dquot: cleanup space allocation / freeing routines

Get rid of the alloc_space, free_space, reserve_space, claim_space and
release_rsv dquot operations - they are always called from the filesystem
and if a filesystem really needs their own (which none currently does)
it can just call into it's own routine directly.

Move shared logic into the common __dquot_alloc_space,
dquot_claim_space_nodirty and __dquot_free_space low-level methods,
and rationalize the wrappers around it to move as much as possible
code into the common block for CONFIG_QUOTA vs not.  Also rename
all these helpers to be named dquot_* instead of vfs_dq_*.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/jfs/xattr.c

@@ -260,14 +260,14 @@ static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
 	nblocks = (size + (sb->s_blocksize - 1)) >> sb->s_blocksize_bits;
 
 	/* Allocate new blocks to quota. */
-	if (vfs_dq_alloc_block(ip, nblocks)) {
-		return -EDQUOT;
-	}
+	rc = dquot_alloc_block(ip, nblocks);
+	if (rc)
+		return rc;
 
 	rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
 	if (rc) {
 		/*Rollback quota allocation. */
-		vfs_dq_free_block(ip, nblocks);
+		dquot_free_block(ip, nblocks);
 		return rc;
 	}
 
@@ -332,7 +332,7 @@ static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
 
       failed:
 	/* Rollback quota allocation. */
-	vfs_dq_free_block(ip, nblocks);
+	dquot_free_block(ip, nblocks);
 
 	dbFree(ip, blkno, nblocks);
 	return rc;
@@ -538,7 +538,8 @@ static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
 
 	if (blocks_needed > current_blocks) {
 		/* Allocate new blocks to quota. */
-		if (vfs_dq_alloc_block(inode, blocks_needed))
+		rc = dquot_alloc_block(inode, blocks_needed);
+		if (rc)
 			return -EDQUOT;
 
 		quota_allocation = blocks_needed;
@@ -602,7 +603,7 @@ static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
       clean_up:
 	/* Rollback quota allocation */
 	if (quota_allocation)
-		vfs_dq_free_block(inode, quota_allocation);
+		dquot_free_block(inode, quota_allocation);
 
 	return (rc);
 }
@@ -677,7 +678,7 @@ static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
 
 	/* If old blocks exist, they must be removed from quota allocation. */
 	if (old_blocks)
-		vfs_dq_free_block(inode, old_blocks);
+		dquot_free_block(inode, old_blocks);
 
 	inode->i_ctime = CURRENT_TIME;