sb, grp);
+ offset = 0;
+ }
+
+ trace_ext4_update_sb(sb, sb_block, handle ? 1 : 0);
+
+ bh = ext4_sb_bread(sb, sb_block, 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
+
+ if (handle) {
+ BUFFER_TRACE(bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, sb,
+ bh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto out_bh;
+ }
+
+ es = (struct ext4_super_block *) (bh->b_data + offset);
+ lock_buffer(bh);
+ if (ext4_has_metadata_csum(sb) &&
+ es->s_checksum != ext4_superblock_csum(sb, es)) {
+ ext4_msg(sb, KERN_ERR, "Invalid checksum for backup "
+ "superblock %llu\n", sb_block);
+ unlock_buffer(bh);
+ err = -EFSBADCRC;
+ goto out_bh;
+ }
+ func(es, arg);
+ if (ext4_has_metadata_csum(sb))
+ es->s_checksum = ext4_superblock_csum(sb, es);
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+
+ if (err)
+ goto out_bh;
+
+ if (handle) {
+ err = ext4_handle_dirty_metadata(handle, NULL, bh);
+ if (err)
+ goto out_bh;
+ } else {
+ BUFFER_TRACE(bh, "marking dirty");
+ mark_buffer_dirty(bh);
+ }
+ err = sync_dirty_buffer(bh);
+
+out_bh:
+ brelse(bh);
+ ext4_std_error(sb, err);
+ return (err) ? err : 1;
+}
+
+/*
+ * Update primary and backup superblocks using the provided function
+ * func and argument arg.
+ *
+ * Only the primary superblock and at most two backup superblock
+ * modifications are journalled; the rest is modified without journal.
+ * This is safe because e2fsck will re-write them if there is a problem,
+ * and we're very unlikely to ever need more than two backups.
+ */
+static
+int ext4_update_superblocks_fn(struct super_block *sb,
+ ext4_update_sb_callback func,
+ const void *arg)
+{
+ handle_t *handle;
+ ext4_group_t ngroups;
+ unsigned int three = 1;
+ unsigned int five = 5;
+ unsigned int seven = 7;
+ int err = 0, ret, i;
+ ext4_group_t grp, primary_grp;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ /*
+ * We can't update superblocks while the online resize is running
+ */
+ if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
+ &sbi->s_ext4_flags)) {
+ ext4_msg(sb, KERN_ERR, "Can't modify superblock while"
+ "performing online resize");
+ return -EBUSY;
+ }
+
+ /*
+ * We're only going to update primary superblock and two
+ * backup superblocks in this transaction.
+ */
+ handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 3);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ goto out;
+ }
+
+ /* Update primary superblock */
+ err = ext4_update_primary_sb(sb, handle, func, arg);
+ if (err) {
+ ext4_msg(sb, KERN_ERR, "Failed to update primary "
+ "superblock");
+ goto out_journal;
+ }
+
+ primary_grp = ext4_get_group_number(sb, sbi->s_sbh->b_blocknr);
+ ngroups = ext4_get_groups_count(sb);
+
+ /*
+ * Update backup superblocks. We have to start from group 0
+ * because it might not be where the primary superblock is
+ * if the fs is mounted with -o sb=<backup_sb_block>
+ */
+ i = 0;
+ grp = 0;
+ while (grp < ngroups) {
+ /* Skip primary superblock */
+ if (grp == primary_grp)
+ goto next_grp;
+
+ ret = ext4_update_backup_sb(sb, handle, grp, func, arg);
+ if (ret < 0) {
+ /* Ignore bad checksum; try to update next sb */
+ if (ret == -EFSBADCRC)
+ goto next_grp;
+ err = ret;
+ goto out_journal;
+ }
+
+ i += ret;
+ if (handle && i > 1) {
+ /*
+ * We're only journalling primary superblock and
+ * two backup superblocks; the rest is not
+ * journalled.
+ */
+ err = ext4_journal_stop(handle);
+ if (err)
+ goto out;
+ handle = NULL;
+ }
+next_grp:
+ grp = ext4_list_backups(sb, &three, &five, &seven);
+ }
+
+out_journal:
+ if (handle) {
+ ret = ext4_journal_stop(handle);
+ if (ret && !err)
+ err = ret;
+ }
+out:
+ clear_bit_unlock(EXT4_FLAGS_RESIZING, &sbi->s_ext4_flags);
+ smp_mb__after_atomic();
+ return err ? err : 0;
+}
+
/**
* Swap memory between @a and @b for @len bytes.
*
return err;
}
+static int ext4_ioctl_setlabel(struct file *filp, const char __user *user_label)
+{
+ size_t len;
+ int ret = 0;
+ char new_label[EXT4_LABEL_MAX + 1];
+ struct super_block *sb = file_inode(filp)->i_sb;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /*
+ * Copy the maximum length allowed for ext4 label with one more to
+ * find the required terminating null byte in order to test the
+ * label length. The on disk label doesn't need to be null terminated.
+ */
+ if (copy_from_user(new_label, user_label, EXT4_LABEL_MAX + 1))
+ return -EFAULT;
+
+ len = strnlen(new_label, EXT4_LABEL_MAX + 1);
+ if (len > EXT4_LABEL_MAX)
+ return -EINVAL;
+
+ /*
+ * Clear the buffer after the new label
+ */
+ memset(new_label + len, 0, EXT4_LABEL_MAX - len);
+
+ ret = mnt_want_write_file(filp);
+ if (ret)
+ return ret;
+
+ ret = ext4_update_superblocks_fn(sb, ext4_sb_setlabel, new_label);
+
+ mnt_drop_write_file(filp);
+ return ret;
+}
+
+static int ext4_ioctl_getlabel(struct ext4_sb_info *sbi, char __user *user_label)
+{
+ char label[EXT4_LABEL_MAX + 1];
+
+ /*
+ * EXT4_LABEL_MAX must always be smaller than FSLABEL_MAX because
+ * FSLABEL_MAX must include terminating null byte, while s_volume_name
+ * does not have to.
+ */
+ BUILD_BUG_ON(EXT4_LABEL_MAX >= FSLABEL_MAX);
+
+ memset(label, 0, sizeof(label));
+ lock_buffer(sbi->s_sbh);
+ strncpy(label, sbi->s_es->s_volume_name, EXT4_LABEL_MAX);
+ unlock_buffer(sbi->s_sbh);
+
+ if (copy_to_user(user_label, label, sizeof(label)))
+ return -EFAULT;
+ return 0;
+}
+
static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
case EXT4_IOC_CHECKPOINT:
return ext4_ioctl_checkpoint(filp, arg);
+ case FS_IOC_GETFSLABEL:
+ return ext4_ioctl_getlabel(EXT4_SB(sb), (void __user *)arg);
+
+ case FS_IOC_SETFSLABEL:
+ return ext4_ioctl_setlabel(filp,
+ (const void __user *)arg);
+
default:
return -ENOTTY;
}
case EXT4_IOC_GETSTATE:
case EXT4_IOC_GET_ES_CACHE:
case EXT4_IOC_CHECKPOINT:
+ case FS_IOC_GETFSLABEL:
+ case FS_IOC_SETFSLABEL:
break;
default:
return -ENOIOCTLCMD;
projects / users / hch / dma-mapping.git / commitdiff