Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

[mirror_qemu.git] / block / export / fuse.c

diff --git a/block/export/fuse.c b/block/export/fuse.c
index 1b26ddfcf3c11bd53c1157d93d3bf24637cf803d..3307b640896d7d4f43a703ea88687723a4f1eb71 100644 (file)
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -21,12 +21,13 @@
 #include "qemu/osdep.h"
 #include "qemu/memalign.h"
 #include "block/aio.h"
-#include "block/block.h"
+#include "block/block_int-common.h"
 #include "block/export.h"
 #include "block/fuse.h"
 #include "block/qapi.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-block.h"
+#include "qemu/main-loop.h"
 #include "sysemu/block-backend.h"
 
 #include <fuse.h>
@@ -49,6 +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;
@@ -77,6 +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),
+                       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),
+                       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)
@@ -100,6 +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();
 
     /*
@@ -223,7 +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),
                        read_from_fuse_export, NULL, NULL, NULL, exp);
     exp->fd_handler_set_up = true;
 
@@ -245,6 +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);
@@ -255,6 +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);
 }
 
@@ -267,7 +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),
                                NULL, NULL, NULL, NULL, NULL);
             exp->fd_handler_set_up = false;
         }
@@ -672,7 +725,16 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode,
         do {
             int size = MIN(length, BDRV_REQUEST_MAX_BYTES);
 
-            ret = blk_pdiscard(exp->common.blk, offset, size);
+            ret = blk_pwrite_zeroes(exp->common.blk, offset, size,
+                                    BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK);
+            if (ret == -ENOTSUP) {
+                /*
+                 * fallocate() specifies to return EOPNOTSUPP for unsupported
+                 * operations
+                 */
+                ret = -EOPNOTSUPP;
+            }
+
             offset += size;
             length -= size;
         } while (ret == 0 && length > 0);