[PATCH] [6/13] quota-6-bytes

This patch implements counting of used space in inodes in bytes.
New field i_bytes is added and used space modulo 512 is kept in
it (rest is still kept in i_blocks). Functions manipulating both
i_blocks and i_bytes are implemented (inode_add_bytes(), inode_sub_bytes()
and inode_set_bytes()). Filesystems allocating only in whole blocks
can safely ignore i_bytes field and continue using i_blocks...

fs/dquot.c

@@ -972,7 +972,7 @@ int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
 			continue;
 		dquot_incr_space(dquot[cnt], number);
 	}
-	inode->i_blocks += number >> 9;
+	inode_add_bytes(inode, number);
 	/* NOBLOCK End */
 	ret = QUOTA_OK;
 warn_put_all:
@@ -1040,7 +1040,7 @@ void dquot_free_space(struct inode *inode, qsize_t number)
 		dquot_decr_space(dquot, number);
 		dqputduplicate(dquot);
 	}
-	inode->i_blocks -= number >> 9;
+	inode_sub_bytes(inode, number);
 	unlock_kernel();
 	/* NOBLOCK End */
 }
@@ -1103,7 +1103,7 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
 		}
 	}
 	/* NOBLOCK START: From now on we shouldn't block */
-	space = ((qsize_t)inode->i_blocks) << 9;
+	space = inode_get_bytes(inode);
 	/* Build the transfer_from list and check the limits */
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 		/* The second test can fail when quotaoff is in progress... */
@@ -1162,9 +1162,9 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
 struct dquot_operations dquot_operations = {
 	initialize:	dquot_initialize,		/* mandatory */
 	drop:		dquot_drop,			/* mandatory */
-	alloc_block:	dquot_alloc_space,
+	alloc_space:	dquot_alloc_space,
 	alloc_inode:	dquot_alloc_inode,
-	free_block:	dquot_free_space,
+	free_space:	dquot_free_space,
 	free_inode:	dquot_free_inode,
 	transfer:	dquot_transfer
 };

fs/inode.c

@@ -95,6 +95,7 @@ static struct inode *alloc_inode(struct super_block *sb)
 		atomic_set(&inode->i_writecount, 0);
 		inode->i_size = 0;
 		inode->i_blocks = 0;
+		inode->i_bytes = 0;
 		inode->i_generation = 0;
 		memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
 		inode->i_pipe = NULL;

include/linux/fs.h

@@ -370,6 +370,7 @@ struct inode {
 	unsigned long		i_blksize;
 	unsigned long		i_blocks;
 	unsigned long		i_version;
+	unsigned short          i_bytes;
 	struct semaphore	i_sem;
 	struct inode_operations	*i_op;
 	struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */
@@ -427,6 +428,39 @@ struct fown_struct {
 	int signum;		/* posix.1b rt signal to be delivered on IO */
 };
 
+static inline void inode_add_bytes(struct inode *inode, loff_t bytes)
+{
+	inode->i_blocks += bytes >> 9;
+	bytes &= 511;
+	inode->i_bytes += bytes;
+	if (inode->i_bytes >= 512) {
+		inode->i_blocks++;
+		inode->i_bytes -= 512;
+	}
+}
+
+static inline void inode_sub_bytes(struct inode *inode, loff_t bytes)
+{
+	inode->i_blocks -= bytes >> 9;
+	bytes &= 511;
+	if (inode->i_bytes < bytes) {
+		inode->i_blocks--;
+		inode->i_bytes += 512;
+	}
+	inode->i_bytes -= bytes;
+}
+
+static inline loff_t inode_get_bytes(struct inode *inode)
+{
+	return (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
+}
+
+static inline void inode_set_bytes(struct inode *inode, loff_t bytes)
+{
+	inode->i_blocks = bytes >> 9;
+	inode->i_bytes = bytes & 511;
+}
+
 /*
  * Track a single file's readahead state
  */

include/linux/quotaops.h

@@ -70,7 +70,7 @@ static __inline__ int DQUOT_PREALLOC_SPACE_NODIRTY(struct inode *inode, qsize_t
 		}
 	}
 	else
-		inode->i_blocks += nr >> 9;
+		inode_add_bytes(inode, nr);
 	unlock_kernel();
 	return 0;
 }
@@ -94,7 +94,7 @@ static __inline__ int DQUOT_ALLOC_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 		}
 	}
 	else
-		inode->i_blocks += nr >> 9;
+		inode_add_bytes(inode, nr);
 	unlock_kernel();
 	return 0;
 }
@@ -127,7 +127,7 @@ static __inline__ void DQUOT_FREE_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 	if (sb_any_quota_enabled(inode->i_sb))
 		inode->i_sb->dq_op->free_space(inode, nr);
 	else
-		inode->i_blocks -= nr >> 9;
+		inode_sub_bytes(inode, nr);
 	unlock_kernel();
 }
 
@@ -177,7 +177,7 @@ static __inline__ int DQUOT_TRANSFER(struct inode *inode, struct iattr *iattr)
 extern __inline__ int DQUOT_PREALLOC_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 {
 	lock_kernel();
-	inode->i_blocks += nr >> 9;
+	inode_add_bytes(inode, nr);
 	unlock_kernel();
 	return 0;
 }
@@ -192,7 +192,7 @@ extern __inline__ int DQUOT_PREALLOC_SPACE(struct inode *inode, qsize_t nr)
 extern __inline__ int DQUOT_ALLOC_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 {
 	lock_kernel();
-	inode->i_blocks += nr >> 9;
+	inode_add_bytes(inode, nr);
 	unlock_kernel();
 	return 0;
 }
@@ -207,7 +207,7 @@ extern __inline__ int DQUOT_ALLOC_SPACE(struct inode *inode, qsize_t nr)
 extern __inline__ void DQUOT_FREE_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 {
 	lock_kernel();
-	inode->i_blocks -= nr >> 9;
+	inode_sub_bytes(inode, nr);
 	unlock_kernel();
 }
 
@@ -222,8 +222,8 @@ extern __inline__ void DQUOT_FREE_SPACE(struct inode *inode, qsize_t nr)
 #define DQUOT_PREALLOC_BLOCK_NODIRTY(inode, nr)	DQUOT_PREALLOC_SPACE_NODIRTY(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
 #define DQUOT_PREALLOC_BLOCK(inode, nr)	DQUOT_PREALLOC_SPACE(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
 #define DQUOT_ALLOC_BLOCK_NODIRTY(inode, nr) DQUOT_ALLOC_SPACE_NODIRTY(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
-#define DQUOT_ALLOC_BLOCK(inode, nr) DQUOT_ALLOC_SPACE(inode, fs_to_dq_blocks(nr, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
+#define DQUOT_ALLOC_BLOCK(inode, nr) DQUOT_ALLOC_SPACE(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
 #define DQUOT_FREE_BLOCK_NODIRTY(inode, nr) DQUOT_FREE_SPACE_NODIRTY(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
-#define DQUOT_FREE_BLOCK(inode, nr) DQUOT_FREE_SPACE(inode, fs_to_dq_blocks(nr, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
+#define DQUOT_FREE_BLOCK(inode, nr) DQUOT_FREE_SPACE(inode, ((qsize_t)(nr)) << (inode)->i_sb->s_blocksize_bits)
 
 #endif /* _LINUX_QUOTAOPS_ */