Re: [Libguestfs] [PATCH libnbd v4 1/2] copy: Store the preferred block size in the operations struct

This will be used in a subsequent commit. At the moment the preferred block size for all sources / destinations is simply calculated and stored. --- copy/file-ops.c | 4 +++- copy/main.c | 29 +++++++++++++++++++++++------ copy/nbd-ops.c | 10 ++++++++++ copy/nbdcopy.h | 4 +++- copy/null-ops.c | 1 + copy/pipe-ops.c | 1 + 6 files changed, 41 insertions(+), 8 deletions(-)

+++ b/copy/main.c @@ -512,10 +512,26 @@ open_local (const char *filename, direction d) fprintf (stderr, "%s: %s: %m\n", prog, filename); exit (EXIT_FAILURE); } - if (S_ISBLK (stat.st_mode) || S_ISREG (stat.st_mode)) - return file_create (filename, fd, stat.st_size, S_ISBLK (stat.st_mode), d); - else { - /* Probably stdin/stdout, a pipe or a socket. */ + if (S_ISREG (stat.st_mode)) /* Regular file. */ + return file_create (filename, fd, + stat.st_size, (uint64_t) stat.st_blksize, false, d);

+ else if (S_ISBLK (stat.st_mode)) { /* Block device. */ + unsigned int blkioopt; + +#ifdef BLKIOOPT + if (ioctl (fd, BLKIOOPT, &blkioopt) == -1) { + fprintf (stderr, "warning: cannot get optimal I/O size: %s: %m", + filename); + blkioopt = 4096; + } +#else + blkioopt = 4096; +#endif + + return file_create (filename, fd, + stat.st_size, (uint64_t) blkioopt, true, d);

+++ b/copy/nbd-ops.c @@ -112,12 +112,22 @@ open_one_nbd_handle (struct rw_nbd *rwn) * the same way. */ if (rwn->handles.len == 0) { + int64_t block_size; + rwn->can_zero = nbd_can_zero (nbd) > 0; + rwn->rw.size = nbd_get_size (nbd); if (rwn->rw.size == -1) { fprintf (stderr, "%s: %s: %s\n", prog, rwn->rw.name, nbd_get_error ()); exit (EXIT_FAILURE); } + + block_size = nbd_get_block_size (nbd, LIBNBD_SIZE_PREFERRED); + if (block_size == -1) { + fprintf (stderr, "%s: %s: %s\n", prog, rwn->rw.name, nbd_get_error ()); + exit (EXIT_FAILURE); + } + rwn->rw.preferred = block_size == 0 ? 4096 : block_size;

} if (handles_append (&rwn->handles, nbd) == -1) { diff --git a/copy/nbdcopy.h b/copy/nbdcopy.h index 19797dfd66..9438cce417 100644 --- a/copy/nbdcopy.h +++ b/copy/nbdcopy.h @@ -43,6 +43,7 @@ struct rw { struct rw_ops *ops; /* Operations. */ const char *name; /* Printable name, for error messages etc. */ int64_t size; /* May be -1 for streams. */ + uint64_t preferred; /* Preferred block size. */

+++ b/copy/pipe-ops.c @@ -43,6 +43,7 @@ pipe_create (const char *name, int fd) rwp->rw.ops = &pipe_ops; rwp->rw.name = name; rwp->rw.size = -1; + rwp->rw.preferred = 4096;