hardlink: add --prioritize-trees

Based on patch from discussion at https://github.com/util-linux/util-linux/issues/3016

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

diff --git a/misc-utils/hardlink.1.adoc b/misc-utils/hardlink.1.adoc
index 471cb1c7ddd1e87c67a9db385f48250bc4a9bd85..d11045941431f708f3c65b9516c0b18b9a47a345 100644 (file)
--- a/misc-utils/hardlink.1.adoc
+++ b/misc-utils/hardlink.1.adoc
@@ -60,6 +60,10 @@ Only try to link files with the same directory name. The top-level directory (as
 *-f*, *--respect-name*::
 Only try to link files with the same (base)name. It's strongly recommended to use long options rather than *-f* which is interpreted in a different way by other *hardlink* implementations.
 
+*-F*, *--prioritize-trees*::
+Keep files found in the earliest specified top-level directory if there are multiple identical files in different trees.
+For example, *hardlink foo/ bar/* will link files in bar/ to equal files in the foo/ directory.
+
 *-i*, *--include* _regex_::
 A regular expression to include files. If the option *--exclude* has been given, this option re-includes files which would otherwise be excluded. If the option is used without *--exclude*, only files matched by the pattern are included.
 

diff --git a/misc-utils/hardlink.c b/misc-utils/hardlink.c
index 56316624277001d0fba6fd1c7e69b04315b594a8..a2a46b904235e1f070456b9ce0a44cdc8da0755d 100644 (file)
--- a/misc-utils/hardlink.c
+++ b/misc-utils/hardlink.c
@@ -68,6 +68,8 @@
 static int quiet;              /* don't print anything */
 static int rootbasesz;         /* size of the directory for nftw() */
 
+static unsigned short curr_tree;       /* seq. number of the current top-level directory */
+
 #ifdef USE_REFLINK
 enum {
        REFLINK_NEVER  = 0,
@@ -106,6 +108,8 @@ struct file {
                char path[1];
 #endif
        } *links;
+
+       unsigned short tree_seqnum;
 };
 
 /**
@@ -163,6 +167,7 @@ struct hdl_regex {
  * @maximise: Chose the file with the highest link count as master
  * @minimise: Chose the file with the lowest link count as master
  * @keep_oldest: Choose the file with oldest timestamp as master (default = FALSE)
+ * @prio_trees: Prioritize trees; choose the file that was found in the earliest specified tree (default = FALSE)
  * @dry_run: Specifies whether hardlink should not link files (default = FALSE)
  * @min_size: Minimum size of files to consider. (default = 1 byte)
  * @max_size: Maximum size of files to consider, 0 means umlimited. (default = 0 byte)
@@ -182,6 +187,7 @@ static struct options {
        unsigned int maximise:1;
        unsigned int minimise:1;
        unsigned int keep_oldest:1;
+       unsigned int prio_trees:1;
        unsigned int dry_run:1;
        uintmax_t min_size;
        uintmax_t max_size;
@@ -199,6 +205,7 @@ static struct options {
        .respect_time = TRUE,
        .respect_xattrs = FALSE,
        .keep_oldest = FALSE,
+       .prio_trees = FALSE,
        .min_size = 1,
        .cache_size = 10*1024*1024
 };
@@ -672,6 +679,8 @@ static int file_compare(const struct file *a, const struct file *b)
                res = CMP(a->st.st_nlink, b->st.st_nlink);
        if (res == 0 && opts.minimise)
                res = CMP(b->st.st_nlink, a->st.st_nlink);
+       if (res == 0 && opts.prio_trees)
+               res = CMP(a->tree_seqnum, b->tree_seqnum);
        if (res == 0)
                res = opts.keep_oldest ? CMP(b->st.st_mtime, a->st.st_mtime)
                    : CMP(a->st.st_mtime, b->st.st_mtime);
@@ -875,6 +884,7 @@ static int inserter(const char *fpath, const struct stat *sb,
        fil->links->basename = ftwbuf->base;
        fil->links->dirname = rootbasesz;
        fil->links->next = NULL;
+       fil->tree_seqnum = curr_tree;
 
        memcpy(fil->links->path, fpath, pathlen);
 
@@ -1173,6 +1183,9 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_(" -M, --minimize             reverse the meaning of -m\n"), out);
        fputs(_(" -n, --dry-run              don't actually link anything\n"), out);
        fputs(_(" -o, --ignore-owner         ignore owner changes\n"), out);
+       fputs(_(" -F, --prioritize-trees     files found in the earliest specified top-level\n"
+                "                              directory have higher priority (lower precedence\n"
+               "                              than minimize/maximize)\n"), out);
        fputs(_(" -O, --keep-oldest          keep the oldest file of multiple equal files\n"
                "                              (lower precedence than minimize/maximize)\n"), out);
        fputs(_(" -p, --ignore-mode          ignore changes of file mode\n"), out);
@@ -1210,7 +1223,7 @@ static int parse_options(int argc, char *argv[])
                OPT_REFLINK = CHAR_MAX + 1,
                OPT_SKIP_RELINKS
        };
-       static const char optstr[] = "VhvndfpotXcmMOx:y:i:r:S:s:b:q";
+       static const char optstr[] = "VhvndfpotXcmMFOx:y:i:r:S:s:b:q";
        static const struct option long_options[] = {
                {"version", no_argument, NULL, 'V'},
                {"help", no_argument, NULL, 'h'},
@@ -1224,6 +1237,7 @@ static int parse_options(int argc, char *argv[])
                {"respect-xattrs", no_argument, NULL, 'X'},
                {"maximize", no_argument, NULL, 'm'},
                {"minimize", no_argument, NULL, 'M'},
+               {"prioritize-trees", no_argument, NULL, 'F'},
                {"keep-oldest", no_argument, NULL, 'O'},
                {"exclude", required_argument, NULL, 'x'},
                {"include", required_argument, NULL, 'i'},
@@ -1273,6 +1287,9 @@ static int parse_options(int argc, char *argv[])
                case 'O':
                        opts.keep_oldest = TRUE;
                        break;
+               case 'F':
+                       opts.prio_trees = TRUE;
+                       break;
                case 'f':
                        opts.respect_name = TRUE;
                        break;
@@ -1443,8 +1460,12 @@ int main(int argc, char *argv[])
                }
                if (opts.respect_dir)
                        rootbasesz = strlen(path);
+               if (opts.prio_trees)
+                       ++curr_tree;
+
                if (nftw(path, inserter, 20, FTW_PHYS) == -1)
                        warn(_("cannot process %s"), path);
+
                free(path);
                rootbasesz = 0;
        }