Re: [PATCH 1/1] fs: Use inode_lock/unlock class of provided APIs in filesystems

Jeff Layton
2019-12-05T16:08:26Z

On Thu, 2019-12-05 at 16:09 +0530, Ritesh Harjani wrote:
> This defines 4 more APIs which some of the filesystem needs
> and reduces the direct use of i_rwsem in filesystem drivers.
> Instead those are replaced with inode_lock/unlock_** APIs.
>
> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
> ---
> fs/btrfs/delayed-inode.c | 2 +-
> fs/btrfs/ioctl.c | 4 ++--
> fs/ceph/io.c | 24 ++++++++++++------------
> fs/nfs/io.c | 24 ++++++++++++------------
> fs/orangefs/file.c | 4 ++--
> fs/overlayfs/readdir.c | 2 +-
> fs/readdir.c | 4 ++--
> include/linux/fs.h | 21 +++++++++++++++++++++
> 8 files changed, 53 insertions(+), 32 deletions(-)
>
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index d3e15e1d4a91..c3e92f2fd915 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -1644,7 +1644,7 @@ void btrfs_readdir_put_delayed_items(struct inode *inode,
> * The VFS is going to do up_read(), so we need to downgrade back to a
> * read lock.
> */
> - downgrade_write(&inode->i_rwsem);
> + inode_lock_downgrade(inode);
> }
>
> int btrfs_should_delete_dir_index(struct list_head *del_list,
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index a1ee0b775e65..1cbd763a46d8 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -955,7 +955,7 @@ static noinline int btrfs_mksubvol(const struct path *parent,
> struct dentry *dentry;
> int error;
>
> - error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
> + error = inode_lock_killable_nested(dir, I_MUTEX_PARENT);
> if (error == -EINTR)
> return error;
>
> @@ -2863,7 +2863,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
> goto out;
>
>
> - err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
> + err = inode_lock_killable_nested(dir, I_MUTEX_PARENT);
> if (err == -EINTR)
> goto out_drop_write;
> dentry = lookup_one_len(vol_args->name, parent, namelen);
> diff --git a/fs/ceph/io.c b/fs/ceph/io.c
> index 97602ea92ff4..e94186259c2e 100644
> --- a/fs/ceph/io.c
> +++ b/fs/ceph/io.c
> @@ -53,14 +53,14 @@ ceph_start_io_read(struct inode *inode)
> struct ceph_inode_info *ci = ceph_inode(inode);
>
> /* Be an optimist! */
> - down_read(&inode->i_rwsem);
> + inode_lock_shared(inode);
> if (!(READ_ONCE(ci->i_ceph_flags) & CEPH_I_ODIRECT))
> return;
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> /* Slow path.... */
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> ceph_block_o_direct(ci, inode);
> - downgrade_write(&inode->i_rwsem);
> + inode_lock_downgrade(inode);
> }
>
> /**
> @@ -73,7 +73,7 @@ ceph_start_io_read(struct inode *inode)
> void
> ceph_end_io_read(struct inode *inode)
> {
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> }
>
> /**
> @@ -86,7 +86,7 @@ ceph_end_io_read(struct inode *inode)
> void
> ceph_start_io_write(struct inode *inode)
> {
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> ceph_block_o_direct(ceph_inode(inode), inode);
> }
>
> @@ -100,7 +100,7 @@ ceph_start_io_write(struct inode *inode)
> void
> ceph_end_io_write(struct inode *inode)
> {
> - up_write(&inode->i_rwsem);
> + inode_unlock(inode);
> }
>
> /* Call with exclusively locked inode->i_rwsem */
> @@ -139,14 +139,14 @@ ceph_start_io_direct(struct inode *inode)
> struct ceph_inode_info *ci = ceph_inode(inode);
>
> /* Be an optimist! */
> - down_read(&inode->i_rwsem);
> + inode_lock_shared(inode);
> if (READ_ONCE(ci->i_ceph_flags) & CEPH_I_ODIRECT)
> return;
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> /* Slow path.... */
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> ceph_block_buffered(ci, inode);
> - downgrade_write(&inode->i_rwsem);
> + inode_lock_downgrade(inode);
> }
>
> /**
> @@ -159,5 +159,5 @@ ceph_start_io_direct(struct inode *inode)
> void
> ceph_end_io_direct(struct inode *inode)
> {
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> }
> diff --git a/fs/nfs/io.c b/fs/nfs/io.c
> index 5088fda9b453..bf5ed7bea59d 100644
> --- a/fs/nfs/io.c
> +++ b/fs/nfs/io.c
> @@ -44,14 +44,14 @@ nfs_start_io_read(struct inode *inode)
> {
> struct nfs_inode *nfsi = NFS_I(inode);
> /* Be an optimist! */
> - down_read(&inode->i_rwsem);
> + inode_lock_shared(inode);
> if (test_bit(NFS_INO_ODIRECT, &nfsi->flags) == 0)
> return;
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> /* Slow path.... */
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> nfs_block_o_direct(nfsi, inode);
> - downgrade_write(&inode->i_rwsem);
> + inode_lock_downgrade(inode);
> }
>
> /**
> @@ -64,7 +64,7 @@ nfs_start_io_read(struct inode *inode)
> void
> nfs_end_io_read(struct inode *inode)
> {
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> }
>
> /**
> @@ -77,7 +77,7 @@ nfs_end_io_read(struct inode *inode)
> void
> nfs_start_io_write(struct inode *inode)
> {
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> nfs_block_o_direct(NFS_I(inode), inode);
> }
>
> @@ -91,7 +91,7 @@ nfs_start_io_write(struct inode *inode)
> void
> nfs_end_io_write(struct inode *inode)
> {
> - up_write(&inode->i_rwsem);
> + inode_unlock(inode);
> }
>
> /* Call with exclusively locked inode->i_rwsem */
> @@ -124,14 +124,14 @@ nfs_start_io_direct(struct inode *inode)
> {
> struct nfs_inode *nfsi = NFS_I(inode);
> /* Be an optimist! */
> - down_read(&inode->i_rwsem);
> + inode_lock_shared(inode);
> if (test_bit(NFS_INO_ODIRECT, &nfsi->flags) != 0)
> return;
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> /* Slow path.... */
> - down_write(&inode->i_rwsem);
> + inode_lock(inode);
> nfs_block_buffered(nfsi, inode);
> - downgrade_write(&inode->i_rwsem);
> + inode_lock_downgrade(inode);
> }
>
> /**
> @@ -144,5 +144,5 @@ nfs_start_io_direct(struct inode *inode)
> void
> nfs_end_io_direct(struct inode *inode)
> {
> - up_read(&inode->i_rwsem);
> + inode_unlock_shared(inode);
> }
> diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
> index a5612abc0936..6420503e1275 100644
> --- a/fs/orangefs/file.c
> +++ b/fs/orangefs/file.c
> @@ -328,14 +328,14 @@ static ssize_t orangefs_file_read_iter(struct kiocb *iocb,
> ro->blksiz = iter->count;
> }
>
> - down_read(&file_inode(iocb->ki_filp)->i_rwsem);
> + inode_lock_shared(file_inode(iocb->ki_filp));
> ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
> if (ret)
> goto out;
>
> ret = generic_file_read_iter(iocb, iter);
> out:
> - up_read(&file_inode(iocb->ki_filp)->i_rwsem);
> + inode_unlock_shared(file_inode(iocb->ki_filp));
> return ret;
> }
>
> diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
> index 47a91c9733a5..c203e73160b0 100644
> --- a/fs/overlayfs/readdir.c
> +++ b/fs/overlayfs/readdir.c
> @@ -273,7 +273,7 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
>
> old_cred = ovl_override_creds(rdd->dentry->d_sb);
>
> - err = down_write_killable(&dir->d_inode->i_rwsem);
> + err = inode_lock_killable(dir->d_inode);
> if (!err) {
> while (rdd->first_maybe_whiteout) {
> p = rdd->first_maybe_whiteout;
> diff --git a/fs/readdir.c b/fs/readdir.c
> index d26d5ea4de7b..10a34efa0af0 100644
> --- a/fs/readdir.c
> +++ b/fs/readdir.c
> @@ -52,9 +52,9 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
> goto out;
>
> if (shared)
> - res = down_read_killable(&inode->i_rwsem);
> + res = inode_lock_shared_killable(inode);
> else
> - res = down_write_killable(&inode->i_rwsem);
> + res = inode_lock_killable(inode);
> if (res)
> goto out;
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 98e0349adb52..2b407464fac1 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -831,6 +831,27 @@ static inline void inode_lock_shared_nested(struct inode *inode, unsigned subcla
> down_read_nested(&inode->i_rwsem, subclass);
> }
>
> +static inline void inode_lock_downgrade(struct inode *inode)
> +{
> + downgrade_write(&inode->i_rwsem);
> +}
> +
> +static inline int inode_lock_killable(struct inode *inode)
> +{
> + return down_write_killable(&inode->i_rwsem);
> +}
> +
> +static inline int inode_lock_shared_killable(struct inode *inode)
> +{
> + return down_read_killable(&inode->i_rwsem);
> +}
> +
> +static inline int inode_lock_killable_nested(struct inode *inode,
> + unsigned subclass)
> +{
> + return down_write_killable_nested(&inode->i_rwsem, subclass);
> +}
> +
> void lock_two_nondirectories(struct inode *, struct inode*);
> void unlock_two_nondirectories(struct inode *, struct inode*);
>

Nice little cleanup.

Reviewed-by: Jeff Layton <jlayton@kernel.org>