diff options
| -rw-r--r-- | fs/ext4/move_extent.c | 117 |
1 files changed, 53 insertions, 64 deletions
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 83f8c9e47c60..a7410b34c5ed 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -77,12 +77,14 @@ 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 +121,18 @@ 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; } } @@ -155,40 +166,15 @@ mext_check_null_inode(struct inode *inode1, struct inode *inode2, } /** - * mext_double_down_read - Acquire two inodes' read semaphore - * - * @orig_inode: original inode structure - * @donor_inode: donor inode structure - * Acquire read semaphore 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 + * 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 write 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_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; @@ -207,28 +193,14 @@ mext_double_down_write(struct inode *orig_inode, struct inode *donor_inode) } /** - * mext_double_up_read - Release two inodes' read 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 read 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_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); -} - -/** - * mext_double_up_write - Release two inodes' write semaphore - * - * @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). - */ -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); @@ -688,8 +660,6 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, int replaced_count = 0; int dext_alen; - mext_double_down_write(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) @@ -785,7 +755,6 @@ out: kfree(donor_path); } - mext_double_up_write(orig_inode, donor_inode); return replaced_count; } @@ -851,6 +820,11 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode, * Just swap data blocks between orig and donor. */ if (uninit) { + /* + * Protect extent trees against block allocations + * via delalloc + */ + double_down_write_data_sem(orig_inode, donor_inode); replaced_count = mext_replace_branches(handle, orig_inode, donor_inode, orig_blk_offset, block_len_in_page, err); @@ -858,6 +832,7 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode, /* Clear the inode cache not to refer to the old data */ ext4_ext_invalidate_cache(orig_inode); ext4_ext_invalidate_cache(donor_inode); + double_up_write_data_sem(orig_inode, donor_inode); goto out2; } @@ -905,6 +880,8 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode, /* Release old bh and drop refs */ try_to_release_page(page, 0); + /* Protect extent trees against block allocations via delalloc */ + double_down_write_data_sem(orig_inode, donor_inode); replaced_count = mext_replace_branches(handle, orig_inode, donor_inode, orig_blk_offset, block_len_in_page, &err2); @@ -913,14 +890,18 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode, block_len_in_page = replaced_count; replaced_size = block_len_in_page << orig_inode->i_blkbits; - } else + } else { + double_up_write_data_sem(orig_inode, donor_inode); 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); + double_up_write_data_sem(orig_inode, donor_inode); + if (!page_has_buffers(page)) create_empty_buffers(page, 1 << orig_inode->i_blkbits, 0); @@ -1236,16 +1217,16 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, return -EINVAL; } - /* protect orig and donor against a truncate */ + /* 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); if (ret1) goto out; @@ -1308,6 +1289,10 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, ext4_ext_get_actual_len(ext_cur), block_end + 1) - max(le32_to_cpu(ext_cur->ee_block), block_start); + /* Discard preallocations of two inodes */ + ext4_discard_preallocations(orig_inode); + ext4_discard_preallocations(donor_inode); + while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) { seq_blocks += add_blocks; @@ -1359,14 +1344,14 @@ 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) { @@ -1381,14 +1366,14 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, /* Count how many blocks we have exchanged */ *moved_len += block_len_in_page; if (ret1 < 0) - goto out; + break; if (*moved_len > len) { ext4_error(orig_inode->i_sb, __func__, "We replaced blocks too much! " "sum of replaced: %llu requested: %llu", *moved_len, len); ret1 = -EIO; - goto out; + break; } orig_page_offset++; @@ -1400,6 +1385,10 @@ 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); @@ -1429,7 +1418,7 @@ 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) |