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Commit 717d44e8 authored by Trond Myklebust's avatar Trond Myklebust Committed by Linus Torvalds
Browse files

[PATCH] NFS: Fix races in nfs_revalidate_mapping() 



Prevent the call to invalidate_inode_pages2() from racing with file writes
by taking the inode->i_mutex across the page cache flush and invalidate.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bde8f00c

fs/nfs/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -532,7 +532,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 


	lock_kernel();



	res = nfs_revalidate_mapping(inode, filp->f_mapping);

	res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping);

	if (res < 0) {

		unlock_kernel();

		return res;

fs/nfs/inode.c

+67 −30
Original line number Diff line number Diff line
@@ -665,34 +665,14 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode) 
	return __nfs_revalidate_inode(server, inode);

}



/**

 * nfs_revalidate_mapping - Revalidate the pagecache

 * @inode - pointer to host inode

 * @mapping - pointer to mapping

 */

int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)

static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	int ret = 0;

	

	if (NFS_STALE(inode))

		ret = -ESTALE;

	if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)

			|| nfs_attribute_timeout(inode))

		ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

	if (ret < 0)

		goto out;



	if (nfsi->cache_validity & NFS_INO_INVALID_DATA) {

	if (mapping->nrpages != 0) {

			if (S_ISREG(inode->i_mode)) {

				ret = nfs_sync_mapping(mapping);

				if (ret < 0)

					goto out;

			}

			ret = invalidate_inode_pages2(mapping);

		int ret = invalidate_inode_pages2(mapping);

		if (ret < 0)

				goto out;

			return ret;

	}

	spin_lock(&inode->i_lock);

	nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
@@ -702,12 +682,69 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) 
		nfsi->cache_change_attribute = jiffies;

	}

	spin_unlock(&inode->i_lock);



	nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);

	dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",

				inode->i_sb->s_id,

				(long long)NFS_FILEID(inode));

			inode->i_sb->s_id, (long long)NFS_FILEID(inode));

	return 0;

}



static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)

{

	int ret = 0;



	mutex_lock(&inode->i_mutex);

	if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) {

		ret = nfs_sync_mapping(mapping);

		if (ret == 0)

			ret = nfs_invalidate_mapping_nolock(inode, mapping);

	}

	mutex_unlock(&inode->i_mutex);

	return ret;

}



/**

 * nfs_revalidate_mapping_nolock - Revalidate the pagecache

 * @inode - pointer to host inode

 * @mapping - pointer to mapping

 */

int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	int ret = 0;



	if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)

			|| nfs_attribute_timeout(inode) || NFS_STALE(inode)) {

		ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

		if (ret < 0)

			goto out;

	}

	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)

		ret = nfs_invalidate_mapping_nolock(inode, mapping);

out:

	return ret;

}



/**

 * nfs_revalidate_mapping - Revalidate the pagecache

 * @inode - pointer to host inode

 * @mapping - pointer to mapping

 *

 * This version of the function will take the inode->i_mutex and attempt to

 * flush out all dirty data if it needs to invalidate the page cache.

 */

int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	int ret = 0;



	if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)

			|| nfs_attribute_timeout(inode) || NFS_STALE(inode)) {

		ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

		if (ret < 0)

			goto out;

	}

	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)

		ret = nfs_invalidate_mapping(inode, mapping);

out:

	return ret;

}

fs/nfs/symlink.c

+3 −1
Original line number Diff line number Diff line
@@ -50,7 +50,9 @@ static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd) 
{

	struct inode *inode = dentry->d_inode;

	struct page *page;

	void *err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));

	void *err;



	err = ERR_PTR(nfs_revalidate_mapping_nolock(inode, inode->i_mapping));

	if (err)

		goto read_failed;

	page = read_cache_page(&inode->i_data, 0,

include/linux/nfs_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -308,6 +308,7 @@ extern int nfs_attribute_timeout(struct inode *inode); 
extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);

extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);

extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);

extern int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping);

extern int nfs_setattr(struct dentry *, struct iattr *);

extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);

extern void nfs_begin_attr_update(struct inode *);