ext4: simplify mpage_add_bh_to_extent()

The argument b_size of mpage_add_bh_to_extent() was bogus since it was
always == blocksize (which we can easily derive from inode->i_blkbits).
Also second branch of condition:
	if (nrblocks >= EXT4_MAX_TRANS_DATA) {
	} else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
						EXT4_MAX_TRANS_DATA) {
	}
was never taken because (b_size >> mpd->inode->i_blkbits) == 1.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 9 insertions, 20 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 8a89cbbf0f1a..6824cb1bd1bb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1647,16 +1647,16 @@ submit_io:
  *
  * @mpd->lbh - extent of blocks
  * @logical - logical number of the block in the file
- * @bh - bh of the block (used to access block's state)
+ * @b_state - b_state of the buffer head added
  *
  * the function is used to collect contig. blocks in same state
  */
-static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
-                                   sector_t logical, size_t b_size,
+static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, sector_t logical,
                                    unsigned long b_state)
 {
         sector_t next;
-        int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
+        int blkbits = mpd->inode->i_blkbits;
+        int nrblocks = mpd->b_size >> blkbits;
 
         /*
          * XXX Don't go larger than mballoc is willing to allocate
@@ -1664,11 +1664,11 @@ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
          * mpage_da_submit_io() into this function and then call
          * ext4_map_blocks() multiple times in a loop
          */
-        if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
+        if (nrblocks >= (8*1024*1024 >> blkbits))
                 goto flush_it;
 
-        /* check if thereserved journal credits might overflow */
-        if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
+        /* check if the reserved journal credits might overflow */
+        if (!ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS)) {
                 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
                         /*
                          * With non-extent format we are limited by the journal
@@ -1677,16 +1677,6 @@ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
                          * 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 */
                 }
         }
         /*
@@ -1694,7 +1684,7 @@ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
          */
         if (mpd->b_size == 0) {
                 mpd->b_blocknr = logical;
-                mpd->b_size = b_size;
+                mpd->b_size = 1 << blkbits;
                 mpd->b_state = b_state & BH_FLAGS;
                 return;
         }
@@ -1704,7 +1694,7 @@ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
          * Can we merge the block to our big extent?
          */
         if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
-                mpd->b_size += b_size;
+                mpd->b_size += 1 << blkbits;
                 return;
         }
 
@@ -2156,7 +2146,6 @@ static int write_cache_pages_da(handle_t *handle,
                                  */
                                 if (ext4_bh_delay_or_unwritten(NULL, bh)) {
                                         mpage_add_bh_to_extent(mpd, logical,
-                                                               bh->b_size,
                                                                bh->b_state);
                                         if (mpd->io_done)
                                                 goto ret_extent_tail;