Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix read errors race after block cloning #16052

Merged
merged 1 commit into from
Apr 8, 2024
Merged

Fix read errors race after block cloning #16052

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
41 changes: 20 additions & 21 deletions module/zfs/dbuf.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1564,7 +1564,7 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags,
zbookmark_phys_t zb;
uint32_t aflags = ARC_FLAG_NOWAIT;
int err, zio_flags;
blkptr_t bp, *bpp;
blkptr_t bp, *bpp = NULL;

DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
Expand All @@ -1580,29 +1580,28 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags,
goto early_unlock;
}

if (db->db_state == DB_UNCACHED) {
if (db->db_blkptr == NULL) {
bpp = NULL;
} else {
bp = *db->db_blkptr;
/*
* If we have a pending block clone, we don't want to read the
* underlying block, but the content of the block being cloned,
* pointed by the dirty record, so we have the most recent data.
* If there is no dirty record, then we hit a race in a sync
* process when the dirty record is already removed, while the
* dbuf is not yet destroyed. Such case is equivalent to uncached.
*/
if (db->db_state == DB_NOFILL) {
dbuf_dirty_record_t *dr = list_head(&db->db_dirty_records);
if (dr != NULL) {
if (!dr->dt.dl.dr_brtwrite) {
err = EIO;
goto early_unlock;
}
bp = dr->dt.dl.dr_overridden_by;
bpp = &bp;
}
} else {
dbuf_dirty_record_t *dr;

ASSERT3S(db->db_state, ==, DB_NOFILL);
}

/*
* Block cloning: If we have a pending block clone,
* we don't want to read the underlying block, but the content
* of the block being cloned, so we have the most recent data.
*/
dr = list_head(&db->db_dirty_records);
if (dr == NULL || !dr->dt.dl.dr_brtwrite) {
err = EIO;
goto early_unlock;
}
bp = dr->dt.dl.dr_overridden_by;
if (bpp == NULL && db->db_blkptr != NULL) {
bp = *db->db_blkptr;
bpp = &bp;
}

Expand Down
Loading