From 3bcd3a26a88ebeafa17dcf7e17d589f78e17500b Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 24 Jul 2018 09:23:26 +0200 Subject: [PATCH 39/89] file-posix: Make .bdrv_co_truncate asynchronous RH-Author: Kevin Wolf Message-id: <20180712144258.17303-7-kwolf@redhat.com> Patchwork-id: 81324 O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 6/6] file-posix: Make .bdrv_co_truncate asynchronous Bugzilla: 1595173 RH-Acked-by: Max Reitz RH-Acked-by: Stefan Hajnoczi RH-Acked-by: John Snow This moves the code to resize an image file to the thread pool to avoid blocking. Creating large images with preallocation with blockdev-create is now actually a background job instead of blocking the monitor (and most other things) until the preallocation has completed. Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi (cherry picked from commit 93f4e2ff4b31205d8bab0856631a52ed442b8b1c) Signed-off-by: Kevin Wolf --- block/file-posix.c | 266 +++++++++++++++++++++++++++--------------------- include/block/raw-aio.h | 4 +- 2 files changed, 154 insertions(+), 116 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index f8488ec..24c2367 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -186,8 +186,16 @@ typedef struct RawPosixAIOData { #define aio_ioctl_cmd aio_nbytes /* for QEMU_AIO_IOCTL */ off_t aio_offset; int aio_type; - int aio_fd2; - off_t aio_offset2; + union { + struct { + int aio_fd2; + off_t aio_offset2; + }; + struct { + PreallocMode prealloc; + Error **errp; + }; + }; } RawPosixAIOData; #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) @@ -1509,6 +1517,122 @@ static ssize_t handle_aiocb_discard(RawPosixAIOData *aiocb) return ret; } +static int handle_aiocb_truncate(RawPosixAIOData *aiocb) +{ + int result = 0; + int64_t current_length = 0; + char *buf = NULL; + struct stat st; + int fd = aiocb->aio_fildes; + int64_t offset = aiocb->aio_offset; + Error **errp = aiocb->errp; + + if (fstat(fd, &st) < 0) { + result = -errno; + error_setg_errno(errp, -result, "Could not stat file"); + return result; + } + + current_length = st.st_size; + if (current_length > offset && aiocb->prealloc != PREALLOC_MODE_OFF) { + error_setg(errp, "Cannot use preallocation for shrinking files"); + return -ENOTSUP; + } + + switch (aiocb->prealloc) { +#ifdef CONFIG_POSIX_FALLOCATE + case PREALLOC_MODE_FALLOC: + /* + * Truncating before posix_fallocate() makes it about twice slower on + * file systems that do not support fallocate(), trying to check if a + * block is allocated before allocating it, so don't do that here. + */ + if (offset != current_length) { + result = -posix_fallocate(fd, current_length, + offset - current_length); + if (result != 0) { + /* posix_fallocate() doesn't set errno. */ + error_setg_errno(errp, -result, + "Could not preallocate new data"); + } + } else { + result = 0; + } + goto out; +#endif + case PREALLOC_MODE_FULL: + { + int64_t num = 0, left = offset - current_length; + off_t seek_result; + + /* + * Knowing the final size from the beginning could allow the file + * system driver to do less allocations and possibly avoid + * fragmentation of the file. + */ + if (ftruncate(fd, offset) != 0) { + result = -errno; + error_setg_errno(errp, -result, "Could not resize file"); + goto out; + } + + buf = g_malloc0(65536); + + seek_result = lseek(fd, current_length, SEEK_SET); + if (seek_result < 0) { + result = -errno; + error_setg_errno(errp, -result, + "Failed to seek to the old end of file"); + goto out; + } + + while (left > 0) { + num = MIN(left, 65536); + result = write(fd, buf, num); + if (result < 0) { + result = -errno; + error_setg_errno(errp, -result, + "Could not write zeros for preallocation"); + goto out; + } + left -= result; + } + if (result >= 0) { + result = fsync(fd); + if (result < 0) { + result = -errno; + error_setg_errno(errp, -result, + "Could not flush file to disk"); + goto out; + } + } + goto out; + } + case PREALLOC_MODE_OFF: + if (ftruncate(fd, offset) != 0) { + result = -errno; + error_setg_errno(errp, -result, "Could not resize file"); + } + return result; + default: + result = -ENOTSUP; + error_setg(errp, "Unsupported preallocation mode: %s", + PreallocMode_str(aiocb->prealloc)); + return result; + } + +out: + if (result < 0) { + if (ftruncate(fd, current_length) < 0) { + error_report("Failed to restore old file length: %s", + strerror(errno)); + } + } + + g_free(buf); + return result; +} + static int aio_worker(void *arg) { RawPosixAIOData *aiocb = arg; @@ -1552,6 +1676,9 @@ static int aio_worker(void *arg) case QEMU_AIO_COPY_RANGE: ret = handle_aiocb_copy_range(aiocb); break; + case QEMU_AIO_TRUNCATE: + ret = handle_aiocb_truncate(aiocb); + break; default: fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type); ret = -EINVAL; @@ -1719,117 +1846,25 @@ static void raw_close(BlockDriverState *bs) * * Returns: 0 on success, -errno on failure. */ -static int raw_regular_truncate(int fd, int64_t offset, PreallocMode prealloc, - Error **errp) +static int coroutine_fn +raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset, + PreallocMode prealloc, Error **errp) { - int result = 0; - int64_t current_length = 0; - char *buf = NULL; - struct stat st; - - if (fstat(fd, &st) < 0) { - result = -errno; - error_setg_errno(errp, -result, "Could not stat file"); - return result; - } - - current_length = st.st_size; - if (current_length > offset && prealloc != PREALLOC_MODE_OFF) { - error_setg(errp, "Cannot use preallocation for shrinking files"); - return -ENOTSUP; - } - - switch (prealloc) { -#ifdef CONFIG_POSIX_FALLOCATE - case PREALLOC_MODE_FALLOC: - /* - * Truncating before posix_fallocate() makes it about twice slower on - * file systems that do not support fallocate(), trying to check if a - * block is allocated before allocating it, so don't do that here. - */ - if (offset != current_length) { - result = -posix_fallocate(fd, current_length, offset - current_length); - if (result != 0) { - /* posix_fallocate() doesn't set errno. */ - error_setg_errno(errp, -result, - "Could not preallocate new data"); - } - } else { - result = 0; - } - goto out; -#endif - case PREALLOC_MODE_FULL: - { - int64_t num = 0, left = offset - current_length; - off_t seek_result; - - /* - * Knowing the final size from the beginning could allow the file - * system driver to do less allocations and possibly avoid - * fragmentation of the file. - */ - if (ftruncate(fd, offset) != 0) { - result = -errno; - error_setg_errno(errp, -result, "Could not resize file"); - goto out; - } - - buf = g_malloc0(65536); - - seek_result = lseek(fd, current_length, SEEK_SET); - if (seek_result < 0) { - result = -errno; - error_setg_errno(errp, -result, - "Failed to seek to the old end of file"); - goto out; - } - - while (left > 0) { - num = MIN(left, 65536); - result = write(fd, buf, num); - if (result < 0) { - result = -errno; - error_setg_errno(errp, -result, - "Could not write zeros for preallocation"); - goto out; - } - left -= result; - } - if (result >= 0) { - result = fsync(fd); - if (result < 0) { - result = -errno; - error_setg_errno(errp, -result, - "Could not flush file to disk"); - goto out; - } - } - goto out; - } - case PREALLOC_MODE_OFF: - if (ftruncate(fd, offset) != 0) { - result = -errno; - error_setg_errno(errp, -result, "Could not resize file"); - } - return result; - default: - result = -ENOTSUP; - error_setg(errp, "Unsupported preallocation mode: %s", - PreallocMode_str(prealloc)); - return result; - } + RawPosixAIOData *acb = g_new(RawPosixAIOData, 1); + ThreadPool *pool; -out: - if (result < 0) { - if (ftruncate(fd, current_length) < 0) { - error_report("Failed to restore old file length: %s", - strerror(errno)); - } - } + *acb = (RawPosixAIOData) { + .bs = bs, + .aio_fildes = fd, + .aio_type = QEMU_AIO_TRUNCATE, + .aio_offset = offset, + .prealloc = prealloc, + .errp = errp, + }; - g_free(buf); - return result; + /* @bs can be NULL, bdrv_get_aio_context() returns the main context then */ + pool = aio_get_thread_pool(bdrv_get_aio_context(bs)); + return thread_pool_submit_co(pool, aio_worker, acb); } static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset, @@ -1846,7 +1881,7 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset, } if (S_ISREG(st.st_mode)) { - return raw_regular_truncate(s->fd, offset, prealloc, errp); + return raw_regular_truncate(bs, s->fd, offset, prealloc, errp); } if (prealloc != PREALLOC_MODE_OFF) { @@ -2048,7 +2083,8 @@ static int64_t raw_get_allocated_file_size(BlockDriverState *bs) return (int64_t)st.st_blocks * 512; } -static int raw_co_create(BlockdevCreateOptions *options, Error **errp) +static int coroutine_fn +raw_co_create(BlockdevCreateOptions *options, Error **errp) { BlockdevCreateOptionsFile *file_opts; Error *local_err = NULL; @@ -2101,7 +2137,7 @@ static int raw_co_create(BlockdevCreateOptions *options, Error **errp) } /* Clear the file by truncating it to 0 */ - result = raw_regular_truncate(fd, 0, PREALLOC_MODE_OFF, errp); + result = raw_regular_truncate(NULL, fd, 0, PREALLOC_MODE_OFF, errp); if (result < 0) { goto out_unlock; } @@ -2123,8 +2159,8 @@ static int raw_co_create(BlockdevCreateOptions *options, Error **errp) /* Resize and potentially preallocate the file to the desired * final size */ - result = raw_regular_truncate(fd, file_opts->size, file_opts->preallocation, - errp); + result = raw_regular_truncate(NULL, fd, file_opts->size, + file_opts->preallocation, errp); if (result < 0) { goto out_unlock; } diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h index 3240530..2ffcd9d 100644 --- a/include/block/raw-aio.h +++ b/include/block/raw-aio.h @@ -26,6 +26,7 @@ #define QEMU_AIO_DISCARD 0x0010 #define QEMU_AIO_WRITE_ZEROES 0x0020 #define QEMU_AIO_COPY_RANGE 0x0040 +#define QEMU_AIO_TRUNCATE 0x0080 #define QEMU_AIO_TYPE_MASK \ (QEMU_AIO_READ | \ QEMU_AIO_WRITE | \ @@ -33,7 +34,8 @@ QEMU_AIO_FLUSH | \ QEMU_AIO_DISCARD | \ QEMU_AIO_WRITE_ZEROES | \ - QEMU_AIO_COPY_RANGE) + QEMU_AIO_COPY_RANGE | \ + QEMU_AIO_TRUNCATE) /* AIO flags */ #define QEMU_AIO_MISALIGNED 0x1000 -- 1.8.3.1