From: Andreas Gruenbacher <agrue...@redhat.com>
First, this function truncates the file in chunks. When the original
file size isn't block aligned, each chunk that is truncated will remain
be misaligned. This is inefficient.
Second, this function doesn't recognize where holes are, so it loops
through them. For each chunk of a hole, it creates a new transaction.
At least avoid creating another transactions whe the current one is
still empty. (An better fix would be to skip large holes, of course.)
Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
Signed-off-by: Bob Peterson <rpete...@redhat.com>
---
fs/gfs2/bmap.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 963117f704bf..de0c3e3c1374 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1003,11 +1003,24 @@ static int gfs2_journaled_truncate(struct inode *inode,
u64 oldsize, u64 newsize
int error;
while (oldsize != newsize) {
+ struct gfs2_trans *tr;
+ unsigned int offs;
+
chunk = oldsize - newsize;
if (chunk > max_chunk)
chunk = max_chunk;
+
+ offs = oldsize & ~PAGE_MASK;
+ if (offs && chunk > PAGE_SIZE)
+ chunk = offs + ((chunk - offs) & PAGE_MASK);
+
truncate_pagecache(inode, oldsize - chunk);
oldsize -= chunk;
+
+ tr = current->journal_info;
+ if (!test_bit(TR_TOUCHED, &tr->tr_flags))
+ continue;
+
gfs2_trans_end(sdp);
error = gfs2_trans_begin(sdp, RES_DINODE, GFS2_JTRUNC_REVOKES);
if (error)
--
2.14.3
