Commit 5a57bca9 authored by Zhang Yi's avatar Zhang Yi Committed by Theodore Ts'o
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ext4: fix reading leftover inlined symlinks 



Since commit 6493792d ("ext4: convert symlink external data block
mapping to bdev"), create new symlink with inline_data is not supported,
but it missing to handle the leftover inlined symlinks, which could
cause below error message and fail to read symlink.

 ls: cannot read symbolic link 'foo': Structure needs cleaning

 EXT4-fs error (device sda): ext4_map_blocks:605: inode #12: block
 2021161080: comm ls: lblock 0 mapped to illegal pblock 2021161080
 (length 1)

Fix this regression by adding ext4_read_inline_link(), which read the
inline data directly and convert it through a kmalloced buffer.

Fixes: 6493792d ("ext4: convert symlink external data block mapping to bdev")
Cc: stable@kernel.org
Reported-by: default avatarTorge Matthies <openglfreak@googlemail.com>
Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Tested-by: default avatarTorge Matthies <openglfreak@googlemail.com>
Link: https://lore.kernel.org/r/20220630090100.2769490-1-yi.zhang@huawei.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 88084a3d

fs/ext4/ext4.h

+1 −0
Original line number Diff line number Diff line
@@ -3583,6 +3583,7 @@ extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode, 
extern int ext4_inline_data_fiemap(struct inode *inode,

				   struct fiemap_extent_info *fieinfo,

				   int *has_inline, __u64 start, __u64 len);

extern void *ext4_read_inline_link(struct inode *inode);



struct iomap;

extern int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap);

fs/ext4/inline.c

+30 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 


#include <linux/iomap.h>

#include <linux/fiemap.h>

#include <linux/namei.h>

#include <linux/iversion.h>

#include <linux/sched/mm.h>
@@ -1588,6 +1589,35 @@ int ext4_read_inline_dir(struct file *file, 
	return ret;

}



void *ext4_read_inline_link(struct inode *inode)

{

	struct ext4_iloc iloc;

	int ret, inline_size;

	void *link;



	ret = ext4_get_inode_loc(inode, &iloc);

	if (ret)

		return ERR_PTR(ret);



	ret = -ENOMEM;

	inline_size = ext4_get_inline_size(inode);

	link = kmalloc(inline_size + 1, GFP_NOFS);

	if (!link)

		goto out;



	ret = ext4_read_inline_data(inode, link, inline_size, &iloc);

	if (ret < 0) {

		kfree(link);

		goto out;

	}

	nd_terminate_link(link, inode->i_size, ret);

out:

	if (ret < 0)

		link = ERR_PTR(ret);

	brelse(iloc.bh);

	return link;

}



struct buffer_head *ext4_get_first_inline_block(struct inode *inode,

					struct ext4_dir_entry_2 **parent_de,

					int *retval)

fs/ext4/symlink.c

+15 −0
Original line number Diff line number Diff line
@@ -74,6 +74,21 @@ static const char *ext4_get_link(struct dentry *dentry, struct inode *inode, 
				 struct delayed_call *callback)

{

	struct buffer_head *bh;

	char *inline_link;



	/*

	 * Create a new inlined symlink is not supported, just provide a

	 * method to read the leftovers.

	 */

	if (ext4_has_inline_data(inode)) {

		if (!dentry)

			return ERR_PTR(-ECHILD);



		inline_link = ext4_read_inline_link(inode);

		if (!IS_ERR(inline_link))

			set_delayed_call(callback, kfree_link, inline_link);

		return inline_link;

	}



	if (!dentry) {

		bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);