From: Dave Chinner <david@fromorbit.com>
To: linux-xfs@vger.kernel.org
Subject: [PATCH] [RFC] spaceman: physically move a regular inode
Date: Wed, 11 Nov 2020 09:59:24 +1100 [thread overview]
Message-ID: <20201110225924.4031404-1-david@fromorbit.com> (raw)
From: Dave Chinner <dchinner@redhat.com>
To be able to shrink a filesystem, we need to be able to physically
move an inode and all it's data and metadata from it's current
location to a new AG. Add a command to spaceman to allow an inode
to be moved to a new AG.
This new command is not intended to be a perfect solution. I am not
trying to handle atomic movement of open files - this is intended to
be run as a maintenance operation on idle filesystem. If root
filesystems are the target, then this should be run via a rescue
environment that is not executing directly on the root fs. With
those caveats in place, we can do the entire inode move as a set of
non-destructive operations finalised by an atomic inode swap
without any needing special kernel support.
To ensure we move metadata such as BMBT blocks even if we don't need
to move data, we clone the data to a new inode that we've allocated
in the destination AG. This will result in new bmbt blocks being
allocated in the new location even though the data is not copied.
Attributes need to be copied one at a time from the original inode.
If data needs to be moved, then we use fallocate(UNSHARE) to create
a private copy of the range of data that needs to be moved in the
new inode. This will be allocated in the destination AG by normal
allocation policy.
Once the new inode has been finalised, use RENAME_EXCHANGE to swap
it into place and unlink the original inode to free up all the
resources it still pins.
There are many optimisations still possible to speed this up, but
the goal here is "functional" rather than "optimal". Performance can
be optimised once all the parts for a "empty the tail of the
filesystem before shrink" operation are implemented and solidly
tested.
This functionality has been smoke tested by creating a 32MB data
file with 4k extents and several hundred attributes:
$ cat test.sh
fname=/mnt/scratch/foo
xfs_io -f -c "pwrite 0 32m" -c sync $fname
for (( i=0; i < 4096 ; i++ )); do
xfs_io -c "fpunch $((i * 8))k 4k" $fname
done
for (( i=0; i < 100 ; i++ )); do
setfattr -n user.blah.$i.$i.blah -v blah.$i.$i.blah $fname
setfattr -n user.foo.$i.$i.foo -v $i.cantbele.$i.ve.$i.tsnotbutter $fname
done
for (( i=0; i < 100 ; i++ )); do
setfattr -n security.baz.$i.$i.baz -v wotchul$i$iookinat $fname
done
xfs_io -c stat -c "bmap -vp" -c "bmap -avp" $fname
xfs_spaceman -c "move_inode -a 22" /mnt/scratch/foo
xfs_io -c stat -c "bmap -vp" -c "bmap -avp" $fname
$
and the output looks something like:
$ sudo ./test.sh
....
fd.path = "/mnt/scratch/foo"
fd.flags = non-sync,non-direct,read-write
stat.ino = 133
/mnt/scratch/foo:
EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS
0: [0..7]: hole 8
1: [8..15]: 208..215 0 (208..215) 8 000000
2: [16..23]: hole 8
3: [24..31]: 224..231 0 (224..231) 8 000000
....
8189: [65512..65519]: 65712..65719 0 (65712..65719) 8 000000
8190: [65520..65527]: hole 8
8191: [65528..65535]: 65728..65735 0 (65728..65735) 8 000000
mnt/scratch/foo:
EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS
0: [0..7]: 392..399 0 (392..399) 8 000000
1: [8..15]: 408..415 0 (408..415) 8 000000
2: [16..23]: 424..431 0 (424..431) 8 000000
3: [24..31]: 456..463 0 (456..463) 8 000000
move mnt /mnt/scratch, path /mnt/scratch/foo, agno 22
fd.path = "/mnt/scratch/foo"
fd.flags = non-sync,non-direct,read-write
stat.ino = 47244651475
....
/mnt/scratch/foo:
EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS
0: [0..7]: hole 8
1: [8..15]: 47244763192..47244763199 22 (123112..123119) 8 000000
2: [16..23]: hole 8
3: [24..31]: 47244763208..47244763215 22 (123128..123135) 8 000000
....
8189: [65512..65519]: 47244828808..47244828815 22 (188728..188735) 8 000000
8190: [65520..65527]: hole 8
8191: [65528..65535]: 47244828824..47244828831 22 (188744..188751) 8 000000
/mnt/scratch/foo:
EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS
0: [0..7]: 47244763176..47244763183 22 (123096..123103) 8 000000
$
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
spaceman/Makefile | 6 +-
spaceman/file.c | 2 +-
spaceman/init.c | 1 +
spaceman/move_inode.c | 518 ++++++++++++++++++++++++++++++++++++++++++
spaceman/space.h | 1 +
5 files changed, 524 insertions(+), 4 deletions(-)
create mode 100644 spaceman/move_inode.c
diff --git a/spaceman/Makefile b/spaceman/Makefile
index 2a3669183a40..e90f66e8abc6 100644
--- a/spaceman/Makefile
+++ b/spaceman/Makefile
@@ -7,11 +7,11 @@ include $(TOPDIR)/include/builddefs
LTCOMMAND = xfs_spaceman
HFILES = init.h space.h
-CFILES = info.c init.c file.c health.c prealloc.c trim.c
+CFILES = info.c init.c file.c health.c move_inode.c prealloc.c trim.c
LSRCFILES = xfs_info.sh
-LLDLIBS = $(LIBXCMD) $(LIBFROG)
-LTDEPENDENCIES = $(LIBXCMD) $(LIBFROG)
+LLDLIBS = $(LIBXCMD) $(LIBFROG) $(LIBHANDLE)
+LTDEPENDENCIES = $(LIBXCMD) $(LIBFROG) $(LIBHANDLE)
LLDFLAGS = -static
ifeq ($(ENABLE_EDITLINE),yes)
diff --git a/spaceman/file.c b/spaceman/file.c
index eec7ee9f4ba9..1777ed7d4602 100644
--- a/spaceman/file.c
+++ b/spaceman/file.c
@@ -52,7 +52,7 @@ openfile(
struct fs_path *fsp;
int ret;
- ret = -xfd_open(xfd, path, O_RDONLY);
+ ret = -xfd_open(xfd, path, O_RDWR);
if (ret) {
if (ret == ENOTTY)
fprintf(stderr,
diff --git a/spaceman/init.c b/spaceman/init.c
index cf1ff3cbb0ee..c3bfe3e5922f 100644
--- a/spaceman/init.c
+++ b/spaceman/init.c
@@ -35,6 +35,7 @@ init_commands(void)
trim_init();
freesp_init();
health_init();
+ move_inode_init();
}
static int
diff --git a/spaceman/move_inode.c b/spaceman/move_inode.c
new file mode 100644
index 000000000000..c3f791c82c45
--- /dev/null
+++ b/spaceman/move_inode.c
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2012 Red Hat, Inc.
+ * All Rights Reserved.
+ */
+
+#include "libxfs.h"
+#include "libfrog/fsgeom.h"
+#include "command.h"
+#include "init.h"
+#include "libfrog/paths.h"
+#include "space.h"
+#include "input.h"
+#include "handle.h"
+
+#include <linux/fiemap.h>
+#include <linux/falloc.h>
+#include <attr/attributes.h>
+
+static cmdinfo_t move_inode_cmd;
+
+/*
+ * We can't entirely use O_TMPFILE here because we want to use RENAME_EXCHANGE
+ * to swap the inode once rebuild is complete. Hence the new file has to be
+ * somewhere in the namespace for rename to act upon. Hence we use a normal
+ * open(O_CREATE) for now.
+ *
+ * This could potentially use O_TMPFILE to rebuild the entire inode, the use
+ * a linkat()/renameat2() pair to add it to the namespace then atomically
+ * replace the original.
+ */
+static int
+create_tmpfile(
+ const char *mnt,
+ struct xfs_fd *xfd,
+ xfs_agnumber_t agno,
+ char **tmpfile,
+ int *tmpfd)
+{
+ char name[PATH_MAX + 1];
+ mode_t mask;
+ int fd;
+ int i;
+ int ret;
+
+ /* construct tmpdir */
+ mask = umask(0);
+
+ snprintf(name, PATH_MAX, "%s/.spaceman", mnt);
+ ret = mkdir(name, 0700);
+ if (ret) {
+ if (errno != EEXIST) {
+ fprintf(stderr, _("could not create tmpdir: %s: %s\n"),
+ name, strerror(errno));
+ ret = -errno;
+ goto out_cleanup;
+ }
+ }
+
+ /* loop creating directories until we get one in the right AG */
+ for (i = 0; i < xfd->fsgeom.agcount; i++) {
+ struct stat st;
+
+ snprintf(name, PATH_MAX, "%s/.spaceman/dir%d", mnt, i);
+ ret = mkdir(name, 0700);
+ if (ret) {
+ if (errno != EEXIST) {
+ fprintf(stderr,
+ _("cannot create tmpdir: %s: %s\n"),
+ name, strerror(errno));
+ ret = -errno;
+ goto out_cleanup_dir;
+ }
+ }
+ ret = lstat(name, &st);
+ if (ret) {
+ fprintf(stderr, _("cannot stat tmpdir: %s: %s\n"),
+ name, strerror(errno));
+ ret = -errno;
+ rmdir(name);
+ goto out_cleanup_dir;
+ }
+ if (cvt_ino_to_agno(xfd, st.st_ino) == agno)
+ break;
+
+ /* remove directory in wrong AG */
+ rmdir(name);
+ }
+
+ if (i == xfd->fsgeom.agcount) {
+ /*
+ * Nothing landed in the selected AG! Must have been skipped
+ * because the AG is out of space.
+ */
+ fprintf(stderr, _("Cannot create AG tmpdir.\n"));
+ ret = -ENOSPC;
+ goto out_cleanup_dir;
+ }
+
+ /* create tmpfile */
+ snprintf(name, PATH_MAX, "%s/.spaceman/dir%d/tmpfile.%d", mnt, i, getpid());
+ fd = open(name, O_CREAT|O_EXCL|O_RDWR, 0700);
+ if (fd < 0) {
+ fprintf(stderr, _("cannot create tmpfile: %s: %s\n"),
+ name, strerror(errno));
+ ret = -errno;
+ }
+
+ /* return name and fd */
+ (void)umask(mask);
+ *tmpfd = fd;
+ *tmpfile = strdup(name);
+
+ return 0;
+out_cleanup_dir:
+ snprintf(name, PATH_MAX, "%s/.spaceman", mnt);
+ rmdir(name);
+out_cleanup:
+ (void)umask(mask);
+ return ret;
+}
+
+static int
+get_attr(
+ void *hdl,
+ size_t hlen,
+ char *name,
+ void *attrbuf,
+ int *attrlen,
+ int attr_ns)
+{
+ struct xfs_attr_multiop ops = {
+ .am_opcode = ATTR_OP_GET,
+ .am_attrname = name,
+ .am_attrvalue = attrbuf,
+ .am_length = *attrlen,
+ .am_flags = attr_ns,
+ };
+ int ret;
+
+ ret = attr_multi_by_handle(hdl, hlen, &ops, 1, 0);
+ if (ret < 0) {
+ fprintf(stderr, _("attr_multi_by_handle(GET): %s\n"),
+ strerror(errno));
+ return -errno;
+ }
+ *attrlen = ops.am_length;
+ return 0;
+}
+
+static int
+set_attr(
+ void *hdl,
+ size_t hlen,
+ char *name,
+ void *attrbuf,
+ int attrlen,
+ int attr_ns)
+{
+ struct xfs_attr_multiop ops = {
+ .am_opcode = ATTR_OP_SET,
+ .am_attrname = name,
+ .am_attrvalue = attrbuf,
+ .am_length = attrlen,
+ .am_flags = ATTR_CREATE | attr_ns,
+ };
+ int ret;
+
+ ret = attr_multi_by_handle(hdl, hlen, &ops, 1, 0);
+ if (ret < 0) {
+ fprintf(stderr, _("attr_multi_by_handle(SET): %s\n"),
+ strerror(errno));
+ return -errno;
+ }
+ return 0;
+}
+
+/*
+ * Copy all the attributes from the original source file into the replacement
+ * destination.
+ *
+ * Oh the humanity of deprecated Irix compatible attr interfaces that are more
+ * functional and useful than their native Linux replacements!
+ */
+static int
+copy_attrs(
+ int srcfd,
+ int dstfd,
+ int attr_ns)
+{
+ void *shdl;
+ void *dhdl;
+ size_t shlen;
+ size_t dhlen;
+ attrlist_cursor_t cursor;
+ attrlist_t *alist;
+ struct attrlist_ent *ent;
+ char alistbuf[XATTR_LIST_MAX];
+ char attrbuf[XATTR_SIZE_MAX];
+ int attrlen;
+ int error;
+ int i;
+
+ memset(&cursor, 0, sizeof(cursor));
+
+ /*
+ * All this handle based stuff is hoop jumping to avoid:
+ *
+ * a) deprecated API warnings because attr_list, attr_get and attr_set
+ * have been deprecated hence through compiler warnings; and
+ *
+ * b) listxattr() failing hard if there are more than 64kB worth of attr
+ * names on the inode so is unusable.
+ *
+ * That leaves libhandle as the only usable interface for iterating all
+ * xattrs on an inode reliably. Lucky for us, libhandle is part of
+ * xfsprogs, so this hoop jump isn't going to get ripped out from under
+ * us any time soon.
+ */
+ error = fd_to_handle(srcfd, (void **)&shdl, &shlen);
+ if (error) {
+ fprintf(stderr, _("fd_to_handle(shdl): %s\n"),
+ strerror(errno));
+ return -errno;
+ }
+ error = fd_to_handle(dstfd, (void **)&dhdl, &dhlen);
+ if (error) {
+ fprintf(stderr, _("fd_to_handle(dhdl): %s\n"),
+ strerror(errno));
+ goto out_free_shdl;
+ }
+
+ /* loop to iterate all xattrs */
+ error = attr_list_by_handle(shdl, shlen, alistbuf,
+ XATTR_LIST_MAX, attr_ns, &cursor);
+ if (error) {
+ fprintf(stderr, _("attr_list_by_handle(shdl): %s\n"),
+ strerror(errno));
+ }
+ while (!error) {
+ alist = (attrlist_t *)alistbuf;
+
+ /*
+ * We loop one attr at a time for initial implementation
+ * simplicity. attr_multi_by_handle() can retrieve and set
+ * multiple attrs in a single call, but that is more complex.
+ * Get it working first, then optimise.
+ */
+ for (i = 0; i < alist->al_count; i++) {
+ ent = ATTR_ENTRY(alist, i);
+
+ /* get xattr (val, len) from name */
+ attrlen = XATTR_SIZE_MAX;
+ error = get_attr(shdl, shlen, ent->a_name, attrbuf,
+ &attrlen, attr_ns);
+ if (error)
+ break;
+
+ /* set xattr (val, len) to name */
+ error = set_attr(dhdl, dhlen, ent->a_name, attrbuf,
+ attrlen, ATTR_CREATE | attr_ns);
+ if (error)
+ break;
+ }
+
+ if (!alist->al_more)
+ break;
+ error = attr_list_by_handle(shdl, shlen, alistbuf,
+ XATTR_LIST_MAX, attr_ns, &cursor);
+ }
+
+ free_handle(dhdl, dhlen);
+out_free_shdl:
+ free_handle(shdl, shlen);
+ return error ? -errno : 0;
+}
+
+/*
+ * scan the range of the new file for data that isn't in the destination AG
+ * and unshare it to create a new copy of it in the current target location
+ * of the new file.
+ */
+#define EXTENT_BATCH 32
+static int
+unshare_data(
+ struct xfs_fd *xfd,
+ int destfd,
+ xfs_agnumber_t agno)
+{
+ int ret;
+ struct fiemap *fiemap;
+ int done = 0;
+ int fiemap_flags = FIEMAP_FLAG_SYNC;
+ int i;
+ int map_size;
+ __u64 last_logical = 0; /* last extent offset handled */
+ off64_t range_end = -1LL; /* mapping end*/
+
+ /* fiemap loop over extents */
+ map_size = sizeof(struct fiemap) +
+ (EXTENT_BATCH * sizeof(struct fiemap_extent));
+ fiemap = malloc(map_size);
+ if (!fiemap) {
+ fprintf(stderr, _("%s: malloc of %d bytes failed.\n"),
+ progname, map_size);
+ return -ENOMEM;
+ }
+
+ while (!done) {
+ memset(fiemap, 0, map_size);
+ fiemap->fm_flags = fiemap_flags;
+ fiemap->fm_start = last_logical;
+ fiemap->fm_length = range_end - last_logical;
+ fiemap->fm_extent_count = EXTENT_BATCH;
+
+ ret = ioctl(destfd, FS_IOC_FIEMAP, (unsigned long)fiemap);
+ if (ret < 0) {
+ fprintf(stderr, "%s: ioctl(FS_IOC_FIEMAP): %s\n",
+ progname, strerror(errno));
+ free(fiemap);
+ return -errno;
+ }
+
+ /* No more extents to map, exit */
+ if (!fiemap->fm_mapped_extents)
+ break;
+
+ for (i = 0; i < fiemap->fm_mapped_extents; i++) {
+ struct fiemap_extent *extent;
+ xfs_agnumber_t this_agno;
+
+ extent = &fiemap->fm_extents[i];
+ this_agno = cvt_daddr_to_agno(xfd,
+ cvt_btobbt(extent->fe_physical));
+
+ /*
+ * If extent not in dst AG, unshare whole extent to
+ * trigger reallocated of the extent to be local to
+ * the current inode.
+ */
+ if (this_agno != agno) {
+ ret = fallocate(destfd, FALLOC_FL_UNSHARE_RANGE,
+ extent->fe_logical, extent->fe_length);
+ if (ret) {
+ fprintf(stderr,
+ "%s: fallocate(UNSHARE): %s\n",
+ progname, strerror(errno));
+ return -errno;
+ }
+ }
+
+ last_logical = extent->fe_logical + extent->fe_length;
+
+ /* Kernel has told us there are no more extents */
+ if (extent->fe_flags & FIEMAP_EXTENT_LAST) {
+ done = 1;
+ break;
+ }
+ }
+ }
+ return 0;
+}
+
+static int
+move_file_to_ag(
+ const char *mnt,
+ const char *path,
+ struct xfs_fd *xfd,
+ xfs_agnumber_t agno)
+{
+ int ret;
+ int tmpfd = -1;
+ char *tmpfile = NULL;
+
+ fprintf(stderr, "move mnt %s, path %s, agno %d\n", mnt, path, agno);
+
+ /* create temporary file in agno */
+ ret = create_tmpfile(mnt, xfd, agno, &tmpfile, &tmpfd);
+
+ /* clone data to tempfile */
+ ret = ioctl(tmpfd, FICLONE, xfd->fd);
+ if (ret)
+ goto out_cleanup;
+
+ /* copy system attributes to tempfile */
+ ret = copy_attrs(xfd->fd, tmpfd, ATTR_ROOT);
+ if (ret)
+ goto out_cleanup;
+
+ /* copy user attributes to tempfile */
+ ret = copy_attrs(xfd->fd, tmpfd, 0);
+ if (ret)
+ goto out_cleanup;
+
+ /* unshare data to move it */
+ ret = unshare_data(xfd, tmpfd, agno);
+ if (ret)
+ goto out_cleanup;
+
+ /* RENAME_EXCHANGE to replace the inode */
+ ret = renameat2(AT_FDCWD, tmpfile, AT_FDCWD, path, RENAME_EXCHANGE);
+
+out_cleanup:
+ if (ret == -1)
+ ret = -errno;
+
+ close(tmpfd);
+ if (tmpfile)
+ unlink(tmpfile);
+ free(tmpfile);
+
+ return ret;
+}
+
+static int
+move_inode_f(
+ int argc,
+ char **argv)
+{
+ void *fshandle;
+ size_t fshdlen;
+ xfs_agnumber_t agno = 0;
+ struct stat st;
+ int ret;
+ int c;
+
+ while ((c = getopt(argc, argv, "a:")) != EOF) {
+ switch (c) {
+ case 'a':
+ agno = cvt_u32(optarg, 10);
+ if (errno) {
+ fprintf(stderr, _("bad agno value %s\n"),
+ optarg);
+ return command_usage(&move_inode_cmd);
+ }
+ break;
+ default:
+ return command_usage(&move_inode_cmd);
+ }
+ }
+
+ if (optind != argc)
+ return command_usage(&move_inode_cmd);
+
+ if (agno >= file->xfd.fsgeom.agcount) {
+ fprintf(stderr,
+_("Destination AG %d does not exist. Filesystem only has %d AGs\n"),
+ agno, file->xfd.fsgeom.agcount);
+ exitcode = 1;
+ return 0;
+ }
+
+ /* this is so we can use fd_to_handle() later on */
+ ret = path_to_fshandle(file->fs_path.fs_dir, &fshandle, &fshdlen);
+ if (ret < 0) {
+ fprintf(stderr, _("Cannot get fshandle for mount %s: %s\n"),
+ file->fs_path.fs_dir, strerror(errno));
+ goto exit_fail;
+ }
+
+ ret = fstat(file->xfd.fd, &st);
+ if (ret) {
+ fprintf(stderr, _("stat(%s) failed: %s\n"),
+ file->name, strerror(errno));
+ goto exit_fail;
+ }
+
+ if (S_ISREG(st.st_mode)) {
+ ret = move_file_to_ag(file->fs_path.fs_dir, file->name,
+ &file->xfd, agno);
+ } else {
+ fprintf(stderr, _("Unsupported: %s is not a regular file.\n"),
+ file->name);
+ goto exit_fail;
+ }
+
+ if (ret) {
+ fprintf(stderr, _("Failed to move inode to AG %d: %s\n"),
+ agno, strerror(-ret));
+ goto exit_fail;
+ }
+ fshandle_destroy();
+ return 0;
+
+exit_fail:
+ fshandle_destroy();
+ exitcode = 1;
+ return 0;
+}
+
+static void
+move_inode_help(void)
+{
+ printf(_(
+"\n"
+"Physically move an inode into a new allocation group\n"
+"\n"
+" -a agno -- destination AG agno for the current open file\n"
+"\n"));
+
+}
+
+void
+move_inode_init(void)
+{
+ move_inode_cmd.name = "move_inode";
+ move_inode_cmd.altname = "mvino";
+ move_inode_cmd.cfunc = move_inode_f;
+ move_inode_cmd.argmin = 2;
+ move_inode_cmd.argmax = 2;
+ move_inode_cmd.args = "-a agno";
+ move_inode_cmd.flags = CMD_FLAG_ONESHOT;
+ move_inode_cmd.oneline = _("Move an inode into a new AG.");
+ move_inode_cmd.help = move_inode_help;
+
+ add_command(&move_inode_cmd);
+}
+
diff --git a/spaceman/space.h b/spaceman/space.h
index 723209edd998..79deed812cdf 100644
--- a/spaceman/space.h
+++ b/spaceman/space.h
@@ -33,5 +33,6 @@ extern void freesp_init(void);
#endif
extern void info_init(void);
extern void health_init(void);
+void move_inode_init(void);
#endif /* XFS_SPACEMAN_SPACE_H_ */
--
2.28.0
next reply other threads:[~2020-11-10 22:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 22:59 Dave Chinner [this message]
2020-11-11 1:26 ` [PATCH] [RFC] spaceman: physically move a regular inode Darrick J. Wong
2020-11-11 4:15 ` Dave Chinner
2020-12-01 14:07 ` Brian Foster
2020-12-01 21:15 ` Dave Chinner
2020-12-02 12:30 ` Brian Foster
2020-12-04 6:10 ` Dave Chinner
2020-12-04 12:40 ` Brian Foster
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201110225924.4031404-1-david@fromorbit.com \
--to=david@fromorbit.com \
--cc=linux-xfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.