diff options
author | Jan Kara <jack@suse.cz> | 2017-11-01 16:36:45 +0100 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2017-11-03 06:26:26 -0700 |
commit | b8a6176c214cf9aa2679131ed7e4515cddaadc33 (patch) | |
tree | e9b6ff2b1ee0459854e64f3195a7af7571b62196 /fs/ext4/inode.c | |
parent | 497f6926d880c57f65bf7c3f1086526fa774c55e (diff) | |
download | linux-b8a6176c214cf9aa2679131ed7e4515cddaadc33.tar.bz2 |
ext4: Support for synchronous DAX faults
We return IOMAP_F_DIRTY flag from ext4_iomap_begin() when asked to
prepare blocks for writing and the inode has some uncommitted metadata
changes. In the fault handler ext4_dax_fault() we then detect this case
(through VM_FAULT_NEEDDSYNC return value) and call helper
dax_finish_sync_fault() to flush metadata changes and insert page table
entry. Note that this will also dirty corresponding radix tree entry
which is what we want - fsync(2) will still provide data integrity
guarantees for applications not using userspace flushing. And
applications using userspace flushing can avoid calling fsync(2) and
thus avoid the performance overhead.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r-- | fs/ext4/inode.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 31db875bc7a1..13a198924a0f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3394,6 +3394,19 @@ static int ext4_releasepage(struct page *page, gfp_t wait) } #ifdef CONFIG_FS_DAX +static bool ext4_inode_datasync_dirty(struct inode *inode) +{ + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; + + if (journal) + return !jbd2_transaction_committed(journal, + EXT4_I(inode)->i_datasync_tid); + /* Any metadata buffers to write? */ + if (!list_empty(&inode->i_mapping->private_list)) + return true; + return inode->i_state & I_DIRTY_DATASYNC; +} + static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, unsigned flags, struct iomap *iomap) { @@ -3466,6 +3479,8 @@ retry: } iomap->flags = 0; + if ((flags & IOMAP_WRITE) && ext4_inode_datasync_dirty(inode)) + iomap->flags |= IOMAP_F_DIRTY; iomap->bdev = inode->i_sb->s_bdev; iomap->dax_dev = sbi->s_daxdev; iomap->offset = first_block << blkbits; |