Patchwork [5/7,v2] ext4: track all extent status in extent status tree

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Submitter Zheng Liu
Date Jan. 11, 2013, 10:53 a.m.
Message ID <1357901627-3068-6-git-send-email-wenqing.lz@taobao.com>
Download mbox | patch
Permalink /patch/211299/
State Superseded
Headers show

Comments

Zheng Liu - Jan. 11, 2013, 10:53 a.m.
From: Zheng Liu <wenqing.lz@taobao.com>

After record phycisal block and status, extent status tree is able to track the
status of every extents.  When we call _map_blocks functions to lookup an extent
or create a new written/unwritten/delayed extent, this extent will be inserted
into extent status tree.

We don't load all extents from disk in alloc_inode() because it costs too much
memory, and, when open/close a file very frequently, it will takes too much time
to load all extent information.  So currently when we create/lookup an extent,
this extent will be inserted into extent status tree.  Hence, the status in
extent status tree might be not completely.

CC: Jan kara <jack@suse.cz>
CC: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
---
 fs/ext4/extents.c |  5 +++-
 fs/ext4/file.c    |  6 +++--
 fs/ext4/inode.c   | 73 ++++++++++++++++++++++++++++++++++++-------------------
 3 files changed, 56 insertions(+), 28 deletions(-)
Theodore Ts'o - Jan. 23, 2013, 4:31 a.m.
On Fri, Jan 11, 2013 at 06:53:45PM +0800, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@taobao.com>
> 

Please line-wrap the commit description to 72 columns.  (This way the
output of "git log" will look nice even on 80 column terminal windows)".

> After record phycisal block and status, extent status tree is able to track the

"By recording the physical block and status, ...."

> status of every extents.  When we call _map_blocks functions to lookup an extent
> or create a new written/unwritten/delayed extent, this extent will be inserted
> into extent status tree.
> 
> We don't load all extents from disk in alloc_inode() because it costs too much
> memory, and, when open/close a file very frequently, it will takes too much time

"...and if a file is opened and closed frequently"..."

> to load all extent information.  So currently when we create/lookup an extent,
> this extent will be inserted into extent status tree.  Hence, the status in
> extent status tree might be not completely.

"Hence, the extent status tree may not comprehensively contain all of
the extents found in the file."

						- Ted
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Patch

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index aa9a6d2..d23a654 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2074,7 +2074,7 @@  static int ext4_fill_fiemap_extents(struct inode *inode,
 		}
 
 		/* This is possible iff next == next_del == EXT_MAX_BLOCKS */
-		if (next == next_del) {
+		if (next == next_del && next_del == EXT_MAX_BLOCKS) {
 			flags |= FIEMAP_EXTENT_LAST;
 			if (unlikely(next_del != EXT_MAX_BLOCKS ||
 				     next != EXT_MAX_BLOCKS)) {
@@ -4570,6 +4570,9 @@  static int ext4_find_delayed_extent(struct inode *inode,
 			/* A hole found. */
 			return 0;
 
+		if (!ext4_es_is_delayed(&es))
+			return 0;
+
 		if (es.es_lblk > newex->ec_block) {
 			/* A hole found. */
 			newex->ec_len = min(es.es_lblk - newex->ec_block,
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 718c49f..afaf9f15 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -466,7 +466,8 @@  static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
 		 */
 		es.es_lblk = last;
 		(void)ext4_es_find_extent(inode, &es);
-		if (last >= es.es_lblk && last < es.es_lblk + es.es_len) {
+		if (ext4_es_is_delayed(&es) &&
+		    last >= es.es_lblk && last < es.es_lblk + es.es_len) {
 			if (last != start)
 				dataoff = last << blkbits;
 			break;
@@ -550,7 +551,8 @@  static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
 		 */
 		es.es_lblk = last;
 		(void)ext4_es_find_extent(inode, &es);
-		if (last >= es.es_lblk && last < es.es_lblk + es.es_len) {
+		if (ext4_es_is_delayed(&es) &&
+		    last >= es.es_lblk && last < es.es_lblk + es.es_len) {
 			last = es.es_lblk + es.es_len;
 			holeoff = last << blkbits;
 			continue;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e09c7cf..f0dda2a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -527,20 +527,20 @@  int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		retval = ext4_ind_map_blocks(handle, inode, map, flags &
 					     EXT4_GET_BLOCKS_KEEP_SIZE);
 	}
+	if (retval > 0) {
+		int ret, status;
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		ret = ext4_es_insert_extent(inode, map->m_lblk,
+					    map->m_len, map->m_pblk, status);
+		if (ret < 0)
+			retval = ret;
+	}
 	if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
 		up_read((&EXT4_I(inode)->i_data_sem));
 
 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
-		int ret;
-		if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
-			/* delayed alloc may be allocated by fallocate and
-			 * coverted to initialized by directIO.
-			 * we need to handle delayed extent here.
-			 */
-			down_write((&EXT4_I(inode)->i_data_sem));
-			goto delayed_mapped;
-		}
-		ret = check_block_validity(inode, map);
+		int ret = check_block_validity(inode, map);
 		if (ret != 0)
 			return ret;
 	}
@@ -615,18 +615,27 @@  int ext4_map_blocks(handle_t *handle, struct inode *inode,
 			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 			ext4_da_update_reserve_space(inode, retval, 1);
 	}
-	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
+	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
 		ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
 
-		if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
-			int ret;
-delayed_mapped:
-			/* delayed allocation blocks has been allocated */
-			ret = ext4_es_remove_extent(inode, map->m_lblk,
-						    map->m_len);
-			if (ret < 0)
-				retval = ret;
-		}
+	if (retval > 0) {
+		int ret, status;
+
+		if (flags & EXT4_GET_BLOCKS_PRE_IO)
+			status = EXTENT_STATUS_UNWRITTEN;
+		else if (flags & EXT4_GET_BLOCKS_CONVERT)
+			status = EXTENT_STATUS_WRITTEN;
+		else if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
+			status = EXTENT_STATUS_UNWRITTEN;
+		else if (flags & EXT4_GET_BLOCKS_CREATE)
+			status = EXTENT_STATUS_WRITTEN;
+		else
+			BUG_ON(1);
+
+		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+					    map->m_pblk, status);
+		if (ret < 0)
+			retval = ret;
 	}
 
 	up_write((&EXT4_I(inode)->i_data_sem));
@@ -1805,6 +1814,7 @@  static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
 		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
 
 	if (retval == 0) {
+		int ret;
 		/*
 		 * XXX: __block_prepare_write() unmaps passed block,
 		 * is it OK?
@@ -1813,20 +1823,33 @@  static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
 		 * then we dont need to reserve it again. */
 		if ((EXT4_SB(inode->i_sb)->s_cluster_ratio == 1) ||
 		    !ext4_find_delalloc_cluster(inode, map->m_lblk)) {
-			retval = ext4_da_reserve_space(inode, iblock);
-			if (retval)
+			ret = ext4_da_reserve_space(inode, iblock);
+			if (ret) {
 				/* not enough space to reserve */
+				retval = ret;
 				goto out_unlock;
+			}
 		}
 
-		retval = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
-					       ~0, EXTENT_STATUS_DELAYED);
-		if (retval)
+		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+					    ~0, EXTENT_STATUS_DELAYED);
+		if (ret) {
+			retval = ret;
 			goto out_unlock;
+		}
 
 		map_bh(bh, inode->i_sb, invalid_block);
 		set_buffer_new(bh);
 		set_buffer_delay(bh);
+	} else if (retval > 0) {
+		int ret, status;
+
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+					    map->m_pblk, status);
+		if (ret != 0)
+			retval = ret;
 	}
 
 out_unlock: