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Date:	Fri, 23 Apr 2010 10:44:21 -0400
From:	Josef Bacik <josef@...hat.com>
To:	torvalds@...ux-foundation.org
Cc:	akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, randy.dunlap@...cle.com
Subject: [PATCH] cleanup block based fiemap

Hello,

I'm resending this patch again since it doesn't seem to have made it in yet.
The generic block fiemap stuff doesn't use the right typing and has a problem
with not setting the last extent flag properly.  Also there is an issue with
GFS2 where it doesn't like non-block aligned requests, so this fixes all these
issues.  Thanks,

Signed-off-by: Josef Bacik <josef@...hat.com>
---
 fs/ioctl.c         |   85 +++++++++++++++++++++++++++++----------------------
 include/linux/fs.h |    5 ++-
 2 files changed, 51 insertions(+), 39 deletions(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 6c75110..f330fec 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -228,14 +228,23 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
 
 #ifdef CONFIG_BLOCK
 
-#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
-#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);
+static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
+{
+	return (offset >> inode->i_blkbits);
+}
+
+static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
+{
+	return (blk << inode->i_blkbits);
+}
 
 /**
  * __generic_block_fiemap - FIEMAP for block based inodes (no locking)
- * @inode - the inode to map
- * @arg - the pointer to userspace where we copy everything to
- * @get_block - the fs's get_block function
+ * @inode: the inode to map
+ * @fieinfo: the fiemap info struct that will be passed back to userspace
+ * @start: where to start mapping in the inode
+ * @len: how much space to map
+ * @get_block: the fs's get_block function
  *
  * This does FIEMAP for block based inodes.  Basically it will just loop
  * through get_block until we hit the number of extents we want to map, or we
@@ -250,46 +259,46 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
  */
 
 int __generic_block_fiemap(struct inode *inode,
-			   struct fiemap_extent_info *fieinfo, u64 start,
-			   u64 len, get_block_t *get_block)
+			   struct fiemap_extent_info *fieinfo, loff_t start,
+			   loff_t len, get_block_t *get_block)
 {
-	struct buffer_head tmp;
-	unsigned long long start_blk;
-	long long length = 0, map_len = 0;
+	struct buffer_head map_bh;
+	sector_t start_blk, last_blk;
 	u64 logical = 0, phys = 0, size = 0;
 	u32 flags = FIEMAP_EXTENT_MERGED;
-	int ret = 0, past_eof = 0, whole_file = 0;
+	bool past_eof = false, whole_file = false;
+	int ret = 0;
 
-	if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
+	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
+	if (ret)
 		return ret;
 
-	start_blk = logical_to_blk(inode, start);
-
-	length = (long long)min_t(u64, len, i_size_read(inode));
-	if (length < len)
-		whole_file = 1;
+	if (len >= i_size_read(inode)) {
+		whole_file = true;
+		len = i_size_read(inode);
+	}
 
-	map_len = length;
+	start_blk = logical_to_blk(inode, start);
+	last_blk = logical_to_blk(inode, start + len - 1);
 
 	do {
 		/*
 		 * we set b_size to the total size we want so it will map as
 		 * many contiguous blocks as possible at once
 		 */
-		memset(&tmp, 0, sizeof(struct buffer_head));
-		tmp.b_size = map_len;
+		memset(&map_bh, 0, sizeof(struct buffer_head));
+		map_bh.b_size = len;
 
-		ret = get_block(inode, start_blk, &tmp, 0);
+		ret = get_block(inode, start_blk, &map_bh, 0);
 		if (ret)
 			break;
 
 		/* HOLE */
-		if (!buffer_mapped(&tmp)) {
-			length -= blk_to_logical(inode, 1);
+		if (!buffer_mapped(&map_bh)) {
 			start_blk++;
 
 			/*
-			 * we want to handle the case where there is an
+			 * We want to handle the case where there is an
 			 * allocated block at the front of the file, and then
 			 * nothing but holes up to the end of the file properly,
 			 * to make sure that extent at the front gets properly
@@ -297,11 +306,11 @@ int __generic_block_fiemap(struct inode *inode,
 			 */
 			if (!past_eof &&
 			    blk_to_logical(inode, start_blk) >=
-			    blk_to_logical(inode, 0)+i_size_read(inode))
+			    blk_to_logical(inode, 0) + i_size_read(inode))
 				past_eof = 1;
 
 			/*
-			 * first hole after going past the EOF, this is our
+			 * First hole after going past the EOF, this is our
 			 * last extent
 			 */
 			if (past_eof && size) {
@@ -309,15 +318,18 @@ int __generic_block_fiemap(struct inode *inode,
 				ret = fiemap_fill_next_extent(fieinfo, logical,
 							      phys, size,
 							      flags);
-				break;
+			} else if (size) {
+				ret = fiemap_fill_next_extent(fieinfo, logical,
+							      phys, size, flags);
+				size = 0;
 			}
 
 			/* if we have holes up to/past EOF then we're done */
-			if (length <= 0 || past_eof)
+			if (start_blk > last_blk || past_eof || ret)
 				break;
 		} else {
 			/*
-			 * we have gone over the length of what we wanted to
+			 * We have gone over the length of what we wanted to
 			 * map, and it wasn't the entire file, so add the extent
 			 * we got last time and exit.
 			 *
@@ -331,7 +343,7 @@ int __generic_block_fiemap(struct inode *inode,
 			 * are good to go, just add the extent to the fieinfo
 			 * and break
 			 */
-			if (length <= 0 && !whole_file) {
+			if (start_blk > last_blk && !whole_file) {
 				ret = fiemap_fill_next_extent(fieinfo, logical,
 							      phys, size,
 							      flags);
@@ -351,11 +363,10 @@ int __generic_block_fiemap(struct inode *inode,
 			}
 
 			logical = blk_to_logical(inode, start_blk);
-			phys = blk_to_logical(inode, tmp.b_blocknr);
-			size = tmp.b_size;
+			phys = blk_to_logical(inode, map_bh.b_blocknr);
+			size = map_bh.b_size;
 			flags = FIEMAP_EXTENT_MERGED;
 
-			length -= tmp.b_size;
 			start_blk += logical_to_blk(inode, size);
 
 			/*
@@ -364,14 +375,14 @@ int __generic_block_fiemap(struct inode *inode,
 			 * is marked with FIEMAP_EXTENT_LAST
 			 */
 			if (!past_eof &&
-			    logical+size >=
-			    blk_to_logical(inode, 0)+i_size_read(inode))
-				past_eof = 1;
+			    logical + size >=
+			    blk_to_logical(inode, 0) + i_size_read(inode))
+				past_eof = true;
 		}
 		cond_resched();
 	} while (1);
 
-	/* if ret is 1 then we just hit the end of the extent array */
+	/* If ret is 1 then we just hit the end of the extent array */
 	if (ret == 1)
 		ret = 0;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ebb1cd5..7e6e47f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2313,8 +2313,9 @@ extern int vfs_fstatat(int , char __user *, struct kstat *, int);
 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		    unsigned long arg);
 extern int __generic_block_fiemap(struct inode *inode,
-				  struct fiemap_extent_info *fieinfo, u64 start,
-				  u64 len, get_block_t *get_block);
+				  struct fiemap_extent_info *fieinfo,
+				  loff_t start, loff_t len,
+				  get_block_t *get_block);
 extern int generic_block_fiemap(struct inode *inode,
 				struct fiemap_extent_info *fieinfo, u64 start,
 				u64 len, get_block_t *get_block);
-- 
1.6.5.rc2

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