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Commit 3ed47db3 authored by Al Viro's avatar Al Viro
Browse files

make sure that freeing shmem fast symlinks is RCU-delayed 



Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5955102c

include/linux/shmem_fs.h

+1 −4
Original line number Diff line number Diff line
@@ -15,10 +15,7 @@ struct shmem_inode_info { 
	unsigned int		seals;		/* shmem seals */

	unsigned long		flags;

	unsigned long		alloced;	/* data pages alloced to file */

	union {

	unsigned long		swapped;	/* subtotal assigned to swap */

		char		*symlink;	/* unswappable short symlink */

	};

	struct shared_policy	policy;		/* NUMA memory alloc policy */

	struct list_head	swaplist;	/* chain of maybes on swap */

	struct simple_xattrs	xattrs;		/* list of xattrs */

mm/shmem.c

+4 −5
Original line number Diff line number Diff line
@@ -701,8 +701,7 @@ static void shmem_evict_inode(struct inode *inode) 
			list_del_init(&info->swaplist);

			mutex_unlock(&shmem_swaplist_mutex);

		}

	} else

		kfree(info->symlink);

	}



	simple_xattrs_free(&info->xattrs);

	WARN_ON(inode->i_blocks);
@@ -2549,13 +2548,12 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s 
	info = SHMEM_I(inode);

	inode->i_size = len-1;

	if (len <= SHORT_SYMLINK_LEN) {

		info->symlink = kmemdup(symname, len, GFP_KERNEL);

		if (!info->symlink) {

		inode->i_link = kmemdup(symname, len, GFP_KERNEL);

		if (!inode->i_link) {

			iput(inode);

			return -ENOMEM;

		}

		inode->i_op = &shmem_short_symlink_operations;

		inode->i_link = info->symlink;

	} else {

		inode_nohighmem(inode);

		error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
@@ -3132,6 +3130,7 @@ static struct inode *shmem_alloc_inode(struct super_block *sb) 
static void shmem_destroy_callback(struct rcu_head *head)

{

	struct inode *inode = container_of(head, struct inode, i_rcu);

	kfree(inode->i_link);

	kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));

}