Re: [RFC 05/10] fs/dax: Refactor wait for dax idle page

Jan Kara
2024-04-12T14:38:00Z

On Thu 11-04-24 10:57:26, Alistair Popple wrote:
> A FS DAX page is considered idle when its refcount drops to one. This
> is currently open-coded in all file systems supporting FS DAX. Move
> the idle detection to a common function to make future changes easier.
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>

Good cleanup. Feel free to add:

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

Honza

> ---
> fs/ext4/inode.c | 5 +----
> fs/fuse/dax.c | 4 +---
> fs/xfs/xfs_file.c | 4 +---
> include/linux/dax.h | 11 +++++++++++
> 4 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 4ce35f1..e9cef7d 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3868,10 +3868,7 @@ int ext4_break_layouts(struct inode *inode)
> if (!page)
> return 0;
>
> - error = ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1,
> - TASK_INTERRUPTIBLE, 0, 0,
> - ext4_wait_dax_page(inode));
> + error = dax_wait_page_idle(page, ext4_wait_dax_page, inode);
> } while (error == 0);
>
> return error;
> diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
> index 23904a6..8a62483 100644
> --- a/fs/fuse/dax.c
> +++ b/fs/fuse/dax.c
> @@ -676,9 +676,7 @@ static int __fuse_dax_break_layouts(struct inode *inode, bool *retry,
> return 0;
>
> *retry = true;
> - return ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
> - 0, 0, fuse_wait_dax_page(inode));
> + return dax_wait_page_idle(page, fuse_wait_dax_page, inode);
> }
>
> /* dmap_end == 0 leads to unmapping of whole file */
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 2037002..099cd70 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -849,9 +849,7 @@ xfs_break_dax_layouts(
> return 0;
>
> *retry = true;
> - return ___wait_var_event(&page->_refcount,
> - atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
> - 0, 0, xfs_wait_dax_page(inode));
> + return dax_wait_page_idle(page, xfs_wait_dax_page, inode);
> }
>
> int
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 22cd990..bced4d4 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -212,6 +212,17 @@ int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
> int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
> const struct iomap_ops *ops);
>
> +static inline int dax_wait_page_idle(struct page *page,
> + void (cb)(struct inode *),
> + struct inode *inode)
> +{
> + int ret;
> +
> + ret = ___wait_var_event(page, page_ref_count(page) == 1,
> + TASK_INTERRUPTIBLE, 0, 0, cb(inode));
> + return ret;
> +}
> +
> #if IS_ENABLED(CONFIG_DAX)
> int dax_read_lock(void);
> void dax_read_unlock(int id);
> --
> git-series 0.9.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR