From 079d37df3397d48aab0f014986c1b0a1ca6256aa Mon Sep 17 00:00:00 2001 From: Eric Ren Date: Thu, 25 Aug 2016 17:20:59 +0800 Subject: [PATCH] dlm: fix malfunction of dlm_tool caused by debugfs changes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 49d200deaa68 ("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 Signed-off-by: David Teigland --- fs/dlm/debug_fs.c | 62 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 48 insertions(+), 14 deletions(-) diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c index eea64912c9c0..466f7d60edc2 100644 --- a/fs/dlm/debug_fs.c +++ b/fs/dlm/debug_fs.c @@ -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 -- 2.20.1