From d7a4a38a03936a04a27042a7b397ccb4f1b4ff06 Mon Sep 17 00:00:00 2001 From: Fabiano Rosas Date: Mon, 17 Jun 2024 15:57:17 -0300 Subject: migration: Fix file migration with fdset MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the "file:" migration support was added we missed the special case in the qemu_open_old implementation that allows for a particular file name format to be used to refer to a set of file descriptors that have been previously provided to QEMU via the add-fd QMP command. When using this fdset feature, we should not truncate the migration file because being given an fd means that the management layer is in control of the file and will likely already have some data written to it. This is further indicated by the presence of the 'offset' argument, which indicates the start of the region where QEMU is allowed to write. Fix the issue by replacing the O_TRUNC flag on open by an ftruncate call, which will take the offset into consideration. Fixes: 385f510df5 ("migration: file URI offset") Suggested-by: Daniel P. Berrangé Reviewed-by: Prasad Pandit Reviewed-by: Peter Xu Reviewed-by: Daniel P. Berrangé Signed-off-by: Fabiano Rosas (cherry picked from commit 6d3279655ac49b806265f08415165f471d33e032) Signed-off-by: Michael Tokarev --- migration/file.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/migration/file.c b/migration/file.c index ab18ba505a..ba5b5c44ff 100644 --- a/migration/file.c +++ b/migration/file.c @@ -84,12 +84,19 @@ void file_start_outgoing_migration(MigrationState *s, trace_migration_file_outgoing(filename); - fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC, - 0600, errp); + fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY, 0600, errp); if (!fioc) { return; } + if (ftruncate(fioc->fd, offset)) { + error_setg_errno(errp, errno, + "failed to truncate migration file to offset %" PRIx64, + offset); + object_unref(OBJECT(fioc)); + return; + } + outgoing_args.fname = g_strdup(filename); ioc = QIO_CHANNEL(fioc); -- cgit v1.2.3