erofs: simplify readdir operation

 - Use i_size instead of i_size_read() due to immutable fses;

 - Get rid of an unneeded goto since erofs_fill_dentries() also works;

 - Remove unnecessary lines.

Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240801112622.2164029-1-hongzhen@linux.alibaba.com
Reviewed-by: Gao Xiang <hsiangkao@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 2193a6710c8f666705a0ac72849fb62768dbca4a..c3b90abdee37af537514449a6b25baae314e04eb 100644 (file)
--- a/fs/erofs/dir.c
+++ b/fs/erofs/dir.c
@@ -8,19 +8,15 @@
 
 static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
                               void *dentry_blk, struct erofs_dirent *de,
-                              unsigned int nameoff, unsigned int maxsize)
+                              unsigned int nameoff0, unsigned int maxsize)
 {
-       const struct erofs_dirent *end = dentry_blk + nameoff;
+       const struct erofs_dirent *end = dentry_blk + nameoff0;
 
        while (de < end) {
-               const char *de_name;
+               unsigned char d_type = fs_ftype_to_dtype(de->file_type);
+               unsigned int nameoff = le16_to_cpu(de->nameoff);
+               const char *de_name = (char *)dentry_blk + nameoff;
                unsigned int de_namelen;
-               unsigned char d_type;
-
-               d_type = fs_ftype_to_dtype(de->file_type);
-
-               nameoff = le16_to_cpu(de->nameoff);
-               de_name = (char *)dentry_blk + nameoff;
 
                /* the last dirent in the block? */
                if (de + 1 >= end)
@@ -52,21 +48,20 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
        struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
        struct super_block *sb = dir->i_sb;
        unsigned long bsz = sb->s_blocksize;
-       const size_t dirsize = i_size_read(dir);
-       unsigned int i = erofs_blknr(sb, ctx->pos);
        unsigned int ofs = erofs_blkoff(sb, ctx->pos);
        int err = 0;
        bool initial = true;
 
        buf.mapping = dir->i_mapping;
-       while (ctx->pos < dirsize) {
+       while (ctx->pos < dir->i_size) {
+               erofs_off_t dbstart = ctx->pos - ofs;
                struct erofs_dirent *de;
                unsigned int nameoff, maxsize;
 
-               de = erofs_bread(&buf, erofs_pos(sb, i), EROFS_KMAP);
+               de = erofs_bread(&buf, dbstart, EROFS_KMAP);
                if (IS_ERR(de)) {
                        erofs_err(sb, "fail to readdir of logical block %u of nid %llu",
-                                 i, EROFS_I(dir)->nid);
+                                 erofs_blknr(sb, dbstart), EROFS_I(dir)->nid);
                        err = PTR_ERR(de);
                        break;
                }
@@ -79,25 +74,19 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
                        break;
                }
 
-               maxsize = min_t(unsigned int, dirsize - ctx->pos + ofs, bsz);
-
+               maxsize = min_t(unsigned int, dir->i_size - dbstart, bsz);
                /* search dirents at the arbitrary position */
                if (initial) {
                        initial = false;
-
                        ofs = roundup(ofs, sizeof(struct erofs_dirent));
-                       ctx->pos = erofs_pos(sb, i) + ofs;
-                       if (ofs >= nameoff)
-                               goto skip_this;
+                       ctx->pos = dbstart + ofs;
                }
 
                err = erofs_fill_dentries(dir, ctx, de, (void *)de + ofs,
                                          nameoff, maxsize);
                if (err)
                        break;
-skip_this:
-               ctx->pos = erofs_pos(sb, i) + maxsize;
-               ++i;
+               ctx->pos = dbstart + maxsize;
                ofs = 0;
        }
        erofs_put_metabuf(&buf);

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 736607675396e8c340bfcde2ae4432167870a3b3..45dc15ebd870ddf2a753fe10b4242d4a3ec5e69c 100644 (file)
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -220,7 +220,7 @@ struct erofs_buf {
 };
 #define __EROFS_BUF_INITIALIZER        ((struct erofs_buf){ .page = NULL })
 
-#define erofs_blknr(sb, addr)  ((addr) >> (sb)->s_blocksize_bits)
+#define erofs_blknr(sb, addr)  ((erofs_blk_t)((addr) >> (sb)->s_blocksize_bits))
 #define erofs_blkoff(sb, addr) ((addr) & ((sb)->s_blocksize - 1))
 #define erofs_pos(sb, blk)     ((erofs_off_t)(blk) << (sb)->s_blocksize_bits)
 #define erofs_iblks(i) (round_up((i)->i_size, i_blocksize(i)) >> (i)->i_blkbits)