ext4: Fix return value of ext4_split_unwritten_extents() to fix direct I/O
[safe/jmp/linux-2.6] / fs / ocfs2 / extent_map.c
index ea0ce41..843db64 100644 (file)
@@ -25,6 +25,7 @@
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/fiemap.h>
 
 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
 #include <cluster/masklog.h>
@@ -32,6 +33,7 @@
 #include "ocfs2.h"
 
 #include "alloc.h"
+#include "dlmglue.h"
 #include "extent_map.h"
 #include "inode.h"
 #include "super.h"
 #include "buffer_head_io.h"
 
 /*
- * Return the index of the extent record which contains cluster #v_cluster.
- * -1 is returned if it was not found.
+ * The extent caching implementation is intentionally trivial.
  *
- * Should work fine on interior and exterior nodes.
+ * We only cache a small number of extents stored directly on the
+ * inode, so linear order operations are acceptable. If we ever want
+ * to increase the size of the extent map, then these algorithms must
+ * get smarter.
  */
-static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
-                                   u32 v_cluster)
+
+void ocfs2_extent_map_init(struct inode *inode)
 {
-       int ret = -1;
-       int i;
-       struct ocfs2_extent_rec *rec;
-       u32 rec_end, rec_start, clusters;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
 
-       for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
-               rec = &el->l_recs[i];
+       oi->ip_extent_map.em_num_items = 0;
+       INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
+}
 
-               rec_start = le32_to_cpu(rec->e_cpos);
-               clusters = ocfs2_rec_clusters(el, rec);
+static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
+                                     unsigned int cpos,
+                                     struct ocfs2_extent_map_item **ret_emi)
+{
+       unsigned int range;
+       struct ocfs2_extent_map_item *emi;
+
+       *ret_emi = NULL;
+
+       list_for_each_entry(emi, &em->em_list, ei_list) {
+               range = emi->ei_cpos + emi->ei_clusters;
 
-               rec_end = rec_start + clusters;
+               if (cpos >= emi->ei_cpos && cpos < range) {
+                       list_move(&emi->ei_list, &em->em_list);
 
-               if (v_cluster >= rec_start && v_cluster < rec_end) {
-                       ret = i;
+                       *ret_emi = emi;
                        break;
                }
        }
+}
 
-       return ret;
+static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
+                                  unsigned int *phys, unsigned int *len,
+                                  unsigned int *flags)
+{
+       unsigned int coff;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map_item *emi;
+
+       spin_lock(&oi->ip_lock);
+
+       __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
+       if (emi) {
+               coff = cpos - emi->ei_cpos;
+               *phys = emi->ei_phys + coff;
+               if (len)
+                       *len = emi->ei_clusters - coff;
+               if (flags)
+                       *flags = emi->ei_flags;
+       }
+
+       spin_unlock(&oi->ip_lock);
+
+       if (emi == NULL)
+               return -ENOENT;
+
+       return 0;
 }
 
-int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
-                      u32 *p_cluster, u32 *num_clusters)
+/*
+ * Forget about all clusters equal to or greater than cpos.
+ */
+void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 {
-       int ret, i;
-       struct buffer_head *di_bh = NULL;
+       struct ocfs2_extent_map_item *emi, *n;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map *em = &oi->ip_extent_map;
+       LIST_HEAD(tmp_list);
+       unsigned int range;
+
+       spin_lock(&oi->ip_lock);
+       list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
+               if (emi->ei_cpos >= cpos) {
+                       /* Full truncate of this record. */
+                       list_move(&emi->ei_list, &tmp_list);
+                       BUG_ON(em->em_num_items == 0);
+                       em->em_num_items--;
+                       continue;
+               }
+
+               range = emi->ei_cpos + emi->ei_clusters;
+               if (range > cpos) {
+                       /* Partial truncate */
+                       emi->ei_clusters = cpos - emi->ei_cpos;
+               }
+       }
+       spin_unlock(&oi->ip_lock);
+
+       list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
+               list_del(&emi->ei_list);
+               kfree(emi);
+       }
+}
+
+/*
+ * Is any part of emi2 contained within emi1
+ */
+static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
+                                struct ocfs2_extent_map_item *emi2)
+{
+       unsigned int range1, range2;
+
+       /*
+        * Check if logical start of emi2 is inside emi1
+        */
+       range1 = emi1->ei_cpos + emi1->ei_clusters;
+       if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
+               return 1;
+
+       /*
+        * Check if logical end of emi2 is inside emi1
+        */
+       range2 = emi2->ei_cpos + emi2->ei_clusters;
+       if (range2 > emi1->ei_cpos && range2 <= range1)
+               return 1;
+
+       return 0;
+}
+
+static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
+                                 struct ocfs2_extent_map_item *src)
+{
+       dest->ei_cpos = src->ei_cpos;
+       dest->ei_phys = src->ei_phys;
+       dest->ei_clusters = src->ei_clusters;
+       dest->ei_flags = src->ei_flags;
+}
+
+/*
+ * Try to merge emi with ins. Returns 1 if merge succeeds, zero
+ * otherwise.
+ */
+static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
+                                        struct ocfs2_extent_map_item *ins)
+{
+       /*
+        * Handle contiguousness
+        */
+       if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
+           ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
+           ins->ei_flags == emi->ei_flags) {
+               emi->ei_clusters += ins->ei_clusters;
+               return 1;
+       } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
+                  (ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
+                  ins->ei_flags == emi->ei_flags) {
+               emi->ei_phys = ins->ei_phys;
+               emi->ei_cpos = ins->ei_cpos;
+               emi->ei_clusters += ins->ei_clusters;
+               return 1;
+       }
+
+       /*
+        * Overlapping extents - this shouldn't happen unless we've
+        * split an extent to change it's flags. That is exceedingly
+        * rare, so there's no sense in trying to optimize it yet.
+        */
+       if (ocfs2_ei_is_contained(emi, ins) ||
+           ocfs2_ei_is_contained(ins, emi)) {
+               ocfs2_copy_emi_fields(emi, ins);
+               return 1;
+       }
+
+       /* No merge was possible. */
+       return 0;
+}
+
+/*
+ * In order to reduce complexity on the caller, this insert function
+ * is intentionally liberal in what it will accept.
+ *
+ * The only rule is that the truncate call *must* be used whenever
+ * records have been deleted. This avoids inserting overlapping
+ * records with different physical mappings.
+ */
+void ocfs2_extent_map_insert_rec(struct inode *inode,
+                                struct ocfs2_extent_rec *rec)
+{
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_extent_map *em = &oi->ip_extent_map;
+       struct ocfs2_extent_map_item *emi, *new_emi = NULL;
+       struct ocfs2_extent_map_item ins;
+
+       ins.ei_cpos = le32_to_cpu(rec->e_cpos);
+       ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
+                                              le64_to_cpu(rec->e_blkno));
+       ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
+       ins.ei_flags = rec->e_flags;
+
+search:
+       spin_lock(&oi->ip_lock);
+
+       list_for_each_entry(emi, &em->em_list, ei_list) {
+               if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
+                       list_move(&emi->ei_list, &em->em_list);
+                       spin_unlock(&oi->ip_lock);
+                       goto out;
+               }
+       }
+
+       /*
+        * No item could be merged.
+        *
+        * Either allocate and add a new item, or overwrite the last recently
+        * inserted.
+        */
+
+       if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
+               if (new_emi == NULL) {
+                       spin_unlock(&oi->ip_lock);
+
+                       new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
+                       if (new_emi == NULL)
+                               goto out;
+
+                       goto search;
+               }
+
+               ocfs2_copy_emi_fields(new_emi, &ins);
+               list_add(&new_emi->ei_list, &em->em_list);
+               em->em_num_items++;
+               new_emi = NULL;
+       } else {
+               BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
+               emi = list_entry(em->em_list.prev,
+                                struct ocfs2_extent_map_item, ei_list);
+               list_move(&emi->ei_list, &em->em_list);
+               ocfs2_copy_emi_fields(emi, &ins);
+       }
+
+       spin_unlock(&oi->ip_lock);
+
+out:
+       if (new_emi)
+               kfree(new_emi);
+}
+
+static int ocfs2_last_eb_is_empty(struct inode *inode,
+                                 struct ocfs2_dinode *di)
+{
+       int ret, next_free;
+       u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
        struct buffer_head *eb_bh = NULL;
-       struct ocfs2_dinode *di;
        struct ocfs2_extent_block *eb;
        struct ocfs2_extent_list *el;
-       struct ocfs2_extent_rec *rec;
-       u32 coff;
 
-       ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
-                              &di_bh, OCFS2_BH_CACHED, inode);
+       ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
+       eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+       el = &eb->h_list;
+
+       if (el->l_tree_depth) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %lu has non zero tree depth in "
+                           "leaf block %llu\n", inode->i_ino,
+                           (unsigned long long)eb_bh->b_blocknr);
+               ret = -EROFS;
+               goto out;
+       }
+
+       next_free = le16_to_cpu(el->l_next_free_rec);
+
+       if (next_free == 0 ||
+           (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
+               ret = 1;
+
+out:
+       brelse(eb_bh);
+       return ret;
+}
+
+/*
+ * Return the 1st index within el which contains an extent start
+ * larger than v_cluster.
+ */
+static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
+                                      u32 v_cluster)
+{
+       int i;
+       struct ocfs2_extent_rec *rec;
+
+       for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+               rec = &el->l_recs[i];
+
+               if (v_cluster < le32_to_cpu(rec->e_cpos))
+                       break;
+       }
+
+       return i;
+}
+
+/*
+ * Figure out the size of a hole which starts at v_cluster within the given
+ * extent list.
+ *
+ * If there is no more allocation past v_cluster, we return the maximum
+ * cluster size minus v_cluster.
+ *
+ * If we have in-inode extents, then el points to the dinode list and
+ * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
+ * containing el.
+ */
+int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
+                              struct ocfs2_extent_list *el,
+                              struct buffer_head *eb_bh,
+                              u32 v_cluster,
+                              u32 *num_clusters)
+{
+       int ret, i;
+       struct buffer_head *next_eb_bh = NULL;
+       struct ocfs2_extent_block *eb, *next_eb;
+
+       i = ocfs2_search_for_hole_index(el, v_cluster);
+
+       if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
+               eb = (struct ocfs2_extent_block *)eb_bh->b_data;
+
+               /*
+                * Check the next leaf for any extents.
+                */
+
+               if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
+                       goto no_more_extents;
+
+               ret = ocfs2_read_extent_block(ci,
+                                             le64_to_cpu(eb->h_next_leaf_blk),
+                                             &next_eb_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
+               el = &next_eb->h_list;
+               i = ocfs2_search_for_hole_index(el, v_cluster);
+       }
+
+no_more_extents:
+       if (i == le16_to_cpu(el->l_next_free_rec)) {
+               /*
+                * We're at the end of our existing allocation. Just
+                * return the maximum number of clusters we could
+                * possibly allocate.
+                */
+               *num_clusters = UINT_MAX - v_cluster;
+       } else {
+               *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
+       }
+
+       ret = 0;
+out:
+       brelse(next_eb_bh);
+       return ret;
+}
+
+static int ocfs2_get_clusters_nocache(struct inode *inode,
+                                     struct buffer_head *di_bh,
+                                     u32 v_cluster, unsigned int *hole_len,
+                                     struct ocfs2_extent_rec *ret_rec,
+                                     unsigned int *is_last)
+{
+       int i, ret, tree_height, len;
+       struct ocfs2_dinode *di;
+       struct ocfs2_extent_block *uninitialized_var(eb);
+       struct ocfs2_extent_list *el;
+       struct ocfs2_extent_rec *rec;
+       struct buffer_head *eb_bh = NULL;
+
+       memset(ret_rec, 0, sizeof(*ret_rec));
+       if (is_last)
+               *is_last = 0;
+
        di = (struct ocfs2_dinode *) di_bh->b_data;
        el = &di->id2.i_list;
+       tree_height = le16_to_cpu(el->l_tree_depth);
 
-       if (el->l_tree_depth) {
-               ret = ocfs2_find_leaf(inode, el, v_cluster, &eb_bh);
+       if (tree_height > 0) {
+               ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+                                     &eb_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
@@ -114,39 +451,215 @@ int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
        i = ocfs2_search_extent_list(el, v_cluster);
        if (i == -1) {
                /*
-                * A hole was found. Return some canned values that
-                * callers can key on.
+                * Holes can be larger than the maximum size of an
+                * extent, so we return their lengths in a seperate
+                * field.
                 */
-               *p_cluster = 0;
-               if (num_clusters)
-                       *num_clusters = 1;
+               if (hole_len) {
+                       ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
+                                                        el, eb_bh,
+                                                        v_cluster, &len);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
+
+                       *hole_len = len;
+               }
+               goto out_hole;
+       }
+
+       rec = &el->l_recs[i];
+
+       BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
+
+       if (!rec->e_blkno) {
+               ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
+                           "record (%u, %u, 0)", inode->i_ino,
+                           le32_to_cpu(rec->e_cpos),
+                           ocfs2_rec_clusters(el, rec));
+               ret = -EROFS;
+               goto out;
+       }
+
+       *ret_rec = *rec;
+
+       /*
+        * Checking for last extent is potentially expensive - we
+        * might have to look at the next leaf over to see if it's
+        * empty.
+        *
+        * The first two checks are to see whether the caller even
+        * cares for this information, and if the extent is at least
+        * the last in it's list.
+        *
+        * If those hold true, then the extent is last if any of the
+        * additional conditions hold true:
+        *  - Extent list is in-inode
+        *  - Extent list is right-most
+        *  - Extent list is 2nd to rightmost, with empty right-most
+        */
+       if (is_last) {
+               if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
+                       if (tree_height == 0)
+                               *is_last = 1;
+                       else if (eb->h_blkno == di->i_last_eb_blk)
+                               *is_last = 1;
+                       else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
+                               ret = ocfs2_last_eb_is_empty(inode, di);
+                               if (ret < 0) {
+                                       mlog_errno(ret);
+                                       goto out;
+                               }
+                               if (ret == 1)
+                                       *is_last = 1;
+                       }
+               }
+       }
+
+out_hole:
+       ret = 0;
+out:
+       brelse(eb_bh);
+       return ret;
+}
+
+static void ocfs2_relative_extent_offsets(struct super_block *sb,
+                                         u32 v_cluster,
+                                         struct ocfs2_extent_rec *rec,
+                                         u32 *p_cluster, u32 *num_clusters)
+
+{
+       u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
+
+       *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
+       *p_cluster = *p_cluster + coff;
+
+       if (num_clusters)
+               *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
+}
+
+int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
+                            u32 *p_cluster, u32 *num_clusters,
+                            struct ocfs2_extent_list *el,
+                            unsigned int *extent_flags)
+{
+       int ret = 0, i;
+       struct buffer_head *eb_bh = NULL;
+       struct ocfs2_extent_block *eb;
+       struct ocfs2_extent_rec *rec;
+       u32 coff;
+
+       if (el->l_tree_depth) {
+               ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+                                     &eb_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+               el = &eb->h_list;
+
+               if (el->l_tree_depth) {
+                       ocfs2_error(inode->i_sb,
+                                   "Inode %lu has non zero tree depth in "
+                                   "xattr leaf block %llu\n", inode->i_ino,
+                                   (unsigned long long)eb_bh->b_blocknr);
+                       ret = -EROFS;
+                       goto out;
+               }
+       }
+
+       i = ocfs2_search_extent_list(el, v_cluster);
+       if (i == -1) {
+               ret = -EROFS;
+               mlog_errno(ret);
+               goto out;
        } else {
                rec = &el->l_recs[i];
-
                BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 
                if (!rec->e_blkno) {
                        ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
-                                   "record (%u, %u, 0)", inode->i_ino,
+                                   "record (%u, %u, 0) in xattr", inode->i_ino,
                                    le32_to_cpu(rec->e_cpos),
                                    ocfs2_rec_clusters(el, rec));
                        ret = -EROFS;
                        goto out;
                }
-
                coff = v_cluster - le32_to_cpu(rec->e_cpos);
-
                *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
                                                    le64_to_cpu(rec->e_blkno));
                *p_cluster = *p_cluster + coff;
-
                if (num_clusters)
                        *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
+
+               if (extent_flags)
+                       *extent_flags = rec->e_flags;
+       }
+out:
+       if (eb_bh)
+               brelse(eb_bh);
+       return ret;
+}
+
+int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
+                      u32 *p_cluster, u32 *num_clusters,
+                      unsigned int *extent_flags)
+{
+       int ret;
+       unsigned int uninitialized_var(hole_len), flags = 0;
+       struct buffer_head *di_bh = NULL;
+       struct ocfs2_extent_rec rec;
+
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+               ret = -ERANGE;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
+                                     num_clusters, extent_flags);
+       if (ret == 0)
+               goto out;
+
+       ret = ocfs2_read_inode_block(inode, &di_bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
+                                        &rec, NULL);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
        }
 
+       if (rec.e_blkno == 0ULL) {
+               /*
+                * A hole was found. Return some canned values that
+                * callers can key on. If asked for, num_clusters will
+                * be populated with the size of the hole.
+                */
+               *p_cluster = 0;
+               if (num_clusters) {
+                       *num_clusters = hole_len;
+               }
+       } else {
+               ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
+                                             p_cluster, num_clusters);
+               flags = rec.e_flags;
+
+               ocfs2_extent_map_insert_rec(inode, &rec);
+       }
+
+       if (extent_flags)
+               *extent_flags = flags;
+
 out:
        brelse(di_bh);
-       brelse(eb_bh);
        return ret;
 }
 
@@ -155,7 +668,7 @@ out:
  * all while the map is in the process of being updated.
  */
 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
-                               int *ret_count)
+                               u64 *ret_count, unsigned int *extent_flags)
 {
        int ret;
        int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
@@ -164,7 +677,8 @@ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
 
        cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 
-       ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters);
+       ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
+                                extent_flags);
        if (ret) {
                mlog_errno(ret);
                goto out;
@@ -188,3 +702,185 @@ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
 out:
        return ret;
 }
+
+static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
+                              struct fiemap_extent_info *fieinfo,
+                              u64 map_start)
+{
+       int ret;
+       unsigned int id_count;
+       struct ocfs2_dinode *di;
+       u64 phys;
+       u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+       di = (struct ocfs2_dinode *)di_bh->b_data;
+       id_count = le16_to_cpu(di->id2.i_data.id_count);
+
+       if (map_start < id_count) {
+               phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
+               phys += offsetof(struct ocfs2_dinode, id2.i_data.id_data);
+
+               ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
+                                             flags);
+               if (ret < 0)
+                       return ret;
+       }
+
+       return 0;
+}
+
+#define OCFS2_FIEMAP_FLAGS     (FIEMAP_FLAG_SYNC)
+
+int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+                u64 map_start, u64 map_len)
+{
+       int ret, is_last;
+       u32 mapping_end, cpos;
+       unsigned int hole_size;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       u64 len_bytes, phys_bytes, virt_bytes;
+       struct buffer_head *di_bh = NULL;
+       struct ocfs2_extent_rec rec;
+
+       ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
+       if (ret)
+               return ret;
+
+       ret = ocfs2_inode_lock(inode, &di_bh, 0);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       down_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+       /*
+        * Handle inline-data separately.
+        */
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+               ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
+               goto out_unlock;
+       }
+
+       cpos = map_start >> osb->s_clustersize_bits;
+       mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
+                                              map_start + map_len);
+       mapping_end -= cpos;
+       is_last = 0;
+       while (cpos < mapping_end && !is_last) {
+               u32 fe_flags;
+
+               ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
+                                                &hole_size, &rec, &is_last);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               if (rec.e_blkno == 0ULL) {
+                       cpos += hole_size;
+                       continue;
+               }
+
+               fe_flags = 0;
+               if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
+                       fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
+               if (is_last)
+                       fe_flags |= FIEMAP_EXTENT_LAST;
+               len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
+               phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
+               virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
+
+               ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
+                                             len_bytes, fe_flags);
+               if (ret)
+                       break;
+
+               cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
+       }
+
+       if (ret > 0)
+               ret = 0;
+
+out_unlock:
+       brelse(di_bh);
+
+       up_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+       ocfs2_inode_unlock(inode, 0);
+out:
+
+       return ret;
+}
+
+int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
+                          struct buffer_head *bhs[], int flags,
+                          int (*validate)(struct super_block *sb,
+                                          struct buffer_head *bh))
+{
+       int rc = 0;
+       u64 p_block, p_count;
+       int i, count, done = 0;
+
+       mlog_entry("(inode = %p, v_block = %llu, nr = %d, bhs = %p, "
+                  "flags = %x, validate = %p)\n",
+                  inode, (unsigned long long)v_block, nr, bhs, flags,
+                  validate);
+
+       if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
+           i_size_read(inode)) {
+               BUG_ON(!(flags & OCFS2_BH_READAHEAD));
+               goto out;
+       }
+
+       while (done < nr) {
+               down_read(&OCFS2_I(inode)->ip_alloc_sem);
+               rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
+                                                &p_block, &p_count, NULL);
+               up_read(&OCFS2_I(inode)->ip_alloc_sem);
+               if (rc) {
+                       mlog_errno(rc);
+                       break;
+               }
+
+               if (!p_block) {
+                       rc = -EIO;
+                       mlog(ML_ERROR,
+                            "Inode #%llu contains a hole at offset %llu\n",
+                            (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                            (unsigned long long)(v_block + done) <<
+                            inode->i_sb->s_blocksize_bits);
+                       break;
+               }
+
+               count = nr - done;
+               if (p_count < count)
+                       count = p_count;
+
+               /*
+                * If the caller passed us bhs, they should have come
+                * from a previous readahead call to this function.  Thus,
+                * they should have the right b_blocknr.
+                */
+               for (i = 0; i < count; i++) {
+                       if (!bhs[done + i])
+                               continue;
+                       BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
+               }
+
+               rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
+                                      bhs + done, flags, validate);
+               if (rc) {
+                       mlog_errno(rc);
+                       break;
+               }
+               done += count;
+       }
+
+out:
+       mlog_exit(rc);
+       return rc;
+}
+
+