Fixed limit of inline files based on LFS_ATTR_MAX

The maximum limit of inline files and attributes are unrelated, but were
not at a point in littlefs v2 development. This should be checking
against the bit-field limit in the littlefs tag.

Found by lsilvaalmeida

.travis.yml

@@ -136,6 +136,7 @@ jobs:
       env:
         - STAGE=test
         - NAME=littlefs-migration
+      if: branch !~ -prefix$
       install:
         - sudo apt-get install libfuse-dev
         - git clone --depth 1 https://github.com/geky/littlefs-fuse -b v2-alpha v2

lfs.c

@@ -29,7 +29,7 @@ static inline void lfs_cache_drop(lfs_t *lfs, lfs_cache_t *rcache) {
 
 static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
     // zero to avoid information leak
-    memset(pcache->buffer, 0xff, lfs->cfg->prog_size);
+    memset(pcache->buffer, 0xff, lfs->cfg->cache_size);
     pcache->block = 0xffffffff;
 }
 
@@ -80,21 +80,6 @@ static int lfs_bd_read(lfs_t *lfs,
             diff = lfs_min(diff, rcache->off-off);
         }
 
-        if (size >= hint && off % lfs->cfg->read_size == 0 &&
-                size >= lfs->cfg->read_size) {
-            // bypass cache?
-            diff = lfs_aligndown(diff, lfs->cfg->read_size);
-            int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
-            if (err) {
-                return err;
-            }
-
-            data += diff;
-            off += diff;
-            size -= diff;
-            continue;
-        }
-
         // load to cache, first condition can no longer fail
         LFS_ASSERT(block < lfs->cfg->block_count);
         rcache->block = block;
@@ -2749,7 +2734,7 @@ lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
 
     if ((file->flags & LFS_F_INLINE) &&
             lfs_max(file->pos+nsize, file->ctz.size) >
-            lfs_min(LFS_ATTR_MAX, lfs_min(
+            lfs_min(0x3fe, lfs_min(
                 lfs->cfg->cache_size, lfs->cfg->block_size/8))) {
         // inline file doesn't fit anymore
         file->off = file->pos;
@@ -2864,6 +2849,10 @@ int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
         return LFS_ERR_BADF;
     }
 
+    if (size > LFS_FILE_MAX) {
+        return LFS_ERR_INVAL;
+    }
+
     lfs_off_t oldsize = lfs_file_size(lfs, file);
     if (size < oldsize) {
         // need to flush since directly changing metadata

lfs.h

@@ -578,7 +578,8 @@ int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir);
 // Read an entry in the directory
 //
 // Fills out the info structure, based on the specified file or directory.
-// Returns a negative error code on failure.
+// Returns a positive value on success, 0 at the end of directory,
+// or a negative error code on failure.
 int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info);
 
 // Change the position of the directory