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linux/fs/9p/vfs_super.c
Eric Van Hensbergen be57855f50
fs/9p: fix dups even in uncached mode
In uncached mode we were still seeing duplicate getattr requests
because of aggressive dropping of inodes.  Inode "freshness" is
guarded by other mechanisms when caches are disabled so this
is unnecessary and increases overhead of almost every operation.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2024-01-26 16:46:56 +00:00

295 lines
6.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/magic.h>
#include <linux/fscache.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "xattr.h"
#include "acl.h"
static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
/**
* v9fs_set_super - set the superblock
* @s: super block
* @data: file system specific data
*
*/
static int v9fs_set_super(struct super_block *s, void *data)
{
s->s_fs_info = data;
return set_anon_super(s, data);
}
/**
* v9fs_fill_super - populate superblock with info
* @sb: superblock
* @v9ses: session information
* @flags: flags propagated from v9fs_mount()
*
*/
static int
v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
int flags)
{
int ret;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
sb->s_blocksize = 1 << sb->s_blocksize_bits;
sb->s_magic = V9FS_MAGIC;
if (v9fs_proto_dotl(v9ses)) {
sb->s_op = &v9fs_super_ops_dotl;
if (!(v9ses->flags & V9FS_NO_XATTR))
sb->s_xattr = v9fs_xattr_handlers;
} else {
sb->s_op = &v9fs_super_ops;
sb->s_time_max = U32_MAX;
}
sb->s_time_min = 0;
ret = super_setup_bdi(sb);
if (ret)
return ret;
if (!v9ses->cache) {
sb->s_bdi->ra_pages = 0;
sb->s_bdi->io_pages = 0;
} else {
sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
}
sb->s_flags |= SB_ACTIVE;
#ifdef CONFIG_9P_FS_POSIX_ACL
if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
sb->s_flags |= SB_POSIXACL;
#endif
return 0;
}
/**
* v9fs_mount - mount a superblock
* @fs_type: file system type
* @flags: mount flags
* @dev_name: device name that was mounted
* @data: mount options
*
*/
static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
struct super_block *sb = NULL;
struct inode *inode = NULL;
struct dentry *root = NULL;
struct v9fs_session_info *v9ses = NULL;
struct p9_fid *fid;
int retval = 0;
p9_debug(P9_DEBUG_VFS, "\n");
v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
if (!v9ses)
return ERR_PTR(-ENOMEM);
fid = v9fs_session_init(v9ses, dev_name, data);
if (IS_ERR(fid)) {
retval = PTR_ERR(fid);
goto free_session;
}
sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
if (IS_ERR(sb)) {
retval = PTR_ERR(sb);
goto clunk_fid;
}
retval = v9fs_fill_super(sb, v9ses, flags);
if (retval)
goto release_sb;
if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
sb->s_d_op = &v9fs_cached_dentry_operations;
else
sb->s_d_op = &v9fs_dentry_operations;
inode = v9fs_get_inode_from_fid(v9ses, fid, sb);
if (IS_ERR(inode)) {
retval = PTR_ERR(inode);
goto release_sb;
}
root = d_make_root(inode);
if (!root) {
retval = -ENOMEM;
goto release_sb;
}
sb->s_root = root;
retval = v9fs_get_acl(inode, fid);
if (retval)
goto release_sb;
v9fs_fid_add(root, &fid);
p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
return dget(sb->s_root);
clunk_fid:
p9_fid_put(fid);
v9fs_session_close(v9ses);
free_session:
kfree(v9ses);
return ERR_PTR(retval);
release_sb:
/*
* we will do the session_close and root dentry release
* in the below call. But we need to clunk fid, because we haven't
* attached the fid to dentry so it won't get clunked
* automatically.
*/
p9_fid_put(fid);
deactivate_locked_super(sb);
return ERR_PTR(retval);
}
/**
* v9fs_kill_super - Kill Superblock
* @s: superblock
*
*/
static void v9fs_kill_super(struct super_block *s)
{
struct v9fs_session_info *v9ses = s->s_fs_info;
p9_debug(P9_DEBUG_VFS, " %p\n", s);
kill_anon_super(s);
v9fs_session_cancel(v9ses);
v9fs_session_close(v9ses);
kfree(v9ses);
s->s_fs_info = NULL;
p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
}
static void
v9fs_umount_begin(struct super_block *sb)
{
struct v9fs_session_info *v9ses;
v9ses = sb->s_fs_info;
v9fs_session_begin_cancel(v9ses);
}
static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
struct p9_rstatfs rs;
int res;
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid)) {
res = PTR_ERR(fid);
goto done;
}
v9ses = v9fs_dentry2v9ses(dentry);
if (v9fs_proto_dotl(v9ses)) {
res = p9_client_statfs(fid, &rs);
if (res == 0) {
buf->f_type = rs.type;
buf->f_bsize = rs.bsize;
buf->f_blocks = rs.blocks;
buf->f_bfree = rs.bfree;
buf->f_bavail = rs.bavail;
buf->f_files = rs.files;
buf->f_ffree = rs.ffree;
buf->f_fsid = u64_to_fsid(rs.fsid);
buf->f_namelen = rs.namelen;
}
if (res != -ENOSYS)
goto done;
}
res = simple_statfs(dentry, buf);
done:
p9_fid_put(fid);
return res;
}
static int v9fs_write_inode(struct inode *inode,
struct writeback_control *wbc)
{
/*
* send an fsync request to server irrespective of
* wbc->sync_mode.
*/
p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
return netfs_unpin_writeback(inode, wbc);
}
static int v9fs_write_inode_dotl(struct inode *inode,
struct writeback_control *wbc)
{
p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
return netfs_unpin_writeback(inode, wbc);
}
static const struct super_operations v9fs_super_ops = {
.alloc_inode = v9fs_alloc_inode,
.free_inode = v9fs_free_inode,
.statfs = simple_statfs,
.evict_inode = v9fs_evict_inode,
.show_options = v9fs_show_options,
.umount_begin = v9fs_umount_begin,
.write_inode = v9fs_write_inode,
};
static const struct super_operations v9fs_super_ops_dotl = {
.alloc_inode = v9fs_alloc_inode,
.free_inode = v9fs_free_inode,
.statfs = v9fs_statfs,
.evict_inode = v9fs_evict_inode,
.show_options = v9fs_show_options,
.umount_begin = v9fs_umount_begin,
.write_inode = v9fs_write_inode_dotl,
};
struct file_system_type v9fs_fs_type = {
.name = "9p",
.mount = v9fs_mount,
.kill_sb = v9fs_kill_super,
.owner = THIS_MODULE,
.fs_flags = FS_RENAME_DOES_D_MOVE,
};
MODULE_ALIAS_FS("9p");