On Tue, 27 Jul 2021, Goldwyn Rodrigues wrote:
> Simplification.
>
> file_ra_state_init() take struct address_space *, just to use inode
> pointer by dereferencing from mapping->host.
>
> The callers also derive mapping either by file->f_mapping, or
> even file->f_mapping->host->i_mapping.
>
> Change file_ra_state_init() to accept struct inode * to reduce pointer
> dereferencing, both in the callee and the caller.
You seem to be assuming that inode->i_mapping->host is always 'inode'.
That is not the case.
In particular, fs/coda/file.c contains
if (coda_inode->i_mapping == &coda_inode->i_data)
coda_inode->i_mapping = host_inode->i_mapping;
So a "coda_inode" shares the mapping with a "host_inode".
This is why an inode has both i_data and i_mapping.
So I'm not really sure this patch is safe. It might break codafs.
But it is more likely that codafs isn't used, doesn't work, should be
removed, and i_data should be renamed to i_mapping.
NeilBrown
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
> ---
> fs/btrfs/free-space-cache.c | 2 +-
> fs/btrfs/ioctl.c | 2 +-
> fs/btrfs/relocation.c | 2 +-
> fs/btrfs/send.c | 2 +-
> fs/nfs/nfs4file.c | 2 +-
> fs/open.c | 2 +-
> fs/verity/enable.c | 2 +-
> include/linux/fs.h | 2 +-
> mm/readahead.c | 4 ++--
> 9 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index 4806295116d8..c43bf9915cda 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -351,7 +351,7 @@ static void readahead_cache(struct inode *inode)
> if (!ra)
> return;
>
> - file_ra_state_init(ra, inode->i_mapping);
> + file_ra_state_init(ra, inode);
> last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
>
> page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 5dc2fd843ae3..b3508887d466 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -1399,7 +1399,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
> if (!file) {
> ra = kzalloc(sizeof(*ra), GFP_KERNEL);
> if (ra)
> - file_ra_state_init(ra, inode->i_mapping);
> + file_ra_state_init(ra, inode);
> } else {
> ra = &file->f_ra;
> }
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index b70be2ac2e9e..4f35672b93a5 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -2911,7 +2911,7 @@ static int relocate_file_extent_cluster(struct inode *inode,
> if (ret)
> goto out;
>
> - file_ra_state_init(ra, inode->i_mapping);
> + file_ra_state_init(ra, inode);
>
> ret = setup_extent_mapping(inode, cluster->start - offset,
> cluster->end - offset, cluster->start);
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index bd69db72acc5..3eb8d2277a3d 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -4949,7 +4949,7 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
>
> /* initial readahead */
> memset(&sctx->ra, 0, sizeof(struct file_ra_state));
> - file_ra_state_init(&sctx->ra, inode->i_mapping);
> + file_ra_state_init(&sctx->ra, inode);
>
> while (index <= last_index) {
> unsigned cur_len = min_t(unsigned, len,
> diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> index a1e5c6b85ded..c810a6151c93 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -385,7 +385,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
> nfs_file_set_open_context(filep, ctx);
> put_nfs_open_context(ctx);
>
> - file_ra_state_init(&filep->f_ra, filep->f_mapping->host->i_mapping);
> + file_ra_state_init(&filep->f_ra, file_inode(filep));
> res = filep;
> out_free_name:
> kfree(read_name);
> diff --git a/fs/open.c b/fs/open.c
> index e53af13b5835..9c6773a4fb30 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -840,7 +840,7 @@ static int do_dentry_open(struct file *f,
> f->f_write_hint = WRITE_LIFE_NOT_SET;
> f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
>
> - file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
> + file_ra_state_init(&f->f_ra, inode);
>
> /* NB: we're sure to have correct a_ops only after f_op->open */
> if (f->f_flags & O_DIRECT) {
> diff --git a/fs/verity/enable.c b/fs/verity/enable.c
> index 77e159a0346b..460d881080ac 100644
> --- a/fs/verity/enable.c
> +++ b/fs/verity/enable.c
> @@ -66,7 +66,7 @@ static int build_merkle_tree_level(struct file *filp, unsigned int level,
> dst_block_num = 0; /* unused */
> }
>
> - file_ra_state_init(&ra, filp->f_mapping);
> + file_ra_state_init(&ra, inode);
>
> for (i = 0; i < num_blocks_to_hash; i++) {
> struct page *src_page;
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index c3c88fdb9b2a..3b8ce0221477 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3260,7 +3260,7 @@ extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
>
>
> extern void
> -file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
> +file_ra_state_init(struct file_ra_state *ra, struct inode *inode);
> extern loff_t noop_llseek(struct file *file, loff_t offset, int whence);
> extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
> extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
> diff --git a/mm/readahead.c b/mm/readahead.c
> index d589f147f4c2..3541941df5e7 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -31,9 +31,9 @@
> * memset *ra to zero.
> */
> void
> -file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)
> +file_ra_state_init(struct file_ra_state *ra, struct inode *inode)
> {
> - ra->ra_pages = inode_to_bdi(mapping->host)->ra_pages;
> + ra->ra_pages = inode_to_bdi(inode)->ra_pages;
> ra->prev_pos = -1;
> }
> EXPORT_SYMBOL_GPL(file_ra_state_init);
> --
> 2.32.0
>
>
> --
> Goldwyn
>
>
