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Message-ID: <alpine.LFD.2.00.1405131310470.2070@localhost.localdomain> Date: Tue, 13 May 2014 13:11:26 +0200 (CEST) From: Lukáš Czerner <lczerner@...hat.com> To: "Darrick J. Wong" <darrick.wong@...cle.com> cc: tytso@....edu, linux-ext4@...r.kernel.org Subject: Re: [PATCH 1/2] libext2fs: support BLKZEROOUT/FALLOC_FL_ZERO_RANGE in ext2fs_zero_blocks On Wed, 7 May 2014, Darrick J. Wong wrote: > Date: Wed, 7 May 2014 17:13:37 -0700 > From: Darrick J. Wong <darrick.wong@...cle.com> > To: Lukáš Czerner <lczerner@...hat.com> > Cc: tytso@....edu, linux-ext4@...r.kernel.org > Subject: [PATCH 1/2] libext2fs: support BLKZEROOUT/FALLOC_FL_ZERO_RANGE in > ext2fs_zero_blocks > > Here's the first part, which teaches the IO manager how to connect with the > zero out ioctls. > > --D > --- > Plumb a new call into the IO manager to support translating > ext2fs_zero_blocks calls into the equivalent kernel-level BLKZEROOUT > ioctl or FALLOC_FL_ZERO_RANGE fallocate flag primitives. > > Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com> > --- > lib/ext2fs/ext2_io.h | 7 +++++- > lib/ext2fs/io_manager.c | 11 ++++++++++ > lib/ext2fs/mkjournal.c | 6 +++++ > lib/ext2fs/unix_io.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 77 insertions(+), 1 deletion(-) > > diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h > index 1894fb8..98d56aa 100644 > --- a/lib/ext2fs/ext2_io.h > +++ b/lib/ext2fs/ext2_io.h > @@ -90,7 +90,9 @@ struct struct_io_manager { > int count, const void *data); > errcode_t (*discard)(io_channel channel, unsigned long long block, > unsigned long long count); > - long reserved[16]; > + errcode_t (*zeroout)(io_channel channel, unsigned long long block, > + unsigned long long count); > + long reserved[15]; > }; > > #define IO_FLAG_RW 0x0001 > @@ -122,6 +124,9 @@ extern errcode_t io_channel_write_blk64(io_channel channel, > extern errcode_t io_channel_discard(io_channel channel, > unsigned long long block, > unsigned long long count); > +extern errcode_t io_channel_zeroout(io_channel channel, > + unsigned long long block, > + unsigned long long count); > extern errcode_t io_channel_alloc_buf(io_channel channel, > int count, void *ptr); > > diff --git a/lib/ext2fs/io_manager.c b/lib/ext2fs/io_manager.c > index 34e4859..569d16a 100644 > --- a/lib/ext2fs/io_manager.c > +++ b/lib/ext2fs/io_manager.c > @@ -112,6 +112,17 @@ errcode_t io_channel_discard(io_channel channel, unsigned long long block, > return EXT2_ET_UNIMPLEMENTED; > } > > +errcode_t io_channel_zeroout(io_channel channel, unsigned long long block, > + unsigned long long count) > +{ > + EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); > + > + if (channel->manager->zeroout) > + return (channel->manager->zeroout)(channel, block, count); > + > + return EXT2_ET_UNIMPLEMENTED; > +} > + > errcode_t io_channel_alloc_buf(io_channel io, int count, void *ptr) > { > size_t size; > diff --git a/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c > index 884d9c0..339c7e1 100644 > --- a/lib/ext2fs/mkjournal.c > +++ b/lib/ext2fs/mkjournal.c > @@ -167,6 +167,12 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, > } > return 0; > } > + > + /* Try a zero out command, if supported */ > + retval = io_channel_zeroout(fs->io, blk, num); > + if (retval == 0) > + return 0; I guess that this should have been in the second patch ? But it's not a big deal. It looks good. Reviewed-by: Lukas Czerner <lczerner@...hat.com> Thanks! -Lukas > + > /* Allocate the zeroizing buffer if necessary */ > if (!buf) { > buf = malloc(fs->blocksize * STRIDE_LENGTH); > diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c > index c3185b6..d070cb0 100644 > --- a/lib/ext2fs/unix_io.c > +++ b/lib/ext2fs/unix_io.c > @@ -922,6 +922,59 @@ unimplemented: > return EXT2_ET_UNIMPLEMENTED; > } > > +#if defined(__linux__) && !defined(BLKZEROOUT) > +#define BLKZEROOUT _IO(0x12,127) > +#endif > + > +#if defined(__linux__) && !defined(FALLOC_FL_ZERO_RANGE) > +#define FALLOC_FL_ZERO_RANGE 0x10 > +#endif > + > +static errcode_t unix_zeroout(io_channel channel, unsigned long long block, > + unsigned long long count) > +{ > + struct unix_private_data *data; > + int ret; > + > + EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); > + data = (struct unix_private_data *) channel->private_data; > + EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL); > + > + if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) { > +#ifdef BLKZEROOUT > + __u64 range[2]; > + > + range[0] = (__u64)(block) * channel->block_size; > + range[1] = (__u64)(count) * channel->block_size; > + > + ret = ioctl(data->dev, BLKZEROOUT, &range); > +#else > + goto unimplemented; > +#endif > + } else { > +#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_ZERO_RANGE) > + /* > + * If we are not on block device, try to use the zero out > + * primitive. > + */ > + ret = fallocate(data->dev, > + FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE, > + (off_t)(block) * channel->block_size, > + (off_t)(count) * channel->block_size); > +#else > + goto unimplemented; > +#endif > + } > + if (ret < 0) { > + if (errno == EOPNOTSUPP) > + goto unimplemented; > + return errno; > + } > + return 0; > +unimplemented: > + return EXT2_ET_UNIMPLEMENTED; > +} > + > static struct struct_io_manager struct_unix_manager = { > EXT2_ET_MAGIC_IO_MANAGER, > "Unix I/O Manager", > @@ -937,6 +990,7 @@ static struct struct_io_manager struct_unix_manager = { > unix_read_blk64, > unix_write_blk64, > unix_discard, > + unix_zeroout, > }; > > io_manager unix_io_manager = &struct_unix_manager; >
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