ext4: Add a comprehensive block validity check to ext4_get_blocks()
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / ext4 / inode.c
index 2a9ffd528dd1271e179a35322ce2e0a522f4d5b2..dadd3f995db5e07aca8e2957daf1a7e296aee8e8 100644 (file)
@@ -372,20 +372,21 @@ static int ext4_block_to_path(struct inode *inode,
 }
 
 static int __ext4_check_blockref(const char *function, struct inode *inode,
-                                __le32 *p, unsigned int max) {
-
-       unsigned int maxblocks = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es);
+                                __le32 *p, unsigned int max)
+{
        __le32 *bref = p;
+       unsigned int blk;
+
        while (bref < p+max) {
-               if (unlikely(le32_to_cpu(*bref) >= maxblocks)) {
+               blk = le32_to_cpu(*bref++);
+               if (blk && 
+                   unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb), 
+                                                   blk, 1))) {
                        ext4_error(inode->i_sb, function,
-                                  "block reference %u >= max (%u) "
-                                  "in inode #%lu, offset=%d",
-                                  le32_to_cpu(*bref), maxblocks,
-                                  inode->i_ino, (int)(bref-p));
+                                  "invalid block reference %u "
+                                  "in inode #%lu", blk, inode->i_ino);
                        return -EIO;
                }
-               bref++;
        }
        return 0;
 }
@@ -892,6 +893,10 @@ err_out:
 }
 
 /*
+ * The ext4_ind_get_blocks() function handles non-extents inodes
+ * (i.e., using the traditional indirect/double-indirect i_blocks
+ * scheme) for ext4_get_blocks().
+ *
  * Allocation strategy is simple: if we have to allocate something, we will
  * have to go the whole way to leaf. So let's do it before attaching anything
  * to tree, set linkage between the newborn blocks, write them if sync is
@@ -909,15 +914,16 @@ err_out:
  * return = 0, if plain lookup failed.
  * return < 0, error case.
  *
- *
- * Need to be called with
- * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
- * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
+ * The ext4_ind_get_blocks() function should be called with
+ * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
+ * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
+ * blocks.
  */
-static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
+static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
                                  ext4_lblk_t iblock, unsigned int maxblocks,
                                  struct buffer_head *bh_result,
-                                 int create, int extend_disksize)
+                                 int flags)
 {
        int err = -EIO;
        ext4_lblk_t offsets[4];
@@ -934,7 +940,7 @@ static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
 
 
        J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
-       J_ASSERT(handle != NULL || create == 0);
+       J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
        depth = ext4_block_to_path(inode, iblock, offsets,
                                        &blocks_to_boundary);
 
@@ -963,7 +969,7 @@ static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
        }
 
        /* Next simple case - plain lookup or failed read of indirect block */
-       if (!create || err == -EIO)
+       if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
                goto cleanup;
 
        /*
@@ -1002,7 +1008,7 @@ static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
         * protect it if you're about to implement concurrent
         * ext4_get_block() -bzzz
        */
-       if (!err && extend_disksize) {
+       if (!err && (flags & EXT4_GET_BLOCKS_EXTEND_DISKSIZE)) {
                disksize = ((loff_t) iblock + count) << inode->i_blkbits;
                if (disksize > i_size_read(inode))
                        disksize = i_size_read(inode);
@@ -1120,8 +1126,23 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
                ext4_discard_preallocations(inode);
 }
 
+static int check_block_validity(struct inode *inode, sector_t logical,
+                               sector_t phys, int len)
+{
+       if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), phys, len)) {
+               ext4_error(inode->i_sb, "check_block_validity",
+                          "inode #%lu logical block %llu mapped to %llu "
+                          "(size %d)", inode->i_ino,
+                          (unsigned long long) logical,
+                          (unsigned long long) phys, len);
+               WARN_ON(1);
+               return -EIO;
+       }
+       return 0;
+}
+
 /*
- * The ext4_get_blocks_wrap() function try to look up the requested blocks,
+ * The ext4_get_blocks() function tries to look up the requested blocks,
  * and returns if the blocks are already mapped.
  *
  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
@@ -1129,7 +1150,7 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
  * mapped.
  *
  * If file type is extents based, it will call ext4_ext_get_blocks(),
- * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
+ * Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
  * based files
  *
  * On success, it returns the number of blocks being mapped or allocate.
@@ -1142,9 +1163,9 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
  *
  * It returns the error in case of allocation failure.
  */
-int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
-                       unsigned int max_blocks, struct buffer_head *bh,
-                       int create, int extend_disksize, int flag)
+int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
+                   unsigned int max_blocks, struct buffer_head *bh,
+                   int flags)
 {
        int retval;
 
@@ -1152,21 +1173,28 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
        clear_buffer_unwritten(bh);
 
        /*
-        * Try to see if we can get  the block without requesting
-        * for new file system block.
+        * Try to see if we can get the block without requesting a new
+        * file system block.
         */
        down_read((&EXT4_I(inode)->i_data_sem));
        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
                retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
-                               bh, 0, 0);
+                               bh, 0);
        } else {
-               retval = ext4_get_blocks_handle(handle,
-                               inode, block, max_blocks, bh, 0, 0);
+               retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
+                                            bh, 0);
        }
        up_read((&EXT4_I(inode)->i_data_sem));
 
+       if (retval > 0 && buffer_mapped(bh)) {
+               int ret = check_block_validity(inode, block, 
+                                              bh->b_blocknr, retval);
+               if (ret != 0)
+                       return ret;
+       }
+
        /* If it is only a block(s) look up */
-       if (!create)
+       if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
                return retval;
 
        /*
@@ -1205,7 +1233,7 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
         * let the underlying get_block() function know to
         * avoid double accounting
         */
-       if (flag)
+       if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
                EXT4_I(inode)->i_delalloc_reserved_flag = 1;
        /*
         * We need to check for EXT4 here because migrate
@@ -1213,10 +1241,10 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
         */
        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
                retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
-                               bh, create, extend_disksize);
+                                             bh, flags);
        } else {
-               retval = ext4_get_blocks_handle(handle, inode, block,
-                               max_blocks, bh, create, extend_disksize);
+               retval = ext4_ind_get_blocks(handle, inode, block,
+                                            max_blocks, bh, flags);
 
                if (retval > 0 && buffer_new(bh)) {
                        /*
@@ -1229,18 +1257,23 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
                }
        }
 
-       if (flag) {
+       if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
                EXT4_I(inode)->i_delalloc_reserved_flag = 0;
-               /*
-                * Update reserved blocks/metadata blocks
-                * after successful block allocation
-                * which were deferred till now
-                */
-               if ((retval > 0) && buffer_delay(bh))
-                       ext4_da_update_reserve_space(inode, retval);
-       }
+
+       /*
+        * Update reserved blocks/metadata blocks after successful
+        * block allocation which had been deferred till now.
+        */
+       if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
+               ext4_da_update_reserve_space(inode, retval);
 
        up_write((&EXT4_I(inode)->i_data_sem));
+       if (retval > 0 && buffer_mapped(bh)) {
+               int ret = check_block_validity(inode, block, 
+                                              bh->b_blocknr, retval);
+               if (ret != 0)
+                       return ret;
+       }
        return retval;
 }
 
@@ -1268,8 +1301,8 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
                started = 1;
        }
 
-       ret = ext4_get_blocks_wrap(handle, inode, iblock,
-                                       max_blocks, bh_result, create, 0, 0);
+       ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
+                             create ? EXT4_GET_BLOCKS_CREATE : 0);
        if (ret > 0) {
                bh_result->b_size = (ret << inode->i_blkbits);
                ret = 0;
@@ -1288,17 +1321,19 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 {
        struct buffer_head dummy;
        int fatal = 0, err;
+       int flags = EXT4_GET_BLOCKS_EXTEND_DISKSIZE;
 
        J_ASSERT(handle != NULL || create == 0);
 
        dummy.b_state = 0;
        dummy.b_blocknr = -1000;
        buffer_trace_init(&dummy.b_history);
-       err = ext4_get_blocks_wrap(handle, inode, block, 1,
-                                       &dummy, create, 1, 0);
+       if (create)
+               flags |= EXT4_GET_BLOCKS_CREATE;
+       err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
        /*
-        * ext4_get_blocks_handle() returns number of blocks
-        * mapped. 0 in case of a HOLE.
+        * ext4_get_blocks() returns number of blocks mapped. 0 in
+        * case of a HOLE.
         */
        if (err > 0) {
                if (err > 1)
@@ -1852,7 +1887,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
  * @logical - first logical block to start assignment with
  *
  * the function goes through all passed space and put actual disk
- * block numbers into buffer heads, dropping BH_Delay
+ * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
  */
 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
                                 struct buffer_head *exbh)
@@ -1902,16 +1937,24 @@ static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
                        do {
                                if (cur_logical >= logical + blocks)
                                        break;
-                               if (buffer_delay(bh)) {
-                                       bh->b_blocknr = pblock;
-                                       clear_buffer_delay(bh);
-                                       bh->b_bdev = inode->i_sb->s_bdev;
-                               } else if (buffer_unwritten(bh)) {
-                                       bh->b_blocknr = pblock;
-                                       clear_buffer_unwritten(bh);
-                                       set_buffer_mapped(bh);
-                                       set_buffer_new(bh);
-                                       bh->b_bdev = inode->i_sb->s_bdev;
+
+                               if (buffer_delay(bh) ||
+                                               buffer_unwritten(bh)) {
+
+                                       BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
+
+                                       if (buffer_delay(bh)) {
+                                               clear_buffer_delay(bh);
+                                               bh->b_blocknr = pblock;
+                                       } else {
+                                               /*
+                                                * unwritten already should have
+                                                * blocknr assigned. Verify that
+                                                */
+                                               clear_buffer_unwritten(bh);
+                                               BUG_ON(bh->b_blocknr != pblock);
+                                       }
+
                                } else if (buffer_mapped(bh))
                                        BUG_ON(bh->b_blocknr != pblock);
 
@@ -1990,51 +2033,6 @@ static void ext4_print_free_blocks(struct inode *inode)
        return;
 }
 
-#define                EXT4_DELALLOC_RSVED     1
-static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
-                                  struct buffer_head *bh_result, int create)
-{
-       int ret;
-       unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
-       loff_t disksize = EXT4_I(inode)->i_disksize;
-       handle_t *handle = NULL;
-
-       handle = ext4_journal_current_handle();
-       BUG_ON(!handle);
-       ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
-                                  bh_result, create, 0, EXT4_DELALLOC_RSVED);
-       if (ret <= 0)
-               return ret;
-
-       bh_result->b_size = (ret << inode->i_blkbits);
-
-       if (ext4_should_order_data(inode)) {
-               int retval;
-               retval = ext4_jbd2_file_inode(handle, inode);
-               if (retval)
-                       /*
-                        * Failed to add inode for ordered mode. Don't
-                        * update file size
-                        */
-                       return retval;
-       }
-
-       /*
-        * Update on-disk size along with block allocation we don't
-        * use 'extend_disksize' as size may change within already
-        * allocated block -bzzz
-        */
-       disksize = ((loff_t) iblock + ret) << inode->i_blkbits;
-       if (disksize > i_size_read(inode))
-               disksize = i_size_read(inode);
-       if (disksize > EXT4_I(inode)->i_disksize) {
-               ext4_update_i_disksize(inode, disksize);
-               ret = ext4_mark_inode_dirty(handle, inode);
-               return ret;
-       }
-       return 0;
-}
-
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -2045,29 +2043,57 @@ static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
  */
 static int mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
-       int err = 0;
+       int err, blks, get_blocks_flags;
        struct buffer_head new;
-       sector_t next;
+       sector_t next = mpd->b_blocknr;
+       unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
+       loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
+       handle_t *handle = NULL;
 
        /*
         * We consider only non-mapped and non-allocated blocks
         */
        if ((mpd->b_state  & (1 << BH_Mapped)) &&
-           !(mpd->b_state & (1 << BH_Delay)))
+               !(mpd->b_state & (1 << BH_Delay)) &&
+               !(mpd->b_state & (1 << BH_Unwritten)))
                return 0;
-       new.b_state = mpd->b_state;
-       new.b_blocknr = 0;
-       new.b_size = mpd->b_size;
-       next = mpd->b_blocknr;
+
        /*
-        * If we didn't accumulate anything
-        * to write simply return
+        * If we didn't accumulate anything to write simply return
         */
-       if (!new.b_size)
+       if (!mpd->b_size)
                return 0;
 
-       err = ext4_da_get_block_write(mpd->inode, next, &new, 1);
-       if (err) {
+       handle = ext4_journal_current_handle();
+       BUG_ON(!handle);
+
+       /*
+        * Call ext4_get_blocks() to allocate any delayed allocation
+        * blocks, or to convert an uninitialized extent to be
+        * initialized (in the case where we have written into
+        * one or more preallocated blocks).
+        *
+        * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
+        * indicate that we are on the delayed allocation path.  This
+        * affects functions in many different parts of the allocation
+        * call path.  This flag exists primarily because we don't
+        * want to change *many* call functions, so ext4_get_blocks()
+        * will set the magic i_delalloc_reserved_flag once the
+        * inode's allocation semaphore is taken.
+        *
+        * If the blocks in questions were delalloc blocks, set
+        * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
+        * variables are updated after the blocks have been allocated.
+        */
+       new.b_state = 0;
+       get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
+                           EXT4_GET_BLOCKS_DELALLOC_RESERVE);
+       if (mpd->b_state & (1 << BH_Delay))
+               get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
+       blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
+                              &new, get_blocks_flags);
+       if (blks < 0) {
+               err = blks;
                /*
                 * If get block returns with error we simply
                 * return. Later writepage will redirty the page and
@@ -2100,12 +2126,14 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
                if (err == -ENOSPC) {
                        ext4_print_free_blocks(mpd->inode);
                }
-               /* invlaidate all the pages */
+               /* invalidate all the pages */
                ext4_da_block_invalidatepages(mpd, next,
                                mpd->b_size >> mpd->inode->i_blkbits);
                return err;
        }
-       BUG_ON(new.b_size == 0);
+       BUG_ON(blks == 0);
+
+       new.b_size = (blks << mpd->inode->i_blkbits);
 
        if (buffer_new(&new))
                __unmap_underlying_blocks(mpd->inode, &new);
@@ -2118,6 +2146,25 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
            (mpd->b_state & (1 << BH_Unwritten)))
                mpage_put_bnr_to_bhs(mpd, next, &new);
 
+       if (ext4_should_order_data(mpd->inode)) {
+               err = ext4_jbd2_file_inode(handle, mpd->inode);
+               if (err)
+                       return err;
+       }
+
+       /*
+        * Update on-disk size along with block allocation we don't
+        * use EXT4_GET_BLOCKS_EXTEND_DISKSIZE as size may change
+        * within already allocated block -bzzz
+        */
+       disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
+       if (disksize > i_size_read(mpd->inode))
+               disksize = i_size_read(mpd->inode);
+       if (disksize > EXT4_I(mpd->inode)->i_disksize) {
+               ext4_update_i_disksize(mpd->inode, disksize);
+               return ext4_mark_inode_dirty(handle, mpd->inode);
+       }
+
        return 0;
 }
 
@@ -2192,6 +2239,17 @@ flush_it:
        return;
 }
 
+static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
+{
+       /*
+        * unmapped buffer is possible for holes.
+        * delay buffer is possible with delayed allocation.
+        * We also need to consider unwritten buffer as unmapped.
+        */
+       return (!buffer_mapped(bh) || buffer_delay(bh) ||
+                               buffer_unwritten(bh)) && buffer_dirty(bh);
+}
+
 /*
  * __mpage_da_writepage - finds extent of pages and blocks
  *
@@ -2276,8 +2334,7 @@ static int __mpage_da_writepage(struct page *page,
                         * Otherwise we won't make progress
                         * with the page in ext4_da_writepage
                         */
-                       if (buffer_dirty(bh) &&
-                           (!buffer_mapped(bh) || buffer_delay(bh))) {
+                       if (ext4_bh_unmapped_or_delay(NULL, bh)) {
                                mpage_add_bh_to_extent(mpd, logical,
                                                       bh->b_size,
                                                       bh->b_state);
@@ -2303,8 +2360,16 @@ static int __mpage_da_writepage(struct page *page,
 }
 
 /*
- * this is a special callback for ->write_begin() only
- * it's intention is to return mapped block or reserve space
+ * This is a special get_blocks_t callback which is used by
+ * ext4_da_write_begin().  It will either return mapped block or
+ * reserve space for a single block.
+ *
+ * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
+ * We also have b_blocknr = -1 and b_bdev initialized properly
+ *
+ * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
+ * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
+ * initialized properly.
  */
 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                                  struct buffer_head *bh_result, int create)
@@ -2323,7 +2388,7 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
         * preallocated blocks are unmapped but should treated
         * the same as allocated blocks.
         */
-       ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1,  bh_result, 0, 0, 0);
+       ret = ext4_get_blocks(NULL, inode, iblock, 1,  bh_result, 0);
        if ((ret == 0) && !buffer_delay(bh_result)) {
                /* the block isn't (pre)allocated yet, let's reserve space */
                /*
@@ -2340,40 +2405,53 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                set_buffer_delay(bh_result);
        } else if (ret > 0) {
                bh_result->b_size = (ret << inode->i_blkbits);
-               /*
-                * With sub-block writes into unwritten extents
-                * we also need to mark the buffer as new so that
-                * the unwritten parts of the buffer gets correctly zeroed.
-                */
-               if (buffer_unwritten(bh_result))
+               if (buffer_unwritten(bh_result)) {
+                       /* A delayed write to unwritten bh should
+                        * be marked new and mapped.  Mapped ensures
+                        * that we don't do get_block multiple times
+                        * when we write to the same offset and new
+                        * ensures that we do proper zero out for
+                        * partial write.
+                        */
                        set_buffer_new(bh_result);
+                       set_buffer_mapped(bh_result);
+               }
                ret = 0;
        }
 
        return ret;
 }
 
-static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
-{
-       /*
-        * unmapped buffer is possible for holes.
-        * delay buffer is possible with delayed allocation
-        */
-       return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh));
-}
-
-static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
+/*
+ * This function is used as a standard get_block_t calback function
+ * when there is no desire to allocate any blocks.  It is used as a
+ * callback function for block_prepare_write(), nobh_writepage(), and
+ * block_write_full_page().  These functions should only try to map a
+ * single block at a time.
+ *
+ * Since this function doesn't do block allocations even if the caller
+ * requests it by passing in create=1, it is critically important that
+ * any caller checks to make sure that any buffer heads are returned
+ * by this function are either all already mapped or marked for
+ * delayed allocation before calling nobh_writepage() or
+ * block_write_full_page().  Otherwise, b_blocknr could be left
+ * unitialized, and the page write functions will be taken by
+ * surprise.
+ */
+static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
                                   struct buffer_head *bh_result, int create)
 {
        int ret = 0;
        unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
 
+       BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
+
        /*
         * we don't want to do block allocation in writepage
         * so call get_block_wrap with create = 0
         */
-       ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks,
-                                  bh_result, 0, 0, 0);
+       ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
+       BUG_ON(create && ret == 0);
        if (ret > 0) {
                bh_result->b_size = (ret << inode->i_blkbits);
                ret = 0;
@@ -2382,10 +2460,11 @@ static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
 }
 
 /*
- * get called vi ext4_da_writepages after taking page lock (have journal handle)
- * get called via journal_submit_inode_data_buffers (no journal handle)
- * get called via shrink_page_list via pdflush (no journal handle)
- * or grab_page_cache when doing write_begin (have journal handle)
+ * This function can get called via...
+ *   - ext4_da_writepages after taking page lock (have journal handle)
+ *   - journal_submit_inode_data_buffers (no journal handle)
+ *   - shrink_page_list via pdflush (no journal handle)
+ *   - grab_page_cache when doing write_begin (have journal handle)
  */
 static int ext4_da_writepage(struct page *page,
                                struct writeback_control *wbc)
@@ -2436,7 +2515,7 @@ static int ext4_da_writepage(struct page *page,
                 * do block allocation here.
                 */
                ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
-                                               ext4_normal_get_block_write);
+                                         noalloc_get_block_write);
                if (!ret) {
                        page_bufs = page_buffers(page);
                        /* check whether all are mapped and non delay */
@@ -2461,11 +2540,10 @@ static int ext4_da_writepage(struct page *page,
        }
 
        if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
-               ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
+               ret = nobh_writepage(page, noalloc_get_block_write, wbc);
        else
-               ret = block_write_full_page(page,
-                                               ext4_normal_get_block_write,
-                                               wbc);
+               ret = block_write_full_page(page, noalloc_get_block_write,
+                                           wbc);
 
        return ret;
 }
@@ -2777,7 +2855,7 @@ retry:
        *pagep = page;
 
        ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-                                                       ext4_da_get_block_prep);
+                               ext4_da_get_block_prep);
        if (ret < 0) {
                unlock_page(page);
                ext4_journal_stop(handle);
@@ -2815,7 +2893,7 @@ static int ext4_da_should_update_i_disksize(struct page *page,
        for (i = 0; i < idx; i++)
                bh = bh->b_this_page;
 
-       if (!buffer_mapped(bh) || (buffer_delay(bh)))
+       if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
                return 0;
        return 1;
 }
@@ -3085,12 +3163,10 @@ static int __ext4_normal_writepage(struct page *page,
        struct inode *inode = page->mapping->host;
 
        if (test_opt(inode->i_sb, NOBH))
-               return nobh_writepage(page,
-                                       ext4_normal_get_block_write, wbc);
+               return nobh_writepage(page, noalloc_get_block_write, wbc);
        else
-               return block_write_full_page(page,
-                                               ext4_normal_get_block_write,
-                                               wbc);
+               return block_write_full_page(page, noalloc_get_block_write,
+                                            wbc);
 }
 
 static int ext4_normal_writepage(struct page *page,
@@ -3142,7 +3218,7 @@ static int __ext4_journalled_writepage(struct page *page,
        int err;
 
        ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
-                                       ext4_normal_get_block_write);
+                                 noalloc_get_block_write);
        if (ret != 0)
                goto out_unlock;
 
@@ -3227,9 +3303,8 @@ static int ext4_journalled_writepage(struct page *page,
                 * really know unless we go poke around in the buffer_heads.
                 * But block_write_full_page will do the right thing.
                 */
-               return block_write_full_page(page,
-                                               ext4_normal_get_block_write,
-                                               wbc);
+               return block_write_full_page(page, noalloc_get_block_write,
+                                            wbc);
        }
 no_write:
        redirty_page_for_writepage(wbc, page);
@@ -4930,7 +5005,8 @@ static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
  */
 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
 {
-       int groups, gdpblocks;
+       ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
+       int gdpblocks;
        int idxblocks;
        int ret = 0;
 
@@ -4957,8 +5033,8 @@ int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
                groups += nrblocks;
 
        gdpblocks = groups;
-       if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
-               groups = EXT4_SB(inode->i_sb)->s_groups_count;
+       if (groups > ngroups)
+               groups = ngroups;
        if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
                gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
 
@@ -4998,7 +5074,7 @@ int ext4_writepage_trans_blocks(struct inode *inode)
  * Calculate the journal credits for a chunk of data modification.
  *
  * This is called from DIO, fallocate or whoever calling
- * ext4_get_blocks_wrap() to map/allocate a chunk of contigous disk blocks.
+ * ext4_get_blocks() to map/allocate a chunk of contigous disk blocks.
  *
  * journal buffers for data blocks are not included here, as DIO
  * and fallocate do no need to journal data buffers.