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Date: Wed, 17 Aug 2022 20:19:03 +0200
From: Jan Kara <jack@...e.cz>
To: Jeff Layton <jlayton@...nel.org>
Cc: tytso@....edu, adilger.kernel@...ger.ca,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
Lukas Czerner <lczerner@...hat.com>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH v2] ext4: fix i_version handling in ext4
On Wed 17-08-22 12:26:38, Jeff Layton wrote:
> ext4 currently updates the i_version counter when the atime is updated
> during a read. This is less than ideal as it can cause unnecessary cache
> invalidations with NFSv4 and unnecessary remeasurements for IMA. The
> increment in ext4_mark_iloc_dirty is also problematic since it can also
> corrupt the i_version counter for ea_inodes. We aren't bumping the file
> times in ext4_mark_iloc_dirty, so changing the i_version there seems
> wrong, and is the cause of both problems.
>
> Remove that callsite and add increments to the setattr, setxattr and
> ioctl codepaths (at the same time that we update the ctime). The
> i_version bump that already happens during timestamp updates should take
> care of the rest.
>
> In ext4_move_extents, increment the i_version on both inodes, and also
> add in missing ctime updates.
>
> Cc: Lukas Czerner <lczerner@...hat.com>
> Cc: Christian Brauner <brauner@...nel.org>
> Cc: Jan Kara <jack@...e.cz>
> Signed-off-by: Jeff Layton <jlayton@...nel.org>
Hopefully all cases covered ;) Feel free to add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> fs/ext4/inode.c | 10 +++++-----
> fs/ext4/ioctl.c | 4 ++++
> fs/ext4/move_extent.c | 6 ++++++
> fs/ext4/xattr.c | 2 ++
> 4 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 601214453c3a..a70921df89a5 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -5342,6 +5342,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
> int error, rc = 0;
> int orphan = 0;
> const unsigned int ia_valid = attr->ia_valid;
> + bool inc_ivers = IS_IVERSION(inode);
>
> if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
> return -EIO;
> @@ -5425,8 +5426,8 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
> return -EINVAL;
> }
>
> - if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
> - inode_inc_iversion(inode);
> + if (attr->ia_size == inode->i_size)
> + inc_ivers = false;
>
> if (shrink) {
> if (ext4_should_order_data(inode)) {
> @@ -5528,6 +5529,8 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
> }
>
> if (!error) {
> + if (inc_ivers)
> + inode_inc_iversion(inode);
> setattr_copy(mnt_userns, inode, attr);
> mark_inode_dirty(inode);
> }
> @@ -5731,9 +5734,6 @@ int ext4_mark_iloc_dirty(handle_t *handle,
> }
> ext4_fc_track_inode(handle, inode);
>
> - if (IS_I_VERSION(inode))
> - inode_inc_iversion(inode);
> -
> /* the do_update_inode consumes one bh->b_count */
> get_bh(iloc->bh);
>
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index 3cf3ec4b1c21..ad3a294a88eb 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -452,6 +452,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
> swap_inode_data(inode, inode_bl);
>
> inode->i_ctime = inode_bl->i_ctime = current_time(inode);
> + inode_inc_iversion(inode);
>
> inode->i_generation = prandom_u32();
> inode_bl->i_generation = prandom_u32();
> @@ -665,6 +666,7 @@ static int ext4_ioctl_setflags(struct inode *inode,
> ext4_set_inode_flags(inode, false);
>
> inode->i_ctime = current_time(inode);
> + inode_inc_iversion(inode);
>
> err = ext4_mark_iloc_dirty(handle, inode, &iloc);
> flags_err:
> @@ -775,6 +777,7 @@ static int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
>
> EXT4_I(inode)->i_projid = kprojid;
> inode->i_ctime = current_time(inode);
> + inode_inc_iversion(inode);
> out_dirty:
> rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
> if (!err)
> @@ -1257,6 +1260,7 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> err = ext4_reserve_inode_write(handle, inode, &iloc);
> if (err == 0) {
> inode->i_ctime = current_time(inode);
> + inode_inc_iversion(inode);
> inode->i_generation = generation;
> err = ext4_mark_iloc_dirty(handle, inode, &iloc);
> }
> diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
> index 701f1d6a217f..285700b00d38 100644
> --- a/fs/ext4/move_extent.c
> +++ b/fs/ext4/move_extent.c
> @@ -6,6 +6,7 @@
> */
>
> #include <linux/fs.h>
> +#include <linux/iversion.h>
> #include <linux/quotaops.h>
> #include <linux/slab.h>
> #include <linux/sched/mm.h>
> @@ -683,6 +684,11 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
> break;
> o_start += cur_len;
> d_start += cur_len;
> +
> + orig_inode->i_ctime = current_time(orig_inode);
> + donor_inode->i_ctime = current_time(donor_inode);
> + inode_inc_iversion(orig_inode);
> + inode_inc_iversion(donor_inode);
> }
> *moved_len = o_start - orig_blk;
> if (*moved_len > len)
> diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
> index 533216e80fa2..4d84919d1c9c 100644
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -2412,6 +2412,8 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
> if (!error) {
> ext4_xattr_update_super_block(handle, inode->i_sb);
> inode->i_ctime = current_time(inode);
> + if (IS_IVERSION(inode))
> + inode_inc_iversion(inode);
> if (!value)
> no_expand = 0;
> error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
> --
> 2.37.2
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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