From 3d28f54589909de7abe477c2ca9d2ff7b0f2404d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sat, 28 Mar 2015 23:01:08 -0400 Subject: [PATCH] libext2fs: zero blocks via FALLOC_FL_ZERO_RANGE in ext2fs_zero_blocks Plumb a new call into the IO manager to support translating ext2fs_zero_blocks calls into the equivalent FALLOC_FL_ZERO_RANGE fallocate flag primitive when possible. This patch provides _only_ support for file-based images. Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o --- lib/ext2fs/ext2_io.h | 7 ++++- lib/ext2fs/io_manager.c | 11 +++++++ lib/ext2fs/mkjournal.c | 5 +++ lib/ext2fs/test_io.c | 21 +++++++++++++ lib/ext2fs/unix_io.c | 67 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 110 insertions(+), 1 deletion(-) diff --git a/lib/ext2fs/ext2_io.h b/lib/ext2fs/ext2_io.h index 4c5a5c5e..1faa720a 100644 --- a/lib/ext2fs/ext2_io.h +++ b/lib/ext2fs/ext2_io.h @@ -93,7 +93,9 @@ struct struct_io_manager { errcode_t (*cache_readahead)(io_channel channel, unsigned long long block, unsigned long long count); - long reserved[15]; + errcode_t (*zeroout)(io_channel channel, unsigned long long block, + unsigned long long count); + long reserved[14]; }; #define IO_FLAG_RW 0x0001 @@ -125,6 +127,9 @@ 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); extern errcode_t io_channel_cache_readahead(io_channel io, diff --git a/lib/ext2fs/io_manager.c b/lib/ext2fs/io_manager.c index dc5888db..c395d615 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 fcc6741f..c42cb98d 100644 --- a/lib/ext2fs/mkjournal.c +++ b/lib/ext2fs/mkjournal.c @@ -170,6 +170,11 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, if (num <= 0) return 0; + /* Try a zero out command, if supported */ + retval = io_channel_zeroout(fs->io, blk, num); + if (retval == 0) + return 0; + /* Allocate the zeroizing buffer if necessary */ if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) { void *p; diff --git a/lib/ext2fs/test_io.c b/lib/ext2fs/test_io.c index b03a9395..f7c50d1b 100644 --- a/lib/ext2fs/test_io.c +++ b/lib/ext2fs/test_io.c @@ -86,6 +86,7 @@ void (*test_io_cb_write_byte) #define TEST_FLAG_SET_OPTION 0x20 #define TEST_FLAG_DISCARD 0x40 #define TEST_FLAG_READAHEAD 0x80 +#define TEST_FLAG_ZEROOUT 0x100 static void test_dump_block(io_channel channel, struct test_private_data *data, @@ -507,6 +508,25 @@ static errcode_t test_cache_readahead(io_channel channel, return retval; } +static errcode_t test_zeroout(io_channel channel, unsigned long long block, + unsigned long long count) +{ + struct test_private_data *data; + errcode_t retval = 0; + + EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL); + data = (struct test_private_data *) channel->private_data; + EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_TEST_IO_CHANNEL); + + if (data->real) + retval = io_channel_zeroout(data->real, block, count); + if (data->flags & TEST_FLAG_ZEROOUT) + fprintf(data->outfile, + "Test_io: zeroout(%llu, %llu) returned %s\n", + block, count, retval ? error_message(retval) : "OK"); + return retval; +} + static struct struct_io_manager struct_test_manager = { .magic = EXT2_ET_MAGIC_IO_MANAGER, .name = "Test I/O Manager", @@ -523,6 +543,7 @@ static struct struct_io_manager struct_test_manager = { .write_blk64 = test_write_blk64, .discard = test_discard, .cache_readahead = test_cache_readahead, + .zeroout = test_zeroout, }; io_manager test_io_manager = &struct_test_manager; diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c index c3a8ea5f..3fce5c01 100644 --- a/lib/ext2fs/unix_io.c +++ b/lib/ext2fs/unix_io.c @@ -987,6 +987,72 @@ unimplemented: return EXT2_ET_UNIMPLEMENTED; } +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 (getenv("UNIX_IO_NOZEROOUT")) + goto unimplemented; + + if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) { + /* Not implemented until the BLKZEROOUT mess is fixed */ + goto unimplemented; + } else { + /* Regular file, try to use truncate/punch/zero. */ +#if defined(HAVE_FALLOCATE) && (defined(FALLOC_FL_ZERO_RANGE) || \ + (defined(FALLOC_FL_PUNCH_HOLE) && defined(FALLOC_FL_KEEP_SIZE))) + struct stat statbuf; + + if (count == 0) + return 0; + /* + * If we're trying to zero a range past the end of the file, + * extend the file size, then punch (or zero_range) everything. + */ + ret = fstat(data->dev, &statbuf); + if (ret) + goto err; + if (statbuf.st_size < (block + count) * channel->block_size) { + ret = ftruncate(data->dev, + (block + count) * channel->block_size); + if (ret) + goto err; + } +#if defined(FALLOC_FL_PUNCH_HOLE) && defined(FALLOC_FL_KEEP_SIZE) + ret = fallocate(data->dev, + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, + (off_t)(block) * channel->block_size, + (off_t)(count) * channel->block_size); + if (ret == 0) + goto err; +#endif +#ifdef FALLOC_FL_ZERO_RANGE + ret = fallocate(data->dev, + FALLOC_FL_ZERO_RANGE, + (off_t)(block) * channel->block_size, + (off_t)(count) * channel->block_size); +#endif +#else + goto unimplemented; +#endif /* HAVE_FALLOCATE && (ZERO_RANGE || (PUNCH_HOLE && KEEP_SIZE)) */ + } +err: + 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 = { .magic = EXT2_ET_MAGIC_IO_MANAGER, .name = "Unix I/O Manager", @@ -1003,6 +1069,7 @@ static struct struct_io_manager struct_unix_manager = { .write_blk64 = unix_write_blk64, .discard = unix_discard, .cache_readahead = unix_cache_readahead, + .zeroout = unix_zeroout, }; io_manager unix_io_manager = &struct_unix_manager;