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Commit be62a1a8 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Theodore Ts'o
Browse files

nfs: use file_dentry() 



NFS may be used as lower layer of overlayfs and accessing f_path.dentry can
lead to a crash.

Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.

Fixes: 4bacc9c9 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Tested-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Acked-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: <stable@vger.kernel.org> # v4.2
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
parent d101a125

fs/nfs/dir.c

+3 −3
Original line number Diff line number Diff line
@@ -377,7 +377,7 @@ int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, 
 again:

	timestamp = jiffies;

	gencount = nfs_inc_attr_generation_counter();

	error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, pages,

	error = NFS_PROTO(inode)->readdir(file_dentry(file), cred, entry->cookie, pages,

					  NFS_SERVER(inode)->dtsize, desc->plus);

	if (error < 0) {

		/* We requested READDIRPLUS, but the server doesn't grok it */
@@ -560,7 +560,7 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en 
		count++;



		if (desc->plus != 0)

			nfs_prime_dcache(desc->file->f_path.dentry, entry);

			nfs_prime_dcache(file_dentry(desc->file), entry);



		status = nfs_readdir_add_to_array(entry, page);

		if (status != 0)
@@ -864,7 +864,7 @@ static bool nfs_dir_mapping_need_revalidate(struct inode *dir) 
 */

static int nfs_readdir(struct file *file, struct dir_context *ctx)

{

	struct dentry	*dentry = file->f_path.dentry;

	struct dentry	*dentry = file_dentry(file);

	struct inode	*inode = d_inode(dentry);

	nfs_readdir_descriptor_t my_desc,

			*desc = &my_desc;

fs/nfs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -940,7 +940,7 @@ int nfs_open(struct inode *inode, struct file *filp) 
{

	struct nfs_open_context *ctx;



	ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);

	ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode);

	if (IS_ERR(ctx))

		return PTR_ERR(ctx);

	nfs_file_set_open_context(filp, ctx);

fs/nfs/nfs4file.c

+2 −2
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ static int 
nfs4_file_open(struct inode *inode, struct file *filp)

{

	struct nfs_open_context *ctx;

	struct dentry *dentry = filp->f_path.dentry;

	struct dentry *dentry = file_dentry(filp);

	struct dentry *parent = NULL;

	struct inode *dir;

	unsigned openflags = filp->f_flags;
@@ -57,7 +57,7 @@ nfs4_file_open(struct inode *inode, struct file *filp) 
	parent = dget_parent(dentry);

	dir = d_inode(parent);



	ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);

	ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode);

	err = PTR_ERR(ctx);

	if (IS_ERR(ctx))

		goto out;