findmnt: add support for fs-root (subvolumes and bind mounts)

This patch modifies the default output for SOURCE column. All btrfs
subvolume mountpoints and all bind-mount (where source is not root of
FS) will be printed as:

   SOURCE               TARGET
   /dev/sda1[/aaa]      /mnt/test

where /aaa is subvolume name or fs root for bind mounts, it means:

   # mount -t btrfs /dev/sda1 /mnt/test -o subvol=aaa

or:

   # mount --bind /aaa /mnt/test

The info about fs-root is 4th column in /proc/self/mountinfo.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/findmnt.8 b/misc-utils/findmnt.8
index 65cef44bb720f49f4f18153de7208a753a6f46f1..2f9dd74a5fc91c3e5dc0d6a1a500844114dcecab 100644 (file)
--- a/misc-utils/findmnt.8
+++ b/misc-utils/findmnt.8
@@ -65,6 +65,8 @@ Print the first matching filesystem only.
 Invert the sense of matching.
 .IP "\fB\-l, \-\-list\fP"
 Use the list output format.
+.IP "\fB\-v, \-\-nofsroot\fP"
+Do not print a [/dir] in the SOURCE column for bind-mounts or btrfs subvolumes.
 .IP "\fB\-n, \-\-noheadings\fP"
 Do not print a header line.
 .IP "\fB\-u, \-\-notruncate\fP"

diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 7314bb6e37ae3e387de50060eafed7785d123fa0..4a83223f2b6a02356c2d2a3fff82de77cd44d0a2 100644 (file)
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -46,6 +46,7 @@ enum {
        FL_FIRSTONLY    = (1 << 3),
        FL_INVERT       = (1 << 4),
        FL_NOSWAPMATCH  = (1 << 6),
+       FL_NOFSROOT     = (1 << 7),
 };
 
 /* column IDs */
@@ -215,7 +216,9 @@ static const char *get_data(mnt_fs *fs, int num)
 
        switch(get_column_id(num)) {
        case COL_SOURCE:
-               /* dir or dev */
+       {
+               const char *root = mnt_fs_get_root(fs);
+
                str = mnt_fs_get_srcpath(fs);
 
                if (str && (flags & FL_CANONICALIZE))
@@ -226,7 +229,14 @@ static const char *get_data(mnt_fs *fs, int num)
                        if (str && (flags & FL_EVALUATE))
                                str = mnt_resolve_spec(str, cache);
                }
+               if (root && str && !(flags & FL_NOFSROOT) && strcmp(root, "/")) {
+                       char *tmp;
+
+                       if (asprintf(&tmp, "%s[%s]", str, root) > 0)
+                               str = tmp;
+               }
                break;
+       }
        case COL_TARGET:
                str = mnt_fs_get_target(fs);
                break;
@@ -450,6 +460,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
        " -r, --raw              use raw format output\n"
        " -a, --ascii            use ascii chars for tree formatting\n"
        " -t, --types <list>     limit the set of filesystem by FS types\n"
+       " -v, --nofsroot         don't print [/dir] for bind or btrfs mounts\n"
        " -S, --source <string>  device, LABEL= or UUID=device\n"
        " -T, --target <string>  mountpoint\n\n"));
 
@@ -508,6 +519,7 @@ int main(int argc, char *argv[])
            { "output",       1, 0, 'o' },
            { "raw",          0, 0, 'r' },
            { "types",        1, 0, 't' },
+           { "fsroot",       0, 0, 'v' },
            { "source",       1, 0, 'S' },
            { "target",       1, 0, 'T' },
 
@@ -530,7 +542,7 @@ int main(int argc, char *argv[])
        tt_flags |= TT_FL_TREE;
 
        while ((c = getopt_long(argc, argv,
-                               "acd:ehifo:O:klmnrst:uS:T:", longopts, NULL)) != -1) {
+                               "acd:ehifo:O:klmnrst:uvS:T:", longopts, NULL)) != -1) {
                switch(c) {
                case 'a':
                        tt_flags |= TT_FL_ASCII;
@@ -603,6 +615,9 @@ int main(int argc, char *argv[])
                case 'n':
                        tt_flags |= TT_FL_NOHEADINGS;
                        break;
+               case 'v':
+                       flags |= FL_NOFSROOT;
+                       break;
                case 'S':
                        set_match(COL_SOURCE, optarg);
                        flags |= FL_NOSWAPMATCH;
@@ -625,6 +640,7 @@ int main(int argc, char *argv[])
                        tt_flags &= ~TT_FL_TREE;
                }
        }
+
        if (optind < argc && (get_match(COL_SOURCE) || get_match(COL_TARGET)))
                errx(EXIT_FAILURE, _(
                        "options --target and --source can't be used together "