Re: [PATCH 6/9] fs/ext4: Only change S_DAX on inode load

Jan Kara
2020-05-13T11:33:31Z

On Tue 12-05-20 22:43:21, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> To prevent complications with in memory inodes we only set S_DAX on
> inode load. FS_XFLAG_DAX can be changed at any time and S_DAX will
> change after inode eviction and reload.
>
> Add init bool to ext4_set_inode_flags() to indicate if the inode is
> being newly initialized.
>
> Assert that S_DAX is not set on an inode which is just being loaded.
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

>
> ---
> Changes from RFC:
> Change J_ASSERT() to WARN_ON_ONCE()
> Fix bug which would clear S_DAX incorrectly
> ---
> fs/ext4/ext4.h | 2 +-
> fs/ext4/ialloc.c | 2 +-
> fs/ext4/inode.c | 13 ++++++++++---
> fs/ext4/ioctl.c | 3 ++-
> fs/ext4/super.c | 4 ++--
> fs/ext4/verity.c | 2 +-
> 6 files changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 1a3daf2d18ef..86a0994332ce 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -2692,7 +2692,7 @@ extern int ext4_can_truncate(struct inode *inode);
> extern int ext4_truncate(struct inode *);
> extern int ext4_break_layouts(struct inode *);
> extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length);
> -extern void ext4_set_inode_flags(struct inode *);
> +extern void ext4_set_inode_flags(struct inode *, bool init);
> extern int ext4_alloc_da_blocks(struct inode *inode);
> extern void ext4_set_aops(struct inode *inode);
> extern int ext4_writepage_trans_blocks(struct inode *);
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 4b8c9a9bdf0c..7941c140723f 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -1116,7 +1116,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
> ei->i_block_group = group;
> ei->i_last_alloc_group = ~0;
>
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, true);
> if (IS_DIRSYNC(inode))
> ext4_handle_sync(handle);
> if (insert_inode_locked(inode) < 0) {
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index d3a4c2ed7a1c..23e42a223235 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4419,11 +4419,13 @@ static bool ext4_should_enable_dax(struct inode *inode)
> return false;
> }
>
> -void ext4_set_inode_flags(struct inode *inode)
> +void ext4_set_inode_flags(struct inode *inode, bool init)
> {
> unsigned int flags = EXT4_I(inode)->i_flags;
> unsigned int new_fl = 0;
>
> + WARN_ON_ONCE(IS_DAX(inode) && init);
> +
> if (flags & EXT4_SYNC_FL)
> new_fl |= S_SYNC;
> if (flags & EXT4_APPEND_FL)
> @@ -4434,8 +4436,13 @@ void ext4_set_inode_flags(struct inode *inode)
> new_fl |= S_NOATIME;
> if (flags & EXT4_DIRSYNC_FL)
> new_fl |= S_DIRSYNC;
> - if (ext4_should_enable_dax(inode))
> +
> + /* Because of the way inode_set_flags() works we must preserve S_DAX
> + * here if already set. */
> + new_fl |= (inode->i_flags & S_DAX);
> + if (init && ext4_should_enable_dax(inode))
> new_fl |= S_DAX;
> +
> if (flags & EXT4_ENCRYPT_FL)
> new_fl |= S_ENCRYPTED;
> if (flags & EXT4_CASEFOLD_FL)
> @@ -4649,7 +4656,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
> * not initialized on a new filesystem. */
> }
> ei->i_flags = le32_to_cpu(raw_inode->i_flags);
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, true);
> inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
> ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
> if (ext4_has_feature_64bit(sb))
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index 5813e5e73eab..145083e8cd1e 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -381,7 +381,8 @@ static int ext4_ioctl_setflags(struct inode *inode,
> ext4_clear_inode_flag(inode, i);
> }
>
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, false);
> +
> inode->i_ctime = current_time(inode);
>
> err = ext4_mark_iloc_dirty(handle, inode, &iloc);
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index d0434b513919..5ec900fdf73c 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1344,7 +1344,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
> ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
> ext4_clear_inode_state(inode,
> EXT4_STATE_MAY_INLINE_DATA);
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, false);
> }
> return res;
> }
> @@ -1367,7 +1367,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
> ctx, len, 0);
> if (!res) {
> ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, false);
> res = ext4_mark_inode_dirty(handle, inode);
> if (res)
> EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
> diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
> index f05a09fb2ae4..89a155ece323 100644
> --- a/fs/ext4/verity.c
> +++ b/fs/ext4/verity.c
> @@ -244,7 +244,7 @@ static int ext4_end_enable_verity(struct file *filp, const void *desc,
> if (err)
> goto out_stop;
> ext4_set_inode_flag(inode, EXT4_INODE_VERITY);
> - ext4_set_inode_flags(inode);
> + ext4_set_inode_flags(inode, false);
> err = ext4_mark_iloc_dirty(handle, inode, &iloc);
> }
> out_stop:
> --
> 2.25.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR