From b6349ac89eacb813f6963f7263da05bc3f483351 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Tue, 20 Apr 2010 21:44:10 +0200 Subject: [PATCH] [LogFS] Split large truncated into smaller chunks Truncate would do an almost limitless amount of work without invoking the garbage collector in between. Split it up into more manageable, though still large, chunks. Signed-off-by: Joern Engel --- fs/logfs/readwrite.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c index aca6c56a107..7e3a1e5fd76 100644 --- a/fs/logfs/readwrite.c +++ b/fs/logfs/readwrite.c @@ -1837,19 +1837,37 @@ static int __logfs_truncate(struct inode *inode, u64 size) return logfs_truncate_direct(inode, size); } -int logfs_truncate(struct inode *inode, u64 size) +/* + * Truncate, by changing the segment file, can consume a fair amount + * of resources. So back off from time to time and do some GC. + * 8 or 2048 blocks should be well within safety limits even if + * every single block resided in a different segment. + */ +#define TRUNCATE_STEP (8 * 1024 * 1024) +int logfs_truncate(struct inode *inode, u64 target) { struct super_block *sb = inode->i_sb; - int err; + u64 size = i_size_read(inode); + int err = 0; - logfs_get_wblocks(sb, NULL, 1); - err = __logfs_truncate(inode, size); - if (!err) - err = __logfs_write_inode(inode, 0); - logfs_put_wblocks(sb, NULL, 1); + size = ALIGN(size, TRUNCATE_STEP); + while (size > target) { + if (size > TRUNCATE_STEP) + size -= TRUNCATE_STEP; + else + size = 0; + if (size < target) + size = target; + + logfs_get_wblocks(sb, NULL, 1); + err = __logfs_truncate(inode, target); + if (!err) + err = __logfs_write_inode(inode, 0); + logfs_put_wblocks(sb, NULL, 1); + } if (!err) - err = vmtruncate(inode, size); + err = vmtruncate(inode, target); /* I don't trust error recovery yet. */ WARN_ON(err); -- 2.20.1