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block/fuse: do not set is_external=true on FUSE fd 

This is part of ongoing work to remove the aio_disable_external() API.

Use BlockDevOps .drained_begin/end/poll() instead of
aio_set_fd_handler(is_external=true).

As a side-effect the FUSE export now follows AioContext changes like the
other export types.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-16-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2023-05-16 15:02:33 -04:00 committed by Kevin Wolf
parent 3d499a43a2
commit 17b69c0fc1
1 changed files with 54 additions and 2 deletions
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56
block/export/fuse.c
View File

@ -50,6 +50,7 @@ typedef struct FuseExport {
struct fuse_session *fuse_session;
struct fuse_buf fuse_buf;
unsigned int in_flight; /* atomic */
bool mounted, fd_handler_set_up;
char *mountpoint;
@ -78,6 +79,42 @@ static void read_from_fuse_export(void *opaque);
static bool is_regular_file(const char *path, Error **errp);
static void fuse_export_drained_begin(void *opaque)
{
FuseExport *exp = opaque;
aio_set_fd_handler(exp->common.ctx,
fuse_session_fd(exp->fuse_session), false,
NULL, NULL, NULL, NULL, NULL);
exp->fd_handler_set_up = false;
}
static void fuse_export_drained_end(void *opaque)
{
FuseExport *exp = opaque;
/* Refresh AioContext in case it changed */
exp->common.ctx = blk_get_aio_context(exp->common.blk);
aio_set_fd_handler(exp->common.ctx,
fuse_session_fd(exp->fuse_session), false,
read_from_fuse_export, NULL, NULL, NULL, exp);
exp->fd_handler_set_up = true;
}
static bool fuse_export_drained_poll(void *opaque)
{
FuseExport *exp = opaque;
return qatomic_read(&exp->in_flight) > 0;
}
static const BlockDevOps fuse_export_blk_dev_ops = {
.drained_begin = fuse_export_drained_begin,
.drained_end = fuse_export_drained_end,
.drained_poll = fuse_export_drained_poll,
};
static int fuse_export_create(BlockExport *blk_exp,
BlockExportOptions *blk_exp_args,
Error **errp)
@ -101,6 +138,15 @@ static int fuse_export_create(BlockExport *blk_exp,
}
}
blk_set_dev_ops(exp->common.blk, &fuse_export_blk_dev_ops, exp);
/*
* We handle draining ourselves using an in-flight counter and by disabling
* the FUSE fd handler. Do not queue BlockBackend requests, they need to
* complete so the in-flight counter reaches zero.
*/
blk_set_disable_request_queuing(exp->common.blk, true);
init_exports_table();
/*
@ -224,7 +270,7 @@ static int setup_fuse_export(FuseExport *exp, const char *mountpoint,
g_hash_table_insert(exports, g_strdup(mountpoint), NULL);
aio_set_fd_handler(exp->common.ctx,
fuse_session_fd(exp->fuse_session), true,
fuse_session_fd(exp->fuse_session), false,
read_from_fuse_export, NULL, NULL, NULL, exp);
exp->fd_handler_set_up = true;
@ -246,6 +292,8 @@ static void read_from_fuse_export(void *opaque)
blk_exp_ref(&exp->common);
qatomic_inc(&exp->in_flight);
do {
ret = fuse_session_receive_buf(exp->fuse_session, &exp->fuse_buf);
} while (ret == -EINTR);
@ -256,6 +304,10 @@ static void read_from_fuse_export(void *opaque)
fuse_session_process_buf(exp->fuse_session, &exp->fuse_buf);
out:
if (qatomic_fetch_dec(&exp->in_flight) == 1) {
aio_wait_kick(); /* wake AIO_WAIT_WHILE() */
}
blk_exp_unref(&exp->common);
}
@ -268,7 +320,7 @@ static void fuse_export_shutdown(BlockExport *blk_exp)
if (exp->fd_handler_set_up) {
aio_set_fd_handler(exp->common.ctx,
fuse_session_fd(exp->fuse_session), true,
fuse_session_fd(exp->fuse_session), false,
NULL, NULL, NULL, NULL, NULL);
exp->fd_handler_set_up = false;
}