[PATCH 5.19 0304/1157] erofs: update ctx->pos for every emitted dirent

Greg Kroah-Hartman
2022-08-15T23:14:59Z

From: Hongnan Li <hongnan.li@linux.alibaba.com>

[ Upstream commit ecce9212d0fd7a2d4a4998f0c4623a66887e14c8 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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..47c85f1b80d8 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;
}

- 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;
}
--
2.35.1