> Before this commit, VolumeDirty will be cleared first in writeback if
> 'dirsync' or 'sync' is not enabled. If the power is suddenly cut off
> after cleaning VolumeDirty but other updates are not written, the exFAT filesystem will not be able to detect the power failure in the next mount.
>
> And VolumeDirty will be set again but not cleared when updating the
> parent directory. It means that BootSector will be written at least once in each write-back, which will shorten the life of the device.
>
> Reviewed-by: Andy Wu <Andy.Wu@xxxxxxxx>
> Reviewed-by: Aoyama Wataru <wataru.aoyama@xxxxxxxx>
> Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
> ---
>
> Changes for v2:
> - Clear VolumeDirty until sync or umount is run
>
> Changes for v3:
> - Add REQ_FUA and REQ_PREFLUSH to guarantee strict write ordering
>
> fs/exfat/file.c | 2 --
> fs/exfat/namei.c | 5 -----
> fs/exfat/super.c | 10 ++--------
> 3 files changed, 2 insertions(+), 15 deletions(-)
>
> diff --git a/fs/exfat/file.c b/fs/exfat/file.c index
> d890fd34bb2d..2f5130059236 100644
> --- a/fs/exfat/file.c
> +++ b/fs/exfat/file.c
> @@ -218,8 +218,6 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
> if (exfat_free_cluster(inode, &clu))
> return -EIO;
>
> - exfat_clear_volume_dirty(sb);
> -
> return 0;
> }
>
> diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c index
> af4eb39cc0c3..39c9bdd6b6aa 100644
> --- a/fs/exfat/namei.c
> +++ b/fs/exfat/namei.c
> @@ -554,7 +554,6 @@ static int exfat_create(struct user_namespace *mnt_userns, struct inode *dir,
> exfat_set_volume_dirty(sb);
> err = exfat_add_entry(dir, dentry->d_name.name, &cdir, TYPE_FILE,
> &info);
> - exfat_clear_volume_dirty(sb);
> if (err)
> goto unlock;
>
> @@ -812,7 +811,6 @@ static int exfat_unlink(struct inode *dir, struct
> dentry *dentry)
>
> /* This doesn't modify ei */
> ei->dir.dir = DIR_DELETED;
> - exfat_clear_volume_dirty(sb);
>
> inode_inc_iversion(dir);
> dir->i_mtime = dir->i_atime = current_time(dir); @@ -846,7 +844,6 @@
> static int exfat_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
> exfat_set_volume_dirty(sb);
> err = exfat_add_entry(dir, dentry->d_name.name, &cdir, TYPE_DIR,
> &info);
> - exfat_clear_volume_dirty(sb);
> if (err)
> goto unlock;
>
> @@ -976,7 +973,6 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
> goto unlock;
> }
> ei->dir.dir = DIR_DELETED;
> - exfat_clear_volume_dirty(sb);
>
> inode_inc_iversion(dir);
> dir->i_mtime = dir->i_atime = current_time(dir); @@ -1311,7 +1307,6
> @@ static int __exfat_rename(struct inode *old_parent_inode,
> */
> new_ei->dir.dir = DIR_DELETED;
> }
> - exfat_clear_volume_dirty(sb);
> out:
> return ret;
> }
> diff --git a/fs/exfat/super.c b/fs/exfat/super.c index
> 8c9fb7dcec16..c1f7f7b7c4ab 100644
> --- a/fs/exfat/super.c
> +++ b/fs/exfat/super.c
> @@ -100,7 +100,6 @@ static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags) {
> struct exfat_sb_info *sbi = EXFAT_SB(sb);
> struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
> - bool sync;
>
> /* retain persistent-flags */
> new_flags |= sbi->vol_flags_persistent; @@ -119,16 +118,11 @@ static
> int exfat_set_vol_flags(struct super_block *sb, unsigned short
> new_flags)
>
> p_boot->vol_flags = cpu_to_le16(new_flags);
>
> - if ((new_flags & VOLUME_DIRTY) && !buffer_dirty(sbi->boot_bh))
> - sync = true;
> - else
> - sync = false;
> -
> set_buffer_uptodate(sbi->boot_bh);
> mark_buffer_dirty(sbi->boot_bh);
>
> - if (sync)
> - sync_dirty_buffer(sbi->boot_bh);
> + __sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA |
> +REQ_PREFLUSH);
> +
> return 0;
> }
Looks good.
BR.
T.Kohada
