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>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 385ebb4..d0e3f33 100644 (file)
--- 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--;