diff options
author | Ralf Baechle <ralf@linux-mips.org> | 1997-12-06 23:51:34 +0000 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 1997-12-06 23:51:34 +0000 |
commit | 230e5ab6a084ed50470f101934782dbf54b0d06b (patch) | |
tree | 5dd821c8d33f450470588e7a543f74bf74306e9e /fs/nfsd/nfsfh.c | |
parent | c9b1c8a64c6444d189856f1e26bdcb8b4cd0113a (diff) |
Merge with Linux 2.1.67.
Diffstat (limited to 'fs/nfsd/nfsfh.c')
-rw-r--r-- | fs/nfsd/nfsfh.c | 1244 |
1 files changed, 1208 insertions, 36 deletions
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index abb2f7fd3..ff341f012 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -7,18 +7,994 @@ */ #include <linux/sched.h> +#include <linux/malloc.h> #include <linux/fs.h> #include <linux/unistd.h> #include <linux/string.h> #include <linux/stat.h> +#include <linux/dcache.h> #include <linux/sunrpc/svc.h> #include <linux/nfsd/nfsd.h> #define NFSDDBG_FACILITY NFSDDBG_FH +#define NFSD_PARANOIA 1 +/* #define NFSD_DEBUG_VERBOSE 1 */ + +extern unsigned long num_physpages; + +#define NFSD_FILE_CACHE 0 +#define NFSD_DIR_CACHE 1 +struct fh_entry { + struct dentry * dentry; + unsigned long reftime; + ino_t ino; + dev_t dev; +}; + +#define NFSD_MAXFH PAGE_SIZE/sizeof(struct fh_entry) +static struct fh_entry filetable[NFSD_MAXFH]; +static struct fh_entry dirstable[NFSD_MAXFH]; + +static int nfsd_nr_verified = 0; +static int nfsd_nr_put = 0; +static unsigned long nfsd_next_expire = 0; + +static int add_to_fhcache(struct dentry *, int); +static int nfsd_d_validate(struct dentry *); +struct dentry * lookup_inode(dev_t, ino_t, ino_t); + +static LIST_HEAD(fixup_head); +static LIST_HEAD(path_inuse); +static int nfsd_nr_fixups = 0; +static int nfsd_nr_paths = 0; +#define NFSD_MAX_PATHS 500 +#define NFSD_MAX_FIXUPAGE 60*HZ + +struct nfsd_fixup { + struct list_head lru; + ino_t dir; + ino_t ino; + dev_t dev; + struct dentry *dentry; + unsigned long reftime; +}; + +struct nfsd_path { + struct list_head lru; + unsigned long reftime; + int users; + ino_t ino; + dev_t dev; + char name[1]; +}; + +static struct nfsd_fixup * find_cached_lookup(dev_t dev, ino_t dir, ino_t ino) +{ + struct list_head *tmp = fixup_head.next; + + for (; tmp != &fixup_head; tmp = tmp->next) { + struct nfsd_fixup *fp; + + fp = list_entry(tmp, struct nfsd_fixup, lru); + if (fp->ino != ino) + continue; + if (fp->dir != dir) + continue; + if (fp->dev != dev) + continue; + list_del(tmp); + list_add(tmp, &fixup_head); + fp->reftime = jiffies; + return fp; + } + return NULL; +} + +/* + * Save the dentry pointer from a successful lookup. + */ +static void add_to_lookup_cache(struct dentry *dentry, struct knfs_fh *fh) +{ + struct nfsd_fixup *fp; + + fp = find_cached_lookup(fh->fh_dev, fh->fh_dirino, fh->fh_ino); + if (fp) { + fp->dentry = dentry; + return; + } + + /* + * Add a new entry. The small race here is unimportant: + * if another task adds the same lookup, both entries + * will be consistent. + */ + fp = kmalloc(sizeof(struct nfsd_fixup), GFP_KERNEL); + if (fp) { + fp->dir = fh->fh_dirino; + fp->ino = fh->fh_ino; + fp->dev = fh->fh_dev; + fp->dentry = dentry; + fp->reftime = jiffies; + list_add(&fp->lru, &fixup_head); + nfsd_nr_fixups++; + } +} + +static void free_fixup_entry(struct nfsd_fixup *fp) +{ + list_del(&fp->lru); + kfree(fp); + nfsd_nr_fixups--; +} + +/* + * Copy a dentry's path into the specified buffer. + */ +static int copy_path(char *buffer, struct dentry *dentry, int namelen) +{ + char *p, *b = buffer; + int result = 0, totlen = 0, len; + + while (1) { + struct dentry *parent; + dentry = dentry->d_covers; + parent = dentry->d_parent; + len = dentry->d_name.len; + p = (char *) dentry->d_name.name + len; + totlen += len; + if (totlen > namelen) + goto out; + while (len--) + *b++ = *(--p); + if (dentry == parent) + break; + dentry = parent; + totlen++; + if (totlen > namelen) + goto out; + *b++ = '/'; + } + *b = 0; + + /* + * Now reverse in place ... + */ + p = buffer; + while (p < b) { + char c = *(--b); + *b = *p; + *p++ = c; + } + result = 1; +out: + return result; +} + +/* + * Add a dentry's path to the path cache. + */ +static int add_to_path_cache(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct dentry *this; + struct nfsd_path *new; + int len, result = 0; + +#ifdef NFSD_DEBUG_VERBOSE +printk("add_to_path_cache: cacheing %s/%s\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + /* + * Get the length of the full pathname. + */ +restart: + len = 0; + this = dentry; + while (1) { + struct dentry *parent; + this = this->d_covers; + parent = this->d_parent; + len += this->d_name.len; + if (this == parent) + break; + this = parent; + len++; + } + /* + * Allocate a structure to hold the path. + */ + new = kmalloc(sizeof(struct nfsd_path) + len, GFP_KERNEL); + if (new) { + new->users = 0; + new->reftime = jiffies; + new->ino = inode->i_ino; + new->dev = inode->i_dev; + result = copy_path(new->name, dentry, len); + if (!result) + goto retry; + list_add(&new->lru, &path_inuse); + nfsd_nr_paths++; +#ifdef NFSD_DEBUG_VERBOSE +printk("add_to_path_cache: added %s, paths=%d\n", new->name, nfsd_nr_paths); +#endif + } + return result; + + /* + * If the dentry's path length changed, just try again ... + */ +retry: + kfree(new); + printk("add_to_path_cache: path length changed, retrying\n"); + goto restart; +} + +/* + * Search for a path entry for the specified (dev, inode). + */ +struct nfsd_path *get_path_entry(dev_t dev, ino_t ino) +{ + struct nfsd_path *pe; + struct list_head *tmp; + + for (tmp = path_inuse.next; tmp != &path_inuse; tmp = tmp->next) { + pe = list_entry(tmp, struct nfsd_path, lru); + if (pe->ino != ino) + continue; + if (pe->dev != dev) + continue; + list_del(tmp); + list_add(tmp, &path_inuse); + pe->users++; + pe->reftime = jiffies; +#ifdef NFSD_PARANOIA +printk("get_path_entry: found %s for %s/%ld\n", pe->name, kdevname(dev), ino); +#endif + return pe; + } + return NULL; +} + +static void put_path(struct nfsd_path *pe) +{ + pe->users--; +} + +static void free_path_entry(struct nfsd_path *pe) +{ + if (pe->users) + printk("free_path_entry: %s in use, users=%d\n", + pe->name, pe->users); + list_del(&pe->lru); + kfree(pe); + nfsd_nr_paths--; +} + +struct nfsd_getdents_callback { + struct nfsd_dirent *dirent; + ino_t dirino; /* parent inode number */ + int found; /* dirent inode matched? */ + int sequence; /* sequence counter */ +}; + +struct nfsd_dirent { + ino_t ino; /* preset to desired entry */ + int len; + char name[256]; +}; + +/* + * A rather strange filldir function to capture the inode number + * for the second entry (the parent inode) and the name matching + * the specified inode number. + */ +static int filldir_one(void * __buf, const char * name, int len, + off_t pos, ino_t ino) +{ + struct nfsd_getdents_callback *buf = __buf; + struct nfsd_dirent *dirent = buf->dirent; + int result = 0; + + buf->sequence++; +#ifdef NFSD_DEBUG_VERBOSE +printk("filldir_one: seq=%d, ino=%ld, name=%s\n", buf->sequence, ino, name); +#endif + if (buf->sequence == 2) { + buf->dirino = ino; + goto out; + } + if (dirent->ino == ino) { + dirent->len = len; + memcpy(dirent->name, name, len); + dirent->name[len] = 0; + buf->found = 1; + result = -1; + } +out: + return result; +} + +/* + * Read a directory and return the parent inode number and the name + * of the specified entry. The dirent must be initialized with the + * inode number of the desired entry. + */ +static int get_parent_ino(struct dentry *dentry, struct nfsd_dirent *dirent) +{ + struct inode *dir = dentry->d_inode; + int error; + struct file file; + struct nfsd_getdents_callback buffer; + + error = -ENOTDIR; + if (!dir || !S_ISDIR(dir->i_mode)) + goto out; + error = -EINVAL; + if (!dir->i_op || !dir->i_op->default_file_ops) + goto out; + /* + * Open the directory ... + */ + error = init_private_file(&file, dentry, FMODE_READ); + if (error) + goto out; + error = -EINVAL; + if (!file.f_op->readdir) + goto out_close; + + buffer.dirent = dirent; + buffer.dirino = 0; + buffer.found = 0; + buffer.sequence = 0; + while (1) { + int old_seq = buffer.sequence; + down(&dir->i_sem); + error = file.f_op->readdir(&file, &buffer, filldir_one); + up(&dir->i_sem); + if (error < 0) + break; + + error = 0; + if (buffer.found) + break; + error = -ENOENT; + if (old_seq == buffer.sequence) + break; + } + dirent->ino = buffer.dirino; + +out_close: + if (file.f_op->release) + file.f_op->release(dir, &file); +out: + return error; +} + +/* + * Look up a dentry given inode and parent inode numbers. + * + * This relies on the ability of a unix-like filesystem to return + * the parent inode of a directory as the ".." (second) entry. + * + * This could be further optimized if we had an efficient way of + * searching for a dentry given the inode: as we walk up the tree, + * it's likely that a dentry exists before we reach the root. + */ +struct dentry * lookup_inode(dev_t dev, ino_t dirino, ino_t ino) +{ + struct super_block *sb; + struct dentry *root, *dentry, *result; + struct inode *dir; + char *name; + unsigned long page; + ino_t root_ino; + int error; + struct nfsd_dirent dirent; + + result = ERR_PTR(-ENOMEM); + page = __get_free_page(GFP_KERNEL); + if (!page) + goto out; + + /* + * Get the root dentry for the device. + */ + result = ERR_PTR(-ENOENT); + sb = get_super(dev); + if (!sb) + goto out_page; + root = dget(sb->s_root); + root_ino = root->d_inode->i_ino; /* usually 2 */ + + name = (char *) page + PAGE_SIZE; + *(--name) = 0; + + /* + * Walk up the tree to construct the name string. + * When we reach the root inode, look up the name + * relative to the root dentry. + */ + while (1) { + if (ino == root_ino) { + if (*name == '/') + name++; + /* + * Note: this dput()s the root dentry. + */ + result = lookup_dentry(name, root, 0); + break; + } + + result = ERR_PTR(-ENOENT); + dir = iget(sb, dirino); + if (!dir) + goto out_root; + dentry = d_alloc_root(dir, NULL); + if (!dentry) + goto out_iput; + + /* + * Get the name for this inode and the next parent inode. + */ + dirent.ino = ino; + error = get_parent_ino(dentry, &dirent); + result = ERR_PTR(error); + dput(dentry); + if (error) + goto out_root; + /* + * Prepend the name to the buffer. + */ + result = ERR_PTR(-ENAMETOOLONG); + name -= (dirent.len + 1); + if ((unsigned long) name <= page) + goto out_root; + memcpy(name + 1, dirent.name, dirent.len); + *name = '/'; + + /* + * Make sure we can't get caught in a loop ... + */ + if (dirino == dirent.ino && dirino != root_ino) { + printk("lookup_inode: looping?? (ino=%ld, path=%s)\n", + dirino, name); + goto out_root; + } + ino = dirino; + dirino = dirent.ino; + } + +out_page: + free_page(page); +out: + return result; + + /* + * Error exits ... + */ +out_iput: + result = ERR_PTR(-ENOMEM); + iput(dir); +out_root: + dput(root); + goto out; +} + +/* + * Find an entry in the cache matching the given dentry pointer. + */ +static struct fh_entry *find_fhe(struct dentry *dentry, int cache, + struct fh_entry **empty) +{ + struct fh_entry *fhe; + int i, found = (empty == NULL) ? 1 : 0; + + fhe = (cache == NFSD_FILE_CACHE) ? &filetable[0] : &dirstable[0]; + for (i = 0; i < NFSD_MAXFH; i++, fhe++) { + if (fhe->dentry == dentry) { + fhe->reftime = jiffies; + return fhe; + } + if (!found && !fhe->dentry) { + found = 1; + *empty = fhe; + } + } + return NULL; +} + +/* + * Expire a cache entry. + */ +static void expire_fhe(struct fh_entry *empty, int cache) +{ + struct dentry *dentry = empty->dentry; + +#ifdef NFSD_DEBUG_VERBOSE +printk("expire_fhe: expiring %s/%s, d_count=%d, ino=%ld\n", +dentry->d_parent->d_name.name, dentry->d_name.name, dentry->d_count,empty->ino); +#endif + empty->dentry = NULL; /* no dentry */ + /* + * Add the parent to the dir cache before releasing the dentry, + * and check whether to save a copy of the dentry's path. + */ + if (dentry != dentry->d_parent) { + struct dentry *parent = dget(dentry->d_parent); + if (add_to_fhcache(parent, NFSD_DIR_CACHE)) + nfsd_nr_verified++; + else + dput(parent); + /* + * If we're expiring a directory, copy its path. + */ + if (cache == NFSD_DIR_CACHE) { + add_to_path_cache(dentry); + } + } + dput(dentry); + nfsd_nr_put++; +} + +/* + * Look for an empty slot, or select one to expire. + */ +static void expire_slot(int cache) +{ + struct fh_entry *fhe, *empty = NULL; + unsigned long oldest = -1; + int i; + + fhe = (cache == NFSD_FILE_CACHE) ? &filetable[0] : &dirstable[0]; + for (i = 0; i < NFSD_MAXFH; i++, fhe++) { + if (!fhe->dentry) + goto out; + if (fhe->reftime < oldest) { + oldest = fhe->reftime; + empty = fhe; + } + } + if (empty) + expire_fhe(empty, cache); + +out: + return; +} + +/* + * Expire any cache entries older than a certain age. + */ +static void expire_old(int cache, int age) +{ + struct list_head *tmp; + struct fh_entry *fhe; + int i; + +#ifdef NFSD_DEBUG_VERBOSE +printk("expire_old: expiring %s older than %d\n", +(cache == NFSD_FILE_CACHE) ? "file" : "dir", age); +#endif + fhe = (cache == NFSD_FILE_CACHE) ? &filetable[0] : &dirstable[0]; + for (i = 0; i < NFSD_MAXFH; i++, fhe++) { + if (!fhe->dentry) + continue; + if ((jiffies - fhe->reftime) > age) + expire_fhe(fhe, cache); + } + + /* + * Remove old entries from the patch-up cache. + */ + while ((tmp = fixup_head.prev) != &fixup_head) { + struct nfsd_fixup *fp; + fp = list_entry(tmp, struct nfsd_fixup, lru); + if ((jiffies - fp->reftime) < NFSD_MAX_FIXUPAGE) + break; + free_fixup_entry(fp); + } + + /* + * Trim the path cache ... + */ + while (nfsd_nr_paths > NFSD_MAX_PATHS) { + struct nfsd_path *pe; + pe = list_entry(path_inuse.prev, struct nfsd_path, lru); + if (pe->users) + break; + free_path_entry(pe); + } +} + +/* + * Add a dentry to the file or dir cache. + * + * Note: As NFS filehandles must have an inode, we don't accept + * negative dentries. + */ +static int add_to_fhcache(struct dentry *dentry, int cache) +{ + struct fh_entry *fhe, *empty = NULL; + struct inode *inode = dentry->d_inode; + + if (!inode) { +#ifdef NFSD_PARANOIA +printk("add_to_fhcache: %s/%s rejected, no inode!\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + return 0; + } + +repeat: + fhe = find_fhe(dentry, cache, &empty); + if (fhe) { + return 0; + } + + /* + * Not found ... make a new entry. + */ + if (empty) { + empty->dentry = dentry; + empty->reftime = jiffies; + empty->ino = inode->i_ino; + empty->dev = inode->i_dev; + return 1; + } + + expire_slot(cache); + goto repeat; +} + +/* + * Find an entry in the dir cache for the specified inode number. + */ +static struct fh_entry *find_fhe_by_ino(dev_t dev, ino_t ino) +{ + struct fh_entry * fhe = &dirstable[0]; + int i; + + for (i = 0; i < NFSD_MAXFH; i++, fhe++) { + if (fhe->ino == ino && fhe->dev == dev) { + fhe->reftime = jiffies; + return fhe; + } + } + return NULL; +} + +/* + * Find the (directory) dentry with the specified (dev, inode) number. + * Note: this leaves the dentry in the cache. + */ +static struct dentry *find_dentry_by_ino(dev_t dev, ino_t ino) +{ + struct fh_entry *fhe; + struct nfsd_path *pe; + struct dentry * dentry; + +#ifdef NFSD_DEBUG_VERBOSE +printk("find_dentry_by_ino: looking for inode %ld\n", ino); +#endif + /* + * Special case: inode number 2 is the root inode, + * so we can use the root dentry for the device. + */ + if (ino == 2) { + struct super_block *sb = get_super(dev); + if (sb) { +#ifdef NFSD_PARANOIA +printk("find_dentry_by_ino: getting root dentry for %s\n", kdevname(dev)); +#endif + if (sb->s_root) { + dentry = dget(sb->s_root); + goto out; + } else { +#ifdef NFSD_PARANOIA + printk("find_dentry_by_ino: %s has no root??\n", + kdevname(dev)); +#endif + } + } + } + + /* + * Search the dentry cache ... + */ + fhe = find_fhe_by_ino(dev, ino); + if (fhe) { + dentry = dget(fhe->dentry); + goto out; + } + + /* + * Search the path cache ... + */ + dentry = NULL; + pe = get_path_entry(dev, ino); + if (pe) { + struct dentry *res; + res = lookup_dentry(pe->name, NULL, 0); + if (!IS_ERR(res)) { + struct inode *inode = res->d_inode; + if (inode && inode->i_ino == ino && + inode->i_dev == dev) { + dentry = res; +#ifdef NFSD_PARANOIA +printk("find_dentry_by_ino: found %s/%s, ino=%ld\n", +dentry->d_parent->d_name.name, dentry->d_name.name, ino); +#endif + if (add_to_fhcache(dentry, NFSD_DIR_CACHE)) { + dget(dentry); + nfsd_nr_verified++; + } + } else { + dput(res); + } + } else { +#ifdef NFSD_PARANOIA +printk("find_dentry_by_ino: %s lookup failed\n", pe->name); +#endif + } + put_path(pe); + } +out: + return dentry; +} + +/* + * Look for an entry in the file cache matching the dentry pointer, + * and verify that the (dev, inode) numbers are correct. If found, + * the entry is removed from the cache. + */ +static struct dentry *find_dentry_in_fhcache(struct knfs_fh *fh) +{ + struct fh_entry * fhe; + + fhe = find_fhe(fh->fh_dcookie, NFSD_FILE_CACHE, NULL); + if (fhe) { + struct dentry *parent, *dentry = fhe->dentry; + struct inode *inode = dentry->d_inode; + if (!inode) { +#ifdef NFSD_PARANOIA +printk("find_dentry_in_fhcache: %s/%s has no inode!\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + goto out; + } + if (inode->i_ino != fh->fh_ino || inode->i_dev != fh->fh_dev) + goto out; + + fhe->dentry = NULL; + fhe->ino = 0; + fhe->dev = 0; + nfsd_nr_put++; + /* + * Make sure the parent is in the dir cache ... + */ + parent = dget(dentry->d_parent); + if (add_to_fhcache(parent, NFSD_DIR_CACHE)) + nfsd_nr_verified++; + else + dput(parent); + return dentry; + } +out: + return NULL; +} + +/* + * Look for an entry in the parent directory with the specified + * inode number. + */ +static struct dentry *lookup_by_inode(struct dentry *parent, ino_t ino) +{ + struct dentry *dentry; + int error; + struct nfsd_dirent dirent; + + /* + * Search the directory for the inode number. + */ + dirent.ino = ino; + error = get_parent_ino(parent, &dirent); + if (error) { +#ifdef NFSD_PARANOIA +printk("lookup_by_inode: ino %ld not found in %s\n", ino, parent->d_name.name); +#endif + goto no_entry; + } +#ifdef NFSD_PARANOIA +printk("lookup_by_inode: found %s\n", dirent.name); +#endif + + dentry = lookup_dentry(dirent.name, dget(parent), 0); + if (!IS_ERR(dentry)) { + if (dentry->d_inode && dentry->d_inode->i_ino == ino) + goto out; +#ifdef NFSD_PARANOIA +printk("lookup_by_inode: %s/%s inode mismatch??\n", +parent->d_name.name, dentry->d_name.name); +#endif + dput(dentry); + } else { +#ifdef NFSD_PARANOIA +printk("lookup_by_inode: %s lookup failed, error=%ld\n", +dirent.name, PTR_ERR(dentry)); +#endif + } + +no_entry: + dentry = NULL; +out: + return dentry; + +} + +/* + * Search the fix-up list for a dentry from a prior lookup. + */ +static struct dentry *nfsd_cached_lookup(struct knfs_fh *fh) +{ + struct nfsd_fixup *fp; + + fp = find_cached_lookup(fh->fh_dev, fh->fh_dirino, fh->fh_ino); + if (fp) + return fp->dentry; + return NULL; +} + +/* + * The is the basic lookup mechanism for turning an NFS filehandle + * into a dentry. There are several levels to the search: + * (1) Look for the dentry pointer the short-term fhcache, + * and verify that it has the correct inode number. + * + * (2) Try to validate the dentry pointer in the filehandle, + * and verify that it has the correct inode number. If this + * fails, check for a cached lookup in the fix-up list and + * repeat step (2) using the new dentry pointer. + * + * (3) Look up the dentry by using the inode and parent inode numbers + * to build the name string. This should succeed for any unix-like + * filesystem. + * + * (4) Search for the parent dentry in the dir cache, and then + * look for the name matching the inode number. + * + * (5) The most general case ... search the whole volume for the inode. + * + * If successful, we return a dentry with the use count incremented. + * + * Note: steps (4) and (5) above are probably unnecessary now that (3) + * is working. Remove the code once this is verified ... + */ +static struct dentry * +find_fh_dentry(struct knfs_fh *fh) +{ + struct dentry *dentry, *parent; + int looked_up = 0, retry = 0; + + /* + * Stage 1: Look for the dentry in the short-term fhcache. + */ + dentry = find_dentry_in_fhcache(fh); + if (dentry) { + nfsdstats.fh_cached++; + goto out; + } + + /* + * Stage 2: Attempt to validate the dentry in the filehandle. + */ + dentry = fh->fh_dcookie; +recheck: + if (nfsd_d_validate(dentry)) { + struct inode * dir = dentry->d_parent->d_inode; + + if (dir->i_ino == fh->fh_dirino && dir->i_dev == fh->fh_dev) { + struct inode * inode = dentry->d_inode; + /* + * NFS filehandles must always have an inode, + * so we won't accept a negative dentry. + */ + if (inode && inode->i_ino == fh->fh_ino) { + dget(dentry); +#ifdef NFSD_DEBUG_VERBOSE +printk("find_fh_dentry: validated %s/%s, ino=%ld\n", +dentry->d_parent->d_name.name, dentry->d_name.name, inode->i_ino); +#endif + if (!retry) + nfsdstats.fh_valid++; + else { + nfsdstats.fh_fixup++; +#ifdef NFSD_DEBUG_VERBOSE +printk("find_fh_dentry: retried validation successful\n"); +#endif + } + goto out; + } + } + } + + /* + * Before proceeding to a lookup, check whether we cached a + * prior lookup. If so, try to validate that dentry ... + */ + if (!retry && (dentry = nfsd_cached_lookup(fh)) != NULL) { + retry = 1; + goto recheck; + } + + /* + * Stage 3: Look up the dentry based on the inode and parent inode + * numbers. This should work for all unix-like filesystems ... + */ + looked_up = 1; + dentry = lookup_inode(fh->fh_dev, fh->fh_dirino, fh->fh_ino); + if (!IS_ERR(dentry)) { + struct inode * inode = dentry->d_inode; +#ifdef NFSD_DEBUG_VERBOSE +printk("find_fh_dentry: looked up %s/%s\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + if (inode && inode->i_ino == fh->fh_ino) { + nfsdstats.fh_lookup++; + goto out; + } +#ifdef NFSD_PARANOIA +printk("find_fh_dentry: %s/%s lookup mismatch!\n", +dentry->d_parent->d_name.name, dentry->d_name.name); +#endif + dput(dentry); + } + + /* + * Stage 4: Look for the parent dentry in the fhcache ... + */ + parent = find_dentry_by_ino(fh->fh_dev, fh->fh_dirino); + if (parent) { + /* + * ... then search for the inode in the parent directory. + */ + dentry = lookup_by_inode(parent, fh->fh_ino); + dput(parent); + if (dentry) + goto out; + } + + /* + * Stage 5: Search the whole volume. + */ +#ifdef NFSD_PARANOIA +printk("find_fh_dentry: %s, %ld/%ld not found -- need full search!\n", +kdevname(fh->fh_dev), fh->fh_dirino, fh->fh_ino); +#endif + dentry = NULL; + nfsdstats.fh_stale++; + +out: + if (looked_up && dentry) { + add_to_lookup_cache(dentry, fh); + } + + /* + * Perform any needed housekeeping ... + * N.B. move this into one of the daemons ... + */ + if (jiffies >= nfsd_next_expire) { + expire_old(NFSD_FILE_CACHE, 5*HZ); + expire_old(NFSD_DIR_CACHE , 60*HZ); + nfsd_next_expire = jiffies + 5*HZ; + } + return dentry; +} /* * Perform sanity checks on the dentry in a client's file handle. + * + * Note that the filehandle dentry may need to be freed even after + * an error return. */ u32 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) @@ -27,50 +1003,53 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) struct dentry *dentry; struct inode *inode; struct knfs_fh *fh = &fhp->fh_handle; + u32 error = 0; if(fhp->fh_dverified) - return 0; + goto out; dprintk("nfsd: fh_lookup(exp %x/%ld fh %p)\n", - fh->fh_xdev, fh->fh_xino, fh->fh_dentry); + fh->fh_xdev, fh->fh_xino, fh->fh_dcookie); - /* Look up the export entry. */ + /* + * Look up the export entry. + * N.B. We need to lock this while in use ... + */ + error = nfserr_stale; exp = exp_get(rqstp->rq_client, fh->fh_xdev, fh->fh_xino); - if (!exp) { - /* nfsdstats.fhstale++; */ - return nfserr_stale; /* export entry revoked */ - } + if (!exp) /* export entry revoked */ + goto out; /* Check if the request originated from a secure port. */ + error = nfserr_perm; if (!rqstp->rq_secure && EX_SECURE(exp)) { printk(KERN_WARNING "nfsd: request from insecure port (%08lx:%d)!\n", ntohl(rqstp->rq_addr.sin_addr.s_addr), ntohs(rqstp->rq_addr.sin_port)); - return nfserr_perm; + goto out; } /* Set user creds if we haven't done so already. */ nfsd_setuser(rqstp, exp); - dentry = fh->fh_dentry; - - if(!d_validate(dentry, fh->fh_dparent, fh->fh_dhash, fh->fh_dlen) || - !(inode = dentry->d_inode) || - !inode->i_nlink) { - /* Currently we cannot tell the difference between - * a bogus pointer and a true unlink between fh - * uses. But who cares about accurate error reporting - * to buggy/malicious clients... -DaveM - */ - - /* nfsdstats.fhstale++; */ - return nfserr_stale; - } - - dget(dentry); - fhp->fh_dverified = 1; + /* + * Look up the dentry using the NFS fh. + */ + error = nfserr_stale; + dentry = find_fh_dentry(fh); + if (!dentry) + goto out; + /* + * Note: it's possible that the returned dentry won't be the + * one in the filehandle. We can correct the FH for our use, + * but unfortunately the client will keep sending the broken + * one. Hopefully the lookup will keep patching things up.. + */ + fhp->fh_dentry = dentry; fhp->fh_export = exp; + fhp->fh_dverified = 1; + nfsd_nr_verified++; /* Type check. The correct error return for type mismatches * does not seem to be generally agreed upon. SunOS seems to @@ -78,33 +1057,226 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) * spec says this is incorrect (implementation notes for the * write call). */ - if (type > 0 && (inode->i_mode & S_IFMT) != type) - return (type == S_IFDIR)? nfserr_notdir : nfserr_isdir; - if (type < 0 && (inode->i_mode & S_IFMT) == -type) - return (type == -S_IFDIR)? nfserr_notdir : nfserr_isdir; + inode = dentry->d_inode; + if (type > 0 && (inode->i_mode & S_IFMT) != type) { + error = (type == S_IFDIR)? nfserr_notdir : nfserr_isdir; + goto out; + } + if (type < 0 && (inode->i_mode & S_IFMT) == -type) { + error = (type == -S_IFDIR)? nfserr_notdir : nfserr_isdir; + goto out; + } /* Finally, check access permissions. */ - return nfsd_permission(fhp->fh_export, dentry, access); + error = nfsd_permission(fhp->fh_export, dentry, access); +if (error) +printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n", +dentry->d_parent->d_name.name, dentry->d_name.name, access, error); + +out: + return error; } /* - * Compose file handle for NFS reply. + * Compose a filehandle for an NFS reply. + * + * Note that when first composed, the dentry may not yet have + * an inode. In this case a call to fh_update should be made + * before the fh goes out on the wire ... */ void fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry) { + struct inode * inode = dentry->d_inode; + dprintk("nfsd: fh_compose(exp %x/%ld dentry %p)\n", exp->ex_dev, exp->ex_ino, dentry); - fh_init(fhp); /* initialize empty fh */ - fhp->fh_handle.fh_dentry = dentry; - fhp->fh_handle.fh_dparent = dentry->d_parent; - fhp->fh_handle.fh_dhash = dentry->d_name.hash; - fhp->fh_handle.fh_dlen = dentry->d_name.len; + /* + * N.B. We shouldn't need to init the fh -- the call to fh_compose + * may not be done on error paths, but the cleanup must call fh_put. + * Fix this soon! + */ + fh_init(fhp); + fhp->fh_handle.fh_dcookie = dentry; + if (inode) { + fhp->fh_handle.fh_ino = inode->i_ino; + } + fhp->fh_handle.fh_dirino = dentry->d_parent->d_inode->i_ino; + fhp->fh_handle.fh_dev = dentry->d_parent->d_inode->i_dev; fhp->fh_handle.fh_xdev = exp->ex_dev; fhp->fh_handle.fh_xino = exp->ex_ino; + + fhp->fh_dentry = dentry; /* our internal copy */ fhp->fh_export = exp; /* We stuck it there, we know it's good. */ fhp->fh_dverified = 1; + nfsd_nr_verified++; +} + +/* + * Update filehandle information after changing a dentry. + */ +void +fh_update(struct svc_fh *fhp) +{ + struct dentry *dentry; + struct inode *inode; + + if (!fhp->fh_dverified) { + printk("fh_update: fh not verified!\n"); + goto out; + } + + dentry = fhp->fh_dentry; + inode = dentry->d_inode; + if (!inode) { + printk("fh_update: %s/%s still negative!\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + goto out; + } + fhp->fh_handle.fh_ino = inode->i_ino; +out: + return; +} + +/* + * Release a filehandle. If the filehandle carries a dentry count, + * we add the dentry to the short-term cache rather than release it. + */ +void +fh_put(struct svc_fh *fhp) +{ + if (fhp->fh_dverified) { + struct dentry * dentry = fhp->fh_dentry; + fh_unlock(fhp); + fhp->fh_dverified = 0; + if (!dentry->d_count) { + printk("fh_put: %s/%s has d_count 0!\n", + dentry->d_parent->d_name.name, dentry->d_name.name); + return; + } + if (!dentry->d_inode || !add_to_fhcache(dentry, 0)) { + dput(dentry); + nfsd_nr_put++; + } + } +} + +/* + * Verify that the FH dentry is still a valid dentry pointer. + * After making some preliminary checks, we ask VFS to verify + * that it is indeed a dentry. + */ +static int nfsd_d_validate(struct dentry *dentry) +{ + unsigned long dent_addr = (unsigned long) dentry; + unsigned long min_addr = PAGE_OFFSET; + unsigned long max_addr = min_addr + (num_physpages << PAGE_SHIFT); + unsigned long align_mask = 0x0F; + unsigned int len; + int valid = 0; + + if (dent_addr < min_addr) + goto bad_addr; + if (dent_addr > max_addr - sizeof(struct dentry)) + goto bad_addr; + if ((dent_addr & ~align_mask) != dent_addr) + goto bad_align; + /* + * Looks safe enough to dereference ... + */ + len = dentry->d_name.len; + if (len > NFS_MAXNAMLEN) + goto out; + /* + * Note: d_validate doesn't dereference the parent pointer ... + * just combines it with the name hash to find the hash chain. + */ + valid = d_validate(dentry, dentry->d_parent, dentry->d_name.hash, len); + +out: + return valid; + +bad_addr: + printk("nfsd_d_validate: invalid address %lx\n", dent_addr); + goto out; +bad_align: + printk("nfsd_d_validate: unaligned address %lx\n", dent_addr); + goto out; +} + +/* + * Flush any cached dentries for the specified device + * or for all devices. + * + * This is called when revoking the last export for a + * device, so that it can be unmounted cleanly. + */ +void nfsd_fh_flush(dev_t dev) +{ + struct fh_entry *fhe; + int i, pass = 2; + + fhe = &filetable[0]; + while (pass--) { + for (i = 0; i < NFSD_MAXFH; i++, fhe++) { + struct dentry *dentry = fhe->dentry; + if (!dentry) + continue; + if (dev && dentry->d_inode->i_dev != dev) + continue; + fhe->dentry = NULL; + dput(dentry); + nfsd_nr_put++; + } + fhe = &dirstable[0]; + } +} + +/* + * Free the dentry and path caches. + */ +void nfsd_fh_free(void) +{ + struct list_head *tmp; + int i; + + /* Flush dentries for all devices */ + nfsd_fh_flush(0); + + /* + * N.B. write a destructor for these lists ... + */ + i = 0; + while ((tmp = fixup_head.next) != &fixup_head) { + struct nfsd_fixup *fp; + fp = list_entry(tmp, struct nfsd_fixup, lru); + free_fixup_entry(fp); + i++; + } + printk("nfsd_fh_free: %d fixups freed\n", i); + + i = 0; + while ((tmp = path_inuse.next) != &path_inuse) { + struct nfsd_path *pe; + pe = list_entry(tmp, struct nfsd_path, lru); + free_path_entry(pe); + i++; + } + printk("nfsd_fh_free: %d paths freed\n", i); + + printk("nfsd_fh_free: verified %d, put %d\n", + nfsd_nr_verified, nfsd_nr_put); +} + +void nfsd_fh_init(void) +{ + memset(filetable, 0, NFSD_MAXFH*sizeof(struct fh_entry)); + memset(dirstable, 0, NFSD_MAXFH*sizeof(struct fh_entry)); + INIT_LIST_HEAD(&path_inuse); + INIT_LIST_HEAD(&fixup_head); + + printk("nfsd_init: initialized fhcache, entries=%lu\n", NFSD_MAXFH); } |