gfs2: Change inode qa_data to allow multiple users

Before this patch, multiple users called gfs2_qa_alloc which allocated
a qadata structure to the inode, if quotas are turned on. Later, in
file close or evict, the structure was deleted with gfs2_qa_delete.
But there can be several competing processes who need access to the
structure. There were races between file close (release) and the others.
Thus, a release could delete the structure out from under a process
that relied upon its existence. For example, chown.

This patch changes the management of the qadata structures to be
a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get
and if the structure is allocated, the count essentially starts out at
1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the
last guy to decrement the count to 0 frees the memory.

Signed-off-by: Bob Peterson <[email protected]>

Author: AstralBob

fs/gfs2/acl.c

@@ -117,14 +117,14 @@ int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
 		return -E2BIG;
 
-	ret = gfs2_qa_alloc(ip);
+	ret = gfs2_qa_get(ip);
 	if (ret)
 		return ret;
 
 	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
 		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
 		if (ret)
-			return ret;
+			goto out;
 		need_unlock = true;
 	}
 
@@ -144,5 +144,7 @@ int gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 unlock:
 	if (need_unlock)
 		gfs2_glock_dq_uninit(&gh);
+out:
+	gfs2_qa_put(ip);
 	return ret;
 }

fs/gfs2/bmap.c

@@ -2183,7 +2183,7 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
 
 	inode_dio_wait(inode);
 
-	ret = gfs2_qa_alloc(ip);
+	ret = gfs2_qa_get(ip);
 	if (ret)
 		goto out;
 

fs/gfs2/file.c

@@ -458,7 +458,7 @@ static vm_fault_t gfs2_page_mkwrite(struct vm_fault *vmf)
 
 	sb_start_pagefault(inode->i_sb);
 
-	ret = gfs2_qa_alloc(ip);
+	ret = gfs2_qa_get(ip);
 	if (ret)
 		goto out;
 
@@ -553,6 +553,7 @@ static vm_fault_t gfs2_page_mkwrite(struct vm_fault *vmf)
 out_unlock:
 	gfs2_glock_dq(&gh);
 out_uninit:
+	gfs2_qa_put(ip);
 	gfs2_holder_uninit(&gh);
 	if (ret == 0) {
 		set_page_dirty(page);
@@ -635,7 +636,17 @@ int gfs2_open_common(struct inode *inode, struct file *file)
 
 	gfs2_assert_warn(GFS2_SB(inode), !file->private_data);
 	file->private_data = fp;
+	if (file->f_mode & FMODE_WRITE) {
+		ret = gfs2_qa_get(GFS2_I(inode));
+		if (ret)
+			goto fail;
+	}
 	return 0;
+
+fail:
+	kfree(file->private_data);
+	file->private_data = NULL;
+	return ret;
 }
 
 /**
@@ -690,10 +701,8 @@ static int gfs2_release(struct inode *inode, struct file *file)
 	kfree(file->private_data);
 	file->private_data = NULL;
 
-	if (!(file->f_mode & FMODE_WRITE))
-		return 0;
-
-	gfs2_rsqa_delete(ip, &inode->i_writecount);
+	if (file->f_mode & FMODE_WRITE)
+		gfs2_rsqa_delete(ip, &inode->i_writecount);
 	return 0;
 }
 
@@ -849,7 +858,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct gfs2_inode *ip = GFS2_I(inode);
 	ssize_t ret;
 
-	ret = gfs2_qa_alloc(ip);
+	ret = gfs2_qa_get(ip);
 	if (ret)
 		return ret;
 
@@ -860,7 +869,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
 		if (ret)
-			return ret;
+			goto out;
 		gfs2_glock_dq_uninit(&gh);
 	}
 
@@ -918,6 +927,8 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 out_unlock:
 	inode_unlock(inode);
+out:
+	gfs2_qa_put(ip);
 	return ret;
 }
 
@@ -1149,14 +1160,15 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t le
 	if (mode & FALLOC_FL_PUNCH_HOLE) {
 		ret = __gfs2_punch_hole(file, offset, len);
 	} else {
-		ret = gfs2_qa_alloc(ip);
+		ret = gfs2_qa_get(ip);
 		if (ret)
 			goto out_putw;
 
 		ret = __gfs2_fallocate(file, mode, offset, len);
 
 		if (ret)
 			gfs2_rs_deltree(&ip->i_res);
+		gfs2_qa_put(ip);
 	}
 
 out_putw:
@@ -1175,14 +1187,17 @@ static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
 {
 	int error;
 	struct gfs2_inode *ip = GFS2_I(out->f_mapping->host);
+	ssize_t ret;
 
-	error = gfs2_qa_alloc(ip);
+	error = gfs2_qa_get(ip);
 	if (error)
 		return (ssize_t)error;
 
 	gfs2_size_hint(out, *ppos, len);
 
-	return iter_file_splice_write(pipe, out, ppos, len, flags);
+	ret = iter_file_splice_write(pipe, out, ppos, len, flags);
+	gfs2_qa_put(ip);
+	return ret;
 }
 
 #ifdef CONFIG_GFS2_FS_LOCKING_DLM

fs/gfs2/incore.h

@@ -295,6 +295,7 @@ struct gfs2_qadata { /* quota allocation data */
 	struct gfs2_quota_data *qa_qd[2 * GFS2_MAXQUOTAS];
 	struct gfs2_holder qa_qd_ghs[2 * GFS2_MAXQUOTAS];
 	unsigned int qa_qd_num;
+	int qa_ref;
 };
 
 /* Resource group multi-block reservation, in order of appearance:

fs/gfs2/inode.c

@@ -588,13 +588,13 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (!name->len || name->len > GFS2_FNAMESIZE)
 		return -ENAMETOOLONG;
 
-	error = gfs2_qa_alloc(dip);
+	error = gfs2_qa_get(dip);
 	if (error)
 		return error;
 
 	error = gfs2_rindex_update(sdp);
 	if (error)
-		return error;
+		goto fail;
 
 	error = gfs2_glock_nq_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
 	if (error)
@@ -641,7 +641,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 		goto fail_gunlock;
 
 	ip = GFS2_I(inode);
-	error = gfs2_qa_alloc(ip);
+	error = gfs2_qa_get(ip);
 	if (error)
 		goto fail_free_acls;
 
@@ -776,6 +776,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
 	gfs2_glock_put(io_gl);
 fail_free_inode:
+	gfs2_qa_put(ip);
 	if (ip->i_gl) {
 		glock_clear_object(ip->i_gl, ip);
 		gfs2_glock_put(ip->i_gl);
@@ -798,6 +799,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (gfs2_holder_initialized(ghs + 1))
 		gfs2_glock_dq_uninit(ghs + 1);
 fail:
+	gfs2_qa_put(dip);
 	return error;
 }
 
@@ -899,7 +901,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
 	if (S_ISDIR(inode->i_mode))
 		return -EPERM;
 
-	error = gfs2_qa_alloc(dip);
+	error = gfs2_qa_get(dip);
 	if (error)
 		return error;
 
@@ -1002,6 +1004,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
 out_child:
 	gfs2_glock_dq(ghs);
 out_parent:
+	gfs2_qa_put(ip);
 	gfs2_holder_uninit(ghs);
 	gfs2_holder_uninit(ghs + 1);
 	return error;
@@ -1362,7 +1365,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	if (error)
 		return error;
 
-	error = gfs2_qa_alloc(ndip);
+	error = gfs2_qa_get(ndip);
 	if (error)
 		return error;
 
@@ -1562,6 +1565,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	if (gfs2_holder_initialized(&r_gh))
 		gfs2_glock_dq_uninit(&r_gh);
 out:
+	gfs2_qa_put(ndip);
 	return error;
 }
 
@@ -1873,10 +1877,9 @@ static int setattr_chown(struct inode *inode, struct iattr *attr)
 		ouid = nuid = NO_UID_QUOTA_CHANGE;
 	if (!(attr->ia_valid & ATTR_GID) || gid_eq(ogid, ngid))
 		ogid = ngid = NO_GID_QUOTA_CHANGE;
-
-	error = gfs2_qa_alloc(ip);
+	error = gfs2_qa_get(ip);
 	if (error)
-		goto out;
+		return error;
 
 	error = gfs2_rindex_update(sdp);
 	if (error)
@@ -1914,6 +1917,7 @@ static int setattr_chown(struct inode *inode, struct iattr *attr)
 out_gunlock_q:
 	gfs2_quota_unlock(ip);
 out:
+	gfs2_qa_put(ip);
 	return error;
 }
 
@@ -1935,21 +1939,21 @@ static int gfs2_setattr(struct dentry *dentry, struct iattr *attr)
 	struct gfs2_holder i_gh;
 	int error;
 
-	error = gfs2_qa_alloc(ip);
+	error = gfs2_qa_get(ip);
 	if (error)
 		return error;
 
 	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
 	if (error)
-		return error;
+		goto out;
 
 	error = -EPERM;
 	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-		goto out;
+		goto error;
 
 	error = setattr_prepare(dentry, attr);
 	if (error)
-		goto out;
+		goto error;
 
 	if (attr->ia_valid & ATTR_SIZE)
 		error = gfs2_setattr_size(inode, attr->ia_size);
@@ -1961,10 +1965,12 @@ static int gfs2_setattr(struct dentry *dentry, struct iattr *attr)
 			error = posix_acl_chmod(inode, inode->i_mode);
 	}
 
-out:
+error:
 	if (!error)
 		mark_inode_dirty(inode);
 	gfs2_glock_dq_uninit(&i_gh);
+out:
+	gfs2_qa_put(ip);
 	return error;
 }