[PATCH v2] vfs: fix readahead(2) on block devices

[PATCH v2] vfs: fix readahead(2) on block devices

[Reuben Hawkins]

Readahead was factored to call generic_fadvise.  That refactor added an
S_ISREG restriction which broke readahead on block devices.

This change removes the S_ISREG restriction to fix block device readahead.
The change also means that readahead will return -ESPIPE on FIFO files
instead of -EINVAL.

Fixes: 3d8f7615319b ("vfs: implement readahead(2) using POSIX_FADV_WILLNEED")
Signed-off-by: Reuben Hawkins <reubenhwk@gmail.com>
---
 mm/readahead.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/readahead.c b/mm/readahead.c
index e815c114de21..ef3b23a41973 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -734,8 +734,7 @@ ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
 	 * on this file, then we must return -EINVAL.
 	 */
 	ret = -EINVAL;
-	if (!f.file->f_mapping || !f.file->f_mapping->a_ops ||
-	    !S_ISREG(file_inode(f.file)->i_mode))
+	if (!f.file->f_mapping || !f.file->f_mapping->a_ops)
 		goto out;
 
 	ret = vfs_fadvise(f.file, offset, count, POSIX_FADV_WILLNEED);
-- 
2.34.1

Re: [PATCH v2] vfs: fix readahead(2) on block devices

[Amir Goldstein]

On Mon, Sep 11, 2023 at 2:49 PM Reuben Hawkins <reubenhwk@gmail.com> wrote:
>
> Readahead was factored to call generic_fadvise.  That refactor added an
> S_ISREG restriction which broke readahead on block devices.
>
> This change removes the S_ISREG restriction to fix block device readahead.
> The change also means that readahead will return -ESPIPE on FIFO files
> instead of -EINVAL.
>
> Fixes: 3d8f7615319b ("vfs: implement readahead(2) using POSIX_FADV_WILLNEED")
> Signed-off-by: Reuben Hawkins <reubenhwk@gmail.com>
> ---

Reviewed-by: Amir Goldstein <amir73il@gmail.com>

Christian,

I suggest adding the link to the original bug report on commit:
Closes: https://lore.kernel.org/linux-fsdevel/CAOQ4uxhE8En64rr3mx1UAOqqzb3A-GoeR7cx2D+V73ytr6YLjw@mail.gmail.com/

Thanks,
Amir.

>  mm/readahead.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/mm/readahead.c b/mm/readahead.c
> index e815c114de21..ef3b23a41973 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -734,8 +734,7 @@ ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
>          * on this file, then we must return -EINVAL.
>          */
>         ret = -EINVAL;
> -       if (!f.file->f_mapping || !f.file->f_mapping->a_ops ||
> -           !S_ISREG(file_inode(f.file)->i_mode))
> +       if (!f.file->f_mapping || !f.file->f_mapping->a_ops)
>                 goto out;
>
>         ret = vfs_fadvise(f.file, offset, count, POSIX_FADV_WILLNEED);
> --
> 2.34.1
>

Re: [PATCH v2] vfs: fix readahead(2) on block devices

[Christian Brauner]

On Mon, 11 Sep 2023 06:47:13 -0500, Reuben Hawkins wrote:
> Readahead was factored to call generic_fadvise.  That refactor added an
> S_ISREG restriction which broke readahead on block devices.
> 
> This change removes the S_ISREG restriction to fix block device readahead.
> The change also means that readahead will return -ESPIPE on FIFO files
> instead of -EINVAL.
> 
> [...]

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] vfs: fix readahead(2) on block devices
      https://git.kernel.org/vfs/vfs/c/d05ad99006a6

Re: [PATCH v2] vfs: fix readahead(2) on block devices

[Jan Kara]

On Mon 11-09-23 06:47:13, Reuben Hawkins wrote:
> Readahead was factored to call generic_fadvise.  That refactor added an
> S_ISREG restriction which broke readahead on block devices.
> 
> This change removes the S_ISREG restriction to fix block device readahead.
> The change also means that readahead will return -ESPIPE on FIFO files
> instead of -EINVAL.
> 
> Fixes: 3d8f7615319b ("vfs: implement readahead(2) using POSIX_FADV_WILLNEED")
> Signed-off-by: Reuben Hawkins <reubenhwk@gmail.com>

Nice catch! Feel free to add:

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

								Honza

> ---
>  mm/readahead.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/readahead.c b/mm/readahead.c
> index e815c114de21..ef3b23a41973 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -734,8 +734,7 @@ ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
>  	 * on this file, then we must return -EINVAL.
>  	 */
>  	ret = -EINVAL;
> -	if (!f.file->f_mapping || !f.file->f_mapping->a_ops ||
> -	    !S_ISREG(file_inode(f.file)->i_mode))
> +	if (!f.file->f_mapping || !f.file->f_mapping->a_ops)
>  		goto out;
>  
>  	ret = vfs_fadvise(f.file, offset, count, POSIX_FADV_WILLNEED);
> -- 
> 2.34.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR