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Date: Fri, 18 Mar 2011 20:03:44 -0700
From: Allison Henderson <achender@...ux.vnet.ibm.com>
To: linux-ext4@...r.kernel.org
Subject: [Ext4 punch hole 1/4 v4] Ext4 Punch Hole Support: Convert Blocks
to Uninit Exts
This patch adds a function to convert a range of blocks
to an uninitialized extent. This function will
be used to first convert the blocks to extents before
punching them out.
This function also adds a routine to split an extent at
a given block. This routine is used when a range of
blocks to be converted is only partially contained in
an extent.
Signed-off-by: Allison Henderson <achender@...ibm.com>
---
:100644 100644 9375e7c... b78b41f... M fs/ext4/extents.c
fs/ext4/extents.c | 209 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 209 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9375e7c..b78b41f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2169,6 +2169,109 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
return 0;
}
+/*
+ * ext4_split_extents() Splits a given extent at the block "split"
+ * @handle: The journal handle
+ * @inode: The file inode
+ * @split: The block where the extent will be split
+ * @path: The path to the extent
+ * @flags: flags used to insert the new extent
+ */
+static int ext4_split_extents(handle_t *handle,
+ struct inode *inode,
+ ext4_lblk_t split,
+ struct ext4_ext_path *path,
+ int flags)
+{
+ struct ext4_extent *ex, newex, orig_ex;
+ struct ext4_extent *ex1 = NULL;
+ struct ext4_extent *ex2 = NULL;
+ struct ext4_extent_header *eh;
+ ext4_lblk_t ee_block;
+ unsigned int ee_len, depth;
+ ext4_fsblk_t newblock, origblock;
+ int err = 0;
+
+ ext_debug("ext4_split_extent: inode %lu, split %u\n",
+ inode->i_ino, split);
+ ext4_ext_show_leaf(inode, path);
+
+ depth = ext_depth(inode);
+ eh = path[depth].p_hdr;
+ ex = path[depth].p_ext;
+ ee_block = le32_to_cpu(ex->ee_block);
+ ee_len = ext4_ext_get_actual_len(ex);
+
+ /* if the block is not actually in the extent, go to out */
+ if (split > ee_block+ee_len || split < ee_block)
+ goto out;
+
+ origblock = ee_block + ext4_ext_pblock(ex);
+ newblock = split - ee_block + ext4_ext_pblock(ex);
+ ext_debug("The new block is %llu, the orig block is: %llu\n",
+ newblock, origblock);
+
+ /* save original block in case split fails */
+ orig_ex.ee_block = ex->ee_block;
+ orig_ex.ee_len = cpu_to_le16(ee_len);
+ ext4_ext_store_pblock(&orig_ex, ext4_ext_pblock(ex));
+
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ goto out;
+
+ ex1 = ex;
+ ex1->ee_len = cpu_to_le16(split-ee_block);
+
+ ex2 = &newex;
+ ex2->ee_len = cpu_to_le16(ee_len-(split-ee_block));
+ ex2->ee_block = split;
+ ext4_ext_store_pblock(ex2, newblock);
+
+ if (ex1->ee_block == ex2->ee_block) {
+ /* Mark modified extent as dirty */
+ err = ext4_ext_dirty(handle, inode, path + depth);
+ ext_debug("out here\n");
+ goto out;
+ }
+
+ /*
+ * If this leaf cannot fit in any more extents
+ * insert it into another leaf
+ */
+ if (EXT_LAST_EXTENT(eh) >= EXT_MAX_EXTENT(eh)) {
+ err = ext4_ext_insert_extent(handle, inode, path,
+ &newex, flags);
+ if (err)
+ goto fix_extent_len;
+
+ depth = ext_depth(inode);
+ path = ext4_ext_find_extent(inode, split, path);
+ }
+
+ /* otherwise just scoot all ther other extents down */
+ else{
+ memmove(ex1+2, ex1+1,
+ (EXT_LAST_EXTENT(eh) - ex1) *
+ sizeof(struct ext4_extent));
+ memcpy(ex1+1, ex2, sizeof(struct ext4_extent));
+ le16_add_cpu(&(eh->eh_entries), 1);
+ }
+
+out:
+ ext4_ext_show_leaf(inode, path);
+ return err;
+
+fix_extent_len:
+ ex->ee_block = orig_ex.ee_block;
+ ex->ee_len = orig_ex.ee_len;
+ ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
+ ext4_ext_mark_uninitialized(ex);
+ ext4_ext_dirty(handle, inode, path + depth);
+
+ return err;
+}
+
static int
ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t start)
@@ -3598,6 +3701,112 @@ out_stop:
ext4_journal_stop(handle);
}
+/*
+ * ext4_ext_convert_blocks_uninit()
+ * Converts a range of blocks to uninitialized
+ *
+ * @handle: The journal handle
+ * @inode: The files inode
+ * @lblock: The logical block where the conversion will start
+ * @len: The max number of blocks to convert
+ *
+ * Returns the number of blocks successfully converted
+ */
+static int ext4_ext_convert_blocks_uninit(handle_t *handle,
+ struct inode *inode,
+ ext4_lblk_t lblock,
+ ext4_lblk_t len){
+
+ ext4_lblk_t ee_block, iblock, blocks_checked;
+ struct ext4_ext_path *path;
+ struct ext4_extent *ex;
+ unsigned int ee_len;
+ int ret = 0;
+ int err = 0;
+
+ iblock = lblock;
+ while (iblock < lblock+len) {
+ blocks_checked = 1;
+ path = ext4_ext_find_extent(inode, iblock, NULL);
+
+ if (path == NULL)
+ goto next;
+
+ err = ext4_ext_get_access(handle, inode, path);
+ if (err < 0)
+ goto next;
+
+ ex = path->p_ext;
+ if (ex == NULL)
+ goto next;
+
+ ee_block = le32_to_cpu(ex->ee_block);
+ ee_len = ext4_ext_get_actual_len(ex);
+
+ if (ee_block > iblock ||
+ ee_block+ee_len <= iblock)
+ goto next;
+
+ /*
+ * If the block is in the middle of the extent,
+ * split the extent to remove the head.
+ * Then find the new extent that contains the block
+ */
+ if (ee_block < iblock) {
+ err = ext4_split_extents(handle, inode,
+ iblock, path, 0);
+
+ if (err)
+ goto next;
+
+ /* Release this path before we get the next one */
+ ext4_ext_drop_refs(path);
+ kfree(path);
+
+ path = ext4_ext_find_extent(inode, iblock, NULL);
+
+ if (path == NULL)
+ goto next;
+
+ ex = path->p_ext;
+ if (ex == NULL)
+ goto next;
+
+ ee_block = le32_to_cpu(ex->ee_block);
+ ee_len = ext4_ext_get_actual_len(ex);
+ }
+
+ /*
+ * If the extent exceeds len, split
+ * the extent to remove the tail
+ */
+ if (ee_len > len) {
+ err = ext4_split_extents(handle, inode,
+ lblock+len, path, 0);
+
+ if (err)
+ goto next;
+
+ ee_len = ext4_ext_get_actual_len(ex);
+ }
+
+ /* Mark the extent uninitialized */
+ ext4_ext_mark_uninitialized(ex);
+
+ blocks_checked = ee_len;
+ ret += ee_len;
+next:
+ if (path) {
+ ext4_ext_drop_refs(path);
+ kfree(path);
+ }
+ iblock += blocks_checked;
+ }
+
+ return ret;
+}
+
+
static void ext4_falloc_update_inode(struct inode *inode,
int mode, loff_t new_size, int update_ctime)
{
--
1.7.1
--
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