From: Jeff Mahoney <jeffm@suse.com>
Subject: reiserfs: locking, push write lock out of xattr code
References: bnc#815320
Patch-mainline: v3.12-rc1
Git-commit: 4c05141df57f4ffc1a9a28f1925434924179bfe4

The reiserfs xattr code doesn't need the write lock and sleeps all over
the place. We can simplify the locking by releasing it and reacquiring
after the xattr call.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 fs/reiserfs/inode.c     |   37 ++++++++++++++++++++-----------------
 fs/reiserfs/super.c     |   48 +++++++++++++++++++++++-------------------------
 fs/reiserfs/xattr.c     |   46 +++++++++++++++++-----------------------------
 fs/reiserfs/xattr_acl.c |   17 ++++++++++-------
 4 files changed, 70 insertions(+), 78 deletions(-)

--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -29,7 +29,6 @@ void reiserfs_evict_inode(struct inode *
 	    JOURNAL_PER_BALANCE_CNT * 2 +
 	    2 * REISERFS_QUOTA_INIT_BLOCKS(inode->i_sb);
 	struct reiserfs_transaction_handle th;
-	int depth;
 	int err;
 
 	if (!inode->i_nlink && !is_bad_inode(inode))
@@ -39,12 +38,14 @@ void reiserfs_evict_inode(struct inode *
 	if (inode->i_nlink)
 		goto no_delete;
 
-	depth = reiserfs_write_lock_once(inode->i_sb);
-
 	/* The = 0 happens when we abort creating a new inode for some reason like lack of space.. */
 	if (!(inode->i_state & I_NEW) && INODE_PKEY(inode)->k_objectid != 0) {	/* also handles bad_inode case */
+		int depth;
+
 		reiserfs_delete_xattrs(inode);
 
+		depth = reiserfs_write_lock_once(inode->i_sb);
+
 		if (journal_begin(&th, inode->i_sb, jbegin_count))
 			goto out;
 		reiserfs_update_inode_transaction(inode);
@@ -71,12 +72,12 @@ void reiserfs_evict_inode(struct inode *
 		/* all items of file are deleted, so we can remove "save" link */
 		remove_save_link(inode, 0 /* not truncate */ );	/* we can't do anything
 								 * about an error here */
+out:
+		reiserfs_write_unlock_once(inode->i_sb, depth);
 	} else {
 		/* no object items are in the tree */
 		;
 	}
-      out:
-	reiserfs_write_unlock_once(inode->i_sb, depth);
 	end_writeback(inode);	/* note this must go after the journal_end to prevent deadlock */
 	dquot_drop(inode);
 	inode->i_blocks = 0;
@@ -1941,7 +1942,9 @@ int reiserfs_new_inode(struct reiserfs_t
 	}
 
 	if (reiserfs_posixacl(inode->i_sb)) {
+		reiserfs_write_unlock(inode->i_sb);
 		retval = reiserfs_inherit_default_acl(th, dir, dentry, inode);
+		reiserfs_write_lock(inode->i_sb);
 		if (retval) {
 			err = retval;
 			reiserfs_check_path(&path_to_key);
@@ -1956,7 +1959,9 @@ int reiserfs_new_inode(struct reiserfs_t
 		inode->i_flags |= S_PRIVATE;
 
 	if (security->name) {
+		reiserfs_write_unlock(inode->i_sb);
 		retval = reiserfs_security_write(th, inode, security);
+		reiserfs_write_lock(inode->i_sb);
 		if (retval) {
 			err = retval;
 			reiserfs_check_path(&path_to_key);
@@ -3115,6 +3120,7 @@ int reiserfs_setattr(struct dentry *dent
 		 */
 		if (get_inode_item_key_version(inode) == KEY_FORMAT_3_5 &&
 		    attr->ia_size > MAX_NON_LFS) {
+			reiserfs_write_unlock_once(inode->i_sb, depth);
 			error = -EFBIG;
 			goto out;
 		}
@@ -3133,8 +3139,10 @@ int reiserfs_setattr(struct dentry *dent
 				if (err)
 					error = err;
 			}
-			if (error)
+			if (error) {
+				reiserfs_write_unlock_once(inode->i_sb, depth);
 				goto out;
+			}
 			/*
 			 * file size is changed, ctime and mtime are
 			 * to be updated
@@ -3142,10 +3150,12 @@ int reiserfs_setattr(struct dentry *dent
 			attr->ia_valid |= (ATTR_MTIME | ATTR_CTIME);
 		}
 	}
+	reiserfs_write_unlock_once(inode->i_sb, depth);
 
 	if ((((attr->ia_valid & ATTR_UID) && (attr->ia_uid & ~0xffff)) ||
 	     ((attr->ia_valid & ATTR_GID) && (attr->ia_gid & ~0xffff))) &&
 	    (get_inode_sd_version(inode) == STAT_DATA_V1)) {
+		reiserfs_write_unlock_once(inode->i_sb, depth);
 		/* stat data of format v3.5 has 16 bit uid and gid */
 		error = -EINVAL;
 		goto out;
@@ -3166,14 +3176,16 @@ int reiserfs_setattr(struct dentry *dent
 			return error;
 
 		/* (user+group)*(old+new) structure - we count quota info and , inode write (sb, inode) */
+		depth = reiserfs_write_lock_once(inode->i_sb);
 		error = journal_begin(&th, inode->i_sb, jbegin_count);
+		reiserfs_write_unlock_once(inode->i_sb, depth);
 		if (error)
 			goto out;
-		reiserfs_write_unlock_once(inode->i_sb, depth);
 		error = dquot_transfer(inode, attr);
 		depth = reiserfs_write_lock_once(inode->i_sb);
 		if (error) {
 			journal_end(&th, inode->i_sb, jbegin_count);
+			reiserfs_write_unlock_once(inode->i_sb, depth);
 			goto out;
 		}
 
@@ -3185,17 +3197,11 @@ int reiserfs_setattr(struct dentry *dent
 			inode->i_gid = attr->ia_gid;
 		mark_inode_dirty(inode);
 		error = journal_end(&th, inode->i_sb, jbegin_count);
+		reiserfs_write_unlock_once(inode->i_sb, depth);
 		if (error)
 			goto out;
 	}
 
-	/*
-	 * Relax the lock here, as it might truncate the
-	 * inode pages and wait for inode pages locks.
-	 * To release such page lock, the owner needs the
-	 * reiserfs lock
-	 */
-	reiserfs_write_unlock_once(inode->i_sb, depth);
 	if ((attr->ia_valid & ATTR_SIZE) &&
 	    attr->ia_size != i_size_read(inode))
 		error = vmtruncate(inode, attr->ia_size);
@@ -3204,7 +3210,6 @@ int reiserfs_setattr(struct dentry *dent
 		setattr_copy(inode, attr);
 		mark_inode_dirty(inode);
 	}
-	depth = reiserfs_write_lock_once(inode->i_sb);
 
 	if (!error && reiserfs_posixacl(inode->i_sb)) {
 		if (attr->ia_valid & ATTR_MODE)
@@ -3212,8 +3217,6 @@ int reiserfs_setattr(struct dentry *dent
 	}
 
       out:
-	reiserfs_write_unlock_once(inode->i_sb, depth);
-
 	return error;
 }
 
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -1219,7 +1219,7 @@ static int reiserfs_remount(struct super
 				kfree(qf_names[i]);
 #endif
 		err = -EINVAL;
-		goto out_unlock;
+		goto out_err_unlock;
 	}
 #ifdef CONFIG_QUOTA
 	handle_quota_files(s, qf_names, &qfmt);
@@ -1262,35 +1262,32 @@ static int reiserfs_remount(struct super
 	if (blocks) {
 		err = reiserfs_resize(s, blocks);
 		if (err != 0)
-			goto out_unlock;
+			goto out_err_unlock;
 	}
 
 	if (*mount_flags & MS_RDONLY) {
+		reiserfs_write_unlock(s);
 		reiserfs_xattr_init(s, *mount_flags);
 		/* remount read-only */
 		if (s->s_flags & MS_RDONLY)
 			/* it is read-only already */
-			goto out_ok;
+			goto out_ok_unlocked;
 
-		/*
-		 * Drop write lock. Quota will retake it when needed and lock
-		 * ordering requires calling dquot_suspend() without it.
-		 */
-		reiserfs_write_unlock(s);
 		err = dquot_suspend(s, -1);
 		if (err < 0)
 			goto out_err;
-		reiserfs_write_lock(s);
 
 		/* try to remount file system with read-only permissions */
 		if (sb_umount_state(rs) == REISERFS_VALID_FS
 		    || REISERFS_SB(s)->s_mount_state != REISERFS_VALID_FS) {
-			goto out_ok;
+			goto out_ok_unlocked;
 		}
 
+		reiserfs_write_lock(s);
+
 		err = journal_begin(&th, s, 10);
 		if (err)
-			goto out_unlock;
+			goto out_err_unlock;
 
 		/* Mounting a rw partition read-only. */
 		reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
@@ -1299,13 +1296,14 @@ static int reiserfs_remount(struct super
 	} else {
 		/* remount read-write */
 		if (!(s->s_flags & MS_RDONLY)) {
+			reiserfs_write_unlock(s);
 			reiserfs_xattr_init(s, *mount_flags);
-			goto out_ok;	/* We are read-write already */
+			goto out_ok_unlocked;	/* We are read-write already */
 		}
 
 		if (reiserfs_is_journal_aborted(journal)) {
 			err = journal->j_errno;
-			goto out_unlock;
+			goto out_err_unlock;
 		}
 
 		handle_data_mode(s, mount_options);
@@ -1314,7 +1312,7 @@ static int reiserfs_remount(struct super
 		s->s_flags &= ~MS_RDONLY;	/* now it is safe to call journal_begin */
 		err = journal_begin(&th, s, 10);
 		if (err)
-			goto out_unlock;
+			goto out_err_unlock;
 
 		/* Mount a partition which is read-only, read-write */
 		reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
@@ -1331,27 +1329,23 @@ static int reiserfs_remount(struct super
 	SB_JOURNAL(s)->j_must_wait = 1;
 	err = journal_end(&th, s, 10);
 	if (err)
-		goto out_unlock;
+		goto out_err_unlock;
 	s->s_dirt = 0;
 
+	reiserfs_write_unlock(s);
 	if (!(*mount_flags & MS_RDONLY)) {
-		/*
-		 * Drop write lock. Quota will retake it when needed and lock
-		 * ordering requires calling dquot_resume() without it.
-		 */
-		reiserfs_write_unlock(s);
 		dquot_resume(s, -1);
 		reiserfs_write_lock(s);
 		finish_unfinished(s);
+		reiserfs_write_unlock(s);
 		reiserfs_xattr_init(s, *mount_flags);
 	}
 
-out_ok:
+out_ok_unlocked:
 	replace_mount_options(s, new_opts);
-	reiserfs_write_unlock(s);
 	return 0;
 
-out_unlock:
+out_err_unlock:
 	reiserfs_write_unlock(s);
 out_err:
 	kfree(new_opts);
@@ -1894,12 +1888,14 @@ static int reiserfs_fill_super(struct su
 			goto error;
 		}
 
+		reiserfs_write_unlock(s);
 		if ((errval = reiserfs_lookup_privroot(s)) ||
 		    (errval = reiserfs_xattr_init(s, s->s_flags))) {
 			dput(s->s_root);
 			s->s_root = NULL;
-			goto error;
+			goto error_unlocked;
 		}
+		reiserfs_write_lock(s);
 
 		/* look for files which were to be removed in previous session */
 		finish_unfinished(s);
@@ -1908,12 +1904,14 @@ static int reiserfs_fill_super(struct su
 			reiserfs_info(s, "using 3.5.x disk format\n");
 		}
 
+		reiserfs_write_unlock(s);
 		if ((errval = reiserfs_lookup_privroot(s)) ||
 		    (errval = reiserfs_xattr_init(s, s->s_flags))) {
 			dput(s->s_root);
 			s->s_root = NULL;
-			goto error;
+			goto error_unlocked;
 		}
+		reiserfs_write_lock(s);
 	}
 	// mark hash in super block: it could be unset. overwrite should be ok
 	set_sb_hash_function_code(rs, function2code(sbi->s_hash_function));
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -81,8 +81,7 @@ static int xattr_unlink(struct inode *di
 	int error;
 	BUG_ON(!mutex_is_locked(&dir->i_mutex));
 
-	reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex,
-					I_MUTEX_CHILD, dir->i_sb);
+	mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
 	error = dir->i_op->unlink(dir, dentry);
 	mutex_unlock(&dentry->d_inode->i_mutex);
 
@@ -96,8 +95,7 @@ static int xattr_rmdir(struct inode *dir
 	int error;
 	BUG_ON(!mutex_is_locked(&dir->i_mutex));
 
-	reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex,
-					I_MUTEX_CHILD, dir->i_sb);
+	mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
 	error = dir->i_op->rmdir(dir, dentry);
 	if (!error)
 		dentry->d_inode->i_flags |= S_DEAD;
@@ -232,22 +230,17 @@ static int reiserfs_for_each_xattr(struc
 	if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
 		return 0;
 
-	reiserfs_write_unlock(inode->i_sb);
 	dir = open_xa_dir(inode, XATTR_REPLACE);
 	if (IS_ERR(dir)) {
 		err = PTR_ERR(dir);
-		reiserfs_write_lock(inode->i_sb);
 		goto out;
 	} else if (!dir->d_inode) {
 		err = 0;
-		reiserfs_write_lock(inode->i_sb);
 		goto out_dir;
 	}
 
 	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR);
 
-	reiserfs_write_lock(inode->i_sb);
-
 	buf.xadir = dir;
 	err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos);
 	while ((err == 0 || err == -ENOSPC) && buf.count) {
@@ -283,14 +276,17 @@ static int reiserfs_for_each_xattr(struc
 		int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
 			     4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
 		struct reiserfs_transaction_handle th;
+		reiserfs_write_lock(inode->i_sb);
 		err = journal_begin(&th, inode->i_sb, blocks);
+		reiserfs_write_unlock(inode->i_sb);
 		if (!err) {
 			int jerror;
-			reiserfs_mutex_lock_nested_safe(
-					  &dir->d_parent->d_inode->i_mutex,
-					  I_MUTEX_XATTR, inode->i_sb);
+			mutex_lock_nested(&dir->d_parent->d_inode->i_mutex,
+					  I_MUTEX_XATTR);
 			err = action(dir, data);
+			reiserfs_write_lock(inode->i_sb);
 			jerror = journal_end(&th, inode->i_sb, blocks);
+			reiserfs_write_unlock(inode->i_sb);
 			mutex_unlock(&dir->d_parent->d_inode->i_mutex);
 			err = jerror ?: err;
 		}
@@ -457,9 +453,7 @@ static int lookup_and_delete_xattr(struc
 	}
 
 	if (dentry->d_inode) {
-		reiserfs_write_lock(inode->i_sb);
 		err = xattr_unlink(xadir->d_inode, dentry);
-		reiserfs_write_unlock(inode->i_sb);
 		update_ctime(inode);
 	}
 
@@ -493,24 +487,17 @@ reiserfs_xattr_set_handle(struct reiserf
 	if (get_inode_sd_version(inode) == STAT_DATA_V1)
 		return -EOPNOTSUPP;
 
-	reiserfs_write_unlock(inode->i_sb);
-
 	if (!buffer) {
 		err = lookup_and_delete_xattr(inode, name);
-		reiserfs_write_lock(inode->i_sb);
 		return err;
 	}
 
 	dentry = xattr_lookup(inode, name, flags);
-	if (IS_ERR(dentry)) {
-		reiserfs_write_lock(inode->i_sb);
+	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
-	}
 
 	down_write(&REISERFS_I(inode)->i_xattr_sem);
 
-	reiserfs_write_lock(inode->i_sb);
-
 	xahash = xattr_hash(buffer, buffer_size);
 	while (buffer_pos < buffer_size || buffer_pos == 0) {
 		size_t chunk;
@@ -540,6 +527,7 @@ reiserfs_xattr_set_handle(struct reiserf
 			rxh->h_hash = cpu_to_le32(xahash);
 		}
 
+		reiserfs_write_lock(inode->i_sb);
 		err = __reiserfs_write_begin(page, page_offset, chunk + skip);
 		if (!err) {
 			if (buffer)
@@ -548,6 +536,7 @@ reiserfs_xattr_set_handle(struct reiserf
 						    page_offset + chunk +
 						    skip);
 		}
+		reiserfs_write_unlock(inode->i_sb);
 		unlock_page(page);
 		reiserfs_put_page(page);
 		buffer_pos += chunk;
@@ -565,10 +554,8 @@ reiserfs_xattr_set_handle(struct reiserf
 			.ia_valid = ATTR_SIZE | ATTR_CTIME,
 		};
 
-		reiserfs_write_unlock(inode->i_sb);
 		mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR);
 		down_write(&dentry->d_inode->i_alloc_sem);
-		reiserfs_write_lock(inode->i_sb);
 
 		err = reiserfs_setattr(dentry, &newattrs);
 		up_write(&dentry->d_inode->i_alloc_sem);
@@ -595,18 +582,19 @@ int reiserfs_xattr_set(struct inode *ino
 
 	reiserfs_write_lock(inode->i_sb);
 	error = journal_begin(&th, inode->i_sb, jbegin_count);
+	reiserfs_write_unlock(inode->i_sb);
 	if (error) {
-		reiserfs_write_unlock(inode->i_sb);
 		return error;
 	}
 
 	error = reiserfs_xattr_set_handle(&th, inode, name,
 					  buffer, buffer_size, flags);
 
+	reiserfs_write_lock(inode->i_sb);
 	error2 = journal_end(&th, inode->i_sb, jbegin_count);
+	reiserfs_write_unlock(inode->i_sb);
 	if (error == 0)
 		error = error2;
-	reiserfs_write_unlock(inode->i_sb);
 
 	return error;
 }
@@ -999,7 +987,7 @@ int reiserfs_lookup_privroot(struct supe
 	int err = 0;
 
 	/* If we don't have the privroot located yet - go find it */
-	reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s);
+	mutex_lock(&s->s_root->d_inode->i_mutex);
 	dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
 				strlen(PRIVROOT_NAME));
 	if (!IS_ERR(dentry)) {
@@ -1027,14 +1015,14 @@ int reiserfs_xattr_init(struct super_blo
 		goto error;
 
 	if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) {
-		reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s);
+		mutex_lock(&s->s_root->d_inode->i_mutex);
 		err = create_privroot(REISERFS_SB(s)->priv_root);
 		mutex_unlock(&s->s_root->d_inode->i_mutex);
 	}
 
 	if (privroot->d_inode) {
 		s->s_xattr = reiserfs_xattr_handlers;
-		reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s);
+		mutex_lock(&privroot->d_inode->i_mutex);
 		if (!REISERFS_SB(s)->xattr_root) {
 			struct dentry *dentry;
 			dentry = lookup_one_len(XAROOT_NAME, privroot,
--- a/fs/reiserfs/xattr_acl.c
+++ b/fs/reiserfs/xattr_acl.c
@@ -49,13 +49,15 @@ posix_acl_set(struct dentry *dentry, con
 
 	reiserfs_write_lock(inode->i_sb);
 	error = journal_begin(&th, inode->i_sb, jcreate_blocks);
+	reiserfs_write_unlock(inode->i_sb);
 	if (error == 0) {
 		error = reiserfs_set_acl(&th, inode, type, acl);
+		reiserfs_write_lock(inode->i_sb);
 		error2 = journal_end(&th, inode->i_sb, jcreate_blocks);
+		reiserfs_write_unlock(inode->i_sb);
 		if (error2)
 			error = error2;
 	}
-	reiserfs_write_unlock(inode->i_sb);
 
       release_and_out:
 	posix_acl_release(acl);
@@ -443,6 +445,9 @@ int reiserfs_cache_default_acl(struct in
 	return nblocks;
 }
 
+/*
+ * Called under i_mutex
+ */
 int reiserfs_acl_chmod(struct inode *inode)
 {
 	struct posix_acl *acl, *clone;
@@ -459,9 +464,7 @@ int reiserfs_acl_chmod(struct inode *ino
 		return 0;
 	}
 
-	reiserfs_write_unlock(inode->i_sb);
 	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
-	reiserfs_write_lock(inode->i_sb);
 	if (!acl)
 		return 0;
 	if (IS_ERR(acl))
@@ -475,19 +478,19 @@ int reiserfs_acl_chmod(struct inode *ino
 		struct reiserfs_transaction_handle th;
 		size_t size = reiserfs_xattr_nblocks(inode,
 					     reiserfs_acl_size(clone->a_count));
-		int depth;
-
-		depth = reiserfs_write_lock_once(inode->i_sb);
+		reiserfs_write_lock(inode->i_sb);
 		error = journal_begin(&th, inode->i_sb, size * 2);
+		reiserfs_write_unlock(inode->i_sb);
 		if (!error) {
 			int error2;
 			error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS,
 						 clone);
+			reiserfs_write_lock(inode->i_sb);
 			error2 = journal_end(&th, inode->i_sb, size * 2);
+			reiserfs_write_unlock(inode->i_sb);
 			if (error2)
 				error = error2;
 		}
-		reiserfs_write_unlock_once(inode->i_sb, depth);
 	}
 	posix_acl_release(clone);
 	return error;
