erofs: update ctx->pos for every emitted dirent

erofs_readdir update ctx->pos after filling a batch of dentries
and it may cause dir/files duplication for NFS readdirplus which
depends on ctx->pos to fill dir correctly. So update ctx->pos for
every emitted dirent in erofs_fill_dentries to fix it.

Also fix the update of ctx->pos when the initial file position has
exceeded nameoff.

Fixes: 3e917cc305c6 ("erofs: make filesystem exportable")
Signed-off-by: Hongnan Li <hongnan.li@linux.alibaba.com>
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20220722082732.30935-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
index 723f5223a4fabf4dabc92eb1c1cd38c577f057ff..ecf28f66b97d55d435b8687a8f53ef9dc33d203e 100644 (file)
--- a/fs/erofs/dir.c
+++ b/fs/erofs/dir.c
@@ -22,10 +22,9 @@ static void debug_one_dentry(unsigned char d_type, const char *de_name,
 }
 
 static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
-                              void *dentry_blk, unsigned int *ofs,
+                              void *dentry_blk, struct erofs_dirent *de,
                               unsigned int nameoff, unsigned int maxsize)
 {
-       struct erofs_dirent *de = dentry_blk + *ofs;
        const struct erofs_dirent *end = dentry_blk + nameoff;
 
        while (de < end) {
@@ -59,9 +58,8 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
                        /* stopped by some reason */
                        return 1;
                ++de;
-               *ofs += sizeof(struct erofs_dirent);
+               ctx->pos += sizeof(struct erofs_dirent);
        }
-       *ofs = maxsize;
        return 0;
 }
 
@@ -95,7 +93,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
                                  "invalid de[0].nameoff %u @ nid %llu",
                                  nameoff, EROFS_I(dir)->nid);
                        err = -EFSCORRUPTED;
-                       goto skip_this;
+                       break;
                }
 
                maxsize = min_t(unsigned int,
@@ -106,17 +104,17 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
                        initial = false;
 
                        ofs = roundup(ofs, sizeof(struct erofs_dirent));
+                       ctx->pos = blknr_to_addr(i) + ofs;
                        if (ofs >= nameoff)
                                goto skip_this;
                }
 
-               err = erofs_fill_dentries(dir, ctx, de, &ofs,
+               err = erofs_fill_dentries(dir, ctx, de, (void *)de + ofs,
                                          nameoff, maxsize);
-skip_this:
-               ctx->pos = blknr_to_addr(i) + ofs;
-
                if (err)
                        break;
+skip_this:
+               ctx->pos = blknr_to_addr(i) + maxsize;
                ++i;
                ofs = 0;
        }