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dlm: fix malfunction of dlm_tool caused by debugfs changes

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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 49d200deaa ("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: Eric Ren <zren@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This commit is contained in:
Eric Ren 2016-08-25 17:20:59 +08:00 committed by David Teigland
parent fa8410b355
commit 079d37df33
1 changed files with 48 additions and 14 deletions
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62
fs/dlm/debug_fs.c
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@ -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)
ret = seq_open(file, &format2_seq_ops);
else if (file->f_op == &format3_fops)
ret = seq_open(file, &format3_seq_ops);
else if (file->f_op == &format4_fops)
ret = seq_open(file, &format4_seq_ops);
ret = seq_open(file, &format1_seq_ops);
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);
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);
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