| Message ID | cover.1711416290.git.naohiro.aota@wdc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | btrfs: zoned: fix EXTENT_BUFFER_ZONED_ZEROOUT handling | expand |
On 26.03.24 06:40, Naohiro Aota wrote: > Btrfs clears the content of an extent buffer marked as > EXTENT_BUFFER_ZONED_ZEROOUT before the bio submission. This mechanism is > introduced to prevent a write hole of an extent buffer, which is once > allocated, marked dirty, but turns out unnecessary and cleaned up within > one transaction operation. > > Currently, btrfs_clear_buffer_dirty() marks the extent buffer as > EXTENT_BUFFER_ZONED_ZEROOUT, and skip the enteri function. If this call > happens while the buffer is under IO (with the WRITEBACK flag set, without > the DIRTY flag), we can add the ZEROOUT flag and clear the buffer's content > just before a bio submission. As a result, 1) it can lead to adding faulty > delayed reference item which leads to a FS corrupted (EUCLEAN) error, and > 2) it writes out cleared tree node on disk > > Fix them by skipping a non-dirty extent buffer. Also, the second patch adds > ASSERT and WARN to catch invalid EXTENT_BUFFER_ZONED_ZEROOUT state. > > Naohiro Aota (2): > btrfs: zoned: do not flag ZEROOUT on non-dirty extent bufffer > btrfs: zoned: add ASSERT and WARN for EXTENT_BUFFER_ZONED_ZEROOUT > handling > > fs/btrfs/extent-tree.c | 8 ++++++++ > fs/btrfs/extent_io.c | 3 ++- > 2 files changed, 10 insertions(+), 1 deletion(-) > Looks good, thanks Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> One minor nit, codespell flagged a typo, but I'm too blind to find it: johannes@nuc:linux (review)$ b4 shazam cover.1711416290.git.naohiro.aota@wdc.com Grabbing thread from lore.kernel.org/all/cover.1711416290.git.naohiro.aota@wdc.com/t.mbox.gz Checking for newer revisions Grabbing search results from lore.kernel.org Analyzing 3 messages in the thread Checking attestation on all messages, may take a moment... --- ✓ [PATCH v2 1/2] btrfs: zoned: do not flag ZEROOUT on non-dirty extent bufffer ✓ [PATCH v2 2/2] btrfs: zoned: add ASSERT and WARN for EXTENT_BUFFER_ZONED_ZEROOUT handling --- ✓ Signed: DKIM/wdc.com --- Total patches: 2 --- Applying: btrfs: zoned: do not flag ZEROOUT on non-dirty extent bufffer Applying: btrfs: zoned: add ASSERT and WARN for EXTENT_BUFFER_ZONED_ZEROOUT handling /home/johannes/src/linux/.git/rebase-apply/final-commit:1: bufffer ==> buffer
On Tue, Mar 26, 2024 at 04:50:46PM +0000, Johannes Thumshirn wrote: > On 26.03.24 06:40, Naohiro Aota wrote: > > Btrfs clears the content of an extent buffer marked as > > EXTENT_BUFFER_ZONED_ZEROOUT before the bio submission. This mechanism is > > introduced to prevent a write hole of an extent buffer, which is once > > allocated, marked dirty, but turns out unnecessary and cleaned up within > > one transaction operation. > > > > Currently, btrfs_clear_buffer_dirty() marks the extent buffer as > > EXTENT_BUFFER_ZONED_ZEROOUT, and skip the enteri function. If this call ^^^^^^ > One minor nit, codespell flagged a typo, but I'm too blind to find it: There's the typo.
Btrfs clears the content of an extent buffer marked as EXTENT_BUFFER_ZONED_ZEROOUT before the bio submission. This mechanism is introduced to prevent a write hole of an extent buffer, which is once allocated, marked dirty, but turns out unnecessary and cleaned up within one transaction operation. Currently, btrfs_clear_buffer_dirty() marks the extent buffer as EXTENT_BUFFER_ZONED_ZEROOUT, and skip the enteri function. If this call happens while the buffer is under IO (with the WRITEBACK flag set, without the DIRTY flag), we can add the ZEROOUT flag and clear the buffer's content just before a bio submission. As a result, 1) it can lead to adding faulty delayed reference item which leads to a FS corrupted (EUCLEAN) error, and 2) it writes out cleared tree node on disk Fix them by skipping a non-dirty extent buffer. Also, the second patch adds ASSERT and WARN to catch invalid EXTENT_BUFFER_ZONED_ZEROOUT state. Naohiro Aota (2): btrfs: zoned: do not flag ZEROOUT on non-dirty extent bufffer btrfs: zoned: add ASSERT and WARN for EXTENT_BUFFER_ZONED_ZEROOUT handling fs/btrfs/extent-tree.c | 8 ++++++++ fs/btrfs/extent_io.c | 3 ++- 2 files changed, 10 insertions(+), 1 deletion(-)