ext4: add new pending reservation mechanism

Add new pending reservation mechanism to help manage reserved cluster
accounting.  Its primary function is to avoid the need to read extents
from the disk when invalidating pages as a result of a truncate, punch
hole, or collapse range operation.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ad2c215720be..fc0f41dbf90b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1030,6 +1030,9 @@ struct ext4_inode_info {
         ext4_lblk_t i_da_metadata_calc_last_lblock;
         int i_da_metadata_calc_len;
 
+        /* pending cluster reservations for bigalloc file systems */
+        struct ext4_pending_tree i_pending_tree;
+
         /* on-disk additional length */
         __u16 i_extra_isize;