[patch 1/3] reiserfs: locking, push write lock out of xattr code

[jeffm@suse.com]

[-- Attachment #1: reiserfs-locking-push-write-lock-out-of-xattr-code --]
[-- Type: text/plain, Size: 17090 bytes --]

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 |   16 ++++++++++------
 4 files changed, 70 insertions(+), 77 deletions(-)

--- a/fs/reiserfs/inode.c	2013-08-05 17:50:12.326240529 -0400
+++ b/fs/reiserfs/inode.c	2013-08-05 17:50:14.042214338 -0400
@@ -30,7 +30,6 @@ 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))
@@ -40,12 +39,14 @@ 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);
@@ -72,12 +73,12 @@ 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);
 	clear_inode(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);
@@ -3129,6 +3134,7 @@ 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;
 		}
@@ -3150,8 +3156,10 @@ 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
@@ -3159,10 +3167,12 @@ 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) && (from_kuid(&init_user_ns, attr->ia_uid) & ~0xffff)) ||
 	     ((attr->ia_valid & ATTR_GID) && (from_kgid(&init_user_ns, 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;
@@ -3183,14 +3193,16 @@ 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;
 		}
 
@@ -3202,17 +3214,11 @@ 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 = inode_newsize_ok(inode, attr->ia_size);
@@ -3226,7 +3232,6 @@ 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)
@@ -3234,8 +3239,6 @@ int reiserfs_setattr(struct dentry *dent
 	}
 
       out:
-	reiserfs_write_unlock_once(inode->i_sb, depth);
-
 	return error;
 }
 
--- a/fs/reiserfs/super.c	2013-08-05 17:50:12.326240529 -0400
+++ b/fs/reiserfs/super.c	2013-08-05 17:50:14.066213971 -0400
@@ -1335,7 +1335,7 @@ 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);
@@ -1379,35 +1379,32 @@ 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);
@@ -1416,13 +1413,14 @@ 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);
@@ -1431,7 +1429,7 @@ 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);
@@ -1448,26 +1446,22 @@ 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;
 
+	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);
@@ -2014,12 +2008,14 @@ 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);
@@ -2028,12 +2024,14 @@ 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	2013-08-05 17:50:12.326240529 -0400
+++ b/fs/reiserfs/xattr.c	2013-08-05 17:50:14.078213788 -0400
@@ -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;
 	while (1) {
 		err = reiserfs_readdir_inode(dir->d_inode, &buf.ctx);
@@ -281,14 +274,17 @@ 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;
 		}
@@ -455,9 +451,7 @@ 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);
 	}
 
@@ -491,24 +485,17 @@ 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;
@@ -538,6 +525,7 @@ 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)
@@ -546,6 +534,7 @@ 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;
@@ -563,10 +552,8 @@ 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);
 		inode_dio_wait(dentry->d_inode);
-		reiserfs_write_lock(inode->i_sb);
 
 		err = reiserfs_setattr(dentry, &newattrs);
 		mutex_unlock(&dentry->d_inode->i_mutex);
@@ -592,18 +579,19 @@ 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;
 }
@@ -968,7 +956,7 @@ 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)) {
@@ -996,14 +984,14 @@ 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	2013-08-05 17:50:12.326240529 -0400
+++ b/fs/reiserfs/xattr_acl.c	2013-08-05 17:50:14.090213605 -0400
@@ -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);
@@ -435,12 +437,14 @@ int reiserfs_cache_default_acl(struct in
 	return nblocks;
 }
 
+/*
+ * Called under i_mutex
+ */
 int reiserfs_acl_chmod(struct inode *inode)
 {
 	struct reiserfs_transaction_handle th;
 	struct posix_acl *acl;
 	size_t size;
-	int depth;
 	int error;
 
 	if (IS_PRIVATE(inode))
@@ -454,9 +458,7 @@ 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))
@@ -466,16 +468,18 @@ int reiserfs_acl_chmod(struct inode *ino
 		return error;
 
 	size = reiserfs_xattr_nblocks(inode, reiserfs_acl_size(acl->a_count));
-	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, acl);
+		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(acl);
 	return error;
 }