From 3778759979a1c6bc141e9ced8c28df2a1d4a9848 Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Fri, 10 Nov 2017 11:02:50 -0600
Subject: [PATCH] Squashed 'littlefs/' changes from 2ab150c..3f31c8c

3f31c8c Fixed corner case with immediate exhaustion and lookahead==block_count
f4aeb83 Fixed issue with aggressively rounding down lookahead configuration
db51a39 Removed stray newline in LFS_ERROR for version

git-subtree-dir: littlefs
git-subtree-split: 3f31c8cba31e0f6cef5b02dba2e050d8df1168b7
---
 .travis.yml |  2 +-
 lfs.c       | 28 ++++++++++++++--------------
 lfs.h       |  1 -
 3 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index f2322761b0..552f7cc9a7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,7 +15,7 @@ script:
     - CFLAGS="-DLFS_READ_SIZE=1   -DLFS_PROG_SIZE=1"   make test
     - CFLAGS="-DLFS_READ_SIZE=512 -DLFS_PROG_SIZE=512" make test
     - CFLAGS="-DLFS_BLOCK_COUNT=1023" make test
-    - CFLAGS="-DLFS_LOOKAHEAD=2047"   make test
+    - CFLAGS="-DLFS_LOOKAHEAD=2048"   make test
 
     # self-host with littlefs-fuse for fuzz test
     - make -C littlefs-fuse
diff --git a/lfs.c b/lfs.c
index f602197778..b043bd907d 100644
--- a/lfs.c
+++ b/lfs.c
@@ -278,7 +278,7 @@ static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
                 % (lfs_soff_t)(lfs->cfg->block_count))
             + lfs->cfg->block_count) % lfs->cfg->block_count;
 
-    if (off < lfs->free.lookahead) {
+    if (off < lfs->cfg->lookahead) {
         lfs->free.buffer[off / 32] |= 1U << (off % 32);
     }
 
@@ -294,7 +294,8 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
                 return LFS_ERR_NOSPC;
             }
 
-            if (lfs->free.off >= lfs->free.lookahead) {
+            if (lfs->free.off >= lfs_min(
+                    lfs->cfg->lookahead, lfs->cfg->block_count)) {
                 break;
             }
 
@@ -308,11 +309,11 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
             }
         }
 
-        lfs->free.begin += lfs->free.lookahead;
+        lfs->free.begin += lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
         lfs->free.off = 0;
 
         // find mask of free blocks from tree
-        memset(lfs->free.buffer, 0, lfs->free.lookahead/8);
+        memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
         int err = lfs_traverse(lfs, lfs_alloc_lookahead, lfs);
         if (err) {
             return err;
@@ -1870,13 +1871,12 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     // setup lookahead, round down to nearest 32-bits
-    lfs->free.lookahead = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
-    lfs->free.lookahead = 32 * (lfs->free.lookahead / 32);
-    assert(lfs->free.lookahead > 0);
+    assert(lfs->cfg->lookahead % 32 == 0);
+    assert(lfs->cfg->lookahead > 0);
     if (lfs->cfg->lookahead_buffer) {
         lfs->free.buffer = lfs->cfg->lookahead_buffer;
     } else {
-        lfs->free.buffer = malloc(lfs->free.lookahead/8);
+        lfs->free.buffer = malloc(lfs->cfg->lookahead/8);
         if (!lfs->free.buffer) {
             return LFS_ERR_NOMEM;
         }
@@ -1919,10 +1919,10 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     // create free lookahead
-    memset(lfs->free.buffer, 0, lfs->free.lookahead/8);
+    memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
     lfs->free.begin = 0;
     lfs->free.off = 0;
-    lfs->free.end = lfs->free.begin + lfs->cfg->block_count;
+    lfs->free.end = lfs->free.begin + lfs->free.off + lfs->cfg->block_count;
 
     // create superblock dir
     lfs_alloc_ack(lfs);
@@ -1998,9 +1998,9 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     // setup free lookahead
-    lfs->free.begin = -lfs->free.lookahead;
-    lfs->free.off = lfs->free.lookahead;
-    lfs->free.end = lfs->free.begin + lfs->cfg->block_count;
+    lfs->free.begin = -lfs->cfg->lookahead;
+    lfs->free.off = lfs->cfg->lookahead;
+    lfs->free.end = lfs->free.begin + lfs->free.off + lfs->cfg->block_count;
 
     // load superblock
     lfs_dir_t dir;
@@ -2027,7 +2027,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     if (superblock.d.version > (0x00010001 | 0x0000ffff)) {
-        LFS_ERROR("Invalid version %d.%d\n",
+        LFS_ERROR("Invalid version %d.%d",
                 0xffff & (superblock.d.version >> 16),
                 0xffff & (superblock.d.version >> 0));
         return LFS_ERR_INVAL;
diff --git a/lfs.h b/lfs.h
index 270a65efb9..e4aab0e4b2 100644
--- a/lfs.h
+++ b/lfs.h
@@ -236,7 +236,6 @@ typedef struct lfs_superblock {
 } lfs_superblock_t;
 
 typedef struct lfs_free {
-    lfs_size_t lookahead;
     lfs_block_t begin;
     lfs_block_t end;
     lfs_block_t off;