linux-ext4 - [PATCH 10/31] libext2fs: Allow callers to punch a single block

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Message-ID: <20131001012746.28415.15964.stgit@birch.djwong.org>
Date:	Mon, 30 Sep 2013 18:27:46 -0700
From:	"Darrick J. Wong" <darrick.wong@...cle.com>
To:	tytso@....edu, darrick.wong@...cle.com
Cc:	linux-ext4@...r.kernel.org
Subject: [PATCH 10/31] libext2fs: Allow callers to punch a single block

The range of blocks to punch is treated as an inclusive range on both ends,
i.e. if start=1 and end=2, both blocks 1 and 2 are punched out.  Thus, start ==
end means that the caller wishes to punch a single block.  Remove the check
that prevents us from punching a single block.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
 lib/ext2fs/ext2fs.h |    4 ++++
 lib/ext2fs/punch.c  |    5 +----
 2 files changed, 5 insertions(+), 4 deletions(-)


diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 311ceda..c37e00b 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1385,6 +1385,10 @@ extern errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
 					  char *mtpt, int mtlen);
 
 /* punch.c */
+/*
+ * NOTE: This function removes from an inode the blocks "start", "end", and
+ * every block in between.
+ */
 extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
 			      struct ext2_inode *inode,
 			      char *block_buf, blk64_t start,
diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c
index 11c7668..aac1942 100644
--- a/lib/ext2fs/punch.c
+++ b/lib/ext2fs/punch.c
@@ -315,9 +315,6 @@ extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
 	if (start > end)
 		return EINVAL;
 
-	if (start == end)
-		return 0;
-
 	/* Read inode structure if necessary */
 	if (!inode) {
 		retval = ext2fs_read_inode(fs, ino, &inode_buf);
@@ -332,7 +329,7 @@ extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
 
 		if (start > ~0U)
 			return 0;
-		count = ((end - start) < ~0U) ? (end - start) : ~0U;
+		count = ((end - start + 1) < ~0U) ? (end - start + 1) : ~0U;
 		retval = ext2fs_punch_ind(fs, inode, block_buf, 
 					  (blk_t) start, count);
 	}

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