erofs: adjust per-CPU buffers according to max_pclusterblks

Adjust per-CPU buffers on demand since big pcluster definition is
available. Also, bail out unsupported pcluster size according to
Z_EROFS_PCLUSTER_MAX_SIZE.

Link: https://lore.kernel.org/r/20210407043927.10623-7-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index fb4838c0f0df9586b4bb4443fdbca90bda811a45..900de4725d35eb51b618e61ab2dbb9f18c637916 100644 (file)
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -32,6 +32,7 @@ int z_erofs_load_lz4_config(struct super_block *sb,
                            struct erofs_super_block *dsb,
                            struct z_erofs_lz4_cfgs *lz4, int size)
 {
+       struct erofs_sb_info *sbi = EROFS_SB(sb);
        u16 distance;
 
        if (lz4) {
@@ -40,16 +41,27 @@ int z_erofs_load_lz4_config(struct super_block *sb,
                        return -EINVAL;
                }
                distance = le16_to_cpu(lz4->max_distance);
+
+               sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
+               if (!sbi->lz4.max_pclusterblks) {
+                       sbi->lz4.max_pclusterblks = 1;  /* reserved case */
+               } else if (sbi->lz4.max_pclusterblks >
+                          Z_EROFS_PCLUSTER_MAX_SIZE / EROFS_BLKSIZ) {
+                       erofs_err(sb, "too large lz4 pclusterblks %u",
+                                 sbi->lz4.max_pclusterblks);
+                       return -EINVAL;
+               } else if (sbi->lz4.max_pclusterblks >= 2) {
+                       erofs_info(sb, "EXPERIMENTAL big pcluster feature in use. Use at your own risk!");
+               }
        } else {
                distance = le16_to_cpu(dsb->u1.lz4_max_distance);
+               sbi->lz4.max_pclusterblks = 1;
        }
 
-       EROFS_SB(sb)->lz4.max_distance_pages = distance ?
+       sbi->lz4.max_distance_pages = distance ?
                                        DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
                                        LZ4_MAX_DISTANCE_PAGES;
-
-       /* TODO: use max pclusterblks after bigpcluster is enabled */
-       return erofs_pcpubuf_growsize(1);
+       return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
 }
 
 static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index c130e3848322c94b0ca3a31cdbfcb9c1aa21504d..5c2388daee6eebfae17abf5a961823373308e03a 100644 (file)
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -63,6 +63,8 @@ struct erofs_fs_context {
 struct erofs_sb_lz4_info {
        /* # of pages needed for EROFS lz4 rolling decompression */
        u16 max_distance_pages;
+       /* maximum possible blocks for pclusters in the filesystem */
+       u16 max_pclusterblks;
 };
 
 struct erofs_sb_info {