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| author |   Chris Mason <chris.mason@oracle.com> | 2009-10-13 13:21:08 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2009-10-13 13:35:12 -0400 |
| commit | 257c62e1bce03e5b9f3f069fd52ad73a56de71fd (patch) | |
| tree | ad047fe5796156aa88e3f3600111bf2b8d12759f /fs/btrfs/tree-log.h | |
| parent | Btrfs: only write one super copy during fsync (diff) | |
| download | linux-dev-257c62e1bce03e5b9f3f069fd52ad73a56de71fd.tar.xz linux-dev-257c62e1bce03e5b9f3f069fd52ad73a56de71fd.zip | |
Btrfs: avoid tree log commit when there are no changes
rpm has a habit of running fdatasync when the file hasn't
changed. We already detect if a file hasn't been changed
in the current transaction but it might have been sent to
the tree-log in this transaction and not changed since
the last call to fsync.
In this case, we want to avoid a tree log sync, which includes
a number of synchronous writes and barriers. This commit
extends the existing tracking of the last transaction to change
a file to also track the last sub-transaction.
The end result is that rpm -ivh and -Uvh are roughly twice as fast,
and on par with ext3.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/tree-log.h')
| -rw-r--r-- | fs/btrfs/tree-log.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/tree-log.h b/fs/btrfs/tree-log.h index d09c7609e16b..0776eacb5083 100644 --- a/fs/btrfs/tree-log.h +++ b/fs/btrfs/tree-log.h @@ -19,6 +19,9 @@ #ifndef __TREE_LOG_ #define __TREE_LOG_ +/* return value for btrfs_log_dentry_safe that means we don't need to log it at all */ +#define BTRFS_NO_LOG_SYNC 256 + int btrfs_sync_log(struct btrfs_trans_handle *trans, struct btrfs_root *root); int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root); |