On Fri, Dec 27, 2013 at 11:05:53AM +0800, Hu Tao wrote: > This patch adds a new option preallocation for raw format, and implements > full preallocation. > > Signed-off-by: Hu Tao <hu...@cn.fujitsu.com> > --- > block/raw-posix.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 46 insertions(+) > > diff --git a/block/raw-posix.c b/block/raw-posix.c > index 6f6b8c1..a722d27 100644 > --- a/block/raw-posix.c > +++ b/block/raw-posix.c > @@ -1160,17 +1160,52 @@ static int64_t > raw_get_allocated_file_size(BlockDriverState *bs) > return (int64_t)st.st_blocks * 512; > } > > +#ifdef __linux__ > +static int raw_preallocate2(int fd, int64_t offset, int64_t length)
Why is this function called raw_preallocate2()? Please choose a descriptive name. > +{ > + int ret = -1; > + > + ret = fallocate(fd, 0, offset, length); > + if (ret < 0) { > + ret = -errno; > + } > + > + /* fallback to posix_fallocate() if fallocate() is not supported */ > + if (ret == -ENOSYS || ret == -EOPNOTSUPP) { > + ret = posix_fallocate(fd, offset, length); >From the posix_fallocate(3) man page: "posix_fallocate() returns zero on success, or an error number on failure. Note that errno is not set." You need to negate the error number: if (ret > 0) { ret = -ret; /* posix_fallocate(3) returns a positive errno */ } > + } > + > + return ret; > +} > +#else > +static int raw_preallocate2(int fd, int64_t offset, int64_t length) > +{ > + return posix_fallocate(fd, offset, length); Same error number problem as above. > @@ -1185,6 +1220,12 @@ static int raw_create(const char *filename, > QEMUOptionParameter *options, > result = -errno; > error_setg_errno(errp, -result, "Could not resize file"); > } > + if (prealloc == PREALLOC_MODE_FULL) { > + result = raw_preallocate2(fd, 0, total_size); What if ftruncate() failed? We should not try to fallocate. Please add a proper error return path. > + if (result != 0) > + error_setg_errno(errp, -result, > + "Could not preallocate data for the new > file"); WARNING: braces {} are necessary for all arms of this statement Please run scripts/checkpatch.pl before submitting patches, it checks QEMU coding style.