static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
sector_t logical, struct buffer_head *bh)
{
- struct buffer_head *lbh = &mpd->lbh;
sector_t next;
+ size_t b_size = bh->b_size;
+ struct buffer_head *lbh = &mpd->lbh;
+ int nrblocks = lbh->b_size >> mpd->inode->i_blkbits;
- next = lbh->b_blocknr + (lbh->b_size >> mpd->inode->i_blkbits);
-
+ /* check if thereserved journal credits might overflow */
+ if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
+ if (nrblocks >= EXT4_MAX_TRANS_DATA) {
+ /*
+ * With non-extent format we are limited by the journal
+ * credit available. Total credit needed to insert
+ * nrblocks contiguous blocks is dependent on the
+ * nrblocks. So limit nrblocks.
+ */
+ goto flush_it;
+ } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
+ EXT4_MAX_TRANS_DATA) {
+ /*
+ * Adding the new buffer_head would make it cross the
+ * allowed limit for which we have journal credit
+ * reserved. So limit the new bh->b_size
+ */
+ b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
+ mpd->inode->i_blkbits;
+ /* we will do mpage_da_submit_io in the next loop */
+ }
+ }
/*
* First block in the extent
*/
if (lbh->b_size == 0) {
lbh->b_blocknr = logical;
- lbh->b_size = bh->b_size;
+ lbh->b_size = b_size;
lbh->b_state = bh->b_state & BH_FLAGS;
return;
}
+ next = lbh->b_blocknr + nrblocks;
/*
* Can we merge the block to our big extent?
*/
if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) {
- lbh->b_size += bh->b_size;
+ lbh->b_size += b_size;
return;
}
+flush_it:
/*
* We couldn't merge the block to our extent, so we
* need to flush current extent and start new one
}
/*
- * For now just follow the DIO way to estimate the max credits
- * needed to write out EXT4_MAX_WRITEBACK_PAGES.
- * todo: need to calculate the max credits need for
- * extent based files, currently the DIO credits is based on
- * indirect-blocks mapping way.
- *
- * Probably should have a generic way to calculate credits
- * for DIO, writepages, and truncate
+ * This is called via ext4_da_writepages() to
+ * calulate the total number of credits to reserve to fit
+ * a single extent allocation into a single transaction,
+ * ext4_da_writpeages() will loop calling this before
+ * the block allocation.
*/
-#define EXT4_MAX_WRITEBACK_PAGES DIO_MAX_BLOCKS
-#define EXT4_MAX_WRITEBACK_CREDITS 25
+
+static int ext4_da_writepages_trans_blocks(struct inode *inode)
+{
+ int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+
+ /*
+ * With non-extent format the journal credit needed to
+ * insert nrblocks contiguous block is dependent on
+ * number of contiguous block. So we will limit
+ * number of contiguous block to a sane value
+ */
+ if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
+ (max_blocks > EXT4_MAX_TRANS_DATA))
+ max_blocks = EXT4_MAX_TRANS_DATA;
+
+ return ext4_chunk_trans_blocks(inode, max_blocks);
+}
static int ext4_da_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
- struct inode *inode = mapping->host;
handle_t *handle = NULL;
- int needed_blocks;
- int ret = 0;
- long to_write;
loff_t range_start = 0;
- long pages_skipped = 0;
+ struct inode *inode = mapping->host;
+ int needed_blocks, ret = 0, nr_to_writebump = 0;
+ long to_write, pages_skipped = 0;
+ struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
/*
* No pages to write? This is mainly a kludge to avoid starting
*/
if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
return 0;
+ /*
+ * Make sure nr_to_write is >= sbi->s_mb_stream_request
+ * This make sure small files blocks are allocated in
+ * single attempt. This ensure that small files
+ * get less fragmented.
+ */
+ if (wbc->nr_to_write < sbi->s_mb_stream_request) {
+ nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
+ wbc->nr_to_write = sbi->s_mb_stream_request;
+ }
if (!wbc->range_cyclic)
/*
* by delalloc
*/
BUG_ON(ext4_should_journal_data(inode));
- needed_blocks = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+ needed_blocks = ext4_da_writepages_trans_blocks(inode);
/* start a new transaction*/
handle = ext4_journal_start(inode, needed_blocks);
}
out_writepages:
- wbc->nr_to_write = to_write;
+ wbc->nr_to_write = to_write - nr_to_writebump;
wbc->range_start = range_start;
return ret;
}
* the modification of a single pages into a single transaction,
* which may include multiple chunks of block allocations.
*
- * This could be called via ext4_write_begin() or later
- * ext4_da_writepages() in delalyed allocation case.
+ * This could be called via ext4_write_begin()
*
- * In both case it's possible that we could allocating multiple
- * chunks of blocks. We need to consider the worse case, when
+ * We need to consider the worse case, when
* one new block per extent.
*/
int ext4_writepage_trans_blocks(struct inode *inode)
projects / linux-2.6 / blobdiff