1 files changed, 150 insertions, 163 deletions

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 25b6b1457360..d1fc662cc311 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -15,6 +15,7 @@
 
 #include <linux/fs.h>
 #include <linux/quotaops.h>
+#include <linux/slab.h>
 #include "ext4_jbd2.h"
 #include "ext4_extents.h"
 #include "ext4.h"
@@ -77,12 +78,14 @@ static int
 mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
                       struct ext4_extent **extent)
 {
+        struct ext4_extent_header *eh;
         int ppos, leaf_ppos = path->p_depth;
 
         ppos = leaf_ppos;
         if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) {
                 /* leaf block */
                 *extent = ++path[ppos].p_ext;
+                path[ppos].p_block = ext_pblock(path[ppos].p_ext);
                 return 0;
         }
 
@@ -119,9 +122,18 @@ mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
                                         ext_block_hdr(path[cur_ppos+1].p_bh);
                         }
 
+                        path[leaf_ppos].p_ext = *extent = NULL;
+
+                        eh = path[leaf_ppos].p_hdr;
+                        if (le16_to_cpu(eh->eh_entries) == 0)
+                                /* empty leaf is found */
+                                return -ENODATA;
+
                         /* leaf block */
                         path[leaf_ppos].p_ext = *extent =
                                 EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr);
+                        path[leaf_ppos].p_block =
+                                        ext_pblock(path[leaf_ppos].p_ext);
                         return 0;
                 }
         }
@@ -141,12 +153,12 @@ mext_check_null_inode(struct inode *inode1, struct inode *inode2,
         int ret = 0;
 
         if (inode1 == NULL) {
-                ext4_error(inode2->i_sb, function,
+                __ext4_error(inode2->i_sb, function,
                         "Both inodes should not be NULL: "
                         "inode1 NULL inode2 %lu", inode2->i_ino);
                 ret = -EIO;
         } else if (inode2 == NULL) {
-                ext4_error(inode1->i_sb, function,
+                __ext4_error(inode1->i_sb, function,
                         "Both inodes should not be NULL: "
                         "inode1 %lu inode2 NULL", inode1->i_ino);
                 ret = -EIO;
@@ -155,40 +167,15 @@ mext_check_null_inode(struct inode *inode1, struct inode *inode2,
 }
 
 /**
- * mext_double_down_read - Acquire two inodes' read semaphore
+ * double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
  *
  * @orig_inode:         original inode structure
  * @donor_inode:        donor inode structure
- * Acquire read semaphore of the two inodes (orig and donor) by i_ino order.
+ * Acquire write lock of i_data_sem of the two inodes (orig and donor) by
+ * i_ino order.
  */
 static void
-mext_double_down_read(struct inode *orig_inode, struct inode *donor_inode)
-{
-        struct inode *first = orig_inode, *second = donor_inode;
-
-        /*
-         * Use the inode number to provide the stable locking order instead
-         * of its address, because the C language doesn't guarantee you can
-         * compare pointers that don't come from the same array.
-         */
-        if (donor_inode->i_ino < orig_inode->i_ino) {
-                first = donor_inode;
-                second = orig_inode;
-        }
-
-        down_read(&EXT4_I(first)->i_data_sem);
-        down_read(&EXT4_I(second)->i_data_sem);
-}
-
-/**
- * mext_double_down_write - Acquire two inodes' write semaphore
- *
- * @orig_inode:         original inode structure
- * @donor_inode:        donor inode structure
- * Acquire write semaphore of the two inodes (orig and donor) by i_ino order.
- */
-static void
-mext_double_down_write(struct inode *orig_inode, struct inode *donor_inode)
+double_down_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
 {
         struct inode *first = orig_inode, *second = donor_inode;
 
@@ -203,32 +190,18 @@ mext_double_down_write(struct inode *orig_inode, struct inode *donor_inode)
         }
 
         down_write(&EXT4_I(first)->i_data_sem);
-        down_write(&EXT4_I(second)->i_data_sem);
-}
-
-/**
- * mext_double_up_read - Release two inodes' read semaphore
- *
- * @orig_inode:         original inode structure to be released its lock first
- * @donor_inode:        donor inode structure to be released its lock second
- * Release read semaphore of two inodes (orig and donor).
- */
-static void
-mext_double_up_read(struct inode *orig_inode, struct inode *donor_inode)
-{
-        up_read(&EXT4_I(orig_inode)->i_data_sem);
-        up_read(&EXT4_I(donor_inode)->i_data_sem);
+        down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
 }
 
 /**
- * mext_double_up_write - Release two inodes' write semaphore
+ * double_up_write_data_sem - Release two inodes' write lock of i_data_sem
  *
  * @orig_inode:         original inode structure to be released its lock first
  * @donor_inode:        donor inode structure to be released its lock second
- * Release write semaphore of two inodes (orig and donor).
+ * Release write lock of i_data_sem of two inodes (orig and donor).
  */
 static void
-mext_double_up_write(struct inode *orig_inode, struct inode *donor_inode)
+double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
 {
         up_write(&EXT4_I(orig_inode)->i_data_sem);
         up_write(&EXT4_I(donor_inode)->i_data_sem);
@@ -280,6 +253,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
                 }
 
                 o_start->ee_len = start_ext->ee_len;
+                eblock = le32_to_cpu(start_ext->ee_block);
                 new_flag = 1;
 
         } else if (start_ext->ee_len && new_ext->ee_len &&
@@ -290,6 +264,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
                  * orig  |------------------------------|
                  */
                 o_start->ee_len = start_ext->ee_len;
+                eblock = le32_to_cpu(start_ext->ee_block);
                 new_flag = 1;
 
         } else if (!start_ext->ee_len && new_ext->ee_len &&
@@ -503,7 +478,6 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
         struct ext4_extent *oext, *o_start, *o_end, *prev_ext;
         struct ext4_extent new_ext, start_ext, end_ext;
         ext4_lblk_t new_ext_end;
-        ext4_fsblk_t new_phys_end;
         int oext_alen, new_ext_alen, end_ext_alen;
         int depth = ext_depth(orig_inode);
         int ret;
@@ -517,7 +491,6 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
         new_ext.ee_len = dext->ee_len;
         new_ext_alen = ext4_ext_get_actual_len(&new_ext);
         new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
-        new_phys_end = ext_pblock(&new_ext) + new_ext_alen - 1;
 
         /*
          * Case: original extent is first
@@ -530,6 +503,7 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
                 le32_to_cpu(oext->ee_block) + oext_alen) {
                 start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
                                                le32_to_cpu(oext->ee_block));
+                start_ext.ee_block = oext->ee_block;
                 copy_extent_status(oext, &start_ext);
         } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
                 prev_ext = oext - 1;
@@ -543,6 +517,7 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
                         start_ext.ee_len = cpu_to_le16(
                                 ext4_ext_get_actual_len(prev_ext) +
                                 new_ext_alen);
+                        start_ext.ee_block = oext->ee_block;
                         copy_extent_status(prev_ext, &start_ext);
                         new_ext.ee_len = 0;
                 }
@@ -554,7 +529,7 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
          * new_ext       |-------|
          */
         if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) {
-                ext4_error(orig_inode->i_sb, __func__,
+                ext4_error(orig_inode->i_sb,
                         "new_ext_end(%u) should be less than or equal to "
                         "oext->ee_block(%u) + oext_alen(%d) - 1",
                         new_ext_end, le32_to_cpu(oext->ee_block),
@@ -596,7 +571,7 @@ out:
  * @tmp_oext:           the extent that will belong to the donor inode
  * @orig_off:           block offset of original inode
  * @donor_off:          block offset of donor inode
- * @max_count:          the maximun length of extents
+ * @max_count:          the maximum length of extents
  *
  * Return 0 on success, or a negative error value on failure.
  */
@@ -661,6 +636,7 @@ mext_calc_swap_extents(struct ext4_extent *tmp_dext,
  * @donor_inode:        donor inode
  * @from:               block offset of orig_inode
  * @count:              block count to be replaced
+ * @err:                pointer to save return value
  *
  * Replace original inode extents and donor inode extents page by page.
  * We implement this replacement in the following three steps:
@@ -671,33 +647,33 @@ mext_calc_swap_extents(struct ext4_extent *tmp_dext,
  * 3. Change the block information of donor inode to point at the saved
  *    original inode blocks in the dummy extents.
  *
- * Return 0 on success, or a negative error value on failure.
+ * Return replaced block count.
  */
 static int
 mext_replace_branches(handle_t *handle, struct inode *orig_inode,
                            struct inode *donor_inode, ext4_lblk_t from,
-                           ext4_lblk_t count)
+                           ext4_lblk_t count, int *err)
 {
         struct ext4_ext_path *orig_path = NULL;
         struct ext4_ext_path *donor_path = NULL;
         struct ext4_extent *oext, *dext;
         struct ext4_extent tmp_dext, tmp_oext;
         ext4_lblk_t orig_off = from, donor_off = from;
-        int err = 0;
         int depth;
         int replaced_count = 0;
         int dext_alen;
 
-        mext_double_down_write(orig_inode, donor_inode);
+        /* Protect extent trees against block allocations via delalloc */
+        double_down_write_data_sem(orig_inode, donor_inode);
 
         /* Get the original extent for the block "orig_off" */
-        err = get_ext_path(orig_inode, orig_off, &orig_path);
-        if (err)
+        *err = get_ext_path(orig_inode, orig_off, &orig_path);
+        if (*err)
                 goto out;
 
         /* Get the donor extent for the head */
-        err = get_ext_path(donor_inode, donor_off, &donor_path);
-        if (err)
+        *err = get_ext_path(donor_inode, donor_off, &donor_path);
+        if (*err)
                 goto out;
         depth = ext_depth(orig_inode);
         oext = orig_path[depth].p_ext;
@@ -707,39 +683,39 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode,
         dext = donor_path[depth].p_ext;
         tmp_dext = *dext;
 
-        err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
+        *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
                                       donor_off, count);
-        if (err)
+        if (*err)
                 goto out;
 
         /* Loop for the donor extents */
         while (1) {
                 /* The extent for donor must be found. */
                 if (!dext) {
-                        ext4_error(donor_inode->i_sb, __func__,
+                        ext4_error(donor_inode->i_sb,
                                    "The extent for donor must be found");
-                        err = -EIO;
+                        *err = -EIO;
                         goto out;
                 } else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) {
-                        ext4_error(donor_inode->i_sb, __func__,
+                        ext4_error(donor_inode->i_sb,
                                 "Donor offset(%u) and the first block of donor "
                                 "extent(%u) should be equal",
                                 donor_off,
                                 le32_to_cpu(tmp_dext.ee_block));
-                        err = -EIO;
+                        *err = -EIO;
                         goto out;
                 }
 
                 /* Set donor extent to orig extent */
-                err = mext_leaf_block(handle, orig_inode,
+                *err = mext_leaf_block(handle, orig_inode,
                                            orig_path, &tmp_dext, &orig_off);
-                if (err < 0)
+                if (*err)
                         goto out;
 
                 /* Set orig extent to donor extent */
-                err = mext_leaf_block(handle, donor_inode,
+                *err = mext_leaf_block(handle, donor_inode,
                                            donor_path, &tmp_oext, &donor_off);
-                if (err < 0)
+                if (*err)
                         goto out;
 
                 dext_alen = ext4_ext_get_actual_len(&tmp_dext);
@@ -753,35 +729,25 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode,
 
                 if (orig_path)
                         ext4_ext_drop_refs(orig_path);
-                err = get_ext_path(orig_inode, orig_off, &orig_path);
-                if (err)
+                *err = get_ext_path(orig_inode, orig_off, &orig_path);
+                if (*err)
                         goto out;
                 depth = ext_depth(orig_inode);
                 oext = orig_path[depth].p_ext;
-                if (le32_to_cpu(oext->ee_block) +
-                                ext4_ext_get_actual_len(oext) <= orig_off) {
-                        err = 0;
-                        goto out;
-                }
                 tmp_oext = *oext;
 
                 if (donor_path)
                         ext4_ext_drop_refs(donor_path);
-                err = get_ext_path(donor_inode, donor_off, &donor_path);
-                if (err)
+                *err = get_ext_path(donor_inode, donor_off, &donor_path);
+                if (*err)
                         goto out;
                 depth = ext_depth(donor_inode);
                 dext = donor_path[depth].p_ext;
-                if (le32_to_cpu(dext->ee_block) +
-                                ext4_ext_get_actual_len(dext) <= donor_off) {
-                        err = 0;
-                        goto out;
-                }
                 tmp_dext = *dext;
 
-                err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
+                *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
                                            donor_off, count - replaced_count);
-                if (err)
+                if (*err)
                         goto out;
         }
 
@@ -795,8 +761,12 @@ out:
                 kfree(donor_path);
         }
 
-        mext_double_up_write(orig_inode, donor_inode);
-        return err;
+        ext4_ext_invalidate_cache(orig_inode);
+        ext4_ext_invalidate_cache(donor_inode);
+
+        double_up_write_data_sem(orig_inode, donor_inode);
+
+        return replaced_count;
 }
 
 /**
@@ -808,16 +778,17 @@ out:
  * @data_offset_in_page:        block index where data swapping starts
  * @block_len_in_page:          the number of blocks to be swapped
  * @uninit:                     orig extent is uninitialized or not
+ * @err:                        pointer to save return value
  *
  * Save the data in original inode blocks and replace original inode extents
  * with donor inode extents by calling mext_replace_branches().
- * Finally, write out the saved data in new original inode blocks. Return 0
- * on success, or a negative error value on failure.
+ * Finally, write out the saved data in new original inode blocks. Return
+ * replaced block count.
  */
 static int
 move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
                   pgoff_t orig_page_offset, int data_offset_in_page,
-                  int block_len_in_page, int uninit)
+                  int block_len_in_page, int uninit, int *err)
 {
         struct inode *orig_inode = o_filp->f_dentry->d_inode;
         struct address_space *mapping = orig_inode->i_mapping;
@@ -829,9 +800,11 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
         long long offs = orig_page_offset << PAGE_CACHE_SHIFT;
         unsigned long blocksize = orig_inode->i_sb->s_blocksize;
         unsigned int w_flags = 0;
-        unsigned int tmp_data_len, data_len;
+        unsigned int tmp_data_size, data_size, replaced_size;
         void *fsdata;
-        int ret, i, jblocks;
+        int i, jblocks;
+        int err2 = 0;
+        int replaced_count = 0;
         int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
 
         /*
@@ -841,8 +814,8 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
         jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
         handle = ext4_journal_start(orig_inode, jblocks);
         if (IS_ERR(handle)) {
-                ret = PTR_ERR(handle);
-                return ret;
+                *err = PTR_ERR(handle);
+                return 0;
         }
 
         if (segment_eq(get_fs(), KERNEL_DS))
@@ -858,39 +831,36 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
          * Just swap data blocks between orig and donor.
          */
         if (uninit) {
-                ret = mext_replace_branches(handle, orig_inode,
-                                                 donor_inode, orig_blk_offset,
-                                                 block_len_in_page);
-
-                /* Clear the inode cache not to refer to the old data */
-                ext4_ext_invalidate_cache(orig_inode);
-                ext4_ext_invalidate_cache(donor_inode);
+                replaced_count = mext_replace_branches(handle, orig_inode,
+                                                donor_inode, orig_blk_offset,
+                                                block_len_in_page, err);
                 goto out2;
         }
 
         offs = (long long)orig_blk_offset << orig_inode->i_blkbits;
 
-        /* Calculate data_len */
+        /* Calculate data_size */
         if ((orig_blk_offset + block_len_in_page - 1) ==
             ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
                 /* Replace the last block */
-                tmp_data_len = orig_inode->i_size & (blocksize - 1);
+                tmp_data_size = orig_inode->i_size & (blocksize - 1);
                 /*
-                 * If data_len equal zero, it shows data_len is multiples of
+                 * If data_size equal zero, it shows data_size is multiples of
                  * blocksize. So we set appropriate value.
                  */
-                if (tmp_data_len == 0)
-                        tmp_data_len = blocksize;
+                if (tmp_data_size == 0)
+                        tmp_data_size = blocksize;
 
-                data_len = tmp_data_len +
+                data_size = tmp_data_size +
                         ((block_len_in_page - 1) << orig_inode->i_blkbits);
-        } else {
-                data_len = block_len_in_page << orig_inode->i_blkbits;
-        }
+        } else
+                data_size = block_len_in_page << orig_inode->i_blkbits;
+
+        replaced_size = data_size;
 
-        ret = a_ops->write_begin(o_filp, mapping, offs, data_len, w_flags,
+        *err = a_ops->write_begin(o_filp, mapping, offs, data_size, w_flags,
                                  &page, &fsdata);
-        if (unlikely(ret < 0))
+        if (unlikely(*err < 0))
                 goto out;
 
         if (!PageUptodate(page)) {
@@ -911,14 +881,17 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
         /* Release old bh and drop refs */
         try_to_release_page(page, 0);
 
-        ret = mext_replace_branches(handle, orig_inode, donor_inode,
-                                         orig_blk_offset, block_len_in_page);
-        if (ret < 0)
-                goto out;
-
-        /* Clear the inode cache not to refer to the old data */
-        ext4_ext_invalidate_cache(orig_inode);
-        ext4_ext_invalidate_cache(donor_inode);
+        replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
+                                        orig_blk_offset, block_len_in_page,
+                                        &err2);
+        if (err2) {
+                if (replaced_count) {
+                        block_len_in_page = replaced_count;
+                        replaced_size =
+                                block_len_in_page << orig_inode->i_blkbits;
+                } else
+                        goto out;
+        }
 
         if (!page_has_buffers(page))
                 create_empty_buffers(page, 1 << orig_inode->i_blkbits, 0);
@@ -928,16 +901,16 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
                 bh = bh->b_this_page;
 
         for (i = 0; i < block_len_in_page; i++) {
-                ret = ext4_get_block(orig_inode,
+                *err = ext4_get_block(orig_inode,
                                 (sector_t)(orig_blk_offset + i), bh, 0);
-                if (ret < 0)
+                if (*err < 0)
                         goto out;
 
                 if (bh->b_this_page != NULL)
                         bh = bh->b_this_page;
         }
 
-        ret = a_ops->write_end(o_filp, mapping, offs, data_len, data_len,
+        *err = a_ops->write_end(o_filp, mapping, offs, data_size, replaced_size,
                                page, fsdata);
         page = NULL;
 
@@ -951,18 +924,20 @@ out:
 out2:
         ext4_journal_stop(handle);
 
-        return ret < 0 ? ret : 0;
+        if (err2)
+                *err = err2;
+
+        return replaced_count;
 }
 
 /**
- * mext_check_argumants - Check whether move extent can be done
+ * mext_check_arguments - Check whether move extent can be done
  *
  * @orig_inode:         original inode
  * @donor_inode:        donor inode
  * @orig_start:         logical start offset in block for orig
  * @donor_start:        logical start offset in block for donor
  * @len:                the number of blocks to be moved
- * @moved_len:          moved block length
  *
  * Check the arguments of ext4_move_extents() whether the files can be
  * exchanged with each other.
@@ -970,18 +945,17 @@ out2:
  */
 static int
 mext_check_arguments(struct inode *orig_inode,
-                          struct inode *donor_inode, __u64 orig_start,
-                          __u64 donor_start, __u64 *len, __u64 moved_len)
+                     struct inode *donor_inode, __u64 orig_start,
+                     __u64 donor_start, __u64 *len)
 {
         ext4_lblk_t orig_blocks, donor_blocks;
         unsigned int blkbits = orig_inode->i_blkbits;
         unsigned int blocksize = 1 << blkbits;
 
-        /* Regular file check */
-        if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
-                ext4_debug("ext4 move extent: The argument files should be "
-                        "regular file [ino:orig %lu, donor %lu]\n",
-                        orig_inode->i_ino, donor_inode->i_ino);
+        if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
+                ext4_debug("ext4 move extent: suid or sgid is set"
+                           " to donor file [ino:orig %lu, donor %lu]\n",
+                           orig_inode->i_ino, donor_inode->i_ino);
                 return -EINVAL;
         }
 
@@ -1025,13 +999,6 @@ mext_check_arguments(struct inode *orig_inode,
                 return -EINVAL;
         }
 
-        if (moved_len) {
-                ext4_debug("ext4 move extent: moved_len should be 0 "
-                        "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
-                        donor_inode->i_ino);
-                return -EINVAL;
-        }
-
         if ((orig_start > EXT_MAX_BLOCK) ||
             (donor_start > EXT_MAX_BLOCK) ||
             (*len > EXT_MAX_BLOCK) ||
@@ -1088,7 +1055,7 @@ mext_check_arguments(struct inode *orig_inode,
         }
 
         if (!*len) {
-                ext4_debug("ext4 move extent: len shoudld not be 0 "
+                ext4_debug("ext4 move extent: len should not be 0 "
                         "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
                         donor_inode->i_ino);
                 return -EINVAL;
@@ -1232,16 +1199,24 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
                 return -EINVAL;
         }
 
-        /* protect orig and donor against a truncate */
+        /* Regular file check */
+        if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
+                ext4_debug("ext4 move extent: The argument files should be "
+                        "regular file [ino:orig %lu, donor %lu]\n",
+                        orig_inode->i_ino, donor_inode->i_ino);
+                return -EINVAL;
+        }
+
+        /* Protect orig and donor inodes against a truncate */
         ret1 = mext_inode_double_lock(orig_inode, donor_inode);
         if (ret1 < 0)
                 return ret1;
 
-        mext_double_down_read(orig_inode, donor_inode);
+        /* Protect extent tree against block allocations via delalloc */
+        double_down_write_data_sem(orig_inode, donor_inode);
         /* Check the filesystem environment whether move_extent can be done */
         ret1 = mext_check_arguments(orig_inode, donor_inode, orig_start,
-                                        donor_start, &len, *moved_len);
-        mext_double_up_read(orig_inode, donor_inode);
+                                    donor_start, &len);
         if (ret1)
                 goto out;
 
@@ -1355,36 +1330,39 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
                 seq_start = le32_to_cpu(ext_cur->ee_block);
                 rest_blocks = seq_blocks;
 
-                /* Discard preallocations of two inodes */
-                down_write(&EXT4_I(orig_inode)->i_data_sem);
-                ext4_discard_preallocations(orig_inode);
-                up_write(&EXT4_I(orig_inode)->i_data_sem);
-
-                down_write(&EXT4_I(donor_inode)->i_data_sem);
-                ext4_discard_preallocations(donor_inode);
-                up_write(&EXT4_I(donor_inode)->i_data_sem);
+                /*
+                 * Up semaphore to avoid following problems:
+                 * a. transaction deadlock among ext4_journal_start,
+                 *    ->write_begin via pagefault, and jbd2_journal_commit
+                 * b. racing with ->readpage, ->write_begin, and ext4_get_block
+                 *    in move_extent_per_page
+                 */
+                double_up_write_data_sem(orig_inode, donor_inode);
 
                 while (orig_page_offset <= seq_end_page) {
 
                         /* Swap original branches with new branches */
-                        ret1 = move_extent_per_page(o_filp, donor_inode,
+                        block_len_in_page = move_extent_per_page(
+                                                o_filp, donor_inode,
                                                 orig_page_offset,
                                                 data_offset_in_page,
-                                                block_len_in_page, uninit);
-                        if (ret1 < 0)
-                                goto out;
-                        orig_page_offset++;
+                                                block_len_in_page, uninit,
+                                                &ret1);
+
                         /* Count how many blocks we have exchanged */
                         *moved_len += block_len_in_page;
+                        if (ret1 < 0)
+                                break;
                         if (*moved_len > len) {
-                                ext4_error(orig_inode->i_sb, __func__,
+                                ext4_error(orig_inode->i_sb,
                                         "We replaced blocks too much! "
                                         "sum of replaced: %llu requested: %llu",
                                         *moved_len, len);
                                 ret1 = -EIO;
-                                goto out;
+                                break;
                         }
 
+                        orig_page_offset++;
                         data_offset_in_page = 0;
                         rest_blocks -= block_len_in_page;
                         if (rest_blocks > blocks_per_page)
@@ -1393,6 +1371,10 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
                                 block_len_in_page = rest_blocks;
                 }
 
+                double_down_write_data_sem(orig_inode, donor_inode);
+                if (ret1 < 0)
+                        break;
+
                 /* Decrease buffer counter */
                 if (holecheck_path)
                         ext4_ext_drop_refs(holecheck_path);
@@ -1414,6 +1396,11 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
 
         }
 out:
+        if (*moved_len) {
+                ext4_discard_preallocations(orig_inode);
+                ext4_discard_preallocations(donor_inode);
+        }
+
         if (orig_path) {
                 ext4_ext_drop_refs(orig_path);
                 kfree(orig_path);
@@ -1422,7 +1409,7 @@ out:
                 ext4_ext_drop_refs(holecheck_path);
                 kfree(holecheck_path);
         }
-
+        double_up_write_data_sem(orig_inode, donor_inode);
         ret2 = mext_inode_double_unlock(orig_inode, donor_inode);
 
         if (ret1)