From e5c4f61a622d84c5346d0fec1ed788a16f4d4a01 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:05:30 +1000
Subject: [PATCH 01/17] print RmFile size (size==192)

---
 lib/session.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/session.c b/lib/session.c
index 45bf41e5..edc3b5d7 100644
--- a/lib/session.c
+++ b/lib/session.c
@@ -76,6 +76,7 @@ bool rm_session_check_kernel_version(int need_major, int need_minor) {
 }
 
 void rm_session_init(RmSession *session, RmCfg *cfg) {
+    rm_log_warning("Sizeof(RmFile): %lu\n", sizeof(RmFile));
     memset(session, 0, sizeof(RmSession));
     session->timer = g_timer_new();
 

From fdf71059056b2d467ba621523411fea238775366 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:01:46 +1000
Subject: [PATCH 02/17] file: retire RmFileState enum in favour of bit flag;
 sizeof(RmFile)==184

---
 lib/file.h     | 19 +++----------------
 lib/shredder.c |  9 +++------
 2 files changed, 6 insertions(+), 22 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 671e61fd..aec168a8 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -29,18 +29,6 @@
 
 #include "cfg.h"
 
-typedef enum RmFileState {
-    /* File still processing
-     */
-    RM_FILE_STATE_NORMAL,
-
-    /* File can be ignored, has a unique hash, gets read failure
-     * or is elsewhise not noteworthy.
-     */
-    RM_FILE_STATE_IGNORE,
-
-} RmFileState;
-
 /* types of lint */
 typedef enum RmLintType {
     RM_LINT_TYPE_UNKNOWN = 0,
@@ -183,6 +171,9 @@ typedef struct RmFile {
     /* Set to true if was read from [json] cache as an original */
     bool cached_original : 1;
 
+    /* File hashing failed (probably read error or user interrupt) */
+    bool hashing_failed : 1;
+
     /* The pre-matched file cluster that this file belongs to (or NULL) */
     GQueue *cluster;
 
@@ -207,10 +198,6 @@ typedef struct RmFile {
      */
     RmOff hash_offset;
 
-    /* Flag for when we do intermediate steps within a hash increment because the file is
-     * fragmented */
-    RmFileState status;
-
     /* digest of this file updated on every hash iteration.  Use a pointer so we can share
      * with RmShredGroup
      */
diff --git a/lib/shredder.c b/lib/shredder.c
index 797e1b30..f5dd3db9 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -520,7 +520,6 @@ static gint32 rm_shred_get_read_size(RmFile *file, RmShredTag *tag) {
             MIN(group->next_offset, group->hash_offset + SHRED_PARANOID_BYTES);
     }
 
-    file->status = RM_FILE_STATE_NORMAL;
     result = (group->next_offset - file->hash_offset);
 
     return result;
@@ -994,10 +993,8 @@ static RmFile *rm_shred_sift(RmFile *file) {
                 g_list_remove(current_group->in_progress_digests, file->digest);
         }
 
-        if(file->status == RM_FILE_STATE_IGNORE) {
-            /* reading/hashing failed somewhere */
+        if(file->hashing_failed) {
             rm_shred_discard_file(file, NULL);
-
         } else {
             g_assert(file->digest);
 
@@ -1651,7 +1648,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
     RmShredTag *tag = session->shredder;
 
     if(rm_session_was_aborted() || session->equal_exit_code == EXIT_FAILURE) {
-        file->status = RM_FILE_STATE_IGNORE;
+        file->hashing_failed = TRUE;
         rm_shred_sift(file);
         return 1;
     }
@@ -1676,7 +1673,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
         if(!rm_hasher_task_hash(task, file_path, file->hash_offset, bytes_to_read,
                                 file->is_symlink, &bytes_read)) {
             /* rm_hasher_start_increment failed somewhere */
-            file->status = RM_FILE_STATE_IGNORE;
+            file->hashing_failed = TRUE;
             shredder_waiting = FALSE;
         }
 

From fc7f406b9d2598d1c0e5f65401c48c82180d70fe Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:51:10 +1000
Subject: [PATCH 03/17] file: re-order fields within struct ->
 sizeof(RmFile)==168

---
 lib/file.h | 182 +++++++++++++++++++++++++++++------------------------
 1 file changed, 99 insertions(+), 83 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index aec168a8..7c750484 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -95,18 +95,100 @@ struct RmDirectory;
  * RmFile structure; used by pretty much all rmlint modules.
  */
 typedef struct RmFile {
+
+    /*----- 64-bit types ----- */
+
     /* file path lookup ID (if using swap table)
      * */
     RmOff path_id;
 
-    /* file path as node of folder n-ary tree
-     * */
-    RmNode *node;
+    /* The index of the path this file belongs to. */
+    RmOff path_index;
+
+    /* Filesize in bytes; this may be less than actual_file_size,
+     * since -q / -Q may limit this number.
+     */
+    RmOff file_size;
+
+    /* Filesize of a file when it was traversed by rmlint.
+     */
+    RmOff actual_file_size;
+
+    /* How many bytes were already read.
+     * (lower or equal file_size)
+     */
+    RmOff hash_offset;
+
+    /* Those are never used at the same time.
+     * disk_offset is used during computation,
+     * twin_count during output.
+     */
+    union {
+        /* Count of twins of this file.
+         * (i.e. length of group of this file)
+         */
+        gint64 twin_count;
+
+        /* Disk fiemap / physical offset at start of file (tests mapping subsequent
+         * file fragments did not deliver any significant additionl benefit) */
+        RmOff disk_offset;
+    };
 
     /* File modification date/time
      * */
     gdouble mtime;
 
+    /* Number of children this file has.
+     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
+     * */
+    size_t n_children;
+
+
+    /*----- pointer types ----- */
+
+    /* The pre-matched file cluster that this file belongs to (or NULL) */
+    GQueue *cluster;
+
+    /* pointer to hardlinks collection (or NULL); one list shared between hardlink twin
+     * set */
+    GQueue *hardlinks;
+
+    /* digest of this file updated on every hash iteration.  Use a pointer so we can share
+     * with RmShredGroup
+     */
+    RmDigest *digest;
+
+    /* digest of this file read from file extended attributes (previously written by
+     * rmlint)
+     */
+    const char *ext_cksum;
+
+    /* multi-disk scheduler disk link */
+    struct _RmMDSDevice *disk;
+
+    /* file path as node of folder n-ary tree
+     * */
+    RmNode *node;
+
+    /* Link to the RmShredGroup that the file currently belongs to */
+    struct RmShredGroup *shred_group;
+
+    /* Required for rm_file_equal and for RM_DEFINE_PATH */
+    const struct RmSession *session;
+
+    struct RmSignal *signal;
+
+    /* Parent directory.
+     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
+     */
+    struct RmDirectory *parent_dir;
+
+    /*----- 32-bit types ----- */
+
+    guint ref_count;
+
+    /*----- 16-bit types ----- */
+
     /* Depth of the file, relative to the command-line path it was found under.
      */
     gint16 depth;
@@ -121,7 +203,20 @@ typedef struct RmFile {
      * */
     gint16 outer_link_count;
 
-    struct _RmMDSDevice *disk;
+
+    /* What kind of lint this file is.
+     */
+    RmLintType lint_type;
+
+    /* Caching bitmasks to ensure each file is only matched once
+     * for every GRegex combination.
+     * See also preprocess.c for more explanation.
+     * */
+    RmPatternBitmask pattern_bitmask_path;
+    RmPatternBitmask pattern_bitmask_basename;
+
+
+    /*----- bitfield types ----- */
 
     /* True if the file is a symlink
      * shredder needs to know this, since the metadata might be about the
@@ -174,85 +269,6 @@ typedef struct RmFile {
     /* File hashing failed (probably read error or user interrupt) */
     bool hashing_failed : 1;
 
-    /* The pre-matched file cluster that this file belongs to (or NULL) */
-    GQueue *cluster;
-
-    /* pointer to hardlinks collection (or NULL); one list shared between hardlink twin
-     * set */
-    GQueue *hardlinks;
-
-    /* The index of the path this file belongs to. */
-    RmOff path_index;
-
-    /* Filesize in bytes; this may be less than actual_file_size,
-     * since -q / -Q may limit this number.
-     */
-    RmOff file_size;
-
-    /* Filesize of a file when it was traversed by rmlint.
-     */
-    RmOff actual_file_size;
-
-    /* How many bytes were already read.
-     * (lower or equal file_size)
-     */
-    RmOff hash_offset;
-
-    /* digest of this file updated on every hash iteration.  Use a pointer so we can share
-     * with RmShredGroup
-     */
-    RmDigest *digest;
-
-    /* digest of this file read from file extended attributes (previously written by
-     * rmlint)
-     */
-    const char *ext_cksum;
-
-    /* Those are never used at the same time.
-     * disk_offset is used during computation,
-     * twin_count during output.
-     */
-    union {
-        /* Count of twins of this file.
-         * (i.e. length of group of this file)
-         */
-        gint64 twin_count;
-
-        /* Disk fiemap / physical offset at start of file (tests mapping subsequent
-         * file fragments did not deliver any significant additionl benefit) */
-        RmOff disk_offset;
-    };
-
-    /* What kind of lint this file is.
-     */
-    RmLintType lint_type;
-
-    /* Link to the RmShredGroup that the file currently belongs to */
-    struct RmShredGroup *shred_group;
-
-    /* Required for rm_file_equal and for RM_DEFINE_PATH */
-    const struct RmSession *session;
-
-    struct RmSignal *signal;
-
-    /* Caching bitmasks to ensure each file is only matched once
-     * for every GRegex combination.
-     * See also preprocess.c for more explanation.
-     * */
-    RmPatternBitmask pattern_bitmask_path;
-    RmPatternBitmask pattern_bitmask_basename;
-
-    /* Parent directory.
-     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
-     */
-    struct RmDirectory *parent_dir;
-
-    /* Number of children this file has.
-     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
-     * */
-    size_t n_children;
-
-    guint ref_count;
 } RmFile;
 
 /* Defines a path variable containing the file's path */

From a786f113172e52cb5773a00e44cd17cefcc4a5e9 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:53:49 +1000
Subject: [PATCH 04/17] file: remove redundant path_id -> sizeof(RmFile)==160

---
 lib/file.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 7c750484..7122ad36 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -98,10 +98,6 @@ typedef struct RmFile {
 
     /*----- 64-bit types ----- */
 
-    /* file path lookup ID (if using swap table)
-     * */
-    RmOff path_id;
-
     /* The index of the path this file belongs to. */
     RmOff path_index;
 

From 6d3514f57f24aa18cbe3f6fdebc62e7f9b587585 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:55:28 +1000
Subject: [PATCH 05/17] file: only use 32 bits for n_children;
 sizeof(RmFile)==160

---
 lib/file.h | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 7122ad36..b28d51d6 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -134,11 +134,6 @@ typedef struct RmFile {
      * */
     gdouble mtime;
 
-    /* Number of children this file has.
-     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
-     * */
-    size_t n_children;
-
 
     /*----- pointer types ----- */
 
@@ -183,6 +178,12 @@ typedef struct RmFile {
 
     guint ref_count;
 
+    /* Number of children this file has.
+     * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
+     * */
+    guint32 n_children;
+
+
     /*----- 16-bit types ----- */
 
     /* Depth of the file, relative to the command-line path it was found under.

From 50add6ab476218b22e9fc4804ccacb8fe1c3d131 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 07:58:06 +1000
Subject: [PATCH 06/17] file: use 16 bits for path_index -> sizeof(RmFile)==152

---
 lib/file.h     | 6 +++---
 lib/shredder.c | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index b28d51d6..33859791 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -98,9 +98,6 @@ typedef struct RmFile {
 
     /*----- 64-bit types ----- */
 
-    /* The index of the path this file belongs to. */
-    RmOff path_index;
-
     /* Filesize in bytes; this may be less than actual_file_size,
      * since -q / -Q may limit this number.
      */
@@ -186,6 +183,9 @@ typedef struct RmFile {
 
     /*----- 16-bit types ----- */
 
+    /* The index of the path this file belongs to. */
+    guint16 path_index;
+
     /* Depth of the file, relative to the command-line path it was found under.
      */
     gint16 depth;
diff --git a/lib/shredder.c b/lib/shredder.c
index f5dd3db9..40a47ab8 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -1102,7 +1102,7 @@ static void rm_shred_file_preprocess(RmFile *file, RmShredGroup **group) {
     /* add reference for this file to the MDS scheduler, and get pointer to its device */
     file->disk = rm_mds_device_get(
         session->mds, file_path,
-        (cfg->fake_pathindex_as_disk) ? file->path_index + 1 : rm_file_dev(file));
+        (cfg->fake_pathindex_as_disk) ? (dev_t)file->path_index + 1 : rm_file_dev(file));
     rm_mds_device_ref(file->disk, 1);
 
     rm_shred_adjust_counters(shredder, 1, (gint64)file->file_size - file->hash_offset);

From e1057c92938caa465591fb00353e63c6a61fcc5e Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 08:00:11 +1000
Subject: [PATCH 07/17] file: only need 4 bits (just!) for RmLintType ->
 sizeof(RmFile)==144

---
 lib/file.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 33859791..7298d141 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -201,10 +201,6 @@ typedef struct RmFile {
     gint16 outer_link_count;
 
 
-    /* What kind of lint this file is.
-     */
-    RmLintType lint_type;
-
     /* Caching bitmasks to ensure each file is only matched once
      * for every GRegex combination.
      * See also preprocess.c for more explanation.
@@ -215,6 +211,11 @@ typedef struct RmFile {
 
     /*----- bitfield types ----- */
 
+    /* What kind of lint this file is.
+     */
+    RmLintType lint_type : 4;
+
+
     /* True if the file is a symlink
      * shredder needs to know this, since the metadata might be about the
      * symlink file itself, while open() returns the pointed file.

From d8762fa08ae273ae72a3acb0f9440b129e79fb9b Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 08:03:25 +1000
Subject: [PATCH 08/17] file: only use 16 bits for ref_count ->
 sizeof(RmFile)==144 breaks threadsafe-ness but should be ok since file unrefs
 are all single-threaded

---
 lib/file.c | 4 ++--
 lib/file.h | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/file.c b/lib/file.c
index 93fd6ffd..e790cc65 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -138,7 +138,7 @@ static gint rm_file_unref_impl(RmFile *file, gboolean unref_hardlinks) {
     if(!file) {
         return 0;
     }
-    if(!g_atomic_int_dec_and_test(&file->ref_count)) {
+    if(--file->ref_count != 0) {
         // somebody still loves me!
         return 0;
     }
@@ -175,7 +175,7 @@ gint rm_file_unref_full(RmFile *file) {
 }
 
 RmFile *rm_file_ref(RmFile *file) {
-    g_atomic_int_inc (&file->ref_count);
+    file->ref_count++;
     return file;
 }
 
diff --git a/lib/file.h b/lib/file.h
index 7298d141..a4adee71 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -173,8 +173,6 @@ typedef struct RmFile {
 
     /*----- 32-bit types ----- */
 
-    guint ref_count;
-
     /* Number of children this file has.
      * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
      * */
@@ -200,6 +198,8 @@ typedef struct RmFile {
      * */
     gint16 outer_link_count;
 
+    guint16 ref_count;
+
 
     /* Caching bitmasks to ensure each file is only matched once
      * for every GRegex combination.
@@ -314,7 +314,7 @@ RmFile *rm_file_new(struct RmSession *session, const char *path, RmStat *statp,
 /**
  * @brief Decrease reference count to file;
  * free resources if this is the last reference.
- * @note threadsafe
+ * @note NOT threadsafe
  * @note nullable
  * @retval 1 if the file freed else 0
  */

From a575d6ef2646c1fac1abaa6df79efecaa88e02d9 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 08:23:25 +1000
Subject: [PATCH 09/17] file: don't cache RmMDSDevice *disk reference ->
 sizeof(RmFile)==136

---
 lib/file.h     |  9 ++++++---
 lib/shredder.c | 31 ++++++++++++++++++++-----------
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index a4adee71..92a715e0 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -151,9 +151,6 @@ typedef struct RmFile {
      */
     const char *ext_cksum;
 
-    /* multi-disk scheduler disk link */
-    struct _RmMDSDevice *disk;
-
     /* file path as node of folder n-ary tree
      * */
     RmNode *node;
@@ -267,6 +264,12 @@ typedef struct RmFile {
     /* File hashing failed (probably read error or user interrupt) */
     bool hashing_failed : 1;
 
+    /* is on a spinning disk medium */
+    bool is_on_rotational_disk : 1;
+
+    /* true if mds disk needs unref */
+    bool has_disk_ref : 1;
+
 } RmFile;
 
 /* Defines a path variable containing the file's path */
diff --git a/lib/shredder.c b/lib/shredder.c
index 40a47ab8..afd6cba0 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -705,6 +705,13 @@ static void rm_shred_write_group_to_xattr(const RmSession *session, GQueue *grou
     }
 }
 
+static RmMDSDevice *rm_shred_disk(RmFile *file, const RmSession *session) {
+    dev_t dev = (session->cfg->fake_pathindex_as_disk) ?
+        (dev_t)file->path_index + 1 :
+        rm_file_dev(file);
+    return rm_mds_device_get(session->mds, NULL, dev);
+}
+
 /* Unlink RmFile from Shredder
  */
 static void rm_shred_discard_file(RmFile *file, _UNUSED gpointer user_data) {
@@ -712,9 +719,9 @@ static void rm_shred_discard_file(RmFile *file, _UNUSED gpointer user_data) {
     RmShredTag *tag = session->shredder;
 
     /* update device counters (unless this file was a bundled hardlink) */
-    if(file->disk) {
-        rm_mds_device_ref(file->disk, -1);
-        file->disk = NULL;
+    if(file->has_disk_ref) {
+        rm_mds_device_ref(rm_shred_disk(file, session), -1);
+        file->has_disk_ref = FALSE;
         rm_shred_adjust_counters(tag, -1, -(gint64)(file->file_size - file->hash_offset));
     }
 
@@ -736,7 +743,8 @@ static void rm_shred_push_queue(RmFile *file) {
             file->disk_offset = rm_file_inode(file);
         }
     }
-    rm_mds_push_task(file->disk, rm_file_dev(file), file->disk_offset, NULL, file);
+    rm_mds_push_task(rm_shred_disk(file, file->session), rm_file_dev(file),
+        file->disk_offset, NULL, file);
 }
 
 //////////////////////////////////
@@ -1099,11 +1107,11 @@ static void rm_shred_file_preprocess(RmFile *file, RmShredGroup **group) {
 
     RM_DEFINE_PATH(file);
 
-    /* add reference for this file to the MDS scheduler, and get pointer to its device */
-    file->disk = rm_mds_device_get(
-        session->mds, file_path,
-        (cfg->fake_pathindex_as_disk) ? (dev_t)file->path_index + 1 : rm_file_dev(file));
-    rm_mds_device_ref(file->disk, 1);
+    /* add reference for this file to the MDS scheduler */
+    RmMDSDevice *device = rm_shred_disk(file, session);
+    file->is_on_rotational_disk = rm_mds_device_is_rotational(device);
+    rm_mds_device_ref(device, 1);
+    file->has_disk_ref = TRUE;
 
     rm_shred_adjust_counters(shredder, 1, (gint64)file->file_size - file->hash_offset);
 
@@ -1665,7 +1673,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
         gboolean shredder_waiting =
             (file->shred_group->next_offset != file->file_size) &&
             (cfg->shred_always_wait ||
-             (!cfg->shred_never_wait && rm_mds_device_is_rotational(file->disk) &&
+             (!cfg->shred_never_wait && file->is_on_rotational_disk &&
               bytes_to_read < SHRED_TOO_MANY_BYTES_TO_WAIT));
 
         gsize bytes_read = 0;
@@ -1718,7 +1726,8 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
     }
     if(file) {
         /* file was not handled by rm_shred_sift so we need to add it back to the queue */
-        rm_mds_push_task(file->disk, rm_file_dev(file), file->disk_offset, NULL, file);
+        rm_mds_push_task(rm_shred_disk(file, session), rm_file_dev(file),
+            file->disk_offset, NULL, file);
     }
     return result;
 }

From 1fc48aba83159e9d0692614659c4d5c46565996a Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 08:27:51 +1000
Subject: [PATCH 10/17] file: remove redundant fadvise_requested flag ->
 sizeof(RmFile)==136

---
 lib/file.h     | 3 ---
 lib/shredder.c | 5 -----
 2 files changed, 8 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 92a715e0..2e929651 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -249,9 +249,6 @@ typedef struct RmFile {
      */
     bool free_digest : 1;
 
-    /* If true, the file will be request to be pre-cached on the next read */
-    bool fadvise_requested : 1;
-
     /* Set to true if rm_shred_process_file() for hash increment */
     bool shredder_waiting : 1;
 
diff --git a/lib/shredder.c b/lib/shredder.c
index afd6cba0..d4aebdc5 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -498,10 +498,6 @@ static gint32 rm_shred_get_read_size(RmFile *file, RmShredTag *tag) {
     g_assert(tag);
     RmOff balanced_bytes = tag->page_size * SHRED_BALANCED_PAGES;
     RmOff target_bytes = balanced_bytes * group->offset_factor;
-    if(group->next_offset == 2) {
-        file->fadvise_requested = 1;
-    }
-
     /* round to even number of pages, round up to MIN_READ_PAGES */
     RmOff target_pages = MAX(target_bytes / tag->page_size, 1);
     target_bytes = target_pages * tag->page_size;
@@ -509,7 +505,6 @@ static gint32 rm_shred_get_read_size(RmFile *file, RmShredTag *tag) {
     /* test if cost-effective to read the whole file */
     if(group->hash_offset + target_bytes + (balanced_bytes) >= group->file_size) {
         group->next_offset = group->file_size;
-        file->fadvise_requested = 1;
     } else {
         group->next_offset = group->hash_offset + target_bytes;
     }

From 3a08bcd366b3279e61c4c5b32591b760b8ebcde7 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 08:28:15 +1000
Subject: [PATCH 11/17] file: remove redundant free_digest flag ->
 sizeof(RmFile)==136

---
 lib/file.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/lib/file.h b/lib/file.h
index 2e929651..60912f65 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -244,11 +244,6 @@ typedef struct RmFile {
      */
     bool is_hidden : 1;
 
-    /* If false rm_file_destroy will not destroy the digest. This is useful
-     * for sharing the digest of duplicates in a group.
-     */
-    bool free_digest : 1;
-
     /* Set to true if rm_shred_process_file() for hash increment */
     bool shredder_waiting : 1;
 

From a0c329bc60565c5208c82c7eac9d281482b2a597 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 09:00:12 +1000
Subject: [PATCH 12/17] rank: size ranking should use actual_file_size, not
 clamped size

---
 lib/rank.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/rank.c b/lib/rank.c
index a7a35e73..1dba299f 100644
--- a/lib/rank.c
+++ b/lib/rank.c
@@ -246,7 +246,7 @@ int rm_rank_orig_criteria(const RmFile *a, const RmFile *b, const RmSession *ses
  * duplicates by splitting whereever rm_rank_group(a, b) != 0 */
 gint rm_rank_group(const RmFile *file_a, const RmFile *file_b) {
 
-    RETURN_IF_NONZERO(SIGN_DIFF(file_a->file_size, file_b->file_size));
+    RETURN_IF_NONZERO(SIGN_DIFF(file_a->actual_file_size, file_b->actual_file_size));
 
     RmCfg *cfg = file_a->session->cfg;
 

From eb243ec2179a04543898137c760468d7951b62ae Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 09:00:44 +1000
Subject: [PATCH 13/17] shredder: test for zero-sized files should use actual
 file size

---
 lib/shredder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/shredder.c b/lib/shredder.c
index d4aebdc5..65485f3c 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -1090,7 +1090,7 @@ static void rm_shred_file_preprocess(RmFile *file, RmShredGroup **group) {
     g_assert(file->lint_type == RM_LINT_TYPE_DUPE_CANDIDATE);
 
     /* Create an empty checksum for empty files */
-    if(file->file_size == 0) {
+    if(file->actual_file_size == 0) {
         file->digest = rm_digest_new(cfg->checksum_type, 0);
     }
 

From a9ac0f41b43808248cb3311dff447209d5a82adf Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Wed, 26 May 2021 09:02:15 +1000
Subject: [PATCH 14/17] file: don't cache [clamped] file_size ->
 sizeof(RmFile)==128

---
 lib/file.c      | 70 +++++++++++++++++++++++++------------------------
 lib/file.h      | 12 ++++-----
 lib/shredder.c  | 11 ++++----
 lib/treemerge.c |  3 +--
 4 files changed, 49 insertions(+), 47 deletions(-)

diff --git a/lib/file.c b/lib/file.c
index e790cc65..8c3098ed 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -28,53 +28,57 @@
 
 #include "session.h"
 
-RmFile *rm_file_new(struct RmSession *session, const char *path, RmStat *statp,
-                    RmLintType type, bool is_ppath, unsigned path_index, short depth,
-                    RmNode *node) {
-    RmCfg *cfg = session->cfg;
-    RmOff actual_file_size = statp->st_size;
-    RmOff start_seek = 0;
-
-    /* Allow an actual file size of 0 for empty files */
-    if(actual_file_size != 0) {
-        if(cfg->use_absolute_start_offset) {
-            start_seek = cfg->skip_start_offset;
-            if(cfg->skip_start_offset >= actual_file_size) {
-                return NULL;
-            }
-        } else {
-            start_seek = cfg->skip_start_factor * actual_file_size;
-            if((int)(actual_file_size * cfg->skip_end_factor) == 0) {
-                return NULL;
-            }
-
-            if(start_seek >= actual_file_size) {
-                return NULL;
-            }
-        }
+static RmOff rm_file_start_seek(RmFile *file) {
+    RmCfg *cfg = file->session->cfg;
+
+    if(cfg->use_absolute_start_offset) {
+        return cfg->skip_start_offset;
+    } else {
+        return cfg->skip_start_factor * file->actual_file_size;
     }
+}
+
+static RmOff rm_file_end_seek(RmFile *file) {
+    RmCfg *cfg = file->session->cfg;
+    RmOff end_seek = file->actual_file_size;
 
-    RmOff file_size;
     if(cfg->use_absolute_end_offset) {
-        file_size = CLAMP(actual_file_size, 1, cfg->skip_end_offset);
+        return end_seek - MIN(cfg->skip_end_offset, end_seek);
     } else {
-        file_size = actual_file_size * cfg->skip_end_factor;
+        return end_seek * cfg->skip_end_factor;
     }
+}
+
+RmOff rm_file_clamped_size(RmFile *file) {
+    RmOff start_seek = rm_file_start_seek(file);
+    RmOff end_seek = rm_file_end_seek(file);
+    return end_seek - MIN(start_seek, end_seek);
+}
+
+
+
+RmFile *rm_file_new(struct RmSession *session, const char *path, RmStat *statp,
+                    RmLintType type, bool is_ppath, unsigned path_index, short depth,
+                    RmNode *node) {
+    RmCfg *cfg = session->cfg;
+    RmFile *self = g_slice_new0(RmFile);
+    self->session = session;
+    self->actual_file_size = statp->st_size;
 
     if(type == RM_LINT_TYPE_DUPE_CANDIDATE || type == RM_LINT_TYPE_PART_OF_DIRECTORY) {
         /* Check if the actual slice the file will be > 0; we don't want empty files in
          * shredder */
-        if((file_size - start_seek) == 0 && actual_file_size != 0) {
+        if(self->actual_file_size != 0 && rm_file_clamped_size(self) == 0) {
+            g_slice_free(RmFile, self);
             return NULL;
         }
     }
     else {
         // report other types as zero-size
-        actual_file_size = 0;
+        // TODO: review this, doesn't seem sensible
+        self->actual_file_size = 0;
     }
 
-    RmFile *self = g_slice_new0(RmFile);
-    self->session = session;
 
     if(!node) {
         node = rm_trie_insert(&cfg->file_trie, path, statp->st_dev, statp->st_ino);
@@ -82,14 +86,12 @@ RmFile *rm_file_new(struct RmSession *session, const char *path, RmStat *statp,
     self->node = node;
 
     self->depth = depth;
-    self->file_size = file_size;
-    self->actual_file_size = actual_file_size;
     self->n_children = 0;
 
     self->mtime = rm_sys_stat_mtime_float(statp);
     self->is_new = (self->mtime >= cfg->min_mtime);
 
-    self->hash_offset = start_seek;
+    self->hash_offset = rm_file_start_seek(self);
 
     self->lint_type = type;
     self->is_prefd = is_ppath;
diff --git a/lib/file.h b/lib/file.h
index 60912f65..351cd66e 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -98,12 +98,7 @@ typedef struct RmFile {
 
     /*----- 64-bit types ----- */
 
-    /* Filesize in bytes; this may be less than actual_file_size,
-     * since -q / -Q may limit this number.
-     */
-    RmOff file_size;
-
-    /* Filesize of a file when it was traversed by rmlint.
+    /* Filesize of a file according to stat when it was traversed by rmlint.
      */
     RmOff actual_file_size;
 
@@ -406,4 +401,9 @@ static inline dev_t rm_file_parent_dev(const RmFile *file) {
     return rm_node_get_dev(file->node->parent);
 }
 
+/**
+ * @brief file size after clamping start and end offsets.
+ */
+RmOff rm_file_clamped_size(RmFile *file);
+
 #endif /* end of include guard */
diff --git a/lib/shredder.c b/lib/shredder.c
index 65485f3c..0edeed1b 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -471,7 +471,7 @@ static RmShredGroup *rm_shred_group_new(RmFile *file) {
     }
 
     self->held_files = g_queue_new();
-    self->file_size = file->file_size;
+    self->file_size = rm_file_clamped_size(file);
     self->hash_offset = file->hash_offset;
 
     self->session = file->session;
@@ -717,7 +717,8 @@ static void rm_shred_discard_file(RmFile *file, _UNUSED gpointer user_data) {
     if(file->has_disk_ref) {
         rm_mds_device_ref(rm_shred_disk(file, session), -1);
         file->has_disk_ref = FALSE;
-        rm_shred_adjust_counters(tag, -1, -(gint64)(file->file_size - file->hash_offset));
+        rm_shred_adjust_counters(tag, -1,
+            -(gint64)(rm_file_clamped_size(file) - file->hash_offset));
     }
 
     /* toss the file (and any embedded hardlinks)*/
@@ -1108,7 +1109,7 @@ static void rm_shred_file_preprocess(RmFile *file, RmShredGroup **group) {
     rm_mds_device_ref(device, 1);
     file->has_disk_ref = TRUE;
 
-    rm_shred_adjust_counters(shredder, 1, (gint64)file->file_size - file->hash_offset);
+    rm_shred_adjust_counters(shredder, 1, rm_file_clamped_size(file) - file->hash_offset);
 
     rm_shred_group_push_file(*group, file, true);
 }
@@ -1666,7 +1667,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
         RmOff bytes_to_read = rm_shred_get_read_size(file, tag);
 
         gboolean shredder_waiting =
-            (file->shred_group->next_offset != file->file_size) &&
+            (file->shred_group->next_offset != rm_file_clamped_size(file)) &&
             (cfg->shred_always_wait ||
              (!cfg->shred_never_wait && file->is_on_rotational_disk &&
               bytes_to_read < SHRED_TOO_MANY_BYTES_TO_WAIT));
@@ -1686,7 +1687,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
         /* Update totals for file, device and session*/
         file->hash_offset += bytes_to_read;
         if(file->is_symlink) {
-            rm_shred_adjust_counters(tag, 0, -(gint64)file->file_size);
+            rm_shred_adjust_counters(tag, 0, -rm_file_clamped_size(file));
         } else {
             rm_shred_adjust_counters(tag, 0, -(gint64)bytes_to_read);
         }
diff --git a/lib/treemerge.c b/lib/treemerge.c
index ed7de6be..f1e20592 100644
--- a/lib/treemerge.c
+++ b/lib/treemerge.c
@@ -378,8 +378,7 @@ static void rm_directory_to_file(RmTreeMerger *merger, const RmDirectory *self,
     file->depth = rm_util_path_depth(self->dirname);
 
     /* Recursively calculate the file size */
-    file->file_size = rm_tm_calc_file_size(self);
-    file->actual_file_size = file->file_size;
+    file->actual_file_size = rm_tm_calc_file_size(self);
     file->is_prefd = (self->prefd_files >= self->dupe_count);
     file->parent_dir = (RmDirectory *)self;
     file->n_children = self->dupe_count;

From c4e2d12d555db0f04b820de2ad717d2fe03952ef Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Fri, 28 May 2021 16:50:47 +1000
Subject: [PATCH 15/17] Revert "file: only use 16 bits for ref_count ->
 sizeof(RmFile)==144"

This reverts commit d8762fa08ae273ae72a3acb0f9440b129e79fb9b.
---
 lib/file.c | 4 ++--
 lib/file.h | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/file.c b/lib/file.c
index 8c3098ed..bc0a974d 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -140,7 +140,7 @@ static gint rm_file_unref_impl(RmFile *file, gboolean unref_hardlinks) {
     if(!file) {
         return 0;
     }
-    if(--file->ref_count != 0) {
+    if(!g_atomic_int_dec_and_test(&file->ref_count)) {
         // somebody still loves me!
         return 0;
     }
@@ -177,7 +177,7 @@ gint rm_file_unref_full(RmFile *file) {
 }
 
 RmFile *rm_file_ref(RmFile *file) {
-    file->ref_count++;
+    g_atomic_int_inc (&file->ref_count);
     return file;
 }
 
diff --git a/lib/file.h b/lib/file.h
index 351cd66e..07bc6177 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -165,6 +165,8 @@ typedef struct RmFile {
 
     /*----- 32-bit types ----- */
 
+    guint ref_count;
+
     /* Number of children this file has.
      * Only filled if type is RM_LINT_TYPE_PART_OF_DIRECTORY.
      * */
@@ -190,8 +192,6 @@ typedef struct RmFile {
      * */
     gint16 outer_link_count;
 
-    guint16 ref_count;
-
 
     /* Caching bitmasks to ensure each file is only matched once
      * for every GRegex combination.
@@ -304,7 +304,7 @@ RmFile *rm_file_new(struct RmSession *session, const char *path, RmStat *statp,
 /**
  * @brief Decrease reference count to file;
  * free resources if this is the last reference.
- * @note NOT threadsafe
+ * @note threadsafe
  * @note nullable
  * @retval 1 if the file freed else 0
  */

From e43972ca7812a12d5376ee8f8e929a30cdaa2887 Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Fri, 28 May 2021 16:51:11 +1000
Subject: [PATCH 16/17] Revert "print RmFile size (size==192)"

This reverts commit e5c4f61a622d84c5346d0fec1ed788a16f4d4a01.
---
 lib/session.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/session.c b/lib/session.c
index edc3b5d7..45bf41e5 100644
--- a/lib/session.c
+++ b/lib/session.c
@@ -76,7 +76,6 @@ bool rm_session_check_kernel_version(int need_major, int need_minor) {
 }
 
 void rm_session_init(RmSession *session, RmCfg *cfg) {
-    rm_log_warning("Sizeof(RmFile): %lu\n", sizeof(RmFile));
     memset(session, 0, sizeof(RmSession));
     session->timer = g_timer_new();
 

From 0032f5e769d02a7a088be5bee17c630153a72c0f Mon Sep 17 00:00:00 2001
From: SeeSpotRun <thomas_d_j@yahoo.com.au>
Date: Fri, 28 May 2021 17:49:07 +1000
Subject: [PATCH 17/17] file: fix clamping

---
 lib/file.c     | 8 ++++----
 lib/file.h     | 5 +++++
 lib/shredder.c | 8 ++++----
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/lib/file.c b/lib/file.c
index bc0a974d..86d8a7eb 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -38,14 +38,14 @@ static RmOff rm_file_start_seek(RmFile *file) {
     }
 }
 
-static RmOff rm_file_end_seek(RmFile *file) {
+RmOff rm_file_end_seek(RmFile *file) {
     RmCfg *cfg = file->session->cfg;
-    RmOff end_seek = file->actual_file_size;
+    RmOff file_size = file->actual_file_size;
 
     if(cfg->use_absolute_end_offset) {
-        return end_seek - MIN(cfg->skip_end_offset, end_seek);
+        return MIN(cfg->skip_end_offset, file_size);
     } else {
-        return end_seek * cfg->skip_end_factor;
+        return MIN(file_size, file_size * cfg->skip_end_factor);
     }
 }
 
diff --git a/lib/file.h b/lib/file.h
index 07bc6177..2c9d9273 100644
--- a/lib/file.h
+++ b/lib/file.h
@@ -406,4 +406,9 @@ static inline dev_t rm_file_parent_dev(const RmFile *file) {
  */
 RmOff rm_file_clamped_size(RmFile *file);
 
+/**
+ * @brief file end position after clamping end offset.
+ */
+RmOff rm_file_end_seek(RmFile *file);
+
 #endif /* end of include guard */
diff --git a/lib/shredder.c b/lib/shredder.c
index 0edeed1b..e773fedd 100644
--- a/lib/shredder.c
+++ b/lib/shredder.c
@@ -471,7 +471,7 @@ static RmShredGroup *rm_shred_group_new(RmFile *file) {
     }
 
     self->held_files = g_queue_new();
-    self->file_size = rm_file_clamped_size(file);
+    self->file_size = rm_file_end_seek(file);
     self->hash_offset = file->hash_offset;
 
     self->session = file->session;
@@ -718,7 +718,7 @@ static void rm_shred_discard_file(RmFile *file, _UNUSED gpointer user_data) {
         rm_mds_device_ref(rm_shred_disk(file, session), -1);
         file->has_disk_ref = FALSE;
         rm_shred_adjust_counters(tag, -1,
-            -(gint64)(rm_file_clamped_size(file) - file->hash_offset));
+            -(gint64)(rm_file_end_seek(file) - file->hash_offset));
     }
 
     /* toss the file (and any embedded hardlinks)*/
@@ -1109,7 +1109,7 @@ static void rm_shred_file_preprocess(RmFile *file, RmShredGroup **group) {
     rm_mds_device_ref(device, 1);
     file->has_disk_ref = TRUE;
 
-    rm_shred_adjust_counters(shredder, 1, rm_file_clamped_size(file) - file->hash_offset);
+    rm_shred_adjust_counters(shredder, 1, rm_file_end_seek(file) - file->hash_offset);
 
     rm_shred_group_push_file(*group, file, true);
 }
@@ -1667,7 +1667,7 @@ static gint rm_shred_process_file(RmFile *file, RmSession *session) {
         RmOff bytes_to_read = rm_shred_get_read_size(file, tag);
 
         gboolean shredder_waiting =
-            (file->shred_group->next_offset != rm_file_clamped_size(file)) &&
+            (file->shred_group->next_offset != rm_file_end_seek(file)) &&
             (cfg->shred_always_wait ||
              (!cfg->shred_never_wait && file->is_on_rotational_disk &&
               bytes_to_read < SHRED_TOO_MANY_BYTES_TO_WAIT));