| Message ID | 20190428043121.30925-11-chandan@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Consolidate FS read I/O callbacks code | expand |
On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > For subpage-sized blocks, this commit now encrypts all blocks mapped by > a page range. > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > --- > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > 1 file changed, 25 insertions(+), 12 deletions(-) > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > index 4f0d832cae71..2d65b431563f 100644 > --- a/fs/crypto/crypto.c > +++ b/fs/crypto/crypto.c > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, Need to update the function comment to clearly explain what this function actually does now. > { > struct fscrypt_ctx *ctx; > struct page *ciphertext_page = page; > + int i, page_nr_blks; > int err; > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, since the code now assumes it. const unsigned int blocksize = i_blocksize(inode); if (!IS_ALIGNED(len | offs, blocksize)) return -EINVAL; However, did you check whether that's always true for ubifs? It looks like it may expect to encrypt a prefix of a block, that is only padded to the next 16-byte boundary. > + page_nr_blks = len >> inode->i_blkbits; > + > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > /* with inplace-encryption we just encrypt the page */ > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > - ciphertext_page, len, offs, > - gfp_flags); > - if (err) > - return ERR_PTR(err); > - > + for (i = 0; i < page_nr_blks; i++) { > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > + lblk_num, page, > + ciphertext_page, > + i_blocksize(inode), offs, > + gfp_flags); > + if (err) > + return ERR_PTR(err); > + ++lblk_num; > + offs += i_blocksize(inode); > + } > return ciphertext_page; > } > > @@ -269,12 +277,17 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > goto errout; > > ctx->control_page = page; > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, > - page, ciphertext_page, len, offs, > - gfp_flags); > - if (err) { > - ciphertext_page = ERR_PTR(err); > - goto errout; > + > + for (i = 0; i < page_nr_blks; i++) { > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, > + page, ciphertext_page, > + i_blocksize(inode), offs, gfp_flags); As I mentioned elsewhere, renaming fscrypt_do_page_crypto() to fscrypt_crypt_block() would make more sense now. > + if (err) { > + ciphertext_page = ERR_PTR(err); > + goto errout; > + } > + ++lblk_num; > + offs += i_blocksize(inode); > } > SetPagePrivate(ciphertext_page); > set_page_private(ciphertext_page, (unsigned long)ctx); > -- > 2.19.1 >
On Tue, Apr 30, 2019 at 10:11:35AM -0700, Eric Biggers wrote: > On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > > For subpage-sized blocks, this commit now encrypts all blocks mapped by > > a page range. > > > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > > --- > > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > > 1 file changed, 25 insertions(+), 12 deletions(-) > > > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > > index 4f0d832cae71..2d65b431563f 100644 > > --- a/fs/crypto/crypto.c > > +++ b/fs/crypto/crypto.c > > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > > Need to update the function comment to clearly explain what this function > actually does now. > > > { > > struct fscrypt_ctx *ctx; > > struct page *ciphertext_page = page; > > + int i, page_nr_blks; > > int err; > > > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > > > > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). > > Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, > since the code now assumes it. > > const unsigned int blocksize = i_blocksize(inode); > > if (!IS_ALIGNED(len | offs, blocksize)) > return -EINVAL; > > However, did you check whether that's always true for ubifs? It looks like it > may expect to encrypt a prefix of a block, that is only padded to the next > 16-byte boundary. > > > + page_nr_blks = len >> inode->i_blkbits; > > + > > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > > /* with inplace-encryption we just encrypt the page */ > > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > > - ciphertext_page, len, offs, > > - gfp_flags); > > - if (err) > > - return ERR_PTR(err); > > - > > + for (i = 0; i < page_nr_blks; i++) { > > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > > + lblk_num, page, > > + ciphertext_page, > > + i_blocksize(inode), offs, > > + gfp_flags); > > + if (err) > > + return ERR_PTR(err); Apparently ubifs does encrypt data shorter than the filesystem block size, so this part is wrong. I suggest we split this into two functions, fscrypt_encrypt_block_inplace() and fscrypt_encrypt_blocks(), so that it's conceptually simpler what each function does. Currently this works completely differently depending on whether the filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations, which is weird. I also noticed that using fscrypt_ctx for writes seems to be unnecessary. AFAICS, page_private(bounce_page) could point directly to the pagecache page. That would simplify things a lot, especially since then fscrypt_ctx could be removed entirely after you convert reads to use read_callbacks_ctx. IMO, these would be worthwhile cleanups for fscrypt by themselves, without waiting for the read_callbacks stuff to be finalized. Finalizing the read_callbacks stuff will probably require reaching a consensus about how they should work with future filesystem features like fsverity and compression. So to move things forward, I'm considering sending out a series with the above cleanups for fscrypt, plus the equivalent of your patches: "fscrypt_encrypt_page: Loop across all blocks mapped by a page range" "fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page" "Add decryption support for sub-pagesized blocks" (fs/crypto/ part only) Then hopefully we can get all that applied for 5.3 so that fs/crypto/ itself is ready for blocksize != PAGE_SIZE; and get your changes to ext4_bio_write_page(), __ext4_block_zero_page_range(), and ext4_block_write_begin() applied too, so that ext4 is partially ready for encryption with blocksize != PAGE_SIZE. Then only the read_callbacks stuff will remain, to get encryption support into fs/mpage.c and fs/buffer.c. Do you think that's a good plan? Thanks! - Eric
On Wednesday, May 1, 2019 4:38:41 AM IST Eric Biggers wrote: > On Tue, Apr 30, 2019 at 10:11:35AM -0700, Eric Biggers wrote: > > On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > > > For subpage-sized blocks, this commit now encrypts all blocks mapped by > > > a page range. > > > > > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > > > --- > > > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > > > 1 file changed, 25 insertions(+), 12 deletions(-) > > > > > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > > > index 4f0d832cae71..2d65b431563f 100644 > > > --- a/fs/crypto/crypto.c > > > +++ b/fs/crypto/crypto.c > > > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > > > > Need to update the function comment to clearly explain what this function > > actually does now. > > > > > { > > > struct fscrypt_ctx *ctx; > > > struct page *ciphertext_page = page; > > > + int i, page_nr_blks; > > > int err; > > > > > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > > > > > > > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). > > > > Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, > > since the code now assumes it. > > > > const unsigned int blocksize = i_blocksize(inode); > > > > if (!IS_ALIGNED(len | offs, blocksize)) > > return -EINVAL; > > > > However, did you check whether that's always true for ubifs? It looks like it > > may expect to encrypt a prefix of a block, that is only padded to the next > > 16-byte boundary. > > > > > + page_nr_blks = len >> inode->i_blkbits; > > > + > > > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > > > /* with inplace-encryption we just encrypt the page */ > > > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > > > - ciphertext_page, len, offs, > > > - gfp_flags); > > > - if (err) > > > - return ERR_PTR(err); > > > - > > > + for (i = 0; i < page_nr_blks; i++) { > > > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > > > + lblk_num, page, > > > + ciphertext_page, > > > + i_blocksize(inode), offs, > > > + gfp_flags); > > > + if (err) > > > + return ERR_PTR(err); > > Apparently ubifs does encrypt data shorter than the filesystem block size, so > this part is wrong. > > I suggest we split this into two functions, fscrypt_encrypt_block_inplace() and > fscrypt_encrypt_blocks(), so that it's conceptually simpler what each function > does. Currently this works completely differently depending on whether the > filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations, which is weird. > > I also noticed that using fscrypt_ctx for writes seems to be unnecessary. > AFAICS, page_private(bounce_page) could point directly to the pagecache page. > That would simplify things a lot, especially since then fscrypt_ctx could be > removed entirely after you convert reads to use read_callbacks_ctx. > > IMO, these would be worthwhile cleanups for fscrypt by themselves, without > waiting for the read_callbacks stuff to be finalized. Finalizing the > read_callbacks stuff will probably require reaching a consensus about how they > should work with future filesystem features like fsverity and compression. > > So to move things forward, I'm considering sending out a series with the above > cleanups for fscrypt, plus the equivalent of your patches: > > "fscrypt_encrypt_page: Loop across all blocks mapped by a page range" > "fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page" > "Add decryption support for sub-pagesized blocks" (fs/crypto/ part only) > > Then hopefully we can get all that applied for 5.3 so that fs/crypto/ itself is > ready for blocksize != PAGE_SIZE; and get your changes to ext4_bio_write_page(), > __ext4_block_zero_page_range(), and ext4_block_write_begin() applied too, so > that ext4 is partially ready for encryption with blocksize != PAGE_SIZE. > > Then only the read_callbacks stuff will remain, to get encryption support into > fs/mpage.c and fs/buffer.c. Do you think that's a good plan? Hi Eric, IMHO, I will continue posting the next version of the current patchset and if there are no serious reservations from FS maintainers the "read callbacks" patchset can be merged. In such a scenario, the cleanups being non-complicated, can be merged later.
Hi Chandan, On Wed, May 01, 2019 at 08:19:35PM +0530, Chandan Rajendra wrote: > On Wednesday, May 1, 2019 4:38:41 AM IST Eric Biggers wrote: > > On Tue, Apr 30, 2019 at 10:11:35AM -0700, Eric Biggers wrote: > > > On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > > > > For subpage-sized blocks, this commit now encrypts all blocks mapped by > > > > a page range. > > > > > > > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > > > > --- > > > > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > > > > 1 file changed, 25 insertions(+), 12 deletions(-) > > > > > > > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > > > > index 4f0d832cae71..2d65b431563f 100644 > > > > --- a/fs/crypto/crypto.c > > > > +++ b/fs/crypto/crypto.c > > > > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > > > > > > Need to update the function comment to clearly explain what this function > > > actually does now. > > > > > > > { > > > > struct fscrypt_ctx *ctx; > > > > struct page *ciphertext_page = page; > > > > + int i, page_nr_blks; > > > > int err; > > > > > > > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > > > > > > > > > > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). > > > > > > Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, > > > since the code now assumes it. > > > > > > const unsigned int blocksize = i_blocksize(inode); > > > > > > if (!IS_ALIGNED(len | offs, blocksize)) > > > return -EINVAL; > > > > > > However, did you check whether that's always true for ubifs? It looks like it > > > may expect to encrypt a prefix of a block, that is only padded to the next > > > 16-byte boundary. > > > > > > > + page_nr_blks = len >> inode->i_blkbits; > > > > + > > > > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > > > > /* with inplace-encryption we just encrypt the page */ > > > > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > > > > - ciphertext_page, len, offs, > > > > - gfp_flags); > > > > - if (err) > > > > - return ERR_PTR(err); > > > > - > > > > + for (i = 0; i < page_nr_blks; i++) { > > > > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > > > > + lblk_num, page, > > > > + ciphertext_page, > > > > + i_blocksize(inode), offs, > > > > + gfp_flags); > > > > + if (err) > > > > + return ERR_PTR(err); > > > > Apparently ubifs does encrypt data shorter than the filesystem block size, so > > this part is wrong. > > > > I suggest we split this into two functions, fscrypt_encrypt_block_inplace() and > > fscrypt_encrypt_blocks(), so that it's conceptually simpler what each function > > does. Currently this works completely differently depending on whether the > > filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations, which is weird. > > > > I also noticed that using fscrypt_ctx for writes seems to be unnecessary. > > AFAICS, page_private(bounce_page) could point directly to the pagecache page. > > That would simplify things a lot, especially since then fscrypt_ctx could be > > removed entirely after you convert reads to use read_callbacks_ctx. > > > > IMO, these would be worthwhile cleanups for fscrypt by themselves, without > > waiting for the read_callbacks stuff to be finalized. Finalizing the > > read_callbacks stuff will probably require reaching a consensus about how they > > should work with future filesystem features like fsverity and compression. > > > > So to move things forward, I'm considering sending out a series with the above > > cleanups for fscrypt, plus the equivalent of your patches: > > > > "fscrypt_encrypt_page: Loop across all blocks mapped by a page range" > > "fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page" > > "Add decryption support for sub-pagesized blocks" (fs/crypto/ part only) > > > > Then hopefully we can get all that applied for 5.3 so that fs/crypto/ itself is > > ready for blocksize != PAGE_SIZE; and get your changes to ext4_bio_write_page(), > > __ext4_block_zero_page_range(), and ext4_block_write_begin() applied too, so > > that ext4 is partially ready for encryption with blocksize != PAGE_SIZE. > > > > Then only the read_callbacks stuff will remain, to get encryption support into > > fs/mpage.c and fs/buffer.c. Do you think that's a good plan? > > Hi Eric, > > IMHO, I will continue posting the next version of the current patchset and if > there are no serious reservations from FS maintainers the "read callbacks" > patchset can be merged. In such a scenario, the cleanups being > non-complicated, can be merged later. > > -- > chandan > Most of the patches I have in mind are actually things that are in your patchset already, or have been requested, or will be requested eventually :-). I'm concerned that people will keep going back and forth on this patchset for a lot longer, arguing about fsverity, compression, details of the fs/crypto/ stuff, etc. Moreover it's based on unmerged patches that add the fsverity feature, so it can't be merged as-is anyway. IMO, it's also difficult for people to review the read_callbacks stuff when it's mixed in with lots of other fscrypt and ext4 changes for blocksize != PAGE_SIZE. I actually have a patchset almost ready already, so I'm going to send it out and see what you think. It *should* make things a lot easier for you, since then you can base a much smaller read_callbacks patchset on top of it. Thanks! - Eric
On Thursday, May 2, 2019 3:59:01 AM IST Eric Biggers wrote: > Hi Chandan, > > On Wed, May 01, 2019 at 08:19:35PM +0530, Chandan Rajendra wrote: > > On Wednesday, May 1, 2019 4:38:41 AM IST Eric Biggers wrote: > > > On Tue, Apr 30, 2019 at 10:11:35AM -0700, Eric Biggers wrote: > > > > On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > > > > > For subpage-sized blocks, this commit now encrypts all blocks mapped by > > > > > a page range. > > > > > > > > > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > > > > > --- > > > > > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > > > > > 1 file changed, 25 insertions(+), 12 deletions(-) > > > > > > > > > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > > > > > index 4f0d832cae71..2d65b431563f 100644 > > > > > --- a/fs/crypto/crypto.c > > > > > +++ b/fs/crypto/crypto.c > > > > > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > > > > > > > > Need to update the function comment to clearly explain what this function > > > > actually does now. > > > > > > > > > { > > > > > struct fscrypt_ctx *ctx; > > > > > struct page *ciphertext_page = page; > > > > > + int i, page_nr_blks; > > > > > int err; > > > > > > > > > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > > > > > > > > > > > > > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). > > > > > > > > Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, > > > > since the code now assumes it. > > > > > > > > const unsigned int blocksize = i_blocksize(inode); > > > > > > > > if (!IS_ALIGNED(len | offs, blocksize)) > > > > return -EINVAL; > > > > > > > > However, did you check whether that's always true for ubifs? It looks like it > > > > may expect to encrypt a prefix of a block, that is only padded to the next > > > > 16-byte boundary. > > > > > > > > > + page_nr_blks = len >> inode->i_blkbits; > > > > > + > > > > > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > > > > > /* with inplace-encryption we just encrypt the page */ > > > > > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > > > > > - ciphertext_page, len, offs, > > > > > - gfp_flags); > > > > > - if (err) > > > > > - return ERR_PTR(err); > > > > > - > > > > > + for (i = 0; i < page_nr_blks; i++) { > > > > > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > > > > > + lblk_num, page, > > > > > + ciphertext_page, > > > > > + i_blocksize(inode), offs, > > > > > + gfp_flags); > > > > > + if (err) > > > > > + return ERR_PTR(err); > > > > > > Apparently ubifs does encrypt data shorter than the filesystem block size, so > > > this part is wrong. > > > > > > I suggest we split this into two functions, fscrypt_encrypt_block_inplace() and > > > fscrypt_encrypt_blocks(), so that it's conceptually simpler what each function > > > does. Currently this works completely differently depending on whether the > > > filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations, which is weird. > > > > > > I also noticed that using fscrypt_ctx for writes seems to be unnecessary. > > > AFAICS, page_private(bounce_page) could point directly to the pagecache page. > > > That would simplify things a lot, especially since then fscrypt_ctx could be > > > removed entirely after you convert reads to use read_callbacks_ctx. > > > > > > IMO, these would be worthwhile cleanups for fscrypt by themselves, without > > > waiting for the read_callbacks stuff to be finalized. Finalizing the > > > read_callbacks stuff will probably require reaching a consensus about how they > > > should work with future filesystem features like fsverity and compression. > > > > > > So to move things forward, I'm considering sending out a series with the above > > > cleanups for fscrypt, plus the equivalent of your patches: > > > > > > "fscrypt_encrypt_page: Loop across all blocks mapped by a page range" > > > "fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page" > > > "Add decryption support for sub-pagesized blocks" (fs/crypto/ part only) > > > > > > Then hopefully we can get all that applied for 5.3 so that fs/crypto/ itself is > > > ready for blocksize != PAGE_SIZE; and get your changes to ext4_bio_write_page(), > > > __ext4_block_zero_page_range(), and ext4_block_write_begin() applied too, so > > > that ext4 is partially ready for encryption with blocksize != PAGE_SIZE. > > > > > > Then only the read_callbacks stuff will remain, to get encryption support into > > > fs/mpage.c and fs/buffer.c. Do you think that's a good plan? > > > > Hi Eric, > > > > IMHO, I will continue posting the next version of the current patchset and if > > there are no serious reservations from FS maintainers the "read callbacks" > > patchset can be merged. In such a scenario, the cleanups being > > non-complicated, can be merged later. > > > > Most of the patches I have in mind are actually things that are in your patchset > already, or have been requested, or will be requested eventually :-). I'm > concerned that people will keep going back and forth on this patchset for a lot > longer, arguing about fsverity, compression, details of the fs/crypto/ stuff, > etc. Moreover it's based on unmerged patches that add the fsverity feature, so > it can't be merged as-is anyway. > > IMO, it's also difficult for people to review the read_callbacks stuff when it's > mixed in with lots of other fscrypt and ext4 changes for blocksize != PAGE_SIZE. > > I actually have a patchset almost ready already, so I'm going to send it out and > see what you think. It *should* make things a lot easier for you, since then > you can base a much smaller read_callbacks patchset on top of it. One of the things that I am concerned most about is the fact that the more we delay merging read_callbacks patchset, the more the chances of filesystems adding further operations that get executed after read I/O completes. Most of the time, these implementations tend to have filesystem specific changes which are going to be very difficult (impossible?) to make them work with read_callback patchset. So instead of making things easier, delaying merging the read_callback patchset ends up actually having the opposite effect. With the read_callback patchset merged, FS feature developers will take read_callback framework into consideration before designing/implementing new related features.
Hi Chandan, On Thu, May 02, 2019 at 11:22:05AM +0530, Chandan Rajendra wrote: > On Thursday, May 2, 2019 3:59:01 AM IST Eric Biggers wrote: > > Hi Chandan, > > > > On Wed, May 01, 2019 at 08:19:35PM +0530, Chandan Rajendra wrote: > > > On Wednesday, May 1, 2019 4:38:41 AM IST Eric Biggers wrote: > > > > On Tue, Apr 30, 2019 at 10:11:35AM -0700, Eric Biggers wrote: > > > > > On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote: > > > > > > For subpage-sized blocks, this commit now encrypts all blocks mapped by > > > > > > a page range. > > > > > > > > > > > > Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> > > > > > > --- > > > > > > fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ > > > > > > 1 file changed, 25 insertions(+), 12 deletions(-) > > > > > > > > > > > > diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c > > > > > > index 4f0d832cae71..2d65b431563f 100644 > > > > > > --- a/fs/crypto/crypto.c > > > > > > +++ b/fs/crypto/crypto.c > > > > > > @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, > > > > > > > > > > Need to update the function comment to clearly explain what this function > > > > > actually does now. > > > > > > > > > > > { > > > > > > struct fscrypt_ctx *ctx; > > > > > > struct page *ciphertext_page = page; > > > > > > + int i, page_nr_blks; > > > > > > int err; > > > > > > > > > > > > BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); > > > > > > > > > > > > > > > > Make a 'blocksize' variable so you don't have to keep calling i_blocksize(). > > > > > > > > > > Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned, > > > > > since the code now assumes it. > > > > > > > > > > const unsigned int blocksize = i_blocksize(inode); > > > > > > > > > > if (!IS_ALIGNED(len | offs, blocksize)) > > > > > return -EINVAL; > > > > > > > > > > However, did you check whether that's always true for ubifs? It looks like it > > > > > may expect to encrypt a prefix of a block, that is only padded to the next > > > > > 16-byte boundary. > > > > > > > > > > > + page_nr_blks = len >> inode->i_blkbits; > > > > > > + > > > > > > if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { > > > > > > /* with inplace-encryption we just encrypt the page */ > > > > > > - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, > > > > > > - ciphertext_page, len, offs, > > > > > > - gfp_flags); > > > > > > - if (err) > > > > > > - return ERR_PTR(err); > > > > > > - > > > > > > + for (i = 0; i < page_nr_blks; i++) { > > > > > > + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, > > > > > > + lblk_num, page, > > > > > > + ciphertext_page, > > > > > > + i_blocksize(inode), offs, > > > > > > + gfp_flags); > > > > > > + if (err) > > > > > > + return ERR_PTR(err); > > > > > > > > Apparently ubifs does encrypt data shorter than the filesystem block size, so > > > > this part is wrong. > > > > > > > > I suggest we split this into two functions, fscrypt_encrypt_block_inplace() and > > > > fscrypt_encrypt_blocks(), so that it's conceptually simpler what each function > > > > does. Currently this works completely differently depending on whether the > > > > filesystem set FS_CFLG_OWN_PAGES in its fscrypt_operations, which is weird. > > > > > > > > I also noticed that using fscrypt_ctx for writes seems to be unnecessary. > > > > AFAICS, page_private(bounce_page) could point directly to the pagecache page. > > > > That would simplify things a lot, especially since then fscrypt_ctx could be > > > > removed entirely after you convert reads to use read_callbacks_ctx. > > > > > > > > IMO, these would be worthwhile cleanups for fscrypt by themselves, without > > > > waiting for the read_callbacks stuff to be finalized. Finalizing the > > > > read_callbacks stuff will probably require reaching a consensus about how they > > > > should work with future filesystem features like fsverity and compression. > > > > > > > > So to move things forward, I'm considering sending out a series with the above > > > > cleanups for fscrypt, plus the equivalent of your patches: > > > > > > > > "fscrypt_encrypt_page: Loop across all blocks mapped by a page range" > > > > "fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page" > > > > "Add decryption support for sub-pagesized blocks" (fs/crypto/ part only) > > > > > > > > Then hopefully we can get all that applied for 5.3 so that fs/crypto/ itself is > > > > ready for blocksize != PAGE_SIZE; and get your changes to ext4_bio_write_page(), > > > > __ext4_block_zero_page_range(), and ext4_block_write_begin() applied too, so > > > > that ext4 is partially ready for encryption with blocksize != PAGE_SIZE. > > > > > > > > Then only the read_callbacks stuff will remain, to get encryption support into > > > > fs/mpage.c and fs/buffer.c. Do you think that's a good plan? > > > > > > Hi Eric, > > > > > > IMHO, I will continue posting the next version of the current patchset and if > > > there are no serious reservations from FS maintainers the "read callbacks" > > > patchset can be merged. In such a scenario, the cleanups being > > > non-complicated, can be merged later. > > > > > > > Most of the patches I have in mind are actually things that are in your patchset > > already, or have been requested, or will be requested eventually :-). I'm > > concerned that people will keep going back and forth on this patchset for a lot > > longer, arguing about fsverity, compression, details of the fs/crypto/ stuff, > > etc. Moreover it's based on unmerged patches that add the fsverity feature, so > > it can't be merged as-is anyway. > > > > IMO, it's also difficult for people to review the read_callbacks stuff when it's > > mixed in with lots of other fscrypt and ext4 changes for blocksize != PAGE_SIZE. > > > > I actually have a patchset almost ready already, so I'm going to send it out and > > see what you think. It *should* make things a lot easier for you, since then > > you can base a much smaller read_callbacks patchset on top of it. > > One of the things that I am concerned most about is the fact that the more we > delay merging read_callbacks patchset, the more the chances of filesystems > adding further operations that get executed after read I/O completes. Most of > the time, these implementations tend to have filesystem specific changes which > are going to be very difficult (impossible?) to make them work with > read_callback patchset. So instead of making things easier, delaying merging > the read_callback patchset ends up actually having the opposite effect. > > With the read_callback patchset merged, FS feature developers will take > read_callback framework into consideration before designing/implementing new > related features. > The main problems are that your patchset mixes up conceptually unrelated changes, and is dependent on future filesystem features. See how it starts by adding read_callbacks support for both fscrypt *and* fsverity (the latter of which is not merged yet), then updates fs/crypto/ to support subpage blocks, *then* goes back and finishes read_callbacks to support buffer_heads since that depended on the fs/crypto/ changes. The ext4 changes for subpage blocks are mixed in too throughout the patchset. So I don't think it can proceed in its current form; it's too much for anyone to handle at once. And I see your first patchset for ext4 encryption with subpage blocks was sent almost a year and a half ago, so it's indeed been going in circles for a while. But based on your work I've been able to get the fs/crypto/ and ext4 preparations for subpage blocks into a clean set of changes by themselves. There are needed in any case, so IMO we should take them first in order to unblock the rest. I don't really understand your point about forcing filesystems to be compatible with read_callbacks. The whole point of read_callbacks is that it's a common support layer which makes it easier for filesystems to do the things they're doing anyway, or will be doing. So it shouldn't affect filesystem designs. Thanks! - Eric
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 4f0d832cae71..2d65b431563f 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, { struct fscrypt_ctx *ctx; struct page *ciphertext_page = page; + int i, page_nr_blks; int err; BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0); + page_nr_blks = len >> inode->i_blkbits; + if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) { /* with inplace-encryption we just encrypt the page */ - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page, - ciphertext_page, len, offs, - gfp_flags); - if (err) - return ERR_PTR(err); - + for (i = 0; i < page_nr_blks; i++) { + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, + lblk_num, page, + ciphertext_page, + i_blocksize(inode), offs, + gfp_flags); + if (err) + return ERR_PTR(err); + ++lblk_num; + offs += i_blocksize(inode); + } return ciphertext_page; } @@ -269,12 +277,17 @@ struct page *fscrypt_encrypt_page(const struct inode *inode, goto errout; ctx->control_page = page; - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, - page, ciphertext_page, len, offs, - gfp_flags); - if (err) { - ciphertext_page = ERR_PTR(err); - goto errout; + + for (i = 0; i < page_nr_blks; i++) { + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, + page, ciphertext_page, + i_blocksize(inode), offs, gfp_flags); + if (err) { + ciphertext_page = ERR_PTR(err); + goto errout; + } + ++lblk_num; + offs += i_blocksize(inode); } SetPagePrivate(ciphertext_page); set_page_private(ciphertext_page, (unsigned long)ctx);
For subpage-sized blocks, this commit now encrypts all blocks mapped by a page range. Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com> --- fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-)