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Message-ID: <2efe4f60-5d4d-4a89-8fbf-5001e013298d@linux.alibaba.com>
Date: Thu, 1 Aug 2024 17:41:36 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: Hongzhen Luo <hongzhen@...ux.alibaba.com>, linux-erofs@...ts.ozlabs.org,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] erofs: simplify readdir operation
On 2024/8/1 11:02, Hongzhen Luo wrote:
> - 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@...ux.alibaba.com>
> ---
BTW, can you send any "kernel" patch to LKML <linux-kernel@...r.kernel.org>
too? Also you'd better to use "scripts/get_maintainers.pl".
> fs/erofs/dir.c | 35 ++++++++++++-----------------------
> fs/erofs/internal.h | 2 +-
> 2 files changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
> index 2193a6710c8f..c3b90abdee37 100644
> --- 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 736607675396..45dc15ebd870 100644
> --- 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)
> -- 2.43.5
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