Re: [PATCH v7 09/15] fs: Split off inode_needs_update_time and __file_update_time

Jan Kara
2022-06-02T08:44:06Z

On Wed 01-06-22 14:01:35, Stefan Roesch wrote:
> This splits off the functions inode_needs_update_time() and
> __file_update_time() from the function file_update_time().
>
> This is required to support async buffered writes.
> No intended functional changes in this patch.
>
> Signed-off-by: Stefan Roesch <shr@fb.com>

Looks good to me. Feel free to add:

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

Honza

> ---
> fs/inode.c | 76 +++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 50 insertions(+), 26 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index ac1cf5aa78c8..c44573a32c6a 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2049,35 +2049,18 @@ int file_remove_privs(struct file *file)
> }
> EXPORT_SYMBOL(file_remove_privs);
>
> -/**
> - * file_update_time - update mtime and ctime time
> - * @file: file accessed
> - *
> - * Update the mtime and ctime members of an inode and mark the inode
> - * for writeback. Note that this function is meant exclusively for
> - * usage in the file write path of filesystems, and filesystems may
> - * choose to explicitly ignore update via this function with the
> - * S_NOCMTIME inode flag, e.g. for network filesystem where these
> - * timestamps are handled by the server. This can return an error for
> - * file systems who need to allocate space in order to update an inode.
> - */
> -
> -int file_update_time(struct file *file)
> +static int inode_needs_update_time(struct inode *inode, struct timespec64 *now)
> {
> - struct inode *inode = file_inode(file);
> - struct timespec64 now;
> int sync_it = 0;
> - int ret;
>
> /* First try to exhaust all avenues to not sync */
> if (IS_NOCMTIME(inode))
> return 0;
>
> - now = current_time(inode);
> - if (!timespec64_equal(&inode->i_mtime, &now))
> + if (!timespec64_equal(&inode->i_mtime, now))
> sync_it = S_MTIME;
>
> - if (!timespec64_equal(&inode->i_ctime, &now))
> + if (!timespec64_equal(&inode->i_ctime, now))
> sync_it |= S_CTIME;
>
> if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
> @@ -2086,15 +2069,50 @@ int file_update_time(struct file *file)
> if (!sync_it)
> return 0;
>
> - /* Finally allowed to write? Takes lock. */
> - if (__mnt_want_write_file(file))
> - return 0;
> + return sync_it;
> +}
> +
> +static int __file_update_time(struct file *file, struct timespec64 *now,
> + int sync_mode)
> +{
> + int ret = 0;
> + struct inode *inode = file_inode(file);
>
> - ret = inode_update_time(inode, &now, sync_it);
> - __mnt_drop_write_file(file);
> + /* try to update time settings */
> + if (!__mnt_want_write_file(file)) {
> + ret = inode_update_time(inode, now, sync_mode);
> + __mnt_drop_write_file(file);
> + }
>
> return ret;
> }
> +
> + /**
> + * file_update_time - update mtime and ctime time
> + * @file: file accessed
> + *
> + * Update the mtime and ctime members of an inode and mark the inode for
> + * writeback. Note that this function is meant exclusively for usage in
> + * the file write path of filesystems, and filesystems may choose to
> + * explicitly ignore updates via this function with the _NOCMTIME inode
> + * flag, e.g. for network filesystem where these imestamps are handled
> + * by the server. This can return an error for file systems who need to
> + * allocate space in order to update an inode.
> + *
> + * Return: 0 on success, negative errno on failure.
> + */
> +int file_update_time(struct file *file)
> +{
> + int ret;
> + struct inode *inode = file_inode(file);
> + struct timespec64 now = current_time(inode);
> +
> + ret = inode_needs_update_time(inode, &now);
> + if (ret <= 0)
> + return ret;
> +
> + return __file_update_time(file, &now, ret);
> +}
> EXPORT_SYMBOL(file_update_time);
>
> /**
> @@ -2111,6 +2129,8 @@ EXPORT_SYMBOL(file_update_time);
> int file_modified(struct file *file)
> {
> int ret;
> + struct inode *inode = file_inode(file);
> + struct timespec64 now = current_time(inode);
>
> /*
> * Clear the security bits if the process is not being run by root.
> @@ -2123,7 +2143,11 @@ int file_modified(struct file *file)
> if (unlikely(file->f_mode & FMODE_NOCMTIME))
> return 0;
>
> - return file_update_time(file);
> + ret = inode_needs_update_time(inode, &now);
> + if (ret <= 0)
> + return ret;
> +
> + return __file_update_time(file, &now, ret);
> }
> EXPORT_SYMBOL(file_modified);
>
> --
> 2.30.2
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR