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Do not break subsequent small writes badly when a big write is canceled

Vitaliy Filippov 2021-01-19 01:43:00 +03:00
parent 29bac892ad
commit 314b20437b
2 changed files with 33 additions and 8 deletions
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1
src/blockstore_impl.h
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@ -271,6 +271,7 @@ class blockstore_impl_t
// Write
bool enqueue_write(blockstore_op_t *op);
void cancel_all_writes(blockstore_op_t *op, blockstore_dirty_db_t::iterator dirty_it, int retval);
int dequeue_write(blockstore_op_t *op);
int dequeue_del(blockstore_op_t *op);
int continue_write(blockstore_op_t *op);

40
src/blockstore_write.cpp
View File

@ -124,6 +124,29 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
return true;
}
void blockstore_impl_t::cancel_all_writes(blockstore_op_t *op, blockstore_dirty_db_t::iterator dirty_it, int retval)
{
while (dirty_it != dirty_db.end() && dirty_it->first.oid == op->oid)
{
dirty_db.erase(dirty_it++);
}
bool found = false;
for (auto other_op: submit_queue)
{
if (!found && other_op == op)
found = true;
else if (found && other_op->oid == op->oid &&
(other_op->opcode == BS_OP_WRITE || other_op->opcode == BS_OP_WRITE_STABLE))
{
// Mark operations to cancel them
PRIV(other_op)->real_version = UINT64_MAX;
other_op->retval = retval;
}
}
op->retval = retval;
FINISH_OP(op);
}
// First step of the write algorithm: dequeue operation and submit initial write(s)
int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
{
@ -143,6 +166,12 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
}
if (PRIV(op)->real_version != 0)
{
if (PRIV(op)->real_version == UINT64_MAX)
{
// This is the flag value used to cancel operations
FINISH_OP(op);
return 1;
}
// Restore original low version number for unblocked operations
#ifdef BLOCKSTORE_DEBUG
printf("Restoring %lx:%lx version: v%lu -> v%lu\n", op->oid.inode, op->oid.stripe, op->version, PRIV(op)->real_version);
@ -152,10 +181,8 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
if (prev_it->first.oid == op->oid && prev_it->first.version >= PRIV(op)->real_version)
{
// Original version is still invalid
// FIXME Oops. Successive small writes will currently break in an unexpected way. Fix it
dirty_db.erase(dirty_it);
op->retval = -EEXIST;
FINISH_OP(op);
// All subsequent writes to the same object must be canceled too
cancel_all_writes(op, dirty_it, -EEXIST);
return 1;
}
op->version = PRIV(op)->real_version;
@ -189,10 +216,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
PRIV(op)->wait_for = WAIT_FREE;
return 0;
}
// FIXME Oops. Successive small writes will currently break in an unexpected way. Fix it
dirty_db.erase(dirty_it);
op->retval = -ENOSPC;
FINISH_OP(op);
cancel_all_writes(op, dirty_it, -ENOSPC);
return 1;
}
write_iodepth++;