/* AFS superblock handling * * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved. * * This software may be freely redistributed under the terms of the * GNU General Public License. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * Authors: David Howells <dhowells@redhat.com> * David Woodhouse <dwmw2@redhat.com> * */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/parser.h> #include "internal.h" #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */ static void afs_i_init_once(void *foo, struct kmem_cache *cachep, unsigned long flags); static int afs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt); static struct inode *afs_alloc_inode(struct super_block *sb); static void afs_put_super(struct super_block *sb); static void afs_destroy_inode(struct inode *inode); struct file_system_type afs_fs_type = { .owner = THIS_MODULE, .name = "afs", .get_sb = afs_get_sb, .kill_sb = kill_anon_super, .fs_flags = 0, }; static const struct super_operations afs_super_ops = { .statfs = simple_statfs, .alloc_inode = afs_alloc_inode, .drop_inode = generic_delete_inode, .destroy_inode = afs_destroy_inode, .clear_inode = afs_clear_inode, .umount_begin = afs_umount_begin, .put_super = afs_put_super, }; static struct kmem_cache *afs_inode_cachep; static atomic_t afs_count_active_inodes; enum { afs_no_opt, afs_opt_cell, afs_opt_rwpath, afs_opt_vol, }; static const match_table_t afs_options_list = { { afs_opt_cell, "cell=%s" }, { afs_opt_rwpath, "rwpath" }, { afs_opt_vol, "vol=%s" }, { afs_no_opt, NULL }, }; /* * initialise the filesystem */ int __init afs_fs_init(void) { int ret; _enter(""); /* create ourselves an inode cache */ atomic_set(&afs_count_active_inodes, 0); ret = -ENOMEM; afs_inode_cachep = kmem_cache_create("afs_inode_cache", sizeof(struct afs_vnode), 0, SLAB_HWCACHE_ALIGN, afs_i_init_once, NULL); if (!afs_inode_cachep) { printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n"); return ret; } /* now export our filesystem to lesser mortals */ ret = register_filesystem(&afs_fs_type); if (ret < 0) { kmem_cache_destroy(afs_inode_cachep); _leave(" = %d", ret); return ret; } _leave(" = 0"); return 0; } /* * clean up the filesystem */ void __exit afs_fs_exit(void) { _enter(""); afs_mntpt_kill_timer(); unregister_filesystem(&afs_fs_type); if (atomic_read(&afs_count_active_inodes) != 0) { printk("kAFS: %d active inode objects still present\n", atomic_read(&afs_count_active_inodes)); BUG(); } kmem_cache_destroy(afs_inode_cachep); _leave(""); } /* * parse the mount options * - this function has been shamelessly adapted from the ext3 fs which * shamelessly adapted it from the msdos fs */ static int afs_parse_options(struct afs_mount_params *params, char *options, const char **devname) { struct afs_cell *cell; substring_t args[MAX_OPT_ARGS]; char *p; int token; _enter("%s", options); options[PAGE_SIZE - 1] = 0; while ((p = strsep(&options, ","))) { if (!*p) continue; token = match_token(p, afs_options_list, args); switch (token) { case afs_opt_cell: cell = afs_cell_lookup(args[0].from, args[0].to - args[0].from); if (IS_ERR(cell)) return PTR_ERR(cell); afs_put_cell(params->cell); params->cell = cell; break; case afs_opt_rwpath: params->rwpath = 1; break; case afs_opt_vol: *devname = args[0].from; break; default: printk(KERN_ERR "kAFS:" " Unknown or invalid mount option: '%s'\n", p); return -EINVAL; } } _leave(" = 0"); return 0; } /* * parse a device name to get cell name, volume name, volume type and R/W * selector * - this can be one of the following: * "%[cell:]volume[.]" R/W volume * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0), * or R/W (rwpath=1) volume * "%[cell:]volume.readonly" R/O volume * "#[cell:]volume.readonly" R/O volume * "%[cell:]volume.backup" Backup volume * "#[cell:]volume.backup" Backup volume */ static int afs_parse_device_name(struct afs_mount_params *params, const char *name) { struct afs_cell *cell; const char *cellname, *suffix; int cellnamesz; _enter(",%s", name); if (!name) { printk(KERN_ERR "kAFS: no volume name specified\n"); return -EINVAL; } if ((name[0] != '%' && name[0] != '#') || !name[1]) { printk(KERN_ERR "kAFS: unparsable volume name\n"); return -EINVAL; } /* determine the type of volume we're looking for */ params->type = AFSVL_ROVOL; params->force = false; if (params->rwpath || name[0] == '%') { params->type = AFSVL_RWVOL; params->force = true; } name++; /* split the cell name out if there is one */ params->volname = strchr(name, ':'); if (params->volname) { cellname = name; cellnamesz = params->volname - name; params->volname++; } else { params->volname = name; cellname = NULL; cellnamesz = 0; } /* the volume type is further affected by a possible suffix */ suffix = strrchr(params->volname, '.'); if (suffix) { if (strcmp(suffix, ".readonly") == 0) { params->type = AFSVL_ROVOL; params->force = true; } else if (strcmp(suffix, ".backup") == 0) { params->type = AFSVL_BACKVOL; params->force = true; } else if (suffix[1] == 0) { } else { suffix = NULL; } } params->volnamesz = suffix ? suffix - params->volname : strlen(params->volname); _debug("cell %*.*s [%p]", cellnamesz, cellnamesz, cellname ?: "", params->cell); /* lookup the cell record */ if (cellname || !params->cell) { cell = afs_cell_lookup(cellname, cellnamesz); if (IS_ERR(cell)) { printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n", cellname ?: ""); return PTR_ERR(cell); } afs_put_cell(params->cell); params->cell = cell; } _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s", params->cell->name, params->cell, params->volnamesz, params->volnamesz, params->volname, suffix ?: "-", params->type, params->force ? " FORCE" : ""); return 0; } /* * check a superblock to see if it's the one we're looking for */ static int afs_test_super(struct super_block *sb, void *data) { struct afs_mount_params *params = data; struct afs_super_info *as = sb->s_fs_info; return as->volume == params->volume; } /* * fill in the superblock */ static int afs_fill_super(struct super_block *sb, void *data) { struct afs_mount_params *params = data; struct afs_super_info *as = NULL; struct afs_fid fid; struct dentry *root = NULL; struct inode *inode = NULL; int ret; _enter(""); /* allocate a superblock info record */ as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL); if (!as) { _leave(" = -ENOMEM"); return -ENOMEM; } afs_get_volume(params->volume); as->volume = params->volume; /* fill in the superblock */ sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = AFS_FS_MAGIC; sb->s_op = &afs_super_ops; sb->s_fs_info = as; /* allocate the root inode and dentry */ fid.vid = as->volume->vid; fid.vnode = 1; fid.unique = 1; inode = afs_iget(sb, params->key, &fid, NULL, NULL); if (IS_ERR(inode)) goto error_inode; ret = -ENOMEM; root = d_alloc_root(inode); if (!root) goto error; sb->s_root = root; _leave(" = 0"); return 0; error_inode: ret = PTR_ERR(inode); inode = NULL; error: iput(inode); afs_put_volume(as->volume); kfree(as); sb->s_fs_info = NULL; _leave(" = %d", ret); return ret; } /* * get an AFS superblock */ static int afs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *options, struct vfsmount *mnt) { struct afs_mount_params params; struct super_block *sb; struct afs_volume *vol; struct key *key; int ret; _enter(",,%s,%p", dev_name, options); memset(¶ms, 0, sizeof(params)); /* parse the options and device name */ if (options) { ret = afs_parse_options(¶ms, options, &dev_name); if (ret < 0) goto error; } ret = afs_parse_device_name(¶ms, dev_name); if (ret < 0) goto error; /* try and do the mount securely */ key = afs_request_key(params.cell); if (IS_ERR(key)) { _leave(" = %ld [key]", PTR_ERR(key)); ret = PTR_ERR(key); goto error; } params.key = key; /* parse the device name */ vol = afs_volume_lookup(¶ms); if (IS_ERR(vol)) { ret = PTR_ERR(vol); goto error; } params.volume = vol; /* allocate a deviceless superblock */ sb = sget(fs_type, afs_test_super, set_anon_super, ¶ms); if (IS_ERR(sb)) { ret = PTR_ERR(sb); goto error; } if (!sb->s_root) { /* initial superblock/root creation */ _debug("create"); sb->s_flags = flags; ret = afs_fill_super(sb, ¶ms); if (ret < 0) { up_write(&sb->s_umount); deactivate_super(sb); goto error; } sb->s_flags |= MS_ACTIVE; } else { _debug("reuse"); ASSERTCMP(sb->s_flags, &, MS_ACTIVE); } simple_set_mnt(mnt, sb); afs_put_volume(params.volume); afs_put_cell(params.cell); _leave(" = 0 [%p]", sb); return 0; error: afs_put_volume(params.volume); afs_put_cell(params.cell); key_put(params.key); _leave(" = %d", ret); return ret; } /* * finish the unmounting process on the superblock */ static void afs_put_super(struct super_block *sb) { struct afs_super_info *as = sb->s_fs_info; _enter(""); afs_put_volume(as->volume); _leave(""); } /* * initialise an inode cache slab element prior to any use */ static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep, unsigned long flags) { struct afs_vnode *vnode = _vnode; if (flags & SLAB_CTOR_CONSTRUCTOR) { memset(vnode, 0, sizeof(*vnode)); inode_init_once(&vnode->vfs_inode); init_waitqueue_head(&vnode->update_waitq); mutex_init(&vnode->permits_lock); mutex_init(&vnode->validate_lock); spin_lock_init(&vnode->lock); INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work); } } /* * allocate an AFS inode struct from our slab cache */ static struct inode *afs_alloc_inode(struct super_block *sb) { struct afs_vnode *vnode; vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL); if (!vnode) return NULL; atomic_inc(&afs_count_active_inodes); memset(&vnode->fid, 0, sizeof(vnode->fid)); memset(&vnode->status, 0, sizeof(vnode->status)); vnode->volume = NULL; vnode->update_cnt = 0; vnode->flags = 1 << AFS_VNODE_UNSET; vnode->cb_promised = false; return &vnode->vfs_inode; } /* * destroy an AFS inode struct */ static void afs_destroy_inode(struct inode *inode) { struct afs_vnode *vnode = AFS_FS_I(inode); _enter("{%lu}", inode->i_ino); _debug("DESTROY INODE %p", inode); ASSERTCMP(vnode->server, ==, NULL); kmem_cache_free(afs_inode_cachep, vnode); atomic_dec(&afs_count_active_inodes); }