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authorJan Kara <jack@suse.cz>2016-03-08 23:36:46 -0500
committerTheodore Ts'o <tytso@mit.edu>2016-03-08 23:36:46 -0500
commit109811c20fb8ec46e2ed01750214a32a9163d164 (patch)
tree63284815eb0c1f0386a93b51cda92682d26ce02e /fs/ext4/ext4.h
parentefe70c29511544b0468723fe92c1847b3b0ca046 (diff)
downloadlinux-109811c20fb8ec46e2ed01750214a32a9163d164.tar.bz2
ext4: simplify io_end handling for AIO DIO
When mapping blocks for direct IO, we allocate io_end structure before mapping blocks and store pointer to it in the inode. This creates a requirement that any AIO DIO using io_end must be protected by i_mutex. This created problems in the past with dioread_nolock mode which was corrupting io_end pointers. Also io_end is allocated unnecessarily in case where we don't need to convert any extents (which is a common case for example when overwriting file). We fix the problem by allocating io_end only once we return unwritten extent from block mapping function for AIO DIO (so we can save some pointless io_end allocations) and we pass pointer to it in bh->b_private which generic DIO code later passes to our end IO callback. That way we remove any need for global pointer to io_end structure and thus fix the races. The downside of this change is that the checking for unwritten IO in flight in ext4_extents_can_be_merged() is more racy since we now increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after dropping i_data_sem. However the check has been racy already before because ext4_writepages() already increment i_unwritten after dropping i_data_sem and reserved blocks save us from hitting ENOSPC in the worst case. Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext4/ext4.h')
-rw-r--r--fs/ext4/ext4.h10
1 files changed, 0 insertions, 10 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d60db18edb4a..9f3156c38b16 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1513,16 +1513,6 @@ static inline void ext4_set_io_unwritten_flag(struct inode *inode,
}
}
-static inline ext4_io_end_t *ext4_inode_aio(struct inode *inode)
-{
- return inode->i_private;
-}
-
-static inline void ext4_inode_aio_set(struct inode *inode, ext4_io_end_t *io)
-{
- inode->i_private = io;
-}
-
/*
* Inode dynamic state flags
*/