1 files changed, 100 insertions, 48 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a0f0c04e79b2..b9ce24129070 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -374,7 +374,7 @@ ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int bloc
                                        le32_to_cpu(ix[-1].ei_block));
                         }
                         BUG_ON(k && le32_to_cpu(ix->ei_block)
-                                           <= le32_to_cpu(ix[-1].ei_block));
+                                           <= le32_to_cpu(ix[-1].ei_block));
                         if (block < le32_to_cpu(ix->ei_block))
                                 break;
                         chix = ix;
@@ -423,8 +423,8 @@ ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
 
         path->p_ext = l - 1;
         ext_debug("  -> %d:%llu:%d ",
-                        le32_to_cpu(path->p_ext->ee_block),
-                        ext_pblock(path->p_ext),
+                        le32_to_cpu(path->p_ext->ee_block),
+                        ext_pblock(path->p_ext),
                         le16_to_cpu(path->p_ext->ee_len));
 
 #ifdef CHECK_BINSEARCH
@@ -435,7 +435,7 @@ ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
                 chex = ex = EXT_FIRST_EXTENT(eh);
                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
                         BUG_ON(k && le32_to_cpu(ex->ee_block)
-                                          <= le32_to_cpu(ex[-1].ee_block));
+                                          <= le32_to_cpu(ex[-1].ee_block));
                         if (block < le32_to_cpu(ex->ee_block))
                                 break;
                         chex = ex;
@@ -577,7 +577,7 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
         curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
 
         BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
-                             > le16_to_cpu(curp->p_hdr->eh_max));
+                             > le16_to_cpu(curp->p_hdr->eh_max));
         BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
 
         err = ext4_ext_dirty(handle, inode, curp);
@@ -621,12 +621,12 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                 border = path[depth].p_ext[1].ee_block;
                 ext_debug("leaf will be split."
                                 " next leaf starts at %d\n",
-                                  le32_to_cpu(border));
+                                  le32_to_cpu(border));
         } else {
                 border = newext->ee_block;
                 ext_debug("leaf will be added."
                                 " next leaf starts at %d\n",
-                                le32_to_cpu(border));
+                                le32_to_cpu(border));
         }
 
         /*
@@ -684,9 +684,9 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
         while (path[depth].p_ext <=
                         EXT_MAX_EXTENT(path[depth].p_hdr)) {
                 ext_debug("move %d:%llu:%d in new leaf %llu\n",
-                                le32_to_cpu(path[depth].p_ext->ee_block),
-                                ext_pblock(path[depth].p_ext),
-                                le16_to_cpu(path[depth].p_ext->ee_len),
+                                le32_to_cpu(path[depth].p_ext->ee_block),
+                                ext_pblock(path[depth].p_ext),
+                                le16_to_cpu(path[depth].p_ext->ee_len),
                                 newblock);
                 /*memmove(ex++, path[depth].p_ext++,
                                 sizeof(struct ext4_extent));
@@ -765,9 +765,9 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                                 EXT_LAST_INDEX(path[i].p_hdr));
                 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
                         ext_debug("%d: move %d:%d in new index %llu\n", i,
-                                        le32_to_cpu(path[i].p_idx->ei_block),
-                                        idx_pblock(path[i].p_idx),
-                                        newblock);
+                                        le32_to_cpu(path[i].p_idx->ei_block),
+                                        idx_pblock(path[i].p_idx),
+                                        newblock);
                         /*memmove(++fidx, path[i].p_idx++,
                                         sizeof(struct ext4_extent_idx));
                         neh->eh_entries++;
@@ -1128,6 +1128,55 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
 }
 
 /*
+ * check if a portion of the "newext" extent overlaps with an
+ * existing extent.
+ *
+ * If there is an overlap discovered, it updates the length of the newext
+ * such that there will be no overlap, and then returns 1.
+ * If there is no overlap found, it returns 0.
+ */
+unsigned int ext4_ext_check_overlap(struct inode *inode,
+                                    struct ext4_extent *newext,
+                                    struct ext4_ext_path *path)
+{
+        unsigned long b1, b2;
+        unsigned int depth, len1;
+        unsigned int ret = 0;
+
+        b1 = le32_to_cpu(newext->ee_block);
+        len1 = le16_to_cpu(newext->ee_len);
+        depth = ext_depth(inode);
+        if (!path[depth].p_ext)
+                goto out;
+        b2 = le32_to_cpu(path[depth].p_ext->ee_block);
+
+        /*
+         * get the next allocated block if the extent in the path
+         * is before the requested block(s) 
+         */
+        if (b2 < b1) {
+                b2 = ext4_ext_next_allocated_block(path);
+                if (b2 == EXT_MAX_BLOCK)
+                        goto out;
+        }
+
+        /* check for wrap through zero */
+        if (b1 + len1 < b1) {
+                len1 = EXT_MAX_BLOCK - b1;
+                newext->ee_len = cpu_to_le16(len1);
+                ret = 1;
+        }
+
+        /* check for overlap */
+        if (b1 + len1 > b2) {
+                newext->ee_len = cpu_to_le16(b2 - b1);
+                ret = 1;
+        }
+out:
+        return ret;
+}
+
+/*
  * ext4_ext_insert_extent:
  * tries to merge requsted extent into the existing extent or
  * inserts requested extent as new one into the tree,
@@ -1212,12 +1261,12 @@ has_space:
         if (!nearex) {
                 /* there is no extent in this leaf, create first one */
                 ext_debug("first extent in the leaf: %d:%llu:%d\n",
-                                le32_to_cpu(newext->ee_block),
-                                ext_pblock(newext),
-                                le16_to_cpu(newext->ee_len));
+                                le32_to_cpu(newext->ee_block),
+                                ext_pblock(newext),
+                                le16_to_cpu(newext->ee_len));
                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
         } else if (le32_to_cpu(newext->ee_block)
-                           > le32_to_cpu(nearex->ee_block)) {
+                           > le32_to_cpu(nearex->ee_block)) {
 /*              BUG_ON(newext->ee_block == nearex->ee_block); */
                 if (nearex != EXT_LAST_EXTENT(eh)) {
                         len = EXT_MAX_EXTENT(eh) - nearex;
@@ -1225,9 +1274,9 @@ has_space:
                         len = len < 0 ? 0 : len;
                         ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
                                         "move %d from 0x%p to 0x%p\n",
-                                        le32_to_cpu(newext->ee_block),
-                                        ext_pblock(newext),
-                                        le16_to_cpu(newext->ee_len),
+                                        le32_to_cpu(newext->ee_block),
+                                        ext_pblock(newext),
+                                        le16_to_cpu(newext->ee_len),
                                         nearex, len, nearex + 1, nearex + 2);
                         memmove(nearex + 2, nearex + 1, len);
                 }
@@ -1358,9 +1407,9 @@ int ext4_ext_walk_space(struct inode *inode, unsigned long block,
                         cbex.ec_start = 0;
                         cbex.ec_type = EXT4_EXT_CACHE_GAP;
                 } else {
-                        cbex.ec_block = le32_to_cpu(ex->ee_block);
-                        cbex.ec_len = le16_to_cpu(ex->ee_len);
-                        cbex.ec_start = ext_pblock(ex);
+                        cbex.ec_block = le32_to_cpu(ex->ee_block);
+                        cbex.ec_len = le16_to_cpu(ex->ee_len);
+                        cbex.ec_start = ext_pblock(ex);
                         cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
                 }
 
@@ -1431,16 +1480,16 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
                 len = le32_to_cpu(ex->ee_block) - block;
                 ext_debug("cache gap(before): %lu [%lu:%lu]",
                                 (unsigned long) block,
-                                (unsigned long) le32_to_cpu(ex->ee_block),
-                                (unsigned long) le16_to_cpu(ex->ee_len));
+                                (unsigned long) le32_to_cpu(ex->ee_block),
+                                (unsigned long) le16_to_cpu(ex->ee_len));
         } else if (block >= le32_to_cpu(ex->ee_block)
-                            + le16_to_cpu(ex->ee_len)) {
-                lblock = le32_to_cpu(ex->ee_block)
-                         + le16_to_cpu(ex->ee_len);
+                            + le16_to_cpu(ex->ee_len)) {
+                lblock = le32_to_cpu(ex->ee_block)
+                         + le16_to_cpu(ex->ee_len);
                 len = ext4_ext_next_allocated_block(path);
                 ext_debug("cache gap(after): [%lu:%lu] %lu",
-                                (unsigned long) le32_to_cpu(ex->ee_block),
-                                (unsigned long) le16_to_cpu(ex->ee_len),
+                                (unsigned long) le32_to_cpu(ex->ee_block),
+                                (unsigned long) le16_to_cpu(ex->ee_len),
                                 (unsigned long) block);
                 BUG_ON(len == lblock);
                 len = len - lblock;
@@ -1468,9 +1517,9 @@ ext4_ext_in_cache(struct inode *inode, unsigned long block,
         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
         if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
-                ex->ee_block = cpu_to_le32(cex->ec_block);
+                ex->ee_block = cpu_to_le32(cex->ec_block);
                 ext4_ext_store_pblock(ex, cex->ec_start);
-                ex->ee_len = cpu_to_le16(cex->ec_len);
+                ex->ee_len = cpu_to_le16(cex->ec_len);
                 ext_debug("%lu cached by %lu:%lu:%llu\n",
                                 (unsigned long) block,
                                 (unsigned long) cex->ec_block,
@@ -1956,9 +2005,9 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                         /* we should allocate requested block */
                 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
                         /* block is already allocated */
-                        newblock = iblock
-                                   - le32_to_cpu(newex.ee_block)
-                                   + ext_pblock(&newex);
+                        newblock = iblock
+                                   - le32_to_cpu(newex.ee_block)
+                                   + ext_pblock(&newex);
                         /* number of remaining blocks in the extent */
                         allocated = le16_to_cpu(newex.ee_len) -
                                         (iblock - le32_to_cpu(newex.ee_block));
@@ -1987,7 +2036,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 
         ex = path[depth].p_ext;
         if (ex) {
-                unsigned long ee_block = le32_to_cpu(ex->ee_block);
+                unsigned long ee_block = le32_to_cpu(ex->ee_block);
                 ext4_fsblk_t ee_start = ext_pblock(ex);
                 unsigned short ee_len  = le16_to_cpu(ex->ee_len);
 
@@ -2000,7 +2049,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                 if (ee_len > EXT_MAX_LEN)
                         goto out2;
                 /* if found extent covers block, simply return it */
-                if (iblock >= ee_block && iblock < ee_block + ee_len) {
+                if (iblock >= ee_block && iblock < ee_block + ee_len) {
                         newblock = iblock - ee_block + ee_start;
                         /* number of remaining blocks in the extent */
                         allocated = ee_len - (iblock - ee_block);
@@ -2031,7 +2080,15 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 
         /* allocate new block */
         goal = ext4_ext_find_goal(inode, path, iblock);
-        allocated = max_blocks;
+
+        /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
+        newex.ee_block = cpu_to_le32(iblock);
+        newex.ee_len = cpu_to_le16(max_blocks);
+        err = ext4_ext_check_overlap(inode, &newex, path);
+        if (err)
+                allocated = le16_to_cpu(newex.ee_len);
+        else
+                allocated = max_blocks;
         newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
         if (!newblock)
                 goto out2;
@@ -2039,12 +2096,15 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                         goal, newblock, allocated);
 
         /* try to insert new extent into found leaf and return */
-        newex.ee_block = cpu_to_le32(iblock);
         ext4_ext_store_pblock(&newex, newblock);
         newex.ee_len = cpu_to_le16(allocated);
         err = ext4_ext_insert_extent(handle, inode, path, &newex);
-        if (err)
+        if (err) {
+                /* free data blocks we just allocated */
+                ext4_free_blocks(handle, inode, ext_pblock(&newex),
+                                        le16_to_cpu(newex.ee_len));
                 goto out2;
+        }
 
         if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
                 EXT4_I(inode)->i_disksize = inode->i_size;
@@ -2157,11 +2217,3 @@ int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
 
         return needed;
 }
-
-EXPORT_SYMBOL(ext4_mark_inode_dirty);
-EXPORT_SYMBOL(ext4_ext_invalidate_cache);
-EXPORT_SYMBOL(ext4_ext_insert_extent);
-EXPORT_SYMBOL(ext4_ext_walk_space);
-EXPORT_SYMBOL(ext4_ext_find_goal);
-EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
-