From 6b523df4fb5ae281ddbc817f40504b33e6226554 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 4 Jun 2013 13:21:11 -0400 Subject: ext4: use transaction reservation for extent conversion in ext4_end_io Later we would like to clear PageWriteback bit only after extent conversion from unwritten to written extents is performed. However it is not possible to start a transaction after PageWriteback is set because that violates lock ordering (and is easy to deadlock). So we have to reserve a transaction before locking pages and sending them for IO and later we use the transaction for extent conversion from ext4_end_io(). Reviewed-by: Zheng Liu Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 736d164dc2ba..510dba785db4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1410,6 +1410,7 @@ static void ext4_da_page_release_reservation(struct page *page, struct mpage_da_data { struct inode *inode; struct writeback_control *wbc; + pgoff_t first_page; /* The first page to write */ pgoff_t next_page; /* Current page to examine */ pgoff_t last_page; /* Last page to examine */ @@ -2108,8 +2109,14 @@ static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd) err = ext4_map_blocks(handle, inode, map, get_blocks_flags); if (err < 0) return err; - if (map->m_flags & EXT4_MAP_UNINIT) + if (map->m_flags & EXT4_MAP_UNINIT) { + if (!mpd->io_submit.io_end->handle && + ext4_handle_valid(handle)) { + mpd->io_submit.io_end->handle = handle->h_rsv_handle; + handle->h_rsv_handle = NULL; + } ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end); + } BUG_ON(map->m_len == 0); if (map->m_flags & EXT4_MAP_NEW) { @@ -2351,7 +2358,7 @@ static int ext4_da_writepages(struct address_space *mapping, handle_t *handle = NULL; struct mpage_da_data mpd; struct inode *inode = mapping->host; - int needed_blocks, ret = 0; + int needed_blocks, rsv_blocks = 0, ret = 0; struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); bool done; struct blk_plug plug; @@ -2379,6 +2386,14 @@ static int ext4_da_writepages(struct address_space *mapping, if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) return -EROFS; + if (ext4_should_dioread_nolock(inode)) { + /* + * We may need to convert upto one extent per block in + * the page and we may dirty the inode. + */ + rsv_blocks = 1 + (PAGE_CACHE_SIZE >> inode->i_blkbits); + } + /* * If we have inline data and arrive here, it means that * we will soon create the block for the 1st page, so @@ -2438,8 +2453,8 @@ retry: needed_blocks = ext4_da_writepages_trans_blocks(inode); /* start a new transaction */ - handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, - needed_blocks); + handle = ext4_journal_start_with_reserve(inode, + EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: " @@ -3120,7 +3135,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, * for non AIO case, since the IO is already * completed, we could do the conversion right here */ - err = ext4_convert_unwritten_extents(inode, + err = ext4_convert_unwritten_extents(NULL, inode, offset, ret); if (err < 0) ret = err; -- cgit v1.2.3