| Message ID | 4360e4f01d47cca45930ea74b02c5d734a9cbfbd.1681093106.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [pre-6.4] btrfs: dev-replace: error out if we have unrepaired metadata error during | expand |
On 10/4/23 10:22, Qu Wenruo wrote: > This is for pre-6.4 kernels, as scrub code goes through a huge rework. > > [BUG] > Even before the scrub rework, if we have some corrupted metadata failed > to be repaired during replace, we still continue replace and let it > finish just as there is nothing wrong: > > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 > BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 > BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad bytenr, has 0 want 5578752 > BTRFS error (device dm-4): unable to fixup (regular) error at logical 5578752 on dev /dev/mapper/test-scratch1 > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 finished > > This can lead to unexpected problems for the result fs. > > [CAUSE] > Btrfs reuses scrub code path for dev-replace to iterate all dev extents. > > But unlike scrub, dev-replace doesn't really bother to check the scrub > progress, which records all the errors found during replace. > > And even if we checks the progress, we can not really determine which > errors are minor, which are critical just by the plain numbers. > (remember we don't treat metadata/data checksum error differently). > > This behavior is there from the very beginning. > > [FIX] > Instead of continue the replace, just error out if we hit an unrepaired > metadata sector. > > Now the dev-replace would be rejected with -EIO, to inform the user. > Although it also means, the fs has some metadata error which can not be > repaired, the user would be super upset anyway. IMO, the original design is fair as it does not capture scrub errors during the replace. Because the purpose of the scrub is different from the replace from the user POV. However, after the replace, if scrubbed it will still capture any errors? No? Thanks, Anand > > The new dmesg would look like this: > > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS error (device dm-4): unable to fixup (regular) error at logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560 > BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 > BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 > BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata sector at 5578752 > BTRFS error (device dm-4): btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, /dev/mapper/test-scratch2) failed -5 > > CC: stable@vger.kernel.org > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > I'm not sure how should we merge this patch. > > The misc-next is already merging the new scrub code, but the problem is > there for all old kernels thus we need such fixes. > > Maybe we can merge this fix before the scrub rework, then the rework, > and finally the better fix using reworked interface? > --- > fs/btrfs/scrub.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c > index ef4046a2572c..71f64b9bcd9f 100644 > --- a/fs/btrfs/scrub.c > +++ b/fs/btrfs/scrub.c > @@ -195,6 +195,7 @@ struct scrub_ctx { > struct mutex wr_lock; > struct btrfs_device *wr_tgtdev; > bool flush_all_writes; > + bool has_meta_failed; > > /* > * statistics > @@ -1380,6 +1381,8 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check) > btrfs_err_rl_in_rcu(fs_info, > "unable to fixup (regular) error at logical %llu on dev %s", > logical, btrfs_dev_name(dev)); > + if (is_metadata) > + sctx->has_meta_failed = true; > } > > out: > @@ -3838,6 +3841,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, > > blk_finish_plug(&plug); > > + /* > + * If we have metadata unable to be repaired, we should error > + * out the dev-replace. > + */ > + if (sctx->is_dev_replace && sctx->has_meta_failed && ret >= 0) > + ret = -EIO; > if (sctx->is_dev_replace && ret >= 0) { > int ret2; >
On 2023/4/10 12:20, Anand Jain wrote: > On 10/4/23 10:22, Qu Wenruo wrote: >> This is for pre-6.4 kernels, as scrub code goes through a huge rework. >> >> [BUG] >> Even before the scrub rework, if we have some corrupted metadata failed >> to be repaired during replace, we still continue replace and let it >> finish just as there is nothing wrong: >> >> BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 >> (devid 1) to /dev/mapper/test-scratch2 started >> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >> csum, has 0x00000000 want 0xade80ca1 >> BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad >> csum, has 0x00000000 want 0xade80ca1 >> BTRFS warning (device dm-4): checksum error at logical 5578752 on >> dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level >> 0) in tree 5 >> BTRFS warning (device dm-4): checksum error at logical 5578752 on >> dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level >> 0) in tree 5 >> BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr >> 0, rd 0, flush 0, corrupt 1, gen 0 >> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >> bytenr, has 0 want 5578752 >> BTRFS error (device dm-4): unable to fixup (regular) error at >> logical 5578752 on dev /dev/mapper/test-scratch1 >> BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 >> (devid 1) to /dev/mapper/test-scratch2 finished >> >> This can lead to unexpected problems for the result fs. >> >> [CAUSE] >> Btrfs reuses scrub code path for dev-replace to iterate all dev extents. >> >> But unlike scrub, dev-replace doesn't really bother to check the scrub >> progress, which records all the errors found during replace. >> >> And even if we checks the progress, we can not really determine which >> errors are minor, which are critical just by the plain numbers. >> (remember we don't treat metadata/data checksum error differently). >> >> This behavior is there from the very beginning. >> >> [FIX] >> Instead of continue the replace, just error out if we hit an unrepaired >> metadata sector. >> >> Now the dev-replace would be rejected with -EIO, to inform the user. >> Although it also means, the fs has some metadata error which can not be >> repaired, the user would be super upset anyway. > > IMO, the original design is fair as it does not capture scrub errors > during the replace. Because the purpose of the scrub is different from > the replace from the user POV. The problem is, after such replace, the corrupted metadata would have different content (we just don't do the writeback at all). Even worse, the end user is not even aware of the problem, unless dmesg is manually checked. This means we changed the result fs during the replace, which removes the tiny chance to do a manual repair (aka, manually re-generate the checksum). > However, after the replace, if scrubbed it will still capture any > errors? No? It's not about scrub after scrub. Such replace should not even finish. Thanks, Qu > > Thanks, Anand > > >> >> The new dmesg would look like this: >> >> BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 >> (devid 1) to /dev/mapper/test-scratch2 started >> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >> csum, has 0x00000000 want 0xade80ca1 >> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >> csum, has 0x00000000 want 0xade80ca1 >> BTRFS error (device dm-4): unable to fixup (regular) error at >> logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560 >> BTRFS warning (device dm-4): header error at logical 5570560 on dev >> /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) >> in tree 5 >> BTRFS warning (device dm-4): header error at logical 5570560 on dev >> /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) >> in tree 5 >> BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata >> sector at 5578752 >> BTRFS error (device dm-4): >> btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, >> /dev/mapper/test-scratch2) failed -5 >> >> CC: stable@vger.kernel.org >> Signed-off-by: Qu Wenruo <wqu@suse.com> >> --- >> I'm not sure how should we merge this patch. >> >> The misc-next is already merging the new scrub code, but the problem is >> there for all old kernels thus we need such fixes. >> >> Maybe we can merge this fix before the scrub rework, then the rework, >> and finally the better fix using reworked interface? >> --- >> fs/btrfs/scrub.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c >> index ef4046a2572c..71f64b9bcd9f 100644 >> --- a/fs/btrfs/scrub.c >> +++ b/fs/btrfs/scrub.c >> @@ -195,6 +195,7 @@ struct scrub_ctx { >> struct mutex wr_lock; >> struct btrfs_device *wr_tgtdev; >> bool flush_all_writes; >> + bool has_meta_failed; >> /* >> * statistics >> @@ -1380,6 +1381,8 @@ static int scrub_handle_errored_block(struct >> scrub_block *sblock_to_check) >> btrfs_err_rl_in_rcu(fs_info, >> "unable to fixup (regular) error at logical %llu on dev >> %s", >> logical, btrfs_dev_name(dev)); >> + if (is_metadata) >> + sctx->has_meta_failed = true; >> } >> out: >> @@ -3838,6 +3841,12 @@ static noinline_for_stack int >> scrub_stripe(struct scrub_ctx *sctx, >> blk_finish_plug(&plug); >> + /* >> + * If we have metadata unable to be repaired, we should error >> + * out the dev-replace. >> + */ >> + if (sctx->is_dev_replace && sctx->has_meta_failed && ret >= 0) >> + ret = -EIO; >> if (sctx->is_dev_replace && ret >= 0) { >> int ret2; >
On Mon, Apr 10, 2023 at 10:22:57AM +0800, Qu Wenruo wrote: > This is for pre-6.4 kernels, as scrub code goes through a huge rework. > > [BUG] > Even before the scrub rework, if we have some corrupted metadata failed > to be repaired during replace, we still continue replace and let it > finish just as there is nothing wrong: > > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 > BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 > BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad bytenr, has 0 want 5578752 > BTRFS error (device dm-4): unable to fixup (regular) error at logical 5578752 on dev /dev/mapper/test-scratch1 > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 finished > > This can lead to unexpected problems for the result fs. > > [CAUSE] > Btrfs reuses scrub code path for dev-replace to iterate all dev extents. > > But unlike scrub, dev-replace doesn't really bother to check the scrub > progress, which records all the errors found during replace. > > And even if we checks the progress, we can not really determine which > errors are minor, which are critical just by the plain numbers. > (remember we don't treat metadata/data checksum error differently). > > This behavior is there from the very beginning. > > [FIX] > Instead of continue the replace, just error out if we hit an unrepaired > metadata sector. > > Now the dev-replace would be rejected with -EIO, to inform the user. > Although it also means, the fs has some metadata error which can not be > repaired, the user would be super upset anyway. > > The new dmesg would look like this: > > BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 > BTRFS error (device dm-4): unable to fixup (regular) error at logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560 > BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 > BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 > BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata sector at 5578752 > BTRFS error (device dm-4): btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, /dev/mapper/test-scratch2) failed -5 > > CC: stable@vger.kernel.org > Signed-off-by: Qu Wenruo <wqu@suse.com> > --- > I'm not sure how should we merge this patch. > > The misc-next is already merging the new scrub code, but the problem is > there for all old kernels thus we need such fixes. > > Maybe we can merge this fix before the scrub rework, then the rework, > and finally the better fix using reworked interface? Rebasing the whole 6.4 queue with the scrub rewrite would be too much and there's no time left for that before merge window. We'd also need to retest it after such change. If we have the fix in master we can do a backport to older stable tree, in this case it would not be close implementation-wise but the effects should be the same. Doing two separate fixes will also avoid merge conflicts.
On 10/4/23 14:42, Qu Wenruo wrote: > > > On 2023/4/10 12:20, Anand Jain wrote: >> On 10/4/23 10:22, Qu Wenruo wrote: >>> This is for pre-6.4 kernels, as scrub code goes through a huge rework. >>> >>> [BUG] >>> Even before the scrub rework, if we have some corrupted metadata failed >>> to be repaired during replace, we still continue replace and let it >>> finish just as there is nothing wrong: >>> >>> BTRFS info (device dm-4): dev_replace from >>> /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started >>> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >>> csum, has 0x00000000 want 0xade80ca1 >>> BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad >>> csum, has 0x00000000 want 0xade80ca1 >>> BTRFS warning (device dm-4): checksum error at logical 5578752 on >>> dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level >>> 0) in tree 5 >>> BTRFS warning (device dm-4): checksum error at logical 5578752 on >>> dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level >>> 0) in tree 5 >>> BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr >>> 0, rd 0, flush 0, corrupt 1, gen 0 >>> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >>> bytenr, has 0 want 5578752 >>> BTRFS error (device dm-4): unable to fixup (regular) error at >>> logical 5578752 on dev /dev/mapper/test-scratch1 >>> BTRFS info (device dm-4): dev_replace from >>> /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 >>> finished >>> >>> This can lead to unexpected problems for the result fs. >>> >>> [CAUSE] >>> Btrfs reuses scrub code path for dev-replace to iterate all dev extents. >>> >>> But unlike scrub, dev-replace doesn't really bother to check the scrub >>> progress, which records all the errors found during replace. >>> >>> And even if we checks the progress, we can not really determine which >>> errors are minor, which are critical just by the plain numbers. >>> (remember we don't treat metadata/data checksum error differently). >>> >>> This behavior is there from the very beginning. >>> >>> [FIX] >>> Instead of continue the replace, just error out if we hit an unrepaired >>> metadata sector. >>> >>> Now the dev-replace would be rejected with -EIO, to inform the user. >>> Although it also means, the fs has some metadata error which can not be >>> repaired, the user would be super upset anyway. >> >> IMO, the original design is fair as it does not capture scrub errors >> during the replace. Because the purpose of the scrub is different from >> the replace from the user POV. > > The problem is, after such replace, the corrupted metadata would have > different content (we just don't do the writeback at all). > Even worse, the end user is not even aware of the problem, unless dmesg > is manually checked. > > This means we changed the result fs during the replace, which removes > the tiny chance to do a manual repair (aka, manually re-generate the > checksum). My concern is, following this patch, the user will be able to replace the device only if the filesystem is healthy (passes scrub). But, I got it, there isn't any other choice. Thanks, Anand > >> However, after the replace, if scrubbed it will still capture any >> errors? No? > > It's not about scrub after scrub. Such replace should not even finish. > > Thanks, > Qu >> >> Thanks, Anand >> >> >>> >>> The new dmesg would look like this: >>> >>> BTRFS info (device dm-4): dev_replace from >>> /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started >>> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >>> csum, has 0x00000000 want 0xade80ca1 >>> BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad >>> csum, has 0x00000000 want 0xade80ca1 >>> BTRFS error (device dm-4): unable to fixup (regular) error at >>> logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560 >>> BTRFS warning (device dm-4): header error at logical 5570560 on dev >>> /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) >>> in tree 5 >>> BTRFS warning (device dm-4): header error at logical 5570560 on dev >>> /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) >>> in tree 5 >>> BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata >>> sector at 5578752 >>> BTRFS error (device dm-4): >>> btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, >>> /dev/mapper/test-scratch2) failed -5 >>> >>> CC: stable@vger.kernel.org >>> Signed-off-by: Qu Wenruo <wqu@suse.com> >>> --- >>> I'm not sure how should we merge this patch. >>> >>> The misc-next is already merging the new scrub code, but the problem is >>> there for all old kernels thus we need such fixes. >>> >>> Maybe we can merge this fix before the scrub rework, then the rework, >>> and finally the better fix using reworked interface? >>> --- >>> fs/btrfs/scrub.c | 9 +++++++++ >>> 1 file changed, 9 insertions(+) >>> >>> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c >>> index ef4046a2572c..71f64b9bcd9f 100644 >>> --- a/fs/btrfs/scrub.c >>> +++ b/fs/btrfs/scrub.c >>> @@ -195,6 +195,7 @@ struct scrub_ctx { >>> struct mutex wr_lock; >>> struct btrfs_device *wr_tgtdev; >>> bool flush_all_writes; >>> + bool has_meta_failed; >>> /* >>> * statistics >>> @@ -1380,6 +1381,8 @@ static int scrub_handle_errored_block(struct >>> scrub_block *sblock_to_check) >>> btrfs_err_rl_in_rcu(fs_info, >>> "unable to fixup (regular) error at logical %llu on dev >>> %s", >>> logical, btrfs_dev_name(dev)); >>> + if (is_metadata) >>> + sctx->has_meta_failed = true; >>> } >>> out: >>> @@ -3838,6 +3841,12 @@ static noinline_for_stack int >>> scrub_stripe(struct scrub_ctx *sctx, >>> blk_finish_plug(&plug); >>> + /* >>> + * If we have metadata unable to be repaired, we should error >>> + * out the dev-replace. >>> + */ >>> + if (sctx->is_dev_replace && sctx->has_meta_failed && ret >= 0) >>> + ret = -EIO; >>> if (sctx->is_dev_replace && ret >= 0) { >>> int ret2; >>
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index ef4046a2572c..71f64b9bcd9f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -195,6 +195,7 @@ struct scrub_ctx { struct mutex wr_lock; struct btrfs_device *wr_tgtdev; bool flush_all_writes; + bool has_meta_failed; /* * statistics @@ -1380,6 +1381,8 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check) btrfs_err_rl_in_rcu(fs_info, "unable to fixup (regular) error at logical %llu on dev %s", logical, btrfs_dev_name(dev)); + if (is_metadata) + sctx->has_meta_failed = true; } out: @@ -3838,6 +3841,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx, blk_finish_plug(&plug); + /* + * If we have metadata unable to be repaired, we should error + * out the dev-replace. + */ + if (sctx->is_dev_replace && sctx->has_meta_failed && ret >= 0) + ret = -EIO; if (sctx->is_dev_replace && ret >= 0) { int ret2;
This is for pre-6.4 kernels, as scrub code goes through a huge rework. [BUG] Even before the scrub rework, if we have some corrupted metadata failed to be repaired during replace, we still continue replace and let it finish just as there is nothing wrong: BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 BTRFS warning (device dm-4): tree block 5578752 mirror 0 has bad csum, has 0x00000000 want 0xade80ca1 BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 BTRFS warning (device dm-4): checksum error at logical 5578752 on dev /dev/mapper/test-scratch1, physical 5578752: metadata leaf (level 0) in tree 5 BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad bytenr, has 0 want 5578752 BTRFS error (device dm-4): unable to fixup (regular) error at logical 5578752 on dev /dev/mapper/test-scratch1 BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 finished This can lead to unexpected problems for the result fs. [CAUSE] Btrfs reuses scrub code path for dev-replace to iterate all dev extents. But unlike scrub, dev-replace doesn't really bother to check the scrub progress, which records all the errors found during replace. And even if we checks the progress, we can not really determine which errors are minor, which are critical just by the plain numbers. (remember we don't treat metadata/data checksum error differently). This behavior is there from the very beginning. [FIX] Instead of continue the replace, just error out if we hit an unrepaired metadata sector. Now the dev-replace would be rejected with -EIO, to inform the user. Although it also means, the fs has some metadata error which can not be repaired, the user would be super upset anyway. The new dmesg would look like this: BTRFS info (device dm-4): dev_replace from /dev/mapper/test-scratch1 (devid 1) to /dev/mapper/test-scratch2 started BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 BTRFS warning (device dm-4): tree block 5578752 mirror 1 has bad csum, has 0x00000000 want 0xade80ca1 BTRFS error (device dm-4): unable to fixup (regular) error at logical 5570560 on dev /dev/mapper/test-scratch1 physical 5570560 BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 BTRFS warning (device dm-4): header error at logical 5570560 on dev /dev/mapper/test-scratch1, physical 5570560: metadata leaf (level 0) in tree 5 BTRFS error (device dm-4): stripe 5570560 has unrepaired metadata sector at 5578752 BTRFS error (device dm-4): btrfs_scrub_dev(/dev/mapper/test-scratch1, 1, /dev/mapper/test-scratch2) failed -5 CC: stable@vger.kernel.org Signed-off-by: Qu Wenruo <wqu@suse.com> --- I'm not sure how should we merge this patch. The misc-next is already merging the new scrub code, but the problem is there for all old kernels thus we need such fixes. Maybe we can merge this fix before the scrub rework, then the rework, and finally the better fix using reworked interface? --- fs/btrfs/scrub.c | 9 +++++++++ 1 file changed, 9 insertions(+)