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Commit 079d37df authored by Eric Ren's avatar Eric Ren Committed by David Teigland
Browse files

dlm: fix malfunction of dlm_tool caused by debugfs changes 



With the current kernel, `dlm_tool lockdebug` fails as below:

"dlm_tool lockdebug ED0BD86DCE724393918A1AE8FDBF1EE3
can't open /sys/kernel/debug/dlm/ED0BD86DCE724393918A1AE8FDBF1EE3:
Operation not permitted"

This is because table_open() depends on file->f_op to tell which
seq_file ops should be passed down. But, the original file ops in
file->f_op is replaced by "debugfs_full_proxy_file_operations" with
commit 49d200de ("debugfs: prevent access to removed files'
private data").

Currently, I can think up 2 solutions: 1st, replace
debugfs_create_file() with debugfs_create_file_unsafe();
2nd, make different table_open#() accordingly. The 1st one
is neat, but I don't thoroughly understand its risk. Maybe
someone has a better one.

Signed-off-by: default avatarEric Ren <zren@suse.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent fa8410b3

fs/dlm/debug_fs.c

+48 −14
Original line number Diff line number Diff line
@@ -607,20 +607,54 @@ static const struct file_operations format2_fops; 
static const struct file_operations format3_fops;

static const struct file_operations format4_fops;



static int table_open(struct inode *inode, struct file *file)

static int table_open1(struct inode *inode, struct file *file)

{

	struct seq_file *seq;

	int ret = -1;

	int ret;



	if (file->f_op == &format1_fops)

	ret = seq_open(file, &format1_seq_ops);

	else if (file->f_op == &format2_fops)

	if (ret)

		return ret;



	seq = file->private_data;

	seq->private = inode->i_private; /* the dlm_ls */

	return 0;

}



static int table_open2(struct inode *inode, struct file *file)

{

	struct seq_file *seq;

	int ret;



	ret = seq_open(file, &format2_seq_ops);

	else if (file->f_op == &format3_fops)

	if (ret)

		return ret;



	seq = file->private_data;

	seq->private = inode->i_private; /* the dlm_ls */

	return 0;

}



static int table_open3(struct inode *inode, struct file *file)

{

	struct seq_file *seq;

	int ret;



	ret = seq_open(file, &format3_seq_ops);

	else if (file->f_op == &format4_fops)

		ret = seq_open(file, &format4_seq_ops);

	if (ret)

		return ret;



	seq = file->private_data;

	seq->private = inode->i_private; /* the dlm_ls */

	return 0;

}



static int table_open4(struct inode *inode, struct file *file)

{

	struct seq_file *seq;

	int ret;



	ret = seq_open(file, &format4_seq_ops);

	if (ret)

		return ret;
@@ -631,7 +665,7 @@ static int table_open(struct inode *inode, struct file *file) 


static const struct file_operations format1_fops = {

	.owner   = THIS_MODULE,

	.open    = table_open,

	.open    = table_open1,

	.read    = seq_read,

	.llseek  = seq_lseek,

	.release = seq_release
@@ -639,7 +673,7 @@ static const struct file_operations format1_fops = { 


static const struct file_operations format2_fops = {

	.owner   = THIS_MODULE,

	.open    = table_open,

	.open    = table_open2,

	.read    = seq_read,

	.llseek  = seq_lseek,

	.release = seq_release
@@ -647,7 +681,7 @@ static const struct file_operations format2_fops = { 


static const struct file_operations format3_fops = {

	.owner   = THIS_MODULE,

	.open    = table_open,

	.open    = table_open3,

	.read    = seq_read,

	.llseek  = seq_lseek,

	.release = seq_release
@@ -655,7 +689,7 @@ static const struct file_operations format3_fops = { 


static const struct file_operations format4_fops = {

	.owner   = THIS_MODULE,

	.open    = table_open,

	.open    = table_open4,

	.read    = seq_read,

	.llseek  = seq_lseek,

	.release = seq_release