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Commit 45996492 authored by Al Viro's avatar Al Viro Committed by Mike Marshall
Browse files

orangefs: fix orangefs_superblock locking 



* switch orangefs_remount() to taking ORANGEFS_SB(sb) instead of sb
* remove from the list _before_ orangefs_unmount() - request_mutex
in the latter will make sure that nothing observed in the loop in
ORANGEFS_DEV_REMOUNT_ALL handling will get freed until the end
of loop
* on removal, keep the forward pointer and zero the back one.  That
way we can drop and regain the spinlock in the loop body (again,
ORANGEFS_DEV_REMOUNT_ALL one) and still be able to get to the
rest of the list.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarMike Marshall <hubcap@omnibond.com>
parent 6d4c1a30

fs/orangefs/devorangefs-req.c

+23 −18
Original line number Diff line number Diff line
@@ -572,8 +572,7 @@ static long dispatch_ioctl_command(unsigned int command, unsigned long arg) 
	struct dev_mask_info_s mask_info = { 0 };

	struct dev_mask2_info_s mask2_info = { 0, 0 };

	int upstream_kmod = 1;

	struct list_head *tmp = NULL;

	struct orangefs_sb_info_s *orangefs_sb = NULL;

	struct orangefs_sb_info_s *orangefs_sb;



	/* mtmoore: add locking here */
@@ -619,18 +618,24 @@ static long dispatch_ioctl_command(unsigned int command, unsigned long arg) 
		gossip_debug(GOSSIP_DEV_DEBUG,

			     "%s: priority remount in progress\n",

			     __func__);

		list_for_each(tmp, &orangefs_superblocks) {

			orangefs_sb =

				list_entry(tmp,

					   struct orangefs_sb_info_s,

					   list);

			if (orangefs_sb && (orangefs_sb->sb)) {

		spin_lock(&orangefs_superblocks_lock);

		list_for_each_entry(orangefs_sb, &orangefs_superblocks, list) {

			/*

			 * We have to drop the spinlock, so entries can be

			 * removed.  They can't be freed, though, so we just

			 * keep the forward pointers and zero the back ones -

			 * that way we can get to the rest of the list.

			 */

			if (!orangefs_sb->list.prev)

				continue;

			gossip_debug(GOSSIP_DEV_DEBUG,

				     "%s: Remounting SB %p\n",

				     __func__,

				     orangefs_sb);



				ret = orangefs_remount(orangefs_sb->sb);

			spin_unlock(&orangefs_superblocks_lock);

			ret = orangefs_remount(orangefs_sb);

			spin_lock(&orangefs_superblocks_lock);

			if (ret) {

				gossip_debug(GOSSIP_DEV_DEBUG,

					     "SB %p remount failed\n",
@@ -638,7 +643,7 @@ static long dispatch_ioctl_command(unsigned int command, unsigned long arg) 
				break;

			}

		}

		}

		spin_unlock(&orangefs_superblocks_lock);

		gossip_debug(GOSSIP_DEV_DEBUG,

			     "%s: priority remount complete\n",

			     __func__);

fs/orangefs/orangefs-kernel.h

+1 −33
Original line number Diff line number Diff line
@@ -462,7 +462,7 @@ struct dentry *orangefs_mount(struct file_system_type *fst, 
			   void *data);



void orangefs_kill_sb(struct super_block *sb);

int orangefs_remount(struct super_block *sb);

int orangefs_remount(struct orangefs_sb_info_s *);



int fsid_key_table_initialize(void);

void fsid_key_table_finalize(void);
@@ -598,38 +598,6 @@ int service_operation(struct orangefs_kernel_op_s *op, 
	((ORANGEFS_SB(inode->i_sb)->flags & ORANGEFS_OPT_INTR) ? \

		ORANGEFS_OP_INTERRUPTIBLE : 0)



#define add_orangefs_sb(sb)						\

do {									\

	gossip_debug(GOSSIP_SUPER_DEBUG,				\

		     "Adding SB %p to orangefs superblocks\n",		\

		     ORANGEFS_SB(sb));					\

	spin_lock(&orangefs_superblocks_lock);				\

	list_add_tail(&ORANGEFS_SB(sb)->list, &orangefs_superblocks);		\

	spin_unlock(&orangefs_superblocks_lock); \

} while (0)



#define remove_orangefs_sb(sb)						\

do {									\

	struct list_head *tmp = NULL;					\

	struct list_head *tmp_safe = NULL;				\

	struct orangefs_sb_info_s *orangefs_sb = NULL;			\

									\

	spin_lock(&orangefs_superblocks_lock);				\

	list_for_each_safe(tmp, tmp_safe, &orangefs_superblocks) {		\

		orangefs_sb = list_entry(tmp,				\

				      struct orangefs_sb_info_s,		\

				      list);				\

		if (orangefs_sb && (orangefs_sb->sb == sb)) {			\

			gossip_debug(GOSSIP_SUPER_DEBUG,		\

			    "Removing SB %p from orangefs superblocks\n",	\

			orangefs_sb);					\

			list_del(&orangefs_sb->list);			\

			break;						\

		}							\

	}								\

	spin_unlock(&orangefs_superblocks_lock);				\

} while (0)



#define fill_default_sys_attrs(sys_attr, type, mode)			\

do {									\

	sys_attr.owner = from_kuid(current_user_ns(), current_fsuid()); \

fs/orangefs/super.c

+23 −7
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ static int orangefs_remount_fs(struct super_block *sb, int *flags, char *data) 
 * the client regains all of the mount information from us.

 * NOTE: this function assumes that the request_mutex is already acquired!

 */

int orangefs_remount(struct super_block *sb)

int orangefs_remount(struct orangefs_sb_info_s *orangefs_sb)

{

	struct orangefs_kernel_op_s *new_op;

	int ret = -EINVAL;
@@ -221,7 +221,7 @@ int orangefs_remount(struct super_block *sb) 
	if (!new_op)

		return -ENOMEM;

	strncpy(new_op->upcall.req.fs_mount.orangefs_config_server,

		ORANGEFS_SB(sb)->devname,

		orangefs_sb->devname,

		ORANGEFS_MAX_SERVER_ADDR_LEN);



	gossip_debug(GOSSIP_SUPER_DEBUG,
@@ -244,8 +244,8 @@ int orangefs_remount(struct super_block *sb) 
		 * short-lived mapping that the system interface uses

		 * to map this superblock to a particular mount entry

		 */

		ORANGEFS_SB(sb)->id = new_op->downcall.resp.fs_mount.id;

		ORANGEFS_SB(sb)->mount_pending = 0;

		orangefs_sb->id = new_op->downcall.resp.fs_mount.id;

		orangefs_sb->mount_pending = 0;

	}



	op_release(new_op);
@@ -485,7 +485,12 @@ struct dentry *orangefs_mount(struct file_system_type *fst, 
	 * finally, add this sb to our list of known orangefs

	 * sb's

	 */

	add_orangefs_sb(sb);

	gossip_debug(GOSSIP_SUPER_DEBUG,

		     "Adding SB %p to orangefs superblocks\n",

		     ORANGEFS_SB(sb));

	spin_lock(&orangefs_superblocks_lock);

	list_add_tail(&ORANGEFS_SB(sb)->list, &orangefs_superblocks);

	spin_unlock(&orangefs_superblocks_lock);

	op_release(new_op);

	return dget(sb->s_root);
@@ -515,7 +520,18 @@ void orangefs_kill_sb(struct super_block *sb) 
	 orangefs_unmount_sb(sb);



	/* remove the sb from our list of orangefs specific sb's */

	remove_orangefs_sb(sb);



	spin_lock(&orangefs_superblocks_lock);

	__list_del_entry(&ORANGEFS_SB(sb)->list);	/* not list_del_init */

	ORANGEFS_SB(sb)->list.prev = NULL;

	spin_unlock(&orangefs_superblocks_lock);



	/*

	 * make sure that ORANGEFS_DEV_REMOUNT_ALL loop that might've seen us

	 * gets completed before we free the dang thing.

	 */

	mutex_lock(&request_mutex);

	mutex_unlock(&request_mutex);



	/* free the orangefs superblock private data */

	kfree(ORANGEFS_SB(sb));