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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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454e2398be
Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
324 lines
7.0 KiB
C
324 lines
7.0 KiB
C
/*
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* Super block/filesystem wide operations
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*
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* Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk> and
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* Michael Callahan <callahan@maths.ox.ac.uk>
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*
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* Rewritten for Linux 2.1. Peter Braam <braam@cs.cmu.edu>
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* Copyright (C) Carnegie Mellon University
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/unistd.h>
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#include <linux/smp_lock.h>
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#include <linux/file.h>
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#include <linux/vfs.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <linux/fs.h>
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#include <linux/vmalloc.h>
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#include <linux/coda.h>
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#include <linux/coda_linux.h>
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#include <linux/coda_psdev.h>
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#include <linux/coda_fs_i.h>
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#include <linux/coda_cache.h>
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#include "coda_int.h"
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/* VFS super_block ops */
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static void coda_clear_inode(struct inode *);
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static void coda_put_super(struct super_block *);
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static int coda_statfs(struct super_block *sb, struct kstatfs *buf);
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static kmem_cache_t * coda_inode_cachep;
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static struct inode *coda_alloc_inode(struct super_block *sb)
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{
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struct coda_inode_info *ei;
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ei = (struct coda_inode_info *)kmem_cache_alloc(coda_inode_cachep, SLAB_KERNEL);
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if (!ei)
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return NULL;
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memset(&ei->c_fid, 0, sizeof(struct CodaFid));
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ei->c_flags = 0;
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ei->c_uid = 0;
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ei->c_cached_perm = 0;
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return &ei->vfs_inode;
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}
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static void coda_destroy_inode(struct inode *inode)
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{
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kmem_cache_free(coda_inode_cachep, ITOC(inode));
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}
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static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
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{
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struct coda_inode_info *ei = (struct coda_inode_info *) foo;
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if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
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SLAB_CTOR_CONSTRUCTOR)
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inode_init_once(&ei->vfs_inode);
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}
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int coda_init_inodecache(void)
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{
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coda_inode_cachep = kmem_cache_create("coda_inode_cache",
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sizeof(struct coda_inode_info),
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0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
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init_once, NULL);
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if (coda_inode_cachep == NULL)
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return -ENOMEM;
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return 0;
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}
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void coda_destroy_inodecache(void)
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{
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if (kmem_cache_destroy(coda_inode_cachep))
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printk(KERN_INFO "coda_inode_cache: not all structures were freed\n");
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}
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static int coda_remount(struct super_block *sb, int *flags, char *data)
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{
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*flags |= MS_NODIRATIME;
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return 0;
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}
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/* exported operations */
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static struct super_operations coda_super_operations =
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{
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.alloc_inode = coda_alloc_inode,
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.destroy_inode = coda_destroy_inode,
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.clear_inode = coda_clear_inode,
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.put_super = coda_put_super,
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.statfs = coda_statfs,
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.remount_fs = coda_remount,
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};
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static int get_device_index(struct coda_mount_data *data)
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{
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struct file *file;
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struct inode *inode;
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int idx;
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if(data == NULL) {
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printk("coda_read_super: Bad mount data\n");
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return -1;
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}
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if(data->version != CODA_MOUNT_VERSION) {
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printk("coda_read_super: Bad mount version\n");
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return -1;
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}
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file = fget(data->fd);
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inode = NULL;
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if(file)
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inode = file->f_dentry->d_inode;
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if(!inode || !S_ISCHR(inode->i_mode) ||
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imajor(inode) != CODA_PSDEV_MAJOR) {
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if(file)
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fput(file);
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printk("coda_read_super: Bad file\n");
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return -1;
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}
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idx = iminor(inode);
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fput(file);
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if(idx < 0 || idx >= MAX_CODADEVS) {
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printk("coda_read_super: Bad minor number\n");
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return -1;
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}
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return idx;
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}
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static int coda_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *root = NULL;
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struct coda_sb_info *sbi = NULL;
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struct venus_comm *vc = NULL;
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struct CodaFid fid;
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int error;
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int idx;
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idx = get_device_index((struct coda_mount_data *) data);
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/* Ignore errors in data, for backward compatibility */
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if(idx == -1)
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idx = 0;
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printk(KERN_INFO "coda_read_super: device index: %i\n", idx);
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vc = &coda_comms[idx];
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if (!vc->vc_inuse) {
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printk("coda_read_super: No pseudo device\n");
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return -EINVAL;
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}
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if ( vc->vc_sb ) {
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printk("coda_read_super: Device already mounted\n");
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return -EBUSY;
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}
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sbi = kmalloc(sizeof(struct coda_sb_info), GFP_KERNEL);
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if(!sbi) {
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return -ENOMEM;
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}
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vc->vc_sb = sb;
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sbi->sbi_vcomm = vc;
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sb->s_fs_info = sbi;
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sb->s_flags |= MS_NODIRATIME; /* probably even noatime */
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sb->s_blocksize = 1024; /* XXXXX what do we put here?? */
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sb->s_blocksize_bits = 10;
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sb->s_magic = CODA_SUPER_MAGIC;
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sb->s_op = &coda_super_operations;
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/* get root fid from Venus: this needs the root inode */
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error = venus_rootfid(sb, &fid);
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if ( error ) {
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printk("coda_read_super: coda_get_rootfid failed with %d\n",
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error);
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goto error;
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}
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printk("coda_read_super: rootfid is %s\n", coda_f2s(&fid));
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/* make root inode */
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error = coda_cnode_make(&root, &fid, sb);
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if ( error || !root ) {
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printk("Failure of coda_cnode_make for root: error %d\n", error);
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goto error;
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}
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printk("coda_read_super: rootinode is %ld dev %s\n",
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root->i_ino, root->i_sb->s_id);
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sb->s_root = d_alloc_root(root);
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if (!sb->s_root)
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goto error;
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return 0;
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error:
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if (sbi) {
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kfree(sbi);
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if(vc)
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vc->vc_sb = NULL;
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}
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if (root)
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iput(root);
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return -EINVAL;
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}
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static void coda_put_super(struct super_block *sb)
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{
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struct coda_sb_info *sbi;
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sbi = coda_sbp(sb);
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sbi->sbi_vcomm->vc_sb = NULL;
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printk("Coda: Bye bye.\n");
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kfree(sbi);
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}
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static void coda_clear_inode(struct inode *inode)
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{
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coda_cache_clear_inode(inode);
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}
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int coda_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
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{
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int err = coda_revalidate_inode(dentry);
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if (!err)
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generic_fillattr(dentry->d_inode, stat);
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return err;
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}
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int coda_setattr(struct dentry *de, struct iattr *iattr)
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{
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struct inode *inode = de->d_inode;
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struct coda_vattr vattr;
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int error;
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lock_kernel();
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memset(&vattr, 0, sizeof(vattr));
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inode->i_ctime = CURRENT_TIME_SEC;
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coda_iattr_to_vattr(iattr, &vattr);
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vattr.va_type = C_VNON; /* cannot set type */
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/* Venus is responsible for truncating the container-file!!! */
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error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);
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if ( !error ) {
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coda_vattr_to_iattr(inode, &vattr);
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coda_cache_clear_inode(inode);
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}
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unlock_kernel();
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return error;
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}
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struct inode_operations coda_file_inode_operations = {
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.permission = coda_permission,
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.getattr = coda_getattr,
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.setattr = coda_setattr,
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};
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static int coda_statfs(struct super_block *sb, struct kstatfs *buf)
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{
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int error;
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lock_kernel();
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error = venus_statfs(sb, buf);
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unlock_kernel();
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if (error) {
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/* fake something like AFS does */
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buf->f_blocks = 9000000;
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buf->f_bfree = 9000000;
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buf->f_bavail = 9000000;
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buf->f_files = 9000000;
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buf->f_ffree = 9000000;
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}
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/* and fill in the rest */
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buf->f_type = CODA_SUPER_MAGIC;
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buf->f_bsize = 1024;
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buf->f_namelen = CODA_MAXNAMLEN;
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return 0;
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}
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/* init_coda: used by filesystems.c to register coda */
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static int coda_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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{
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return get_sb_nodev(fs_type, flags, data, coda_fill_super, mnt);
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}
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struct file_system_type coda_fs_type = {
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.owner = THIS_MODULE,
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.name = "coda",
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.get_sb = coda_get_sb,
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.kill_sb = kill_anon_super,
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.fs_flags = FS_BINARY_MOUNTDATA,
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};
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