Messages in this thread |  | | Date | Fri, 22 Jul 2022 16:16:26 +0800 | Subject | Re: [PATCH v3] erofs: update ctx->pos for every emitted dirent | From | JeffleXu <> |
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The patch itself looks good to me.
On 6/29/22 4:15 PM, Hongnan Li wrote: > 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. > > Fixes: 3e917cc305c6 ("erofs: make filesystem exportable") > Signed-off-by: Hongnan Li <hongnan.li@linux.alibaba.com> > --- > fs/erofs/dir.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c > index 18e59821c597..6fc325052853 100644 > --- 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;
Besides, I thinks there's another issue with erofs_readdir() here (though unrelated to the issue this patch wants to fix).
We need to update ctx->pos correctly if the initial file position has exceeded nameoff. ctx->pos needs to be updated to the end of EROFS_BLKSIZ or directory's i_size, surpassing the remaining name string in the current EROFS block.
> } > > - 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;
> + ctx->pos = blknr_to_addr(i) + maxsize;
It's quite easy to fix the above issue. We only need to move this line beneath skip_this label.
> +skip_this:> ++i; > ofs = 0; > }
like:
skip_this: ctx->pos = blknr_to_addr(i) + maxsize; ++i; ofs = 0;
Thus we'd better fold this simple fix into this patch.
-- Thanks, Jeffle
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