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Message-Id: <1373517542-21234-1-git-send-email-tytso@mit.edu>
Date: Thu, 11 Jul 2013 00:39:00 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Zheng Liu <gnehzuil.liu@...il.com>, Theodore Ts'o <tytso@....edu>
Subject: [RFC PATCH 1/3] ext4: refactor code to read the extent tree block
Refactor out the code needed to read the extent tree block into a
single read_extent_tree_block() function. In addition to simplifying
the code, it also makes sure that we call the ext4_ext_load_extent
tracepoint whenever we need to read an extent tree block from disk.
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/extents.c | 100 ++++++++++++++++++++++++------------------------------
1 file changed, 45 insertions(+), 55 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7097b0f..e174814 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -464,25 +464,41 @@ int ext4_ext_check_inode(struct inode *inode)
return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
}
-static int __ext4_ext_check_block(const char *function, unsigned int line,
- struct inode *inode,
- struct ext4_extent_header *eh,
- int depth,
- struct buffer_head *bh)
+static struct buffer_head *
+__read_extent_tree_block(const char *function, unsigned int line,
+ struct inode *inode, ext4_fsblk_t pblk, int depth)
{
- int ret;
+ struct buffer_head *bh;
+ int err;
+
+ BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
+
+ bh = sb_getblk(inode->i_sb, pblk);
+ if (unlikely(!bh))
+ return ERR_PTR(-ENOMEM);
+ if (!bh_uptodate_or_lock(bh)) {
+ trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
+ err = bh_submit_read(bh);
+ if (err < 0)
+ goto errout;
+ }
if (buffer_verified(bh))
- return 0;
- ret = ext4_ext_check(inode, eh, depth);
- if (ret)
- return ret;
+ return bh;
+ err = __ext4_ext_check(function, line, inode,
+ ext_block_hdr(bh), depth);
+ if (err)
+ goto errout;
set_buffer_verified(bh);
- return ret;
+ return bh;
+errout:
+ put_bh(bh);
+ return ERR_PTR(err);
+
}
-#define ext4_ext_check_block(inode, eh, depth, bh) \
- __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh)
+#define read_extent_tree_block(inode, pblk, depth) \
+ __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), (depth))
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
@@ -748,20 +764,12 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;
- bh = sb_getblk(inode->i_sb, path[ppos].p_block);
- if (unlikely(!bh)) {
- ret = -ENOMEM;
+ bh = read_extent_tree_block(inode, path[ppos].p_block, --i);
+ if (IS_ERR(bh)) {
+ ret = PTR_ERR(bh);
goto err;
}
- if (!bh_uptodate_or_lock(bh)) {
- trace_ext4_ext_load_extent(inode, block,
- path[ppos].p_block);
- ret = bh_submit_read(bh);
- if (ret < 0) {
- put_bh(bh);
- goto err;
- }
- }
+
eh = ext_block_hdr(bh);
ppos++;
if (unlikely(ppos > depth)) {
@@ -773,11 +781,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
}
path[ppos].p_bh = bh;
path[ppos].p_hdr = eh;
- i--;
-
- ret = ext4_ext_check_block(inode, eh, i, bh);
- if (ret < 0)
- goto err;
}
path[ppos].p_depth = i;
@@ -1412,29 +1415,21 @@ got_index:
ix++;
block = ext4_idx_pblock(ix);
while (++depth < path->p_depth) {
- bh = sb_bread(inode->i_sb, block);
- if (bh == NULL)
- return -EIO;
- eh = ext_block_hdr(bh);
/* subtract from p_depth to get proper eh_depth */
- if (ext4_ext_check_block(inode, eh,
- path->p_depth - depth, bh)) {
- put_bh(bh);
- return -EIO;
- }
+ bh = read_extent_tree_block(inode, *logical,
+ path->p_depth - depth);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
+ eh = ext_block_hdr(bh);
ix = EXT_FIRST_INDEX(eh);
block = ext4_idx_pblock(ix);
put_bh(bh);
}
- bh = sb_bread(inode->i_sb, block);
- if (bh == NULL)
- return -EIO;
+ bh = read_extent_tree_block(inode, *logical, path->p_depth - depth);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
eh = ext_block_hdr(bh);
- if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) {
- put_bh(bh);
- return -EIO;
- }
ex = EXT_FIRST_EXTENT(eh);
found_extent:
*logical = le32_to_cpu(ex->ee_block);
@@ -2829,21 +2824,16 @@ again:
ext_debug("move to level %d (block %llu)\n",
i + 1, ext4_idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
- bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
- if (!bh) {
- /* should we reset i_size? */
- err = -EIO;
+ bh = read_extent_tree_block(inode,
+ ext4_idx_pblock(path[i].p_idx), depth - i - 1);
+ if (IS_ERR(bh)) {
+ err = PTR_ERR(bh);
break;
}
if (WARN_ON(i + 1 > depth)) {
err = -EIO;
break;
}
- if (ext4_ext_check_block(inode, ext_block_hdr(bh),
- depth - i - 1, bh)) {
- err = -EIO;
- break;
- }
path[i + 1].p_bh = bh;
/* save actual number of indexes since this
--
1.7.12.rc0.22.gcdd159b
--
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