ext4: journal credits reservation fixes for DIO, fallocate

DIO and fallocate credit calculation is different than writepage, as
they do start a new journal right for each call to ext4_get_blocks_wrap().
This patch uses the helper function in DIO and fallocate case, passing
a flag indicating that the modified data are contigous thus could account
less indirect/index blocks.

This patch also fixed the journal credit reservation for direct I/O
(DIO).  Previously the estimated credits for DIO only was calculated for
non-extent files, which was not enough if the file is extent-based.

Also fixed was fallocate double-counting credits for modifying the the
superblock.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 5 insertions, 6 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 5c5dd3a1d657..5596b70efa20 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1758,7 +1758,7 @@ int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int num,
 {
         if (path) {
                 int depth = ext_depth(inode);
-                int ret;
+                int ret = 0;
 
                 /* probably there is space in leaf? */
                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
@@ -1777,7 +1777,7 @@ int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int num,
                 }
         }
 
-        return ext4_meta_trans_blocks(inode, num, 1);
+        return ext4_chunk_trans_blocks(inode, num);
 }
 
 /*
@@ -2810,7 +2810,7 @@ void ext4_ext_truncate(struct inode *inode)
         /*
          * probably first extent we're gonna free will be last in block
          */
-        err = ext4_writepage_trans_blocks(inode) + 3;
+        err = ext4_writepage_trans_blocks(inode);
         handle = ext4_journal_start(inode, err);
         if (IS_ERR(handle))
                 return;
@@ -2923,10 +2923,9 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
                                                         - block;
         /*
-         * credits to insert 1 extent into extent tree + buffers to be able to
-         * modify 1 super block, 1 block bitmap and 1 group descriptor.
+         * credits to insert 1 extent into extent tree
          */
-        credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
+        credits = ext4_chunk_trans_blocks(inode, max_blocks);
         mutex_lock(&inode->i_mutex);
 retry:
         while (ret >= 0 && ret < max_blocks) {