ext4: remove messy logic from ext4_ext_rm_leaf (750c9c47) · Commits · 戴 / test

fs/ext4/extents.c

+12 −91

Original line number	Diff line number	Diff line
		@@ -2311,13 +2311,12 @@ ext4_ext_rm_leaf(handle_t handle, struct inode inode,
		int err = 0, correct_index = 0;
		int depth = ext_depth(inode), credits;
		struct ext4_extent_header *eh;
		ext4_lblk_t a, b, block;
		ext4_lblk_t a, b;
		unsigned num;
		ext4_lblk_t ex_ee_block;
		unsigned short ex_ee_len;
		unsigned uninitialized = 0;
		struct ext4_extent *ex;
		struct ext4_map_blocks map;

		/* the header must be checked already in ext4_ext_remove_space() */
		ext_debug("truncate since %u in leaf\n", start);
		@@ -2360,86 +2359,18 @@ ext4_ext_rm_leaf(handle_t handle, struct inode inode,
		ex_ee_block = le32_to_cpu(ex->ee_block);
		ex_ee_len = ext4_ext_get_actual_len(ex);
		continue;
		} else if (a != ex_ee_block &&
		b != ex_ee_block + ex_ee_len - 1) {
		/*
		* If this is a truncate, then this condition should
		* never happen because at least one of the end points
		* needs to be on the edge of the extent.
		*/
		if (end == EXT_MAX_BLOCKS - 1) {
		ext_debug(" bad truncate %u:%u\n",
		} else if (b != ex_ee_block + ex_ee_len - 1) {
		EXT4_ERROR_INODE(inode," bad truncate %u:%u\n",
		start, end);
		block = 0;
		num = 0;
		err = -EIO;
		goto out;
		}
		/*
		* else this is a hole punch, so the extent needs to
		* be split since neither edge of the hole is on the
		* extent edge
		*/
		else{
		map.m_pblk = ext4_ext_pblock(ex);
		map.m_lblk = ex_ee_block;
		map.m_len = b - ex_ee_block;

		err = ext4_split_extent(handle,
		inode, path, &map, 0,
		EXT4_GET_BLOCKS_PUNCH_OUT_EXT \|
		EXT4_GET_BLOCKS_PRE_IO);

		if (err < 0)
		goto out;

		ex_ee_len = ext4_ext_get_actual_len(ex);

		b = ex_ee_block+ex_ee_len - 1 < end ?
		ex_ee_block+ex_ee_len - 1 : end;

		/* Then remove tail of this extent */
		block = ex_ee_block;
		num = a - block;
		}
		} else if (a != ex_ee_block) {
		/* remove tail of the extent */
		block = ex_ee_block;
		num = a - block;
		} else if (b != ex_ee_block + ex_ee_len - 1) {
		/* remove head of the extent */
		block = b;
		num = ex_ee_block + ex_ee_len - b;

		/*
		* If this is a truncate, this condition
		* should never happen
		*/
		if (end == EXT_MAX_BLOCKS - 1) {
		ext_debug(" bad truncate %u:%u\n",
		start, end);
		err = -EIO;
		goto out;
		}
		num = a - ex_ee_block;
		} else {
		/* remove whole extent: excellent! */
		block = ex_ee_block;
		num = 0;
		if (a != ex_ee_block) {
		ext_debug(" bad truncate %u:%u\n",
		start, end);
		err = -EIO;
		goto out;
		}

		if (b != ex_ee_block + ex_ee_len - 1) {
		ext_debug(" bad truncate %u:%u\n",
		start, end);
		err = -EIO;
		goto out;
		}
		}

		/*
		* 3 for leaf, sb, and inode plus 2 (bmap and group
		* descriptor) for each block group; assume two block
		@@ -2466,19 +2397,10 @@ ext4_ext_rm_leaf(handle_t handle, struct inode inode,
		if (err)
		goto out;

		if (num == 0) {
		if (num == 0)
		/* this extent is removed; mark slot entirely unused */
		ext4_ext_store_pblock(ex, 0);
		} else if (block != ex_ee_block) {
		/*
		* If this was a head removal, then we need to update
		* the physical block since it is now at a different
		* location
		*/
		ext4_ext_store_pblock(ex, ext4_ext_pblock(ex) + (b-a));
		}

		ex->ee_block = cpu_to_le32(block);
		ex->ee_len = cpu_to_le16(num);
		/*
		* Do not mark uninitialized if all the blocks in the
		@@ -2486,11 +2408,6 @@ ext4_ext_rm_leaf(handle_t handle, struct inode inode,
		*/
		if (uninitialized && num)
		ext4_ext_mark_uninitialized(ex);

		err = ext4_ext_dirty(handle, inode, path + depth);
		if (err)
		goto out;

		/*
		* If the extent was completely released,
		* we need to remove it from the leaf
		@@ -2513,6 +2430,10 @@ ext4_ext_rm_leaf(handle_t handle, struct inode inode,
		} else
		*partial_cluster = 0;

		err = ext4_ext_dirty(handle, inode, path + depth);
		if (err)
		goto out;

		ext_debug("new extent: %u:%u:%llu\n", block, num,
		ext4_ext_pblock(ex));
		ex--;

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