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Commit c4d8b023 authored by Tao Ma's avatar Tao Ma Committed by Theodore Ts'o
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ext4: fix readdir error in case inline_data+^dir_index. 



Zach reported a problem that if inline data is enabled, we don't
tell the difference between the offset of '.' and '..'. And a
getdents will fail if the user only want to get '.'. And what's
worse, we may meet with duplicate dir entries as the offset
for inline dir and non-inline one is quite different.

This patch just try to resolve this problem if dir_index
is disabled. In this case, f_pos is the real offset with
the dir block, so for inline dir, we just pretend as if
we are a dir block and returns the offset like a norml
dir block does.

Reported-by: default avatarZach Brown <zab@redhat.com>
Signed-off-by: default avatarTao Ma <boyu.mt@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 8af0f082

fs/ext4/inline.c

+51 −18
Original line number Diff line number Diff line
@@ -1396,6 +1396,14 @@ out: 
	return ret;

}



/*

 * So this function is called when the volume is mkfsed with

 * dir_index disabled. In order to keep f_pos persistent

 * after we convert from an inlined dir to a blocked based,

 * we just pretend that we are a normal dir and return the

 * offset as if '.' and '..' really take place.

 *

 */

int ext4_read_inline_dir(struct file *filp,

			 void *dirent, filldir_t filldir,

			 int *has_inline_data)
@@ -1409,6 +1417,7 @@ int ext4_read_inline_dir(struct file *filp, 
	int ret, inline_size = 0;

	struct ext4_iloc iloc;

	void *dir_buf = NULL;

	int dotdot_offset, dotdot_size, extra_offset, extra_size;



	ret = ext4_get_inode_loc(inode, &iloc);

	if (ret)
@@ -1437,8 +1446,21 @@ int ext4_read_inline_dir(struct file *filp, 
	sb = inode->i_sb;

	stored = 0;

	parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);

	offset = filp->f_pos;



	/*

	 * dotdot_offset and dotdot_size is the real offset and

	 * size for ".." and "." if the dir is block based while

	 * the real size for them are only EXT4_INLINE_DOTDOT_SIZE.

	 * So we will use extra_offset and extra_size to indicate them

	 * during the inline dir iteration.

	 */

	dotdot_offset = EXT4_DIR_REC_LEN(1);

	dotdot_size = dotdot_offset + EXT4_DIR_REC_LEN(2);

	extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;

	extra_size = extra_offset + inline_size;



	while (!error && !stored && filp->f_pos < inode->i_size) {

	while (!error && !stored && filp->f_pos < extra_size) {

revalidate:

		/*

		 * If the version has changed since the last call to
@@ -1447,15 +1469,23 @@ revalidate: 
		 * dir to make sure.

		 */

		if (filp->f_version != inode->i_version) {

			for (i = 0;

			     i < inode->i_size && i < offset;) {

			for (i = 0; i < extra_size && i < offset;) {

				/*

				 * "." is with offset 0 and

				 * ".." is dotdot_offset.

				 */

				if (!i) {

					/* skip "." and ".." if needed. */

					i += EXT4_INLINE_DOTDOT_SIZE;

					i = dotdot_offset;

					continue;

				} else if (i == dotdot_offset) {

					i = dotdot_size;

					continue;

				}

				/* for other entry, the real offset in

				 * the buf has to be tuned accordingly.

				 */

				de = (struct ext4_dir_entry_2 *)

					(dir_buf + i);

					(dir_buf + i - extra_offset);

				/* It's too expensive to do a full

				 * dirent test each time round this

				 * loop, but we do have to test at
@@ -1463,43 +1493,47 @@ revalidate: 
				 * failure will be detected in the

				 * dirent test below. */

				if (ext4_rec_len_from_disk(de->rec_len,

					inline_size) < EXT4_DIR_REC_LEN(1))

					extra_size) < EXT4_DIR_REC_LEN(1))

					break;

				i += ext4_rec_len_from_disk(de->rec_len,

							    inline_size);

							    extra_size);

			}

			offset = i;

			filp->f_pos = offset;

			filp->f_version = inode->i_version;

		}



		while (!error && filp->f_pos < inode->i_size) {

		while (!error && filp->f_pos < extra_size) {

			if (filp->f_pos == 0) {

				error = filldir(dirent, ".", 1, 0, inode->i_ino,

						DT_DIR);

				if (error)

					break;

				stored++;

				filp->f_pos = dotdot_offset;

				continue;

			}



				error = filldir(dirent, "..", 2, 0, parent_ino,

						DT_DIR);

			if (filp->f_pos == dotdot_offset) {

				error = filldir(dirent, "..", 2,

						dotdot_offset,

						parent_ino, DT_DIR);

				if (error)

					break;

				stored++;



				filp->f_pos = offset = EXT4_INLINE_DOTDOT_SIZE;

				filp->f_pos = dotdot_size;

				continue;

			}



			de = (struct ext4_dir_entry_2 *)(dir_buf + offset);

			de = (struct ext4_dir_entry_2 *)

				(dir_buf + filp->f_pos - extra_offset);

			if (ext4_check_dir_entry(inode, filp, de,

						 iloc.bh, dir_buf,

						 inline_size, offset)) {

						 extra_size, filp->f_pos)) {

				ret = stored;

				goto out;

			}

			offset += ext4_rec_len_from_disk(de->rec_len,

							 inline_size);

			if (le32_to_cpu(de->inode)) {

				/* We might block in the next section

				 * if the data destination is
@@ -1522,9 +1556,8 @@ revalidate: 
				stored++;

			}

			filp->f_pos += ext4_rec_len_from_disk(de->rec_len,

							      inline_size);

							      extra_size);

		}

		offset = 0;

	}

out:

	kfree(dir_buf);