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Commit f77f21bb authored by Jeff Layton's avatar Jeff Layton Committed by Ilya Dryomov
Browse files

ceph: use __getname/__putname in ceph_mdsc_build_path 



Al suggested we get rid of the kmalloc here and just use __getname
and __putname to get a full PATH_MAX pathname buffer.

Since we build the path in reverse, we continue to return a pointer
to the beginning of the string and the length, and add a new helper
to free the thing at the end.

Suggested-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatar"Yan, Zheng" <zyan@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 964fff74

fs/ceph/debugfs.c

+2 −2
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static int mdsc_show(struct seq_file *s, void *p) 
				   req->r_dentry,

				   path ? path : "");

			spin_unlock(&req->r_dentry->d_lock);

			kfree(path);

			ceph_mdsc_free_path(path, pathlen);

		} else if (req->r_path1) {

			seq_printf(s, " #%llx/%s", req->r_ino1.ino,

				   req->r_path1);
@@ -108,7 +108,7 @@ static int mdsc_show(struct seq_file *s, void *p) 
				   req->r_old_dentry,

				   path ? path : "");

			spin_unlock(&req->r_old_dentry->d_lock);

			kfree(path);

			ceph_mdsc_free_path(path, pathlen);

		} else if (req->r_path2 && req->r_op != CEPH_MDS_OP_SYMLINK) {

			if (req->r_ino2.ino)

				seq_printf(s, " #%llx/%s", req->r_ino2.ino,

fs/ceph/mds_client.c

+28 −37
Original line number Diff line number Diff line
@@ -2094,39 +2094,24 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, 
{

	struct dentry *temp;

	char *path;

	int len, pos;

	int pos;

	unsigned seq;

	u64 base;



	if (!dentry)

		return ERR_PTR(-EINVAL);



retry:

	len = 0;

	seq = read_seqbegin(&rename_lock);

	rcu_read_lock();

	for (temp = dentry; !IS_ROOT(temp);) {

		struct inode *inode = d_inode(temp);

		if (inode && ceph_snap(inode) == CEPH_SNAPDIR)

			len++;  /* slash only */

		else if (stop_on_nosnap && inode &&

			 ceph_snap(inode) == CEPH_NOSNAP)

			break;

		else

			len += 1 + temp->d_name.len;

		temp = temp->d_parent;

	}

	rcu_read_unlock();

	if (len)

		len--;  /* no leading '/' */



	path = kmalloc(len+1, GFP_NOFS);

	path = __getname();

	if (!path)

		return ERR_PTR(-ENOMEM);

	pos = len;

	path[pos] = 0;	/* trailing null */

retry:

	pos = PATH_MAX - 1;

	path[pos] = '\0';



	seq = read_seqbegin(&rename_lock);

	rcu_read_lock();

	for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {

	temp = dentry;

	for (;;) {

		struct inode *inode;



		spin_lock(&temp->d_lock);
@@ -2144,32 +2129,38 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, 
				spin_unlock(&temp->d_lock);

				break;

			}

			strncpy(path + pos, temp->d_name.name,

				temp->d_name.len);

			memcpy(path + pos, temp->d_name.name, temp->d_name.len);

		}

		spin_unlock(&temp->d_lock);

		if (pos)

			path[--pos] = '/';

		temp = temp->d_parent;



		/* Are we at the root? */

		if (IS_ROOT(temp))

			break;



		/* Are we out of buffer? */

		if (--pos < 0)

			break;



		path[pos] = '/';

	}

	base = ceph_ino(d_inode(temp));

	rcu_read_unlock();

	if (pos != 0 || read_seqretry(&rename_lock, seq)) {

	if (pos < 0 || read_seqretry(&rename_lock, seq)) {

		pr_err("build_path did not end path lookup where "

		       "expected, namelen is %d, pos is %d\n", len, pos);

		       "expected, pos is %d\n", pos);

		/* presumably this is only possible if racing with a

		   rename of one of the parent directories (we can not

		   lock the dentries above us to prevent this, but

		   retrying should be harmless) */

		kfree(path);

		goto retry;

	}



	*pbase = base;

	*plen = len;

	*plen = PATH_MAX - 1 - pos;

	dout("build_path on %p %d built %llx '%.*s'\n",

	     dentry, d_count(dentry), base, len, path);

	return path;

	     dentry, d_count(dentry), base, *plen, path + pos);

	return path + pos;

}



static int build_dentry_path(struct dentry *dentry, struct inode *dir,
@@ -2376,10 +2367,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc, 


out_free2:

	if (freepath2)

		kfree((char *)path2);

		ceph_mdsc_free_path((char *)path2, pathlen2);

out_free1:

	if (freepath1)

		kfree((char *)path1);

		ceph_mdsc_free_path((char *)path1, pathlen1);

out:

	return msg;

}
@@ -3451,7 +3442,7 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap, 
		ceph_pagelist_encode_string(pagelist, path, pathlen);

		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v1));

out_freepath:

		kfree(path);

		ceph_mdsc_free_path(path, pathlen);

	}



out_err:

fs/ceph/mds_client.h

+6 −0
Original line number Diff line number Diff line
@@ -492,6 +492,12 @@ extern int ceph_iterate_session_caps(struct ceph_mds_session *session, 
				     void *arg);

extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);



static inline void ceph_mdsc_free_path(char *path, int len)

{

	if (path)

		__putname(path - (PATH_MAX - 1 - len));

}



extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,

				  int stop_on_nosnap);