about rsyncing of block devices
Václav Ovsík
vaclav.ovsik at i.cz
Tue Jun 15 10:10:07 MDT 2010
Hi,
On Tue, Jun 15, 2010 at 04:12:18PM +0100, Stephane Chazelas wrote:
> Hiya,
>
> I can see it's a regular subject on this list.
>
> I, like others wanted to use rsync to synchronise two block
> devices (as it happens one lvm volume and one nbd device served
> by qemu-img on a remote host from a qcow2 disk image so that I
> can keep the old versions)
I already wrote a patch, but without response there.
http://lists.samba.org/archive/rsync/2010-January/024538.html
Oh yeah, the patch is not in the archive! 8-)
Ok, including it here now:
<<<<<<<<<<<<<<<<<<<< snip >>>>>>>>>>>>>>>>>>>>
diff --git a/flist.c b/flist.c
index 6d450bf..68f1ea0 100644
--- a/flist.c
+++ b/flist.c
@@ -63,6 +63,7 @@ extern int non_perishable_cnt;
extern int prune_empty_dirs;
extern int copy_links;
extern int copy_unsafe_links;
+extern int rw_devices;
extern int protocol_version;
extern int sanitize_paths;
extern int munge_symlinks;
@@ -228,7 +229,7 @@ static int readlink_stat(const char *path, STRUCT_STAT *stp, char *linkbuf)
#endif
}
-int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
+static int link_stat2(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
{
#ifdef SUPPORT_LINKS
if (copy_links)
@@ -246,6 +247,28 @@ int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
#endif
}
+int link_stat(const char *path, STRUCT_STAT *stp, int follow_dirlinks)
+{
+ if (link_stat2(path, stp, follow_dirlinks) != 0)
+ return -1;
+ if (rw_devices && S_ISBLK(stp->st_mode) && stp->st_size == 0) {
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ int fdx = do_open(path, O_RDONLY, 0);
+ if (fdx == -1)
+ rsyserr(FERROR, errno, "failed to open device %s to determine size", path);
+ else {
+ OFF_T off = lseek(fdx, 0, SEEK_END);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to end of %s to determine size", path);
+ else
+ stp->st_size = off;
+ close(fdx);
+ }
+ }
+ return 0;
+}
+
static inline int is_daemon_excluded(const char *fname, int is_dir)
{
if (daemon_filter_list.head
@@ -671,7 +694,7 @@ static void send_file_entry(int f, const char *fname, struct file_struct *file,
#endif
strlcpy(lastname, fname, MAXPATHLEN);
- if (S_ISREG(mode) || S_ISLNK(mode))
+ if (S_ISREG(mode) || S_ISLNK(mode) || (rw_devices && S_ISBLK(mode)))
stats.total_size += F_LENGTH(file);
}
@@ -1351,7 +1374,8 @@ struct file_struct *make_file(const char *fname, struct file_list *flist,
#ifdef HAVE_STRUCT_STAT_ST_RDEV
if (IS_DEVICE(st.st_mode)) {
tmp_rdev = st.st_rdev;
- st.st_size = 0;
+ if (!rw_devices || !S_ISBLK(st.st_mode))
+ st.st_size = 0;
} else if (IS_SPECIAL(st.st_mode))
st.st_size = 0;
#endif
diff --git a/generator.c b/generator.c
index e7c1ef7..78169ef 100644
--- a/generator.c
+++ b/generator.c
@@ -39,6 +39,7 @@ extern int preserve_acls;
extern int preserve_xattrs;
extern int preserve_links;
extern int preserve_devices;
+extern int rw_devices;
extern int preserve_specials;
extern int preserve_hard_links;
extern int preserve_executability;
@@ -1181,6 +1182,23 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
statret = link_stat(fname, &sx.st, keep_dirlinks && is_dir);
stat_errno = errno;
+
+ if (statret == 0 && IS_DEVICE(sx.st.st_mode) && sx.st.st_size == 0) {
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ int fdx = do_open(fname, O_RDONLY, 0);
+ if ( fdx == -1 ) {
+ rsyserr(FERROR, errno, "failed to open device %s to determine size", fname);
+ }
+ else {
+ OFF_T off = lseek(fdx, 0, SEEK_END);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to end of %s to determine size", fname);
+ else
+ sx.st.st_size = off;
+ close(fdx);
+ }
+ }
}
if (missing_args == 2 && file->mode == 0) {
@@ -1494,7 +1512,7 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
goto cleanup;
}
- if (!S_ISREG(file->mode)) {
+ if (!(S_ISREG(file->mode) || (rw_devices && IS_DEVICE(file->mode)))) {
if (solo_file)
fname = f_name(file, NULL);
rprintf(FINFO, "skipping non-regular file \"%s\"\n", fname);
@@ -1532,7 +1550,7 @@ static void recv_generator(char *fname, struct file_struct *file, int ndx,
fnamecmp = fname;
fnamecmp_type = FNAMECMP_FNAME;
- if (statret == 0 && !S_ISREG(sx.st.st_mode)) {
+ if (statret == 0 && !(S_ISREG(sx.st.st_mode) || (rw_devices && IS_DEVICE(sx.st.st_mode)))) {
if (delete_item(fname, sx.st.st_mode, del_opts | DEL_FOR_FILE) != 0)
goto cleanup;
statret = -1;
diff --git a/options.c b/options.c
index 6ee3e01..0d60293 100644
--- a/options.c
+++ b/options.c
@@ -48,6 +48,7 @@ int append_mode = 0;
int keep_dirlinks = 0;
int copy_dirlinks = 0;
int copy_links = 0;
+int rw_devices = 0;
int preserve_links = 0;
int preserve_hard_links = 0;
int preserve_acls = 0;
@@ -695,6 +696,7 @@ void usage(enum logcode F)
rprintf(F," -o, --owner preserve owner (super-user only)\n");
rprintf(F," -g, --group preserve group\n");
rprintf(F," --devices preserve device files (super-user only)\n");
+ rprintf(F," --rw-devices read/write device contents as regular file (implies --inplace)\n");
rprintf(F," --specials preserve special files\n");
rprintf(F," -D same as --devices --specials\n");
rprintf(F," -t, --times preserve modification times\n");
@@ -863,6 +865,7 @@ static struct poptOption long_options[] = {
{"no-D", 0, POPT_ARG_NONE, 0, OPT_NO_D, 0, 0 },
{"devices", 0, POPT_ARG_VAL, &preserve_devices, 1, 0, 0 },
{"no-devices", 0, POPT_ARG_VAL, &preserve_devices, 0, 0, 0 },
+ {"rw-devices", 0, POPT_ARG_NONE, &rw_devices, 0, 0, 0 },
{"specials", 0, POPT_ARG_VAL, &preserve_specials, 1, 0, 0 },
{"no-specials", 0, POPT_ARG_VAL, &preserve_specials, 0, 0, 0 },
{"links", 'l', POPT_ARG_VAL, &preserve_links, 1, 0, 0 },
@@ -1801,6 +1804,11 @@ int parse_arguments(int *argc_p, const char ***argv_p)
set_output_verbosity(verbose, DEFAULT_PRIORITY);
+ if (rw_devices) {
+ inplace = 1;
+ ignore_times = 1;
+ }
+
if (do_stats) {
parse_output_words(info_words, info_levels,
verbose > 1 ? "stats3" : "stats2", DEFAULT_PRIORITY);
@@ -2661,6 +2669,9 @@ void server_options(char **args, int *argc_p)
else if (remove_source_files)
args[ac++] = "--remove-sent-files";
+ if (rw_devices)
+ args[ac++] = "--rw-devices";
+
if (ac > MAX_SERVER_ARGS) { /* Not possible... */
rprintf(FERROR, "argc overflow in server_options().\n");
exit_cleanup(RERR_MALLOC);
diff --git a/receiver.c b/receiver.c
index 6688dda..ec11802 100644
--- a/receiver.c
+++ b/receiver.c
@@ -37,6 +37,7 @@ extern int protocol_version;
extern int relative_paths;
extern int preserve_hard_links;
extern int preserve_perms;
+extern int rw_devices;
extern int preserve_xattrs;
extern int basis_dir_cnt;
extern int make_backups;
@@ -199,6 +200,7 @@ int open_tmpfile(char *fnametmp, const char *fname, struct file_struct *file)
static int receive_data(int f_in, char *fname_r, int fd_r, OFF_T size_r,
const char *fname, int fd, OFF_T total_size)
{
+ STRUCT_STAT st;
static char file_sum1[MAX_DIGEST_LEN];
struct map_struct *mapbuf;
struct sum_struct sum;
@@ -321,10 +323,14 @@ static int receive_data(int f_in, char *fname_r, int fd_r, OFF_T size_r,
goto report_write_error;
#ifdef HAVE_FTRUNCATE
- if (inplace && fd != -1
- && ftruncate(fd, offset) < 0) {
- rsyserr(FERROR_XFER, errno, "ftruncate failed on %s",
- full_fname(fname));
+ (void)do_fstat(fd,&st);
+ /* Makes no sense to attempt to ftruncate() a block device: */
+ if (!(IS_DEVICE(st.st_mode))) {
+ if (inplace && fd != -1
+ && ftruncate(fd, offset) < 0) {
+ rsyserr(FERROR_XFER, errno, "ftruncate failed on %s",
+ full_fname(fname));
+ }
}
#endif
@@ -732,11 +738,25 @@ int recv_files(int f_in, int f_out, char *local_name)
continue;
}
- if (fd1 != -1 && !S_ISREG(st.st_mode)) {
+ if (fd1 != -1 && !(S_ISREG(st.st_mode) || (rw_devices && IS_DEVICE(st.st_mode)))) {
close(fd1);
fd1 = -1;
}
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ if (fd1 != -1 && IS_DEVICE(st.st_mode) && st.st_size == 0) {
+ OFF_T off = lseek(fd1, 0, SEEK_END);
+ if (off == (OFF_T) -1)
+ rsyserr(FERROR, errno, "failed to seek to end of %s to determine size", fname);
+ else {
+ st.st_size = off;
+ off = lseek(fd1, 0, SEEK_SET);
+ if (off != 0)
+ rsyserr(FERROR, errno, "failed to seek back to beginning of %s to read it", fname);
+ }
+ }
+
/* If we're not preserving permissions, change the file-list's
* mode based on the local permissions and some heuristics. */
if (!preserve_perms) {
diff --git a/rsync.c b/rsync.c
index cefbe5f..6b6ffea 100644
--- a/rsync.c
+++ b/rsync.c
@@ -33,6 +33,7 @@ extern int preserve_xattrs;
extern int preserve_perms;
extern int preserve_executability;
extern int preserve_times;
+extern int rw_devices;
extern int am_root;
extern int am_server;
extern int am_sender;
@@ -397,7 +398,8 @@ int read_ndx_and_attrs(int f_in, int f_out, int *iflag_ptr, uchar *type_ptr,
if (iflags & ITEM_TRANSFER) {
int i = ndx - cur_flist->ndx_start;
- if (i < 0 || !S_ISREG(cur_flist->files[i]->mode)) {
+ struct file_struct *file = cur_flist->files[i];
+ if (i < 0 || !(S_ISREG(file->mode) || (rw_devices && IS_DEVICE(file->mode)))) {
rprintf(FERROR,
"received request to transfer non-regular file: %d [%s]\n",
ndx, who_am_i());
diff --git a/syscall.c b/syscall.c
index aba0009..7096110 100644
--- a/syscall.c
+++ b/syscall.c
@@ -36,6 +36,7 @@ extern int read_only;
extern int list_only;
extern int preserve_perms;
extern int preserve_executability;
+extern int rw_devices;
#define RETURN_ERROR_IF(x,e) \
do { \
@@ -286,20 +287,56 @@ int do_mkstemp(char *template, mode_t perms)
int do_stat(const char *fname, STRUCT_STAT *st)
{
#ifdef USE_STAT64_FUNCS
- return stat64(fname, st);
+ if (stat64(fname, st) != 0)
+ return -1;
#else
- return stat(fname, st);
+ if (stat(fname, st) != 0)
+ return -1;
#endif
+ if (rw_devices && S_ISBLK(st->st_mode) && st->st_size == 0) {
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ int fdx = do_open(fname, O_RDONLY, 0);
+ if (fdx == -1)
+ rsyserr(FERROR, errno, "failed to open device %s to determine size", fname);
+ else {
+ OFF_T off = lseek(fdx, 0, SEEK_END);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to end of %s to determine size", fname);
+ else
+ st->st_size = off;
+ close(fdx);
+ }
+ }
+ return 0;
}
int do_lstat(const char *fname, STRUCT_STAT *st)
{
#ifdef SUPPORT_LINKS
# ifdef USE_STAT64_FUNCS
- return lstat64(fname, st);
+ if (lstat64(fname, st) != 0)
+ return -1;
# else
- return lstat(fname, st);
+ if (lstat(fname, st) != 0)
+ return -1;
# endif
+ if (rw_devices && S_ISBLK(st->st_mode) && st->st_size == 0) {
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ int fdx = do_open(fname, O_RDONLY, 0);
+ if (fdx == -1)
+ rsyserr(FERROR, errno, "failed to open device %s to determine size", fname);
+ else {
+ OFF_T off = lseek(fdx, 0, SEEK_END);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to end of %s to determine size", fname);
+ else
+ st->st_size = off;
+ close(fdx);
+ }
+ }
+ return 0;
#else
return do_stat(fname, st);
#endif
@@ -308,10 +345,30 @@ int do_lstat(const char *fname, STRUCT_STAT *st)
int do_fstat(int fd, STRUCT_STAT *st)
{
#ifdef USE_STAT64_FUNCS
- return fstat64(fd, st);
+ if (fstat64(fd, st) != 0)
+ return -1;
#else
- return fstat(fd, st);
+ if (fstat(fd, st) != 0)
+ return -1;
#endif
+ if (rw_devices && S_ISBLK(st->st_mode) && st->st_size == 0) {
+ /* On Linux systems (at least), st_size is typically 0 for devices.
+ * If so, try to determine the actual device size. */
+ OFF_T off_save = lseek(fd, 0, SEEK_CUR);
+ if (off_save == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek on device inode %lld to read current position", (long long int)(st->st_ino));
+ else {
+ OFF_T off = lseek(fd, 0, SEEK_END);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to end on device inode %lld to determine size", (long long int)(st->st_ino));
+ else
+ st->st_size = off;
+ off = lseek(fd, off_save, SEEK_SET);
+ if (off == (OFF_T)-1)
+ rsyserr(FERROR, errno, "failed to seek to origin position on device inode %lld", (long long int)(st->st_ino));
+ }
+ }
+ return 0;
}
OFF_T do_lseek(int fd, OFF_T offset, int whence)
<<<<<<<<<<<<<<<<<<<< snip >>>>>>>>>>>>>>>>>>>>
Can someone review a patch and include it somewhere?
Thanks
--
Zito
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