Re: [PATCH v3 1/3] ext4: don't increase iversion counter for ea_inodes
From: Jeff Layton <jlayton@kernel.org>
Date: 2022-08-12 18:42:43
Also in:
linux-fsdevel
On Fri, 2022-08-12 at 14:37 +0200, Lukas Czerner wrote:
quoted hunk ↗ jump to hunk
ea_inodes are using i_version for storing part of the reference count so we really need to leave it alone. The problem can be reproduced by xfstest ext4/026 when iversion is enabled. Fix it by not calling inode_inc_iversion() for EXT4_EA_INODE_FL inodes in ext4_mark_iloc_dirty(). Signed-off-by: Lukas Czerner <redacted> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jeff Layton <jlayton@kernel.org> --- v2, v3: no change fs/ext4/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 601214453c3a..2a220be34caa 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c@@ -5731,7 +5731,12 @@ int ext4_mark_iloc_dirty(handle_t *handle, } ext4_fc_track_inode(handle, inode); - if (IS_I_VERSION(inode)) + /* + * ea_inodes are using i_version for storing reference count, don't + * mess with it + */ + if (IS_I_VERSION(inode) && + !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) inode_inc_iversion(inode); /* the do_update_inode consumes one bh->b_count */
I've spent some time writing tests for the i_version counter (still quite rough right now), and what I've found is that this particular inode_inc_iversion results in the counter being bumped on _reads_ as well as writes, due to the atime changing. This call to inode_inc_iversion seems to make no sense, as we aren't bumping the mtime here. I'm still working on and testing this, but I think we'll probably just want to remove this inode_inc_iversion entirely, and leave the i_version bumping for normal files to happen when the timestamps are updated. So far, my testing seems to indicate that that does the right thing. Hopefully I'll have some testcases + patches for this next week sometime. Cheers, -- Jeff Layton [off-list ref]