ext2_readdir() filp->f_pos fix

This is a 2.4 backport of a linux-2.6 change by Jan Blunck
(old-2.6-bkcvs commit 2196b4744393d4f6c06fc4d63b98556d05b90933)

Commit log from 2.6 follows.

  [PATCH] ext2_readdir() filp->f_pos fix

  If the whole directory is read, ext2_readdir() sets the f_pos to a multiple
  of the page size (because of the conditions of the outer for loop).  This
  sets the wrong f_pos for directory inodes on ext2 partitions with a block
  size differing from the page size.

Signed-off-by: dann frazier <dannf@hp.com>

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 58b76dd..b158e60 100644 (file)
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -240,7 +240,7 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
        loff_t pos = filp->f_pos;
        struct inode *inode = filp->f_dentry->d_inode;
        struct super_block *sb = inode->i_sb;
-       unsigned offset = pos & ~PAGE_CACHE_MASK;
+       unsigned int offset = pos & ~PAGE_CACHE_MASK;
        unsigned long n = pos >> PAGE_CACHE_SHIFT;
        unsigned long npages = dir_pages(inode);
        unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
@@ -258,8 +258,13 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
                ext2_dirent *de;
                struct page *page = ext2_get_page(inode, n);
 
-               if (IS_ERR(page))
+               if (IS_ERR(page)) {
+                       ext2_error(sb, __FUNCTION__,
+                                  "bad page in #%lu",
+                                  inode->i_ino);
+                       filp->f_pos += PAGE_CACHE_SIZE - offset;
                        continue;
+               }
                kaddr = page_address(page);
                if (need_revalidate) {
                        offset = ext2_validate_entry(kaddr, offset, chunk_mask);
@@ -283,12 +288,12 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
                                        ext2_put_page(page);
                                        goto done;
                                }
+                       filp->f_pos += le16_to_cpu(de->rec_len);
                        }
                ext2_put_page(page);
        }
 
 done:
-       filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
        filp->f_version = inode->i_version;
        UPDATE_ATIME(inode);
        return 0;