On Sat 02-11-19 16:13:00, Konstantin Khlebnikov wrote:
> This helper prints warning if direct I/O write failed to invalidate cache,
> and set EIO at inode to warn usersapce about possible data corruption.
> See also commit 5a9d929d6e13 ("iomap: report collisions between directio and
> buffered writes to userspace").
>
> Direct I/O is supported by non-disk filesystems, for example NFS.
> Thus generic code needs this even in kernel without CONFIG_BLOCK.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/direct-io.c | 21 ---------------------
> include/linux/fs.h | 6 +++++-
> mm/filemap.c | 21 +++++++++++++++++++++
> 3 files changed, 26 insertions(+), 22 deletions(-)
>
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index 9329ced91f1d..0ec4f270139f 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -220,27 +220,6 @@ static inline struct page *dio_get_page(struct dio *dio,
> return dio->pages[sdio->head];
> }
>
> -/*
> - * Warn about a page cache invalidation failure during a direct io write.
> - */
> -void dio_warn_stale_pagecache(struct file *filp)
> -{
> - static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
> - char pathname[128];
> - struct inode *inode = file_inode(filp);
> - char *path;
> -
> - errseq_set(&inode->i_mapping->wb_err, -EIO);
> - if (__ratelimit(&_rs)) {
> - path = file_path(filp, pathname, sizeof(pathname));
> - if (IS_ERR(path))
> - path = "(unknown)";
> - pr_crit("Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!\n");
> - pr_crit("File: %s PID: %d Comm: %.20s\n", path, current->pid,
> - current->comm);
> - }
> -}
> -
> /*
> * dio_complete() - called when all DIO BIO I/O has been completed
> *
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index e0d909d35763..b4e4560d1c38 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3153,7 +3153,6 @@ enum {
> };
>
> void dio_end_io(struct bio *bio);
> -void dio_warn_stale_pagecache(struct file *filp);
>
> ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
> struct block_device *bdev, struct iov_iter *iter,
> @@ -3198,6 +3197,11 @@ static inline void inode_dio_end(struct inode *inode)
> wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
> }
>
> +/*
> + * Warn about a page cache invalidation failure diring a direct I/O write.
> + */
> +void dio_warn_stale_pagecache(struct file *filp);
> +
> extern void inode_set_flags(struct inode *inode, unsigned int flags,
> unsigned int mask);
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 288e38199068..189b8f318da2 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -3161,6 +3161,27 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
> }
> EXPORT_SYMBOL(pagecache_write_end);
>
> +/*
> + * Warn about a page cache invalidation failure during a direct I/O write.
> + */
> +void dio_warn_stale_pagecache(struct file *filp)
> +{
> + static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
> + char pathname[128];
> + struct inode *inode = file_inode(filp);
> + char *path;
> +
> + errseq_set(&inode->i_mapping->wb_err, -EIO);
> + if (__ratelimit(&_rs)) {
> + path = file_path(filp, pathname, sizeof(pathname));
> + if (IS_ERR(path))
> + path = "(unknown)";
> + pr_crit("Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!\n");
> + pr_crit("File: %s PID: %d Comm: %.20s\n", path, current->pid,
> + current->comm);
> + }
> +}
> +
> ssize_t
> generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
> {
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
