[PATCH] proc: avoid extra pde_put() in proc_fill_super()

From: Maxim Patlasov
Date: Tue Jan 22 2013 - 12:04:05 EST


If proc_get_inode() succeeded, but d_make_root() failed, pde_put() for
proc_root will be called twice: the first time due to iput() called from
d_make_root() and the second time directly in the end of proc_fill_super().

Signed-off-by: Maxim Patlasov <mpatlasov@xxxxxxxxxxxxx>
---
fs/proc/inode.c | 21 +++++++++++++++------
1 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 439ae688..c7f8b24 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -486,6 +486,8 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)

int proc_fill_super(struct super_block *s)
{
+ struct inode *root_inode;
+
s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
@@ -494,11 +496,18 @@ int proc_fill_super(struct super_block *s)
s->s_time_gran = 1;

pde_get(&proc_root);
- s->s_root = d_make_root(proc_get_inode(s, &proc_root));
- if (s->s_root)
- return 0;
+ root_inode = proc_get_inode(s, &proc_root);
+ if (!root_inode) {
+ printk(KERN_ERR "proc_fill_super: get root inode failed\n");
+ pde_put(&proc_root);
+ return -ENOMEM;
+ }

- printk("proc_read_super: get root inode failed\n");
- pde_put(&proc_root);
- return -ENOMEM;
+ s->s_root = d_make_root(root_inode);
+ if (!s->s_root) {
+ printk(KERN_ERR "proc_fill_super: allocate dentry failed\n");
+ return -ENOMEM;
+ }
+
+ return 0;
}

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