ext4: remove messy logic from ext4_ext_rm_leaf

- Both callers(truncate and punch_hole) already aligned left end point
  so we no longer need split logic here.
- Remove dead duplicated code.
- Call ext4_ext_dirty only after we have updated eh_entries, otherwise
  we'll loose entries update. Regression caused by d583fb87a3ff0
  266'th testcase in xfstests (http://patchwork.ozlabs.org/patch/120872)

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 12 insertions, 91 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 385ebb43533..d0e3f333d3f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -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",
-                                                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 (b != ex_ee_block + ex_ee_len - 1) {
+                        EXT4_ERROR_INODE(inode,"  bad truncate %u:%u\n",
+                                         start, end);
+                        err = -EIO;
+                        goto out;
                 } 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--;