Unverified Commit eae9e789 authored by David Howells's avatar David Howells Committed by Christian Brauner
Browse files

afs: Use netfslib for symlinks, allowing them to be cached 



Use netfslib to read symlinks, thereby allowing them to be cached by
fscache and cachefiles.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-23-dhowells@redhat.com


cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 6dd80936

fs/afs/file.c

+0 −32
Original line number Diff line number Diff line
@@ -20,7 +20,6 @@ 
#include "internal.h"



static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);

static int afs_symlink_read_folio(struct file *file, struct folio *folio);



static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);

static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
@@ -61,13 +60,6 @@ const struct address_space_operations afs_file_aops = { 
	.writepages	= afs_writepages,

};



const struct address_space_operations afs_symlink_aops = {

	.read_folio	= afs_symlink_read_folio,

	.release_folio	= netfs_release_folio,

	.invalidate_folio = netfs_invalidate_folio,

	.migrate_folio	= filemap_migrate_folio,

};



static const struct vm_operations_struct afs_vm_ops = {

	.open		= afs_vm_open,

	.close		= afs_vm_close,
@@ -346,30 +338,6 @@ static void afs_issue_read(struct netfs_io_subrequest *subreq) 
	queue_work(system_long_wq, &subreq->work);

}



static int afs_symlink_read_folio(struct file *file, struct folio *folio)

{

	struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);

	struct afs_read *fsreq;

	int ret;



	fsreq = afs_alloc_read(GFP_NOFS);

	if (!fsreq)

		return -ENOMEM;



	fsreq->pos	= folio_pos(folio);

	fsreq->len	= folio_size(folio);

	fsreq->vnode	= vnode;

	fsreq->iter	= &fsreq->def_iter;

	iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,

			fsreq->pos, fsreq->len);



	ret = afs_fetch_data(fsreq->vnode, fsreq);

	if (ret == 0)

		folio_mark_uptodate(folio);

	folio_unlock(folio);

	return ret;

}



static int afs_init_request(struct netfs_io_request *rreq, struct file *file)

{

	struct afs_vnode *vnode = AFS_FS_I(rreq->inode);

fs/afs/inode.c

+59 −5
Original line number Diff line number Diff line
@@ -25,8 +25,60 @@ 
#include "internal.h"

#include "afs_fs.h"



static void afs_put_link(void *arg)

{

	struct folio *folio = virt_to_folio(arg);



	kunmap_local(arg);

	folio_put(folio);

}



const char *afs_get_link(struct dentry *dentry, struct inode *inode,

			 struct delayed_call *callback)

{

	struct afs_vnode *vnode = AFS_FS_I(inode);

	struct folio *folio;

	char *content;

	ssize_t ret;



	if (atomic64_read(&vnode->cb_expires_at) == AFS_NO_CB_PROMISE ||

	    !test_bit(AFS_VNODE_DIR_READ, &vnode->flags)) {

		if (!dentry)

			return ERR_PTR(-ECHILD);

		ret = afs_read_single(vnode, NULL);

		if (ret < 0)

			return ERR_PTR(ret);

	}



	folio = folioq_folio(vnode->directory, 0);

	folio_get(folio);

	content = kmap_local_folio(folio, 0);

	set_delayed_call(callback, afs_put_link, content);

	return content;

}



int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen)

{

	DEFINE_DELAYED_CALL(done);

	const char *content;

	int len;



	content = afs_get_link(dentry, d_inode(dentry), &done);

	if (IS_ERR(content)) {

		do_delayed_call(&done);

		return PTR_ERR(content);

	}



	len = umin(strlen(content), buflen);

	if (copy_to_user(buffer, content, len))

		len = -EFAULT;

	do_delayed_call(&done);

	return len;

}



static const struct inode_operations afs_symlink_inode_operations = {

	.get_link	= page_get_link,

	.get_link	= afs_get_link,

	.readlink	= afs_readlink,

};



static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
@@ -124,13 +176,13 @@ static int afs_inode_init_from_status(struct afs_operation *op, 
			inode->i_mode	= S_IFDIR | 0555;

			inode->i_op	= &afs_mntpt_inode_operations;

			inode->i_fop	= &afs_mntpt_file_operations;

			inode->i_mapping->a_ops	= &afs_symlink_aops;

		} else {

			inode->i_mode	= S_IFLNK | status->mode;

			inode->i_op	= &afs_symlink_inode_operations;

			inode->i_mapping->a_ops	= &afs_symlink_aops;

		}

		inode->i_mapping->a_ops	= &afs_dir_aops;

		inode_nohighmem(inode);

		mapping_set_release_always(inode->i_mapping);

		break;

	default:

		dump_vnode(vnode, op->file[0].vnode != vnode ? op->file[0].vnode : NULL);
@@ -443,7 +495,8 @@ static void afs_get_inode_cache(struct afs_vnode *vnode) 
	struct afs_vnode_cache_aux aux;



	if (vnode->status.type != AFS_FTYPE_FILE &&

	    vnode->status.type != AFS_FTYPE_DIR) {

	    vnode->status.type != AFS_FTYPE_DIR &&

	    vnode->status.type != AFS_FTYPE_SYMLINK) {

		vnode->netfs.cache = NULL;

		return;

	}
@@ -657,7 +710,8 @@ void afs_evict_inode(struct inode *inode) 


	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);



	if ((S_ISDIR(inode->i_mode)) &&

	if ((S_ISDIR(inode->i_mode) ||

	     S_ISLNK(inode->i_mode)) &&

	    (inode->i_state & I_DIRTY) &&

	    !sbi->dyn_root) {

		struct writeback_control wbc = {

fs/afs/internal.h

+3 −1
Original line number Diff line number Diff line
@@ -1116,7 +1116,6 @@ extern void afs_dynroot_depopulate(struct super_block *); 
 * file.c

 */

extern const struct address_space_operations afs_file_aops;

extern const struct address_space_operations afs_symlink_aops;

extern const struct inode_operations afs_file_inode_operations;

extern const struct file_operations afs_file_operations;

extern const struct netfs_request_ops afs_req_ops;
@@ -1222,6 +1221,9 @@ extern void afs_fs_probe_cleanup(struct afs_net *); 
 */

extern const struct afs_operation_ops afs_fetch_status_operation;



const char *afs_get_link(struct dentry *dentry, struct inode *inode,

			 struct delayed_call *callback);

int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen);

extern void afs_vnode_commit_status(struct afs_operation *, struct afs_vnode_param *);

extern int afs_fetch_status(struct afs_vnode *, struct key *, bool, afs_access_t *);

extern int afs_ilookup5_test_by_fid(struct inode *, void *);

fs/afs/mntpt.c

+11 −11
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ const struct file_operations afs_mntpt_file_operations = { 


const struct inode_operations afs_mntpt_inode_operations = {

	.lookup		= afs_mntpt_lookup,

	.readlink	= page_readlink,

	.readlink	= afs_readlink,

	.getattr	= afs_getattr,

};
@@ -118,9 +118,9 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) 
		ctx->volnamesz = sizeof(afs_root_volume) - 1;

	} else {

		/* read the contents of the AFS special symlink */

		struct page *page;

		DEFINE_DELAYED_CALL(cleanup);

		const char *content;

		loff_t size = i_size_read(d_inode(mntpt));

		char *buf;



		if (src_as->cell)

			ctx->cell = afs_use_cell(src_as->cell, afs_cell_trace_use_mntpt);
@@ -128,16 +128,16 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) 
		if (size < 2 || size > PAGE_SIZE - 1)

			return -EINVAL;



		page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);

		if (IS_ERR(page))

			return PTR_ERR(page);

		content = afs_get_link(mntpt, d_inode(mntpt), &cleanup);

		if (IS_ERR(content)) {

			do_delayed_call(&cleanup);

			return PTR_ERR(content);

		}



		buf = kmap(page);

		ret = -EINVAL;

		if (buf[size - 1] == '.')

			ret = vfs_parse_fs_string(fc, "source", buf, size - 1);

		kunmap(page);

		put_page(page);

		if (content[size - 1] == '.')

			ret = vfs_parse_fs_string(fc, "source", content, size - 1);

		do_delayed_call(&cleanup);

		if (ret < 0)

			return ret;

include/trace/events/afs.h

+1 −0
Original line number Diff line number Diff line
@@ -422,6 +422,7 @@ enum yfs_cm_operation { 
	EM(afs_file_error_dir_over_end,		"DIR_ENT_OVER_END")	\

	EM(afs_file_error_dir_small,		"DIR_SMALL")		\

	EM(afs_file_error_dir_unmarked_ext,	"DIR_UNMARKED_EXT")	\

	EM(afs_file_error_symlink_big,		"SYM_BIG")		\

	EM(afs_file_error_mntpt,		"MNTPT_READ_FAILED")	\

	E_(afs_file_error_writeback_fail,	"WRITEBACK_FAILED")