From eae96caffc98b9ad8ad3a56bf5f59576f3eb110f Mon Sep 17 00:00:00 2001 From: Hanna Czenczek Date: Mon, 9 Mar 2026 16:08:49 +0100 Subject: [PATCH] fuse: Reduce max read size We are going to introduce parallel processing via coroutines, a maximum read size of 64 MB may be problematic, allowing users of the export to force us to allocate quite large amounts of memory with just a few requests. At least tone it down to 1 MB, which is still probably far more than enough. (Larger requests are split automatically by the FUSE kernel driver anyway.) (Yes, we inadvertently already had parallel request processing due to nested polling before. Better to fix this late than never.) Reviewed-by: Stefan Hajnoczi Signed-off-by: Hanna Czenczek Message-ID: <20260309150856.26800-19-hreitz@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/export/fuse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/export/fuse.c b/block/export/fuse.c index bd099d1291..f32e74f39d 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -45,7 +45,7 @@ #endif /* Prevent overly long bounce buffer allocations */ -#define FUSE_MAX_READ_BYTES (MIN(BDRV_REQUEST_MAX_BYTES, 64 * 1024 * 1024)) +#define FUSE_MAX_READ_BYTES (MIN(BDRV_REQUEST_MAX_BYTES, 1 * 1024 * 1024)) #define FUSE_MAX_WRITE_BYTES (64 * 1024) /*