From: "Darrick J. Wong" <darrick.wong@oracle.com> To: Eric Biggers <ebiggers@kernel.org> Cc: Dave Chinner <david@fromorbit.com>, Satya Tangirala <satyat@google.com>, linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH v4 3/7] iomap: support direct I/O with fscrypt using blk-crypto Date: Wed, 22 Jul 2020 16:32:47 -0700 [thread overview] Message-ID: <20200722233247.GO3151642@magnolia> (raw) In-Reply-To: <20200722232625.GB83434@sol.localdomain> On Wed, Jul 22, 2020 at 04:26:25PM -0700, Eric Biggers wrote: > On Wed, Jul 22, 2020 at 03:34:04PM -0700, Eric Biggers wrote: > > So, something like this: > > > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index 44bad4bb8831..2816194db46c 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -3437,6 +3437,15 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, > > EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; > > > > + /* > > + * When inline encryption is enabled, sometimes I/O to an encrypted file > > + * has to be broken up to guarantee DUN contiguity. Handle this by > > + * limiting the length of the mapping returned. > > + */ > > + if (!(flags & IOMAP_REPORT)) > > + map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, > > + map.m_len); > > + > > if (flags & IOMAP_WRITE) > > ret = ext4_iomap_alloc(inode, &map, flags); > > else > > > > > > That also avoids any confusion between pages and blocks, which is nice. > > Correction: for fiemap, ext4 actually uses ext4_iomap_begin_report() instead of > ext4_iomap_begin(). So we don't need to check for !IOMAP_REPORT. > > Also it could make sense to limit map.m_len after ext4_iomap_alloc() rather than > before, so that we don't limit the length of the extent that gets allocated but > rather just the length that gets returned to iomap. Naïve question here -- if the decision to truncate the bio depends on the file block offset, can you achieve the same thing by capping the length of the iovec prior to iomap_dio_rw? Granted that probably only makes sense if the LBLK IV thing is only supposed to be used infrequently, and having to opencode a silly loop might be more hassle than it's worth... --D > - Eric
WARNING: multiple messages have this Message-ID (diff)
From: "Darrick J. Wong" <darrick.wong@oracle.com> To: Eric Biggers <ebiggers@kernel.org> Cc: Satya Tangirala <satyat@google.com>, Dave Chinner <david@fromorbit.com>, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [f2fs-dev] [PATCH v4 3/7] iomap: support direct I/O with fscrypt using blk-crypto Date: Wed, 22 Jul 2020 16:32:47 -0700 [thread overview] Message-ID: <20200722233247.GO3151642@magnolia> (raw) In-Reply-To: <20200722232625.GB83434@sol.localdomain> On Wed, Jul 22, 2020 at 04:26:25PM -0700, Eric Biggers wrote: > On Wed, Jul 22, 2020 at 03:34:04PM -0700, Eric Biggers wrote: > > So, something like this: > > > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index 44bad4bb8831..2816194db46c 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -3437,6 +3437,15 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, > > EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; > > > > + /* > > + * When inline encryption is enabled, sometimes I/O to an encrypted file > > + * has to be broken up to guarantee DUN contiguity. Handle this by > > + * limiting the length of the mapping returned. > > + */ > > + if (!(flags & IOMAP_REPORT)) > > + map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, > > + map.m_len); > > + > > if (flags & IOMAP_WRITE) > > ret = ext4_iomap_alloc(inode, &map, flags); > > else > > > > > > That also avoids any confusion between pages and blocks, which is nice. > > Correction: for fiemap, ext4 actually uses ext4_iomap_begin_report() instead of > ext4_iomap_begin(). So we don't need to check for !IOMAP_REPORT. > > Also it could make sense to limit map.m_len after ext4_iomap_alloc() rather than > before, so that we don't limit the length of the extent that gets allocated but > rather just the length that gets returned to iomap. Naïve question here -- if the decision to truncate the bio depends on the file block offset, can you achieve the same thing by capping the length of the iovec prior to iomap_dio_rw? Granted that probably only makes sense if the LBLK IV thing is only supposed to be used infrequently, and having to opencode a silly loop might be more hassle than it's worth... --D > - Eric _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2020-07-22 23:33 UTC|newest] Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-20 23:37 [PATCH v4 0/7] add support for direct I/O with fscrypt using blk-crypto Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-20 23:37 ` [PATCH v4 1/7] fscrypt: Add functions for direct I/O support Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-22 17:04 ` Jaegeuk Kim 2020-07-22 17:04 ` [f2fs-dev] " Jaegeuk Kim 2020-07-20 23:37 ` [PATCH v4 2/7] direct-io: add support for fscrypt using blk-crypto Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-22 17:05 ` Jaegeuk Kim 2020-07-22 17:05 ` [f2fs-dev] " Jaegeuk Kim 2020-07-20 23:37 ` [PATCH v4 3/7] iomap: support direct I/O with " Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-22 17:06 ` Jaegeuk Kim 2020-07-22 17:06 ` [f2fs-dev] " Jaegeuk Kim 2020-07-22 21:16 ` Dave Chinner 2020-07-22 21:16 ` [f2fs-dev] " Dave Chinner 2020-07-22 22:34 ` Eric Biggers 2020-07-22 22:34 ` [f2fs-dev] " Eric Biggers 2020-07-22 22:44 ` Matthew Wilcox 2020-07-22 22:44 ` [f2fs-dev] " Matthew Wilcox 2020-07-22 23:12 ` Eric Biggers 2020-07-22 23:12 ` [f2fs-dev] " Eric Biggers 2020-07-22 23:26 ` Eric Biggers 2020-07-22 23:26 ` [f2fs-dev] " Eric Biggers 2020-07-22 23:32 ` Darrick J. Wong [this message] 2020-07-22 23:32 ` Darrick J. Wong 2020-07-22 23:43 ` Eric Biggers 2020-07-22 23:43 ` [f2fs-dev] " Eric Biggers 2020-07-23 22:07 ` Dave Chinner 2020-07-23 22:07 ` [f2fs-dev] " Dave Chinner 2020-07-23 23:03 ` Eric Biggers 2020-07-23 23:03 ` [f2fs-dev] " Eric Biggers 2020-07-24 1:39 ` Dave Chinner 2020-07-24 1:39 ` [f2fs-dev] " Dave Chinner 2020-07-24 3:46 ` Eric Biggers 2020-07-24 3:46 ` [f2fs-dev] " Eric Biggers 2020-07-24 5:31 ` Dave Chinner 2020-07-24 5:31 ` [f2fs-dev] " Dave Chinner 2020-07-24 17:41 ` Eric Biggers 2020-07-24 17:41 ` [f2fs-dev] " Eric Biggers 2020-07-25 23:47 ` Dave Chinner 2020-07-25 23:47 ` [f2fs-dev] " Dave Chinner 2020-07-25 23:59 ` Dave Chinner 2020-07-25 23:59 ` [f2fs-dev] " Dave Chinner 2020-07-26 2:42 ` Eric Biggers 2020-07-26 2:42 ` [f2fs-dev] " Eric Biggers 2020-07-27 17:16 ` Eric Biggers 2020-07-27 17:16 ` [f2fs-dev] " Eric Biggers 2020-07-20 23:37 ` [PATCH v4 4/7] ext4: " Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-22 17:07 ` Jaegeuk Kim 2020-07-22 17:07 ` [f2fs-dev] " Jaegeuk Kim 2020-07-20 23:37 ` [PATCH v4 5/7] f2fs: " Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-21 20:11 ` Jaegeuk Kim 2020-07-21 20:11 ` [f2fs-dev] " Jaegeuk Kim 2020-07-20 23:37 ` [PATCH v4 6/7] fscrypt: document inline encryption support Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-22 17:01 ` Jaegeuk Kim 2020-07-22 17:01 ` [f2fs-dev] " Jaegeuk Kim 2020-07-20 23:37 ` [PATCH v4 7/7] fscrypt: update documentation for direct I/O support Satya Tangirala 2020-07-20 23:37 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-07-21 0:47 ` Eric Biggers 2020-07-21 0:47 ` [f2fs-dev] " Eric Biggers 2020-07-22 16:57 ` Jaegeuk Kim 2020-07-22 16:57 ` [f2fs-dev] " Jaegeuk Kim 2020-07-21 0:56 ` [PATCH v4 0/7] add support for direct I/O with fscrypt using blk-crypto Eric Biggers 2020-07-21 0:56 ` [f2fs-dev] " Eric Biggers
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