2019-06-16 16:08:49

by Chandan Rajendra

Subject: [PATCH V3 4/7] fs/mpage.c: Integrate read callbacks

This commit adds code to make do_mpage_readpage() to be "read callbacks"
aware i.e. for files requiring decryption, do_mpage_readpage() now
sets up the read callbacks state machine when allocating a bio and later
starts execution of the state machine after file data is read from the
underlying disk.

Signed-off-by: Chandan Rajendra <[email protected]>
---
fs/mpage.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/mpage.c b/fs/mpage.c
index 436a85260394..611ad122fc92 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -30,6 +30,7 @@
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include <linux/cleancache.h>
+#include <linux/read_callbacks.h>
#include "internal.h"

/*
@@ -49,6 +50,8 @@ static void mpage_end_io(struct bio *bio)
struct bio_vec *bv;
struct bvec_iter_all iter_all;

+ if (read_callbacks_end_bio(bio))
+ return;
bio_for_each_segment_all(bv, bio, iter_all) {
struct page *page = bv->bv_page;
page_endio(page, bio_op(bio),
@@ -309,6 +312,12 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
gfp);
if (args->bio == NULL)
goto confused;
+
+ if (read_callbacks_setup(inode, args->bio, NULL)) {
+ bio_put(args->bio);
+ args->bio = NULL;
+ goto confused;
+ }
}

length = first_hole << blkbits;
@@ -330,7 +339,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
confused:
if (args->bio)
args->bio = mpage_bio_submit(REQ_OP_READ, op_flags, args->bio);
- if (!PageUptodate(page))
+ if (!PageUptodate(page) && !PageError(page))
block_read_full_page(page, args->get_block);
else
unlock_page(page);
--
2.19.1

2019-06-21 21:16:43

by Eric Biggers

Subject: Re: [PATCH V3 4/7] fs/mpage.c: Integrate read callbacks

On Sun, Jun 16, 2019 at 09:38:10PM +0530, Chandan Rajendra wrote:
> This commit adds code to make do_mpage_readpage() to be "read callbacks"
> aware i.e. for files requiring decryption, do_mpage_readpage() now
> sets up the read callbacks state machine when allocating a bio and later
> starts execution of the state machine after file data is read from the
> underlying disk.
>
> Signed-off-by: Chandan Rajendra <[email protected]>
> ---
> fs/mpage.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/fs/mpage.c b/fs/mpage.c
> index 436a85260394..611ad122fc92 100644
> --- a/fs/mpage.c
> +++ b/fs/mpage.c
> @@ -30,6 +30,7 @@
> #include <linux/backing-dev.h>
> #include <linux/pagevec.h>
> #include <linux/cleancache.h>
> +#include <linux/read_callbacks.h>
> #include "internal.h"
>
> /*
> @@ -49,6 +50,8 @@ static void mpage_end_io(struct bio *bio)
> struct bio_vec *bv;
> struct bvec_iter_all iter_all;
>
> + if (read_callbacks_end_bio(bio))
> + return;
> bio_for_each_segment_all(bv, bio, iter_all) {
> struct page *page = bv->bv_page;
> page_endio(page, bio_op(bio),
> @@ -309,6 +312,12 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> gfp);
> if (args->bio == NULL)
> goto confused;
> +
> + if (read_callbacks_setup(inode, args->bio, NULL)) {
> + bio_put(args->bio);
> + args->bio = NULL;
> + goto confused;
> + }
> }
>
> length = first_hole << blkbits;
> @@ -330,7 +339,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> confused:
> if (args->bio)
> args->bio = mpage_bio_submit(REQ_OP_READ, op_flags, args->bio);
> - if (!PageUptodate(page))
> + if (!PageUptodate(page) && !PageError(page))
> block_read_full_page(page, args->get_block);
> else
> unlock_page(page);
> --
> 2.19.1

Why is the !PageError() check needed here?

- Eric

2019-06-25 07:39:16

by Chandan Rajendra

Subject: Re: [PATCH V3 4/7] fs/mpage.c: Integrate read callbacks

On Saturday, June 22, 2019 2:44:55 AM IST Eric Biggers wrote:
> On Sun, Jun 16, 2019 at 09:38:10PM +0530, Chandan Rajendra wrote:
> > This commit adds code to make do_mpage_readpage() to be "read callbacks"
> > aware i.e. for files requiring decryption, do_mpage_readpage() now
> > sets up the read callbacks state machine when allocating a bio and later
> > starts execution of the state machine after file data is read from the
> > underlying disk.
> >
> > Signed-off-by: Chandan Rajendra <[email protected]>
> > ---
> > fs/mpage.c | 11 ++++++++++-
> > 1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/mpage.c b/fs/mpage.c
> > index 436a85260394..611ad122fc92 100644
> > --- a/fs/mpage.c
> > +++ b/fs/mpage.c
> > @@ -30,6 +30,7 @@
> > #include <linux/backing-dev.h>
> > #include <linux/pagevec.h>
> > #include <linux/cleancache.h>
> > +#include <linux/read_callbacks.h>
> > #include "internal.h"
> >
> > /*
> > @@ -49,6 +50,8 @@ static void mpage_end_io(struct bio *bio)
> > struct bio_vec *bv;
> > struct bvec_iter_all iter_all;
> >
> > + if (read_callbacks_end_bio(bio))
> > + return;
> > bio_for_each_segment_all(bv, bio, iter_all) {
> > struct page *page = bv->bv_page;
> > page_endio(page, bio_op(bio),
> > @@ -309,6 +312,12 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> > gfp);
> > if (args->bio == NULL)
> > goto confused;
> > +
> > + if (read_callbacks_setup(inode, args->bio, NULL)) {
> > + bio_put(args->bio);
> > + args->bio = NULL;
> > + goto confused;
> > + }
> > }
> >
> > length = first_hole << blkbits;
> > @@ -330,7 +339,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
> > confused:
> > if (args->bio)
> > args->bio = mpage_bio_submit(REQ_OP_READ, op_flags, args->bio);
> > - if (!PageUptodate(page))
> > + if (!PageUptodate(page) && !PageError(page))
> > block_read_full_page(page, args->get_block);
> > else
> > unlock_page(page);
>
> Why is the !PageError() check needed here?
>

Sorry, Its a remnant from when I was debugging the patchset. I will remove
this.

--
chandan