[V3,4/7] fs/mpage.c: Integrate read callbacks
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Message ID 20190616160813.24464-5-chandan@linux.ibm.com
State New
Headers show
Series
  • Consolidate FS read I/O callbacks code
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Commit Message

Chandan Rajendra June 16, 2019, 4:08 p.m. UTC
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 <chandan@linux.ibm.com>
---
 fs/mpage.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Comments

Eric Biggers June 21, 2019, 9:14 p.m. UTC | #1
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 <chandan@linux.ibm.com>
> ---
>  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
Chandan Rajendra June 25, 2019, 6:21 a.m. UTC | #2
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 <chandan@linux.ibm.com>
> > ---
> >  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.

Patch
diff mbox series

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);