Hi,

在 2023/12/12 14:35, Gao Xiang 写道:


On 2023/12/11 22:07, Yu Kuai wrote:
From: Yu Kuai <yuku...@huawei.com>

Avoid to access bd_inode directly, prepare to remove bd_inode from
block_devcie.

Signed-off-by: Yu Kuai <yuku...@huawei.com>
---
  fs/erofs/data.c     | 18 ++++++++++++------
  fs/erofs/internal.h |  2 ++
  2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index c98aeda8abb2..8cf3618190ab 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -32,8 +32,7 @@ void erofs_put_metabuf(struct erofs_buf *buf)
  void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
            enum erofs_kmap_type type)
  {
-    struct inode *inode = buf->inode;
-    erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
+    erofs_off_t offset = (erofs_off_t)blkaddr << buf->blkszbits;
I'd suggest that use `buf->blkszbits` only for bdev_read_folio() since
erofs_init_metabuf() is not always called before erofs_bread() is used.

For example, buf->inode can be one of directory inodes other than
initialized by erofs_init_metabuf().

Thanks for the notice, and you're right, I'll update code in v3:

u8 blkszbits = buf->inode ? inode->i_blkbits : buf->blkszbits;
erofs_off_t offset = (erofs_off_t)blkaddr << blkszbits;

Kuai

Thanks,
Gao Xiang


      pgoff_t index = offset >> PAGE_SHIFT;
      struct page *page = buf->page;
      struct folio *folio;
@@ -43,7 +42,9 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
          erofs_put_metabuf(buf);
          nofs_flag = memalloc_nofs_save();
-        folio = read_cache_folio(inode->i_mapping, index, NULL, NULL);
+        folio = buf->inode ?
+            read_mapping_folio(buf->inode->i_mapping, index, NULL) :
+            bdev_read_folio(buf->bdev, offset);
          memalloc_nofs_restore(nofs_flag);
          if (IS_ERR(folio))
              return folio;
@@ -67,10 +68,15 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
  void erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb)
  {
-    if (erofs_is_fscache_mode(sb))
+    if (erofs_is_fscache_mode(sb)) {
          buf->inode = EROFS_SB(sb)->s_fscache->inode;
-    else
-        buf->inode = sb->s_bdev->bd_inode;
+        buf->bdev = NULL;
+        buf->blkszbits = buf->inode->i_blkbits;
+    } else {
+        buf->inode = NULL;
+        buf->bdev = sb->s_bdev;
+        buf->blkszbits = EROFS_SB(sb)->blkszbits;
+    }
  }
  void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index b0409badb017..c9206351b485 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -224,8 +224,10 @@ enum erofs_kmap_type {
  struct erofs_buf {
      struct inode *inode;
+    struct block_device *bdev;
      struct page *page;
      void *base;
+    u8 blkszbits;
      enum erofs_kmap_type kmap_type;
  };
  #define __EROFS_BUF_INITIALIZER    ((struct erofs_buf){ .page = NULL })
.



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