When you bind-mount a subdirectory of a local filesystem, the
path to that subdirectory appears as the fourth field in mountinfo.
For nfs mounts, the fourth field is always "/", and the subdirectory
part is appended to the "special" (aka "device") field. This is
consistent with historical NFS usage which always includes a path in
the fs_spec field.
libmount needs to know about this when "mount -a" checks to see if
a filesystem is already mounted.
Without this fix, fstab lines like:
server::/path /dir nfs defaults 0 0
/dir/subdir /mnt/test none bind 0 0
result in a new mount at /mnt/test every time "mount -a" is run.
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
libmount/src/tab.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 968057e429f5..21e37aea7f5d 100644
--- a/libmount/src/tab.c
+++ b/libmount/src/tab.c
@@ -1542,6 +1542,7 @@ int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
struct libmnt_fs *fs;
char *root = NULL;
+ char *src2 = NULL;
const char *src = NULL, *tgt = NULL;
char *xtgt = NULL;
int rc = 0;
@@ -1566,8 +1567,18 @@ int mnt_table_is_fs_mounted(struct libmnt_table *tb, struct libmnt_fs *fstab_fs)
flags = MS_BIND;
rootfs = mnt_table_get_fs_root(tb, fstab_fs, flags, &root);
- if (rootfs)
+ if (rootfs) {
+ const char *fstype = mnt_fs_get_fstype(rootfs);
+
src = mnt_fs_get_srcpath(rootfs);
+ if (fstype && strncmp(fstype, "nfs", 3) == 0 && root) {
+ /* NFS stores the root at the end of the source */
+ asprintf(&src2, "%s%s", src, root);
+ src = src2;
+ free(root);
+ root = NULL;
+ }
+ }
}
if (!src)
@@ -1667,6 +1678,7 @@ done:
free(root);
DBG(TAB, ul_debugobj(tb, "mnt_table_is_fs_mounted: %s [rc=%d]", src, rc));
+ free(src2);
return rc;
}
--
2.14.0.rc0.dirty
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