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ext4: remove wait for unwritten extent conversion from ext4_truncate() 

Since PageWriteback bit is now cleared after extents are converted
from unwritten to written ones, we have full exclusion of writeback
path from truncate (truncate_inode_pages() waits for PageWriteback
bits to get cleared on all invalidated pages).  Exclusion from DIO
path is achieved by inode_dio_wait() call in ext4_setattr().  So
there's no need to wait for extent convertion in ext4_truncate()
anymore.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
hifive-unleashed-5.1
Jan Kara 2013-06-04 14:30:00 -04:00 committed by Theodore Ts'o
parent e83403959f
commit a115f749c1
2 changed files with 8 additions and 7 deletions
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6
fs/ext4/inode.c
View File

@ -3643,12 +3643,6 @@ void ext4_truncate(struct inode *inode)
return;
}
/*
* finish any pending end_io work so we won't run the risk of
* converting any truncated blocks to initialized later
*/
ext4_flush_unwritten_io(inode);
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
credits = ext4_writepage_trans_blocks(inode);
else

9
fs/ext4/page-io.c
View File

@ -158,7 +158,14 @@ static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
wake_up_all(ext4_ioend_wq(inode));
}
/* check a range of space and convert unwritten extents to written. */
/*
* Check a range of space and convert unwritten extents to written. Note that
* we are protected from truncate touching same part of extent tree by the
* fact that truncate code waits for all DIO to finish (thus exclusion from
* direct IO is achieved) and also waits for PageWriteback bits. Thus we
* cannot get to ext4_ext_truncate() before all IOs overlapping that range are
* completed (happens from ext4_free_ioend()).
*/
static int ext4_end_io(ext4_io_end_t *io)
{
struct inode *inode = io->inode;