| Message ID | 152167305782.5268.13485258587227210521.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed 21-03-18 15:57:37, Dan Williams wrote: > In preparation for the dax implementation to start associating dax pages > to inodes via page->mapping, we need to provide a 'struct > address_space_operations' instance for dax. Otherwise, direct-I/O > triggers incorrect page cache assumptions and warnings. > > Cc: "Theodore Ts'o" <tytso@mit.edu> > Cc: Andreas Dilger <adilger.kernel@dilger.ca> > Cc: linux-ext4@vger.kernel.org > Cc: Jan Kara <jack@suse.cz> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Looks good, just one nit below. > @@ -3946,6 +3961,13 @@ static const struct address_space_operations ext4_da_aops = { > .error_remove_page = generic_error_remove_page, > }; > > +static const struct address_space_operations ext4_dax_aops = { > + .direct_IO = ext4_direct_IO, So ext4_direct_IO() for IS_DAX() files will just bail out. So could you just provide ext4_dax_direct_IO() which will bail out and use it here? With a similar comment as in xfs_vm_direct_IO() that open still needs this method set... Thanks! Honza
On Thu, Mar 29, 2018 at 05:40:35PM +0200, Jan Kara wrote: > So ext4_direct_IO() for IS_DAX() files will just bail out. So could you > just provide ext4_dax_direct_IO() which will bail out and use it here? With > a similar comment as in xfs_vm_direct_IO() that open still needs this > method set... Thanks! In fact a common noop_direct_IO might make sense.
On Thu, Mar 29, 2018 at 11:09 AM, Christoph Hellwig <hch@lst.de> wrote: > On Thu, Mar 29, 2018 at 05:40:35PM +0200, Jan Kara wrote: >> So ext4_direct_IO() for IS_DAX() files will just bail out. So could you >> just provide ext4_dax_direct_IO() which will bail out and use it here? With >> a similar comment as in xfs_vm_direct_IO() that open still needs this >> method set... Thanks! > > In fact a common noop_direct_IO might make sense. Ok, I introduced noop_direct_IO() in "fs, dax: prepare for dax-specific address_space_operations", and cleaned up xfs, ext4, and ext2 accordingly. Let me know if you want to see a resend of the series with those changes. Otherwise this will appear in -next shortly.
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c94780075b04..f9884e41cb39 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2725,12 +2725,6 @@ static int ext4_writepages(struct address_space *mapping, percpu_down_read(&sbi->s_journal_flag_rwsem); trace_ext4_writepages(inode, wbc); - if (dax_mapping(mapping)) { - ret = dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev, - wbc); - goto out_writepages; - } - /* * No pages to write? This is mainly a kludge to avoid starting * a transaction for special inodes like journal inode on last iput() @@ -2955,6 +2949,27 @@ static int ext4_writepages(struct address_space *mapping, return ret; } +static int ext4_dax_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + int ret; + long nr_to_write = wbc->nr_to_write; + struct inode *inode = mapping->host; + struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); + + if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) + return -EIO; + + percpu_down_read(&sbi->s_journal_flag_rwsem); + trace_ext4_writepages(inode, wbc); + + ret = dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev, wbc); + trace_ext4_writepages_result(inode, wbc, ret, + nr_to_write - wbc->nr_to_write); + percpu_up_read(&sbi->s_journal_flag_rwsem); + return ret; +} + static int ext4_nonda_switch(struct super_block *sb) { s64 free_clusters, dirty_clusters; @@ -3946,6 +3961,13 @@ static const struct address_space_operations ext4_da_aops = { .error_remove_page = generic_error_remove_page, }; +static const struct address_space_operations ext4_dax_aops = { + .direct_IO = ext4_direct_IO, + .writepages = ext4_dax_writepages, + .set_page_dirty = noop_set_page_dirty, + .invalidatepage = noop_invalidatepage, +}; + void ext4_set_aops(struct inode *inode) { switch (ext4_inode_journal_mode(inode)) { @@ -3958,7 +3980,9 @@ void ext4_set_aops(struct inode *inode) default: BUG(); } - if (test_opt(inode->i_sb, DELALLOC)) + if (IS_DAX(inode)) + inode->i_mapping->a_ops = &ext4_dax_aops; + else if (test_opt(inode->i_sb, DELALLOC)) inode->i_mapping->a_ops = &ext4_da_aops; else inode->i_mapping->a_ops = &ext4_aops;
In preparation for the dax implementation to start associating dax pages to inodes via page->mapping, we need to provide a 'struct address_space_operations' instance for dax. Otherwise, direct-I/O triggers incorrect page cache assumptions and warnings. Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: linux-ext4@vger.kernel.org Cc: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- fs/ext4/inode.c | 38 +++++++++++++++++++++++++++++++------- 1 file changed, 31 insertions(+), 7 deletions(-)