On Tue, Feb 06, 2018 at 08:02:47AM -0500, Brian Foster wrote:
> Extent swap is a low level mechanism exported by XFS to facilitate
> filesystem defragmentation. It is typically invoked by xfs_fsr under
> conditions that will atomically adjust inode extent state without
> loss of file data.
>
> xfs_fsr does not provide the necessary controls for low-level
> testing of the extent swap command, however. For example, xfs_fsr
> implements policies that dictate when to perform an extent swap and
> offers no control over the donor file characteristics.
>
> Add a basic swapext command to xfs_io that allows userspace
> invocation of the command under more controlled conditions. This
> command makes no effort to retain data across the operation. As
> such, it is primarily for testing purposes (i.e., in support of
> xfstests, etc.).
>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> ---
>
> This command is in support of an xfstests test to be posted shortly...
>
> Brian
>
> io/Makefile | 3 +-
> io/init.c | 1 +
> io/io.h | 1 +
> io/swapext.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 111 insertions(+), 1 deletion(-)
> create mode 100644 io/swapext.c
>
> diff --git a/io/Makefile b/io/Makefile
> index 6725936d..2f9249e8 100644
> --- a/io/Makefile
> +++ b/io/Makefile
> @@ -11,7 +11,8 @@ HFILES = init.h io.h
> CFILES = init.c \
> attr.c bmap.c cowextsize.c encrypt.c file.c freeze.c fsync.c \
> getrusage.c imap.c link.c mmap.c open.c parent.c pread.c prealloc.c \
> - pwrite.c reflink.c seek.c shutdown.c stat.c sync.c truncate.c utimes.c
> + pwrite.c reflink.c seek.c shutdown.c stat.c swapext.c sync.c \
> + truncate.c utimes.c
>
> LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBPTHREAD)
> LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE)
> diff --git a/io/init.c b/io/init.c
> index 20d5f80d..2ade03f4 100644
> --- a/io/init.c
> +++ b/io/init.c
> @@ -88,6 +88,7 @@ init_commands(void)
> sendfile_init();
> shutdown_init();
> stat_init();
> + swapext_init();
> sync_init();
> sync_range_init();
> truncate_init();
> diff --git a/io/io.h b/io/io.h
> index 3862985f..258311f1 100644
> --- a/io/io.h
> +++ b/io/io.h
> @@ -118,6 +118,7 @@ extern void quit_init(void);
> extern void seek_init(void);
> extern void shutdown_init(void);
> extern void stat_init(void);
> +extern void swapext_init(void);
> extern void sync_init(void);
> extern void truncate_init(void);
> extern void utimes_init(void);
> diff --git a/io/swapext.c b/io/swapext.c
> new file mode 100644
> index 00000000..5e161d69
> --- /dev/null
> +++ b/io/swapext.c
> @@ -0,0 +1,107 @@
> +/*
> + * Copyright (c) 2018 Red Hat, Inc.
> + * All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include "command.h"
> +#include "input.h"
> +#include "init.h"
> +#include "io.h"
> +
> +static cmdinfo_t swapext_cmd;
> +
> +static void
> +swapext_help(void)
> +{
> + printf(_(
> +"\n"
> +" Swaps extents between the open file descriptor and the supplied filename.\n"
An update to the xfs_io manpage is needed, but this otherwise looks ok to me.
--D
> +"\n"));
> +}
> +
> +static int
> +xfs_bulkstat_single(
> + int fd,
> + xfs_ino_t *lastip,
> + struct xfs_bstat *ubuffer)
> +{
> + struct xfs_fsop_bulkreq bulkreq;
> +
> + bulkreq.lastip = (__u64 *)lastip;
> + bulkreq.icount = 1;
> + bulkreq.ubuffer = ubuffer;
> + bulkreq.ocount = NULL;
> + return ioctl(fd, XFS_IOC_FSBULKSTAT_SINGLE, &bulkreq);
> +}
> +
> +static int
> +swapext_f(
> + int argc,
> + char **argv)
> +{
> + int fd;
> + int error;
> + struct xfs_swapext sx;
> + struct stat stat;
> +
> + /* open the donor file */
> + fd = openfile(argv[1], NULL, 0, 0, NULL);
> + if (fd < 0)
> + return 0;
> +
> + /*
> + * stat the target file to get the inode number and use the latter to
> + * get the bulkstat info for the swapext cmd.
> + */
> + error = fstat(file->fd, &stat);
> + if (error) {
> + perror("fstat");
> + goto out;
> + }
> +
> + error = xfs_bulkstat_single(file->fd, &stat.st_ino, &sx.sx_stat);
> + if (error) {
> + perror("bulkstat");
> + goto out;
> + }
> + sx.sx_version = XFS_SX_VERSION;
> + sx.sx_fdtarget = file->fd;
> + sx.sx_fdtmp = fd;
> + sx.sx_offset = 0;
> + sx.sx_length = stat.st_size;
> + error = ioctl(file->fd, XFS_IOC_SWAPEXT, &sx);
> + if (error)
> + perror("swapext");
> +
> +out:
> + close(fd);
> + return 0;
> +}
> +
> +void
> +swapext_init(void)
> +{
> + swapext_cmd.name = "swapext";
> + swapext_cmd.cfunc = swapext_f;
> + swapext_cmd.argmin = 1;
> + swapext_cmd.argmax = 1;
> + swapext_cmd.flags = CMD_NOMAP_OK;
> + swapext_cmd.args = _("<donorfile>");
> + swapext_cmd.oneline = _("Swap extents between files.");
> + swapext_cmd.help = swapext_help;
> +
> + add_command(&swapext_cmd);
> +}
> --
> 2.13.6
>
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