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Commit f7e86ab9 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: cache must take a reference to the cache detail's module on open() 



Otherwise we Oops if the module containing the cache detail is removed
before all cache readers have closed the file.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 7d7ea882

net/sunrpc/cache.c

+76 −4
Original line number Diff line number Diff line
@@ -836,6 +836,8 @@ static int cache_open(struct inode *inode, struct file *filp, 
{

	struct cache_reader *rp = NULL;



	if (!cd || !try_module_get(cd->owner))

		return -EACCES;

	nonseekable_open(inode, filp);

	if (filp->f_mode & FMODE_READ) {

		rp = kmalloc(sizeof(*rp), GFP_KERNEL);
@@ -879,6 +881,7 @@ static int cache_release(struct inode *inode, struct file *filp, 
		cd->last_close = get_seconds();

		atomic_dec(&cd->readers);

	}

	module_put(cd->owner);

	return 0;

}
@@ -1215,6 +1218,8 @@ static int content_open(struct inode *inode, struct file *file, 
{

	struct handle *han;



	if (!cd || !try_module_get(cd->owner))

		return -EACCES;

	han = __seq_open_private(file, &cache_content_op, sizeof(*han));

	if (han == NULL)

		return -ENOMEM;
@@ -1223,6 +1228,29 @@ static int content_open(struct inode *inode, struct file *file, 
	return 0;

}



static int content_release(struct inode *inode, struct file *file,

		struct cache_detail *cd)

{

	int ret = seq_release_private(inode, file);

	module_put(cd->owner);

	return ret;

}



static int open_flush(struct inode *inode, struct file *file,

			struct cache_detail *cd)

{

	if (!cd || !try_module_get(cd->owner))

		return -EACCES;

	return nonseekable_open(inode, file);

}



static int release_flush(struct inode *inode, struct file *file,

			struct cache_detail *cd)

{

	module_put(cd->owner);

	return 0;

}



static ssize_t read_flush(struct file *file, char __user *buf,

			  size_t count, loff_t *ppos,

			  struct cache_detail *cd)
@@ -1331,13 +1359,34 @@ static int content_open_procfs(struct inode *inode, struct file *filp) 
	return content_open(inode, filp, cd);

}



static int content_release_procfs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = PDE(inode)->data;



	return content_release(inode, filp, cd);

}



static const struct file_operations content_file_operations_procfs = {

	.open		= content_open_procfs,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= seq_release_private,

	.release	= content_release_procfs,

};



static int open_flush_procfs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = PDE(inode)->data;



	return open_flush(inode, filp, cd);

}



static int release_flush_procfs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = PDE(inode)->data;



	return release_flush(inode, filp, cd);

}



static ssize_t read_flush_procfs(struct file *filp, char __user *buf,

			    size_t count, loff_t *ppos)

{
@@ -1356,9 +1405,10 @@ static ssize_t write_flush_procfs(struct file *filp, 
}



static const struct file_operations cache_flush_operations_procfs = {

	.open		= nonseekable_open,

	.open		= open_flush_procfs,

	.read		= read_flush_procfs,

	.write		= write_flush_procfs,

	.release	= release_flush_procfs,

};



static void remove_cache_proc_entries(struct cache_detail *cd)
@@ -1503,13 +1553,34 @@ static int content_open_pipefs(struct inode *inode, struct file *filp) 
	return content_open(inode, filp, cd);

}



static int content_release_pipefs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = RPC_I(inode)->private;



	return content_release(inode, filp, cd);

}



const struct file_operations content_file_operations_pipefs = {

	.open		= content_open_pipefs,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= seq_release_private,

	.release	= content_release_pipefs,

};



static int open_flush_pipefs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = RPC_I(inode)->private;



	return open_flush(inode, filp, cd);

}



static int release_flush_pipefs(struct inode *inode, struct file *filp)

{

	struct cache_detail *cd = RPC_I(inode)->private;



	return release_flush(inode, filp, cd);

}



static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,

			    size_t count, loff_t *ppos)

{
@@ -1528,9 +1599,10 @@ static ssize_t write_flush_pipefs(struct file *filp, 
}



const struct file_operations cache_flush_operations_pipefs = {

	.open		= nonseekable_open,

	.open		= open_flush_pipefs,

	.read		= read_flush_pipefs,

	.write		= write_flush_pipefs,

	.release	= release_flush_pipefs,

};



int sunrpc_cache_register_pipefs(struct dentry *parent,