f2fs: fix readdir incorrectness

In the previous Al Viro's readdir patch set, there occurs a bug when
running
xfstest: 006 as follows.

[Error output]
alpha size = 4, name length = 6, total files = 4096, nproc=1
1023 files created
rm: cannot remove `/mnt/f2fs/permname.15150/a': Directory not empty

[Correct output]
alpha size = 4, name length = 6, total files = 4096, nproc=1
4097 files created

This bug is due to the misupdate of directory position in ctx.
So, this patch fixes this.

[AV: fixed a braino]

CC: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 9 insertions, 11 deletions

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 9d1cd423450d..62f0d5977c64 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -610,13 +610,12 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
 {
         struct inode *inode = file_inode(file);
         unsigned long npages = dir_blocks(inode);
-        unsigned int bit_pos = 0, start_bit_pos = 0;
+        unsigned int bit_pos = 0;
         struct f2fs_dentry_block *dentry_blk = NULL;
         struct f2fs_dir_entry *de = NULL;
         struct page *dentry_page = NULL;
         unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
         unsigned char d_type = DT_UNKNOWN;
-        int slots;
 
         bit_pos = ((unsigned long)ctx->pos % NR_DENTRY_IN_BLOCK);
 
@@ -625,7 +624,6 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
                 if (IS_ERR(dentry_page))
                         continue;
 
-                start_bit_pos = bit_pos;
                 dentry_blk = kmap(dentry_page);
                 while (bit_pos < NR_DENTRY_IN_BLOCK) {
                         bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
@@ -634,19 +632,19 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
                         if (bit_pos >= NR_DENTRY_IN_BLOCK)
                                 break;
 
-                        ctx->pos += bit_pos - start_bit_pos;
                         de = &dentry_blk->dentry[bit_pos];
                         if (de->file_type < F2FS_FT_MAX)
                                 d_type = f2fs_filetype_table[de->file_type];
                         else
                                 d_type = DT_UNKNOWN;
                         if (!dir_emit(ctx,
-                                      dentry_blk->filename[bit_pos],
-                                      le16_to_cpu(de->name_len),
-                                      le32_to_cpu(de->ino), d_type))
-                                goto success;
-                        slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
-                        bit_pos += slots;
+                                        dentry_blk->filename[bit_pos],
+                                        le16_to_cpu(de->name_len),
+                                        le32_to_cpu(de->ino), d_type))
+                                goto stop;
+
+                        bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+                        ctx->pos = n * NR_DENTRY_IN_BLOCK + bit_pos;
                 }
                 bit_pos = 0;
                 ctx->pos = (n + 1) * NR_DENTRY_IN_BLOCK;
@@ -654,7 +652,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
                 f2fs_put_page(dentry_page, 1);
                 dentry_page = NULL;
         }
-success:
+stop:
         if (dentry_page && !IS_ERR(dentry_page)) {
                 kunmap(dentry_page);
                 f2fs_put_page(dentry_page, 1);