| Message ID | 91f25251b1d57ee972179d707d13b453f43b5614.1714963428.git.anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs-progs: add support ext4 unwritten file extent | expand |
在 2024/5/6 12:34, Anand Jain 写道: > This patch, along with the dependent patches below, adds support for > ext4 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 flag > > The patch is developed with POV of portability with the current > e2fsprogs library. > > This patch will handle independent unwritten extents by marking them with prealloc > flag 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/foo > 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/foo > > Convert 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/foo > 6874a1733e5785682210d69c07f256f684cf5433c7235ed29848b4a4d52030e0 /mnt/test/foo > > After: > > $ 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/foo > 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/foo > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > --- > 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) 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
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 for >> ext4 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 flag >> >> The patch is developed with POV of portability with the current >> e2fsprogs library. >> >> This patch will handle independent unwritten extents by marking them >> with prealloc >> flag 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/foo >> >> 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 >> /mnt/test/foo >> >> Convert 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/foo >> >> 6874a1733e5785682210d69c07f256f684cf5433c7235ed29848b4a4d52030e0 >> /mnt/test/foo >> >> After: >> >> $ 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/foo >> >> 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 >> /mnt/test/foo >> >> Signed-off-by: Anand Jain <anand.jain@oracle.com> >> --- >> 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
>>> . 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: This patch and the below test case are working as designed it is not a bug/crack, with the current limitation that it should fail (safer than silent corruption) (as shown below) when there is a merged unwritten data extent. ERROR: inode 13 index 0: identified unsupported merged block length 1 wanted 4 This is an intermediary stage while the full support is being added. Given this option, the user will have a choice to work on the identified inode and make it a non-unwritten extent so that btrfs-convert shall be successful. >> >> # 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. > I've tried fixes without success. Empirically, I found that the main issue is extent optimization and merging, which ignores the unwritten flag, idk where is this happening. I think it is during writing the ext4 image at the inode BTRFS_FIRST_FREE_OBJECTID + 1. If avoiding this optimization possible, the extent boundary will align with ext4 and thus its flags. Thanks, Anand
在 2024/5/6 19:26, Anand Jain 写道: > >>>> . 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: > > > This patch and the below test case are working as designed it is not > a bug/crack, with the current limitation that it should fail (safer > than silent corruption) (as shown below) when there is a merged > unwritten data extent. > > > ERROR: inode 13 index 0: identified unsupported merged block length 1 > wanted 4 > > > This is an intermediary stage while the full support is being added. > > > Given this option, the user will have a choice to work on the identified > inode and make it a non-unwritten extent so that btrfs-convert shall be > successful. Nope, this is not acceptable. If a completely valid ext4 (with enough space) can not be converted to btrfs, it's a bug in btrfs-convert and that's why we're here fixing the bug. Requiring interruption from end user is NOT a solution. Please update the patchset to handle such case, especially this is not impossible to solve. Just mark the written part as regular data file extents, and mark the really unwritten one as preallocated. If you really find it too hard to do, just let me take over. Thanks, Qu > > >>> >>> # 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. >> > > I've tried fixes without success. Empirically, I found > that the main issue is extent optimization and merging, > which ignores the unwritten flag, idk where is this > happening. I think it is during writing the ext4 image > at the inode BTRFS_FIRST_FREE_OBJECTID + 1. > > If avoiding this optimization possible, the extent boundary > will align with ext4 and thus its flags. > > Thanks, Anand > >
在 2024/5/6 12:34, Anand Jain 写道: [...] > 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/foo > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > --- > v2: > > . Remove RFC Nope, you didn't even test the patch using the selftests. (Despite the RST introduced failure, the first ext2 is enough to expose your bug). Not to mention the lack of functionality to handle part written part unwritten extents. This is NOT acceptable at all. > + if (ext2fs_extent_open2(src->ext2_fs, src->ext2_ino, > + src->ext2_inode, &handle)) { > + error("ext2fs_extent_open2 failed, inode %d", src->ext2_ino); > + return -EINVAL; > + } Have you tried ext2? ext2fs_extent_open()/open2() all needs the inode to have EXT4_EXTENTS_FL flag, or it would immediately return error. > + > + if (ext2fs_extent_goto2(handle, 0, index)) { > + error("ext2fs_extent_goto2 failed, inode %d num_blocks %llu", > + src->ext2_ino, data->num_blocks); > + ext2fs_extent_free(handle); > + return -EINVAL; > + } > + > + 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 didn't handle the halfwritten extent correctly. And it looks like you didn't even understand how to properly iterate through all the extents. In fact, if you really spent your time to check how debugfs "dump_extents" command works, it would be clear that we can easily iterate the split extents. I strongly doubt if you're handling the case correctly or with any responsibly. I already have a small patch to properly handle all the legacy and newer EXTENTS_FL features, and handle the uninit extents correctly. I'll do cleanup the RST test case first, run the full convert tests at least, with proper test case for it. I appreciate your effort so far, but this is really below our standard. Thanks, Qu
On 5/7/24 09:25, Qu Wenruo wrote: > > > 在 2024/5/6 12:34, Anand Jain 写道: > [...] >> >> 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 >> /mnt/test/foo >> >> Signed-off-by: Anand Jain <anand.jain@oracle.com> >> --- >> v2: >> >> . Remove RFC > > Nope, you didn't even test the patch using the selftests. > (Despite the RST introduced failure, the first ext2 is enough to expose > your bug). > Realizing the existing test case missed testing unwritten extents, I wrote my own, and they passed as expected. Later, I completely forgot running the existing test cases, my bad. Overall, the initial work inspired better designs. I'm glad the issue was resolved.
diff --git a/convert/source-ext2.c b/convert/source-ext2.c index 477c39d9d658..9de591e34c18 100644 --- a/convert/source-ext2.c +++ b/convert/source-ext2.c @@ -208,6 +208,54 @@ static u8 ext2_filetype_conversion_table[EXT2_FT_MAX] = { [EXT2_FT_SYMLINK] = BTRFS_FT_SYMLINK, }; +int ext2_find_unwritten(struct blk_iterate_data *data, int index, + bool *has_unwritten) +{ + ext2_extent_handle_t handle; + struct ext2fs_extent extent; + struct ext2_source_fs *src = (struct ext2_source_fs *) data->source_fs; + + if (ext2fs_extent_open2(src->ext2_fs, src->ext2_ino, + src->ext2_inode, &handle)) { + error("ext2fs_extent_open2 failed, inode %d", src->ext2_ino); + return -EINVAL; + } + + if (ext2fs_extent_goto2(handle, 0, index)) { + error("ext2fs_extent_goto2 failed, inode %d num_blocks %llu", + src->ext2_ino, data->num_blocks); + ext2fs_extent_free(handle); + return -EINVAL; + } + + 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; + } + + 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
This patch, along with the dependent patches below, adds support for ext4 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 flag The patch is developed with POV of portability with the current e2fsprogs library. This patch will handle independent unwritten extents by marking them with prealloc flag 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/foo 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/foo Convert 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/foo 6874a1733e5785682210d69c07f256f684cf5433c7235ed29848b4a4d52030e0 /mnt/test/foo After: $ 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/foo 18619b678a5c207a971a0aa931604f48162e307c57ecdec450d5f095fe9f32c7 /mnt/test/foo Signed-off-by: Anand Jain <anand.jain@oracle.com> --- 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. . Updated the change log. convert/source-ext2.c | 48 +++++++++++++++++++++++++++++++++++++++++++ convert/source-ext2.h | 3 +++ convert/source-fs.c | 25 ++++++++++++++++++++-- convert/source-fs.h | 1 + 4 files changed, 75 insertions(+), 2 deletions(-)