Re: [f2fs-dev] [PATCH] f2fs: avoid wrong decrypted data from disk
On Thu, Aug 30, 2018 at 11:59:03AM +0530, Sahitya Tummala wrote:
> On Mon, Aug 27, 2018 at 03:52:26PM -0700, Jaegeuk Kim wrote:
> > 1. Create a file in an encrypted directory
> > 2. Do GC & drop caches
> > 3. Read stale data before its bio for metapage was not issued yet
> >
> > Signed-off-by: Jaegeuk Kim
> > ---
> > fs/f2fs/data.c | 7 +++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 382c1ef9a9e4..c3557fd4a0bd 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -1550,6 +1550,13 @@ static int f2fs_mpage_readpages(struct address_space
> > *mapping,
> > bio = NULL;
> > }
> > if (bio == NULL) {
> > + /*
> > +* If the page is under writeback, we need to wait for
> > +* its completion to see the correct decrypted data.
> > +*/
> > + if (unlikely(f2fs_encrypted_file(inode)))
> > + f2fs_wait_on_block_writeback(F2FS_I_SB(inode),
> > block_nr);
> > +
>
> I am not sure if this really helps the case.
>
> When the data is being moved by GC, the writeback is set on the encrypted page
> which belongs to meta mapping. But before that writeback could complete, the
> read
> will happen on the original file where it's corresponding page will not have
> any
> writeback set, right?
Never mind, got it. Tested with your latest v3 patch and it is fixing the
problem. Thanks.
>
> > bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
> > is_readahead ? REQ_RAHEAD : 0);
> > if (IS_ERR(bio)) {
> > --
> > 2.17.0.441.gb46fe60e1d-goog
> >
> >
> > --
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>
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Re: [f2fs-dev] [PATCH] f2fs: avoid wrong decrypted data from disk
On Mon, Aug 27, 2018 at 03:52:26PM -0700, Jaegeuk Kim wrote:
> 1. Create a file in an encrypted directory
> 2. Do GC & drop caches
> 3. Read stale data before its bio for metapage was not issued yet
>
> Signed-off-by: Jaegeuk Kim
> ---
> fs/f2fs/data.c | 7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 382c1ef9a9e4..c3557fd4a0bd 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1550,6 +1550,13 @@ static int f2fs_mpage_readpages(struct address_space
> *mapping,
> bio = NULL;
> }
> if (bio == NULL) {
> + /*
> + * If the page is under writeback, we need to wait for
> + * its completion to see the correct decrypted data.
> + */
> + if (unlikely(f2fs_encrypted_file(inode)))
> + f2fs_wait_on_block_writeback(F2FS_I_SB(inode),
> block_nr);
> +
I am not sure if this really helps the case.
When the data is being moved by GC, the writeback is set on the encrypted page
which belongs to meta mapping. But before that writeback could complete, the
read
will happen on the original file where it's corresponding page will not have any
writeback set, right?
> bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
> is_readahead ? REQ_RAHEAD : 0);
> if (IS_ERR(bio)) {
> --
> 2.17.0.441.gb46fe60e1d-goog
>
>
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
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Re: [f2fs-dev] [PATCH] f2fs: avoid wrong decrypted data from disk
On 2018/8/28 6:52, Jaegeuk Kim wrote:
> 1. Create a file in an encrypted directory
> 2. Do GC & drop caches
> 3. Read stale data before its bio for metapage was not issued yet
>
> Signed-off-by: Jaegeuk Kim
> ---
> fs/f2fs/data.c | 7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 382c1ef9a9e4..c3557fd4a0bd 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1550,6 +1550,13 @@ static int f2fs_mpage_readpages(struct address_space
> *mapping,
> bio = NULL;
> }
> if (bio == NULL) {
> + /*
> + * If the page is under writeback, we need to wait for
> + * its completion to see the correct decrypted data.
> + */
> + if (unlikely(f2fs_encrypted_file(inode)))
> + f2fs_wait_on_block_writeback(F2FS_I_SB(inode),
> block_nr);
I think we have did this in f2fs_grab_read_bio(), so we just need to cover 'bio
!= NULL' case, right?
Thanks,
> +
> bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
> is_readahead ? REQ_RAHEAD : 0);
> if (IS_ERR(bio)) {
>
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[f2fs-dev] [PATCH] f2fs: avoid wrong decrypted data from disk
1. Create a file in an encrypted directory
2. Do GC & drop caches
3. Read stale data before its bio for metapage was not issued yet
Signed-off-by: Jaegeuk Kim
---
fs/f2fs/data.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 382c1ef9a9e4..c3557fd4a0bd 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1550,6 +1550,13 @@ static int f2fs_mpage_readpages(struct address_space
*mapping,
bio = NULL;
}
if (bio == NULL) {
+ /*
+* If the page is under writeback, we need to wait for
+* its completion to see the correct decrypted data.
+*/
+ if (unlikely(f2fs_encrypted_file(inode)))
+ f2fs_wait_on_block_writeback(F2FS_I_SB(inode),
block_nr);
+
bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
is_readahead ? REQ_RAHEAD : 0);
if (IS_ERR(bio)) {
--
2.17.0.441.gb46fe60e1d-goog
--
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