linux-ext4 - [PATCHv2 1/3] ext4: Refactor ext4_overwrite_io() to take ext4_map

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Date:   Sat, 22 Aug 2020 17:04:35 +0530
From:   Ritesh Harjani <riteshh@...ux.ibm.com>
To:     linux-ext4@...r.kernel.org
Cc:     jack@...e.cz, tytso@....edu,
        Dan Williams <dan.j.williams@...el.com>,
        Anju T Sudhakar <anju@...ux.vnet.ibm.com>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ritesh Harjani <riteshh@...ux.ibm.com>
Subject: [PATCHv2 1/3] ext4: Refactor ext4_overwrite_io() to take ext4_map_blocks as argument

Refactor ext4_overwrite_io() to take struct ext4_map_blocks
as it's function argument with m_lblk and m_len filled
from caller

There should be no functionality change in this patch.

Signed-off-by: Ritesh Harjani <riteshh@...ux.ibm.com>
---
 fs/ext4/file.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2a01e31a032c..84f73ed91af2 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -188,26 +188,22 @@ ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
 }
 
 /* Is IO overwriting allocated and initialized blocks? */
-static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
+static bool ext4_overwrite_io(struct inode *inode, struct ext4_map_blocks *map)
 {
-	struct ext4_map_blocks map;
 	unsigned int blkbits = inode->i_blkbits;
-	int err, blklen;
+	loff_t end = (map->m_lblk + map->m_len) << blkbits;
+	int err, blklen = map->m_len;
 
-	if (pos + len > i_size_read(inode))
+	if (end > i_size_read(inode))
 		return false;
 
-	map.m_lblk = pos >> blkbits;
-	map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
-	blklen = map.m_len;
-
-	err = ext4_map_blocks(NULL, inode, &map, 0);
+	err = ext4_map_blocks(NULL, inode, map, 0);
 	/*
 	 * 'err==len' means that all of the blocks have been preallocated,
 	 * regardless of whether they have been initialized or not. To exclude
 	 * unwritten extents, we need to check m_flags.
 	 */
-	return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
+	return err == blklen && (map->m_flags & EXT4_MAP_MAPPED);
 }
 
 static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
@@ -407,6 +403,7 @@ static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
+	struct ext4_map_blocks map;
 	loff_t offset;
 	size_t count;
 	ssize_t ret;
@@ -420,6 +417,9 @@ static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
 	count = ret;
 	if (ext4_extending_io(inode, offset, count))
 		*extend = true;
+
+	map.m_lblk = offset >> inode->i_blkbits;
+	map.m_len = EXT4_MAX_BLOCKS(count, offset, inode->i_blkbits);
 	/*
 	 * Determine whether the IO operation will overwrite allocated
 	 * and initialized blocks.
@@ -427,7 +427,7 @@ static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
 	 * in file_modified().
 	 */
 	if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
-	     !ext4_overwrite_io(inode, offset, count))) {
+	     !ext4_overwrite_io(inode, &map))) {
 		inode_unlock_shared(inode);
 		*ilock_shared = false;
 		inode_lock(inode);
-- 
2.25.4