Re: [f2fs-dev] [PATCH V3 6/7] Add decryption support for sub-pagesized blocks

2019-06-25 Thread Chandan Rajendra 
On Saturday, June 22, 2019 2:59:17 AM IST Eric Biggers wrote:
> On Sun, Jun 16, 2019 at 09:38:12PM +0530, Chandan Rajendra wrote:
> > To support decryption of sub-pagesized blocks this commit adds code to,
> > 1. Track buffer head in "struct read_callbacks_ctx".
> > 2. Pass buffer head argument to all read callbacks.
> > 3. Add new fscrypt helper to decrypt the file data referred to by a
> >buffer head.
> > 
> > Signed-off-by: Chandan Rajendra 
> > ---
> >  fs/buffer.c|  55 +--
> >  fs/crypto/bio.c|  21 +-
> >  fs/f2fs/data.c |   2 +-
> >  fs/mpage.c |   2 +-
> >  fs/read_callbacks.c| 118 +
> >  include/linux/buffer_head.h|   1 +
> >  include/linux/read_callbacks.h |  13 +++-
> >  7 files changed, 158 insertions(+), 54 deletions(-)
> > 
> 
> This is another patch that unnecessarily changes way too many components at
> once.  My suggestions elsewhere would resolve this, though:
> 
> - This patch changes fs/f2fs/data.c and fs/mpage.c only to pass a NULL
>   buffer_head to read_callbacks_setup().  But as per my comments on patch 1,
>   read_callbacks_setup() should be split into read_callbacks_setup_bio() and
>   read_callbacks_end_bh().
> 
> - This patch changes fs/crypto/ only to add support for the buffer_head
>   decryption work.  But as per my comments on patch 1, that should be in
>   read_callbacks.c instead.
> 
> And adding buffer_head support to fs/read_callbacks.c should be its own patch,
> *or* should simply be folded into the patch that adds fs/read_callbacks.c.
> 
> Then the only thing remaining in this patch would be updating fs/buffer.c to
> make it use the read_callbacks, which should be retitled to something like
> "fs/buffer.c: add decryption support via read_callbacks".
> 

I agree.

-- 
chandan





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Re: [f2fs-dev] [PATCH V3 6/7] Add decryption support for sub-pagesized blocks

2019-06-21 Thread Eric Biggers 
On Sun, Jun 16, 2019 at 09:38:12PM +0530, Chandan Rajendra wrote:
> To support decryption of sub-pagesized blocks this commit adds code to,
> 1. Track buffer head in "struct read_callbacks_ctx".
> 2. Pass buffer head argument to all read callbacks.
> 3. Add new fscrypt helper to decrypt the file data referred to by a
>buffer head.
> 
> Signed-off-by: Chandan Rajendra 
> ---
>  fs/buffer.c|  55 +--
>  fs/crypto/bio.c|  21 +-
>  fs/f2fs/data.c |   2 +-
>  fs/mpage.c |   2 +-
>  fs/read_callbacks.c| 118 +
>  include/linux/buffer_head.h|   1 +
>  include/linux/read_callbacks.h |  13 +++-
>  7 files changed, 158 insertions(+), 54 deletions(-)
> 

This is another patch that unnecessarily changes way too many components at
once.  My suggestions elsewhere would resolve this, though:

- This patch changes fs/f2fs/data.c and fs/mpage.c only to pass a NULL
  buffer_head to read_callbacks_setup().  But as per my comments on patch 1,
  read_callbacks_setup() should be split into read_callbacks_setup_bio() and
  read_callbacks_end_bh().

- This patch changes fs/crypto/ only to add support for the buffer_head
  decryption work.  But as per my comments on patch 1, that should be in
  read_callbacks.c instead.

And adding buffer_head support to fs/read_callbacks.c should be its own patch,
*or* should simply be folded into the patch that adds fs/read_callbacks.c.

Then the only thing remaining in this patch would be updating fs/buffer.c to
make it use the read_callbacks, which should be retitled to something like
"fs/buffer.c: add decryption support via read_callbacks".

- Eric


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[f2fs-dev] [PATCH V3 6/7] Add decryption support for sub-pagesized blocks

2019-06-16 Thread Chandan Rajendra 
To support decryption of sub-pagesized blocks this commit adds code to,
1. Track buffer head in "struct read_callbacks_ctx".
2. Pass buffer head argument to all read callbacks.
3. Add new fscrypt helper to decrypt the file data referred to by a
   buffer head.

Signed-off-by: Chandan Rajendra 
---
 fs/buffer.c|  55 +--
 fs/crypto/bio.c|  21 +-
 fs/f2fs/data.c |   2 +-
 fs/mpage.c |   2 +-
 fs/read_callbacks.c| 118 +
 include/linux/buffer_head.h|   1 +
 include/linux/read_callbacks.h |  13 +++-
 7 files changed, 158 insertions(+), 54 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index e450c55f6434..dcb67525dac9 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -46,6 +46,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
@@ -246,11 +247,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t 
block)
return ret;
 }
 
-/*
- * I/O completion handler for block_read_full_page() - pages
- * which come unlocked at the end of I/O.
- */
-static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
+void end_buffer_async_read(struct buffer_head *bh)
 {
unsigned long flags;
struct buffer_head *first;
@@ -258,17 +255,7 @@ static void end_buffer_async_read(struct buffer_head *bh, 
int uptodate)
struct page *page;
int page_uptodate = 1;
 
-   BUG_ON(!buffer_async_read(bh));
-
page = bh->b_page;
-   if (uptodate) {
-   set_buffer_uptodate(bh);
-   } else {
-   clear_buffer_uptodate(bh);
-   buffer_io_error(bh, ", async page read");
-   SetPageError(page);
-   }
-
/*
 * Be _very_ careful from here on. Bad things can happen if
 * two buffer heads end IO at almost the same time and both
@@ -307,6 +294,31 @@ static void end_buffer_async_read(struct buffer_head *bh, 
int uptodate)
return;
 }
 
+/*
+ * I/O completion handler for block_read_full_page().  Pages are unlocked
+ * after the I/O completes and the read callbacks (if any) have executed.
+ */
+static void __end_buffer_async_read(struct buffer_head *bh, int uptodate)
+{
+   struct page *page;
+
+   BUG_ON(!buffer_async_read(bh));
+
+   if (read_callbacks_end_bh(bh, uptodate))
+   return;
+
+   page = bh->b_page;
+   if (uptodate) {
+   set_buffer_uptodate(bh);
+   } else {
+   clear_buffer_uptodate(bh);
+   buffer_io_error(bh, ", async page read");
+   SetPageError(page);
+   }
+
+   end_buffer_async_read(bh);
+}
+
 /*
  * Completion handler for block_write_full_page() - pages which are unlocked
  * during I/O, and which have PageWriteback cleared upon I/O completion.
@@ -379,7 +391,7 @@ EXPORT_SYMBOL(end_buffer_async_write);
  */
 static void mark_buffer_async_read(struct buffer_head *bh)
 {
-   bh->b_end_io = end_buffer_async_read;
+   bh->b_end_io = __end_buffer_async_read;
set_buffer_async_read(bh);
 }
 
@@ -2294,10 +2306,15 @@ int block_read_full_page(struct page *page, get_block_t 
*get_block)
 */
for (i = 0; i < nr; i++) {
bh = arr[i];
-   if (buffer_uptodate(bh))
-   end_buffer_async_read(bh, 1);
-   else
+   if (buffer_uptodate(bh)) {
+   __end_buffer_async_read(bh, 1);
+   } else {
+   if (WARN_ON(read_callbacks_setup(inode, NULL, bh, 
NULL))) {
+   __end_buffer_async_read(bh, 0);
+   continue;
+   }
submit_bh(REQ_OP_READ, 0, bh);
+   }
}
return 0;
 }
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 4076d704e2e4..b836d648fd27 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -24,6 +24,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include "fscrypt_private.h"
 
@@ -41,12 +42,30 @@ static void fscrypt_decrypt_bio(struct bio *bio)
}
 }
 
+static void fscrypt_decrypt_bh(struct buffer_head *bh)
+{
+   struct page *page;
+   int ret;
+
+   page = bh->b_page;
+
+   ret = fscrypt_decrypt_pagecache_blocks(page, bh->b_size,
+   bh_offset(bh));
+   if (ret)
+   SetPageError(page);
+}
+
 void fscrypt_decrypt_work(struct work_struct *work)
 {
struct read_callbacks_ctx *ctx =
container_of(work, struct read_callbacks_ctx, work);
 
-   fscrypt_decrypt_bio(ctx->bio);
+   WARN_ON(!ctx->bh && !ctx->bio);
+
+   if (ctx->bio)
+   fscrypt_decrypt_bio(ctx->bio);
+   else
+   fscrypt_decrypt_bh(ctx->bh);
 
read_callbacks(ctx);
 }
diff --git a/fs/f2fs/data.c