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Commit 19690ddb authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: make fuse_permission() RCU aware 



Only bail out of fuse_permission() on IPERM_FLAG_RCU when blocking is
actually necessary.

CC: Nick Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 357ccf2b

fs/fuse/dir.c

+22 −8
Original line number Diff line number Diff line
@@ -970,6 +970,14 @@ static int fuse_access(struct inode *inode, int mask) 
	return err;

}



static int fuse_perm_getattr(struct inode *inode, int flags)

{

	if (flags & IPERM_FLAG_RCU)

		return -ECHILD;



	return fuse_do_getattr(inode, NULL, NULL);

}



/*

 * Check permission.  The two basic access models of FUSE are:

 *
@@ -989,9 +997,6 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) 
	bool refreshed = false;

	int err = 0;



	if (flags & IPERM_FLAG_RCU)

		return -ECHILD;



	if (!fuse_allow_task(fc, current))

		return -EACCES;
@@ -1000,10 +1005,16 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) 
	 */

	if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||

	    ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {

		err = fuse_update_attributes(inode, NULL, NULL, &refreshed);

		struct fuse_inode *fi = get_fuse_inode(inode);



		if (fi->i_time < get_jiffies_64()) {

			refreshed = true;



			err = fuse_perm_getattr(inode, flags);

			if (err)

				return err;

		}

	}



	if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {

		err = generic_permission(inode, mask, flags, NULL);
@@ -1012,7 +1023,7 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) 
		   attributes.  This is also needed, because the root

		   node will at first have no permissions */

		if (err == -EACCES && !refreshed) {

			err = fuse_do_getattr(inode, NULL, NULL);

			err = fuse_perm_getattr(inode, flags);

			if (!err)

				err = generic_permission(inode, mask,

							flags, NULL);
@@ -1023,13 +1034,16 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) 
		   noticed immediately, only after the attribute

		   timeout has expired */

	} else if (mask & (MAY_ACCESS | MAY_CHDIR)) {

		if (flags & IPERM_FLAG_RCU)

			return -ECHILD;



		err = fuse_access(inode, mask);

	} else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {

		if (!(inode->i_mode & S_IXUGO)) {

			if (refreshed)

				return -EACCES;



			err = fuse_do_getattr(inode, NULL, NULL);

			err = fuse_perm_getattr(inode, flags);

			if (!err && !(inode->i_mode & S_IXUGO))

				return -EACCES;

		}