Merge pull request #911 from littlefs-project/fix-release-structs

Fix struct sizes missing from generated release notes
Merge pull request #910 from littlefs-project/fix-superblock-expansion-thresh
2023-12-21 00:08:16 -06:00 · 2023-12-21 00:07:55 -06:00 · 2023-12-21 00:06:29 -06:00 · 2023-12-20 23:42:26 -06:00 · 2023-12-19 22:00:18 -06:00 · 2023-12-19 16:51:17 -06:00
3 changed files with 8 additions and 6 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -112,7 +112,7 @@ jobs:
            table[$i,$j]=$c_camel
            ((j+=1))

-            for s in code stack struct
+            for s in code stack structs
            do
              f=sizes/thumb${c:+-$c}.$s.csv
              [ -e $f ] && table[$i,$j]=$( \
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -59,7 +59,7 @@ This leaves us with three major requirements for an embedded filesystem.
   RAM to temporarily store filesystem metadata.

   For ROM, this means we need to keep our design simple and reuse code paths
-   were possible. For RAM we have a stronger requirement, all RAM usage is
+   where possible. For RAM we have a stronger requirement, all RAM usage is
   bounded. This means RAM usage does not grow as the filesystem changes in
   size or number of files. This creates a unique challenge as even presumably
   simple operations, such as traversing the filesystem, become surprisingly
@@ -626,7 +626,7 @@ log&#8322;_n_ pointers that skip to different preceding elements of the
 skip-list.

 The name comes from heavy use of the [CTZ instruction][wikipedia-ctz], which
-lets us calculate the power-of-two factors efficiently. For a give block _n_,
+lets us calculate the power-of-two factors efficiently. For a given block _n_,
 that block contains ctz(_n_)+1 pointers.

 ```
--- a/lfs.c
+++ b/lfs.c
@@ -2151,9 +2151,11 @@ static int lfs_dir_splittingcompact(lfs_t *lfs, lfs_mdir_t *dir,
            return size;
        }

-        // do we have extra space? littlefs can't reclaim this space
-        // by itself, so expand cautiously
-        if ((lfs_size_t)size < lfs->block_count/2) {
+        // littlefs cannot reclaim expanded superblocks, so expand cautiously
+        //
+        // if our filesystem is more than ~88% full, don't expand, this is
+        // somewhat arbitrary
+        if (lfs->block_count - size > lfs->block_count/8) {
            LFS_DEBUG("Expanding superblock at rev %"PRIu32, dir->rev);
            int err = lfs_dir_split(lfs, dir, attrs, attrcount,
                    source, begin, end);
Author	SHA1	Message	Date
Christopher Haster	3513ff1afc	Merge pull request #911 from littlefs-project/fix-release-structs Fix struct sizes missing from generated release notes	2023-12-21 00:08:16 -06:00
Christopher Haster	8a22bd6e67	Merge pull request #910 from littlefs-project/fix-superblock-expansion-thresh Increase threshold for superblock expansion from ~50% -> ~88% full	2023-12-21 00:07:55 -06:00
Christopher Haster	9b82db72d8	Merge pull request #898 from zchen24/patch-1 Update DESIGN.md minor typo	2023-12-21 00:06:29 -06:00
Zihan Chen	99b84ee3db	Update DESIGN.md, fix minor typo	2023-12-20 23:42:26 -06:00
Christopher Haster	e91a29d2b5	Fixed struct sizes missing from generated release notes This script was missed during a struct -> structs naming change	2023-12-19 22:00:18 -06:00
Christopher Haster	b9b95ab4bc	Increase threshold for superblock expansion from ~50% -> ~88% full Superblock expansion is an irreversible operation. In an effort to prevent superblock expansion from claiming valuable scratch space (important for small, <~8 block filesystems), littlefs prevents superblock expansion when the disk is "mostly full". In true computer-scientist fashion, this "mostly full" threshold was set to ~50%. As pointed out by gbolgradov and rojer, >~50% utilization is not uncommon, and it can lead to a situation where superblock expansion does not occur in a relatively healthy filesystem, causing focused wear at the root. To remedy this, the threshold is now increased to ~88% (7/8) full. This may change in the future and should probably be eventually user configurable. Found by gbolgradov and rojer	2023-12-19 16:51:17 -06:00
Zihan Chen	10bcff1af8	Update DESIGN.md minor typo	2023-11-26 11:10:24 -08:00