在 2024/5/6 15:11, Qu Wenruo 写道:
在 2024/5/6 12:34, Anand Jain 写道:This patch, along with the dependent patches below, adds support forext4 unmerged unwritten file extents as preallocated file extent in btrfs.btrfs-progs: convert: refactor ext2_create_file_extents add argument ext2_inode btrfs-progs: convert: struct blk_iterate_data, add ext2-specific file inode pointers btrfs-progs: convert: refactor __btrfs_record_file_extent to add a prealloc flagThe patch is developed with POV of portability with the current e2fsprogs library.This patch will handle independent unwritten extents by marking them with preallocflag and will identify merged unwritten extents, triggering a fail. Testcase:$ dd if=/dev/urandom of=/mnt/test/foo bs=4K count=1 conv=fsync status=none $ dd if=/dev/urandom of=/mnt/test/foo bs=4K count=2 conv=fsync seek=1 status=none$ xfs_io -f -c 'falloc -k 12K 12K' /mnt/test/foo$ dd if=/dev/zero of=/mnt/test/foo bs=4K count=1 conv=fsync seek=6 status=none$ filefrag -v /mnt/test/foo Filesystem type is: ef53 File size of /mnt/test/foo is 28672 (7 blocks of 4096 bytes)ext: logical_offset: physical_offset: length: expected: flags:0: 0.. 0: 33280.. 33280: 1: 1: 1.. 2: 33792.. 33793: 2: 33281:2: 3.. 5: 33281.. 33283: 3: 33794: unwritten 3: 6.. 6: 33794.. 33794: 1: 33284: last,eof$ sha256sum /mnt/test/foo18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/fooConvert and compare the checksum Before: $ filefrag -v /mnt/test/foo Filesystem type is: 9123683e File size of /mnt/test/foo is 28672 (7 blocks of 4096 bytes)ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 0: 33280.. 33280: 1: shared 1: 1.. 2: 33792.. 33793: 2: 33281: shared 2: 3.. 6: 33281.. 33284: 4: 33794: last,shared,eof/mnt/test/foo: 3 extents found $ sha256sum /mnt/test/foo6874a1733e5785682210d69c07f256f684cf5433c7235ed29848b4a4d52030e0 /mnt/test/fooAfter: $ filefrag -v /mnt/test/foo Filesystem type is: 9123683e File size of /mnt/test/foo is 28672 (7 blocks of 4096 bytes)ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 0: 33280.. 33280: 1: shared 1: 1.. 2: 33792.. 33793: 2: 33281: shared 2: 3.. 5: 33281.. 33283: 3: 33794: unwritten,shared 3: 6.. 6: 33794.. 33794: 1: 33284: last,shared,eof/mnt/test/foo: 4 extents found $ sha256sum /mnt/test/foo18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/fooSigned-off-by: Anand Jain <anand.jain@xxxxxxxxxx> --- v2: . Remove RFC . Identify the block with a merged preallocated extent and call fail-safe . Qu has an idea that it could be marked as a hole, which may be based on top of this patch.Well, my idea of going holes other than preallocated extents is mostly to avoid the extra @prealloc flag parameter. But that's not a big deal for now, as I found the following way to easily crack your v2 patchset: # fallocate -l 1G test.img # mkfs.ext4 -F test.img # mount test.img $mnt # xfs_io -f -c "falloc 0 16K" $mnt/file # sync # xfs_io -f -c "pwrite 0 4k" -c "pwrite 12k 4k" $mnt/file # umount $mnt # ./btrfs-convert test.img btrfs-convert from btrfs-progs v6.8 Source filesystem: Type: ext2 Label: Blocksize: 4096 UUID: 0f98aa2a-b1ee-4e91-8815-9b9a7b4af00a Target filesystem: Label: Blocksize: 4096 Nodesize: 16384 UUID: 3b8db399-8e25-495b-a41c-47afcb672020 Checksum: crc32c Features: extref, skinny-metadata, no-holes, free-space-tree (default) Data csum: yes Inline data: yes Copy xattr: yes Reported stats: Total space: 1073741824 Free space: 872349696 (81.24%) Inode count: 65536 Free inodes: 65523 Block count: 262144 Create initial btrfs filesystem Create ext2 image file Create btrfs metadata ERROR: inode 13 index 0: identified unsupported merged block length 1 wanted 4 ERROR: failed to copy ext2 inode 13: -22 ERROR: error during copy_inodes -22 WARNING: error during conversion, the original filesystem is not modified [...]+ + memset(&extent, 0, sizeof(struct ext2fs_extent)); + if (ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent)) { + error("ext2fs_extent_get EXT2_EXTENT_CURRENT failed inode %d", + src->ext2_ino); + ext2fs_extent_free(handle); + return -EINVAL; + } + + if (extent.e_pblk != data->disk_block) {+ error("inode %d index %d found wrong extent e_pblk %llu wanted disk_block %llu",+ src->ext2_ino, index, extent.e_pblk, data->disk_block); + ext2fs_extent_free(handle); + return -EINVAL; + } + + if (extent.e_len != data->num_blocks) {+ error("inode %d index %d: identified unsupported merged block length %u wanted %llu",+ src->ext2_ino, index, extent.e_len, data->num_blocks); + ext2fs_extent_free(handle); + return -EINVAL; + }You have to split the extent in this case. As the example I gave, part of the extent can have been written. (And I'm not sure if the e_pblk check is also correct) I believe the example I gave could be a pretty good test case. (Or you can go one step further to interleave every 4K)
Furthermore, I have to consider what is the best way to iterate all data extents of an ext2 inode.
Instead of ext2fs_block_iterate2(), I'm wondering if ext2fs_extent_goto() would be a better solution. (As long as if it can handle holes).
Another thing is, please Cc this series to ext4 mailing list if possible.I hope to get some feedback from the ext4 exports as they may have a much better idea than us.
Thanks, Qu
Thanks, Qu+ + if (extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT) + *has_unwritten = true; + + return 0; +} + static int ext2_dir_iterate_proc(ext2_ino_t dir, int entry, struct ext2_dir_entry *dirent, int offset, int blocksize, diff --git a/convert/source-ext2.h b/convert/source-ext2.h index 026a7cad8ac8..19014d3c25e6 100644 --- a/convert/source-ext2.h +++ b/convert/source-ext2.h @@ -82,6 +82,9 @@ struct ext2_source_fs { ext2_ino_t ext2_ino; }; +int ext2_find_unwritten(struct blk_iterate_data *data, int index, + bool *has_unwritten); + #define EXT2_ACL_VERSION 0x0001 #endif /* BTRFSCONVERT_EXT2 */ diff --git a/convert/source-fs.c b/convert/source-fs.c index df5ce66caf7f..88a6ceaf41f6 100644 --- a/convert/source-fs.c +++ b/convert/source-fs.c @@ -31,6 +31,7 @@ #include "common/extent-tree-utils.h" #include "convert/common.h" #include "convert/source-fs.h" +#include "convert/source-ext2.h" const struct simple_range btrfs_reserved_ranges[3] = { { 0, SZ_1M }, @@ -239,6 +240,15 @@ fail: return ret; } +int find_prealloc(struct blk_iterate_data *data, int index, + bool *has_prealloc) +{ + if (data->source_fs) + return ext2_find_unwritten(data, index, has_prealloc); + + return -EINVAL; +} + /* * Record a file extent in original filesystem into btrfs one. * The special point is, old disk_block can point to a reserved range. @@ -257,6 +267,7 @@ int record_file_blocks(struct blk_iterate_data *data, u64 old_disk_bytenr = disk_block * sectorsize; u64 num_bytes = num_blocks * sectorsize; u64 cur_off = old_disk_bytenr; + int index = data->first_block; /* Hole, pass it to record_file_extent directly */ if (old_disk_bytenr == 0)@@ -276,6 +287,16 @@ int record_file_blocks(struct blk_iterate_data *data,u64 extent_num_bytes; u64 real_disk_bytenr; u64 cur_len; + u64 flags = BTRFS_FILE_EXTENT_REG; + bool has_prealloc = false; + + if (find_prealloc(data, index, &has_prealloc)) { + data->errcode = -1; + return -EINVAL; + } + + if (has_prealloc) + flags = BTRFS_FILE_EXTENT_PREALLOC; key.objectid = data->convert_ino; key.type = BTRFS_EXTENT_DATA_KEY;@@ -316,12 +337,12 @@ int record_file_blocks(struct blk_iterate_data *data,old_disk_bytenr + num_bytes) - cur_off; ret = btrfs_record_file_extent(data->trans, data->root, data->objectid, data->inode, file_pos, - real_disk_bytenr, cur_len, - BTRFS_FILE_EXTENT_REG); + real_disk_bytenr, cur_len, flags); if (ret < 0) break; cur_off += cur_len; file_pos += cur_len; + index++; /* * No need to care about csum diff --git a/convert/source-fs.h b/convert/source-fs.h index 25916c65681b..db7ead422585 100644 --- a/convert/source-fs.h +++ b/convert/source-fs.h@@ -153,5 +153,6 @@ int read_disk_extent(struct btrfs_root *root, u64 bytenr,u32 num_bytes, char *buffer); int record_file_blocks(struct blk_iterate_data *data, u64 file_block, u64 disk_block, u64 num_blocks);+int find_prealloc(struct blk_iterate_data *data, int index, bool *has_prealloc);#endif
