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[/] [or1k/] [tags/] [LINUX_2_4_26_OR32/] [linux/] [linux-2.4/] [fs/] [intermezzo/] [dcache.c] - Rev 1279
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/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*- * vim:expandtab:shiftwidth=8:tabstop=8: * * Original version: Copyright (C) 1996 P. Braam and M. Callahan * Rewritten for Linux 2.1. Copyright (C) 1997 Carnegie Mellon University * d_fsdata and NFS compatiblity fixes Copyright (C) 2001 Tacit Networks, Inc. * * This file is part of InterMezzo, http://www.inter-mezzo.org. * * InterMezzo is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * InterMezzo is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with InterMezzo; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * Directory operations for InterMezzo filesystem */ /* inode dentry alias list walking code adapted from linux/fs/dcache.c * * fs/dcache.c * * (C) 1997 Thomas Schoebel-Theuer, * with heavy changes by Linus Torvalds */ #define __NO_VERSION__ #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/fs.h> #include <linux/stat.h> #include <linux/errno.h> #include <linux/locks.h> #include <linux/slab.h> #include <asm/segment.h> #include <asm/uaccess.h> #include <linux/string.h> #include <linux/smp_lock.h> #include <linux/vmalloc.h> #include <linux/intermezzo_fs.h> kmem_cache_t * presto_dentry_slab; /* called when a cache lookup succeeds */ static int presto_d_revalidate(struct dentry *de, int flag) { struct inode *inode = de->d_inode; struct presto_file_set * root_fset; ENTRY; if (!inode) { EXIT; return 0; } if (is_bad_inode(inode)) { EXIT; return 0; } if (!presto_d2d(de)) { presto_set_dd(de); } if (!presto_d2d(de)) { EXIT; return 0; } root_fset = presto_d2d(de->d_inode->i_sb->s_root)->dd_fset; if (root_fset->fset_flags & FSET_FLAT_BRANCH && (presto_d2d(de)->dd_fset != root_fset )) { presto_d2d(de)->dd_fset = root_fset; } EXIT; return 1; #if 0 /* The following is needed for metadata on demand. */ if ( S_ISDIR(inode->i_mode) ) { EXIT; return (presto_chk(de, PRESTO_DATA) && (presto_chk(de, PRESTO_ATTR))); } else { EXIT; return presto_chk(de, PRESTO_ATTR); } #endif } static void presto_d_release(struct dentry *dentry) { if (!presto_d2d(dentry)) { /* This can happen for dentries from NFSd */ return; } presto_d2d(dentry)->dd_count--; if (!presto_d2d(dentry)->dd_count) { kmem_cache_free(presto_dentry_slab, presto_d2d(dentry)); dentry->d_fsdata = NULL; } } struct dentry_operations presto_dentry_ops = { .d_revalidate = presto_d_revalidate, .d_release = presto_d_release }; static inline int presto_is_dentry_ROOT (struct dentry *dentry) { return(dentry_name_cmp(dentry,"ROOT") && !dentry_name_cmp(dentry->d_parent,".intermezzo")); } static struct presto_file_set* presto_try_find_fset(struct dentry* dentry, int *is_under_d_intermezzo) { struct dentry* temp_dentry; struct presto_dentry_data *d_data; int found_root=0; ENTRY; CDEBUG(D_FSDATA, "finding fileset for %p:%s\n", dentry, dentry->d_name.name); *is_under_d_intermezzo = 0; /* walk up through the branch to get the fileset */ /* The dentry we are passed presumably does not have the correct * fset information. However, we still want to start walking up * the branch from this dentry to get our found_root and * is_under_d_intermezzo decisions correct */ for (temp_dentry = dentry ; ; temp_dentry = temp_dentry->d_parent) { CDEBUG(D_FSDATA, "--->dentry %p:%*s\n", temp_dentry, temp_dentry->d_name.len,temp_dentry->d_name.name); if (presto_is_dentry_ROOT(temp_dentry)) found_root = 1; if (!found_root && dentry_name_cmp(temp_dentry, ".intermezzo")) { *is_under_d_intermezzo = 1; } d_data = presto_d2d(temp_dentry); if (d_data) { /* If we found a "ROOT" dentry while walking up the * branch, we will journal regardless of whether * we are under .intermezzo or not. * If we are already under d_intermezzo don't reverse * the decision here...even if we found a "ROOT" * dentry above .intermezzo (if we were ever to * modify the directory structure). */ if (!*is_under_d_intermezzo) *is_under_d_intermezzo = !found_root && (d_data->dd_flags & PRESTO_DONT_JOURNAL); EXIT; return d_data->dd_fset; } if (temp_dentry->d_parent == temp_dentry) { break; } } EXIT; return NULL; } /* Only call this function on positive dentries */ static struct presto_dentry_data* presto_try_find_alias_with_dd ( struct dentry* dentry) { struct inode *inode=dentry->d_inode; struct list_head *head, *next, *tmp; struct dentry *tmp_dentry; /* Search through the alias list for dentries with d_fsdata */ spin_lock(&dcache_lock); head = &inode->i_dentry; next = inode->i_dentry.next; while (next != head) { tmp = next; next = tmp->next; tmp_dentry = list_entry(tmp, struct dentry, d_alias); if (!presto_d2d(tmp_dentry)) { spin_unlock(&dcache_lock); return presto_d2d(tmp_dentry); } } spin_unlock(&dcache_lock); return NULL; } /* Only call this function on positive dentries */ static void presto_set_alias_dd (struct dentry *dentry, struct presto_dentry_data* dd) { struct inode *inode=dentry->d_inode; struct list_head *head, *next, *tmp; struct dentry *tmp_dentry; /* Set d_fsdata for this dentry */ dd->dd_count++; dentry->d_fsdata = dd; /* Now set d_fsdata for all dentries in the alias list. */ spin_lock(&dcache_lock); head = &inode->i_dentry; next = inode->i_dentry.next; while (next != head) { tmp = next; next = tmp->next; tmp_dentry = list_entry(tmp, struct dentry, d_alias); if (!presto_d2d(tmp_dentry)) { dd->dd_count++; tmp_dentry->d_fsdata = dd; } } spin_unlock(&dcache_lock); return; } inline struct presto_dentry_data *izo_alloc_ddata(void) { struct presto_dentry_data *dd; dd = kmem_cache_alloc(presto_dentry_slab, SLAB_KERNEL); if (dd == NULL) { CERROR("IZO: out of memory trying to allocate presto_dentry_data\n"); return NULL; } memset(dd, 0, sizeof(*dd)); dd->dd_count = 1; return dd; } /* This uses the BKL! */ int presto_set_dd(struct dentry * dentry) { struct presto_file_set *fset; struct presto_dentry_data *dd; int is_under_d_izo; int error=0; ENTRY; if (!dentry) BUG(); lock_kernel(); /* Did we lose a race? */ if (dentry->d_fsdata) { CERROR("dentry %p already has d_fsdata set\n", dentry); if (dentry->d_inode) CERROR(" inode: %ld\n", dentry->d_inode->i_ino); EXIT; goto out_unlock; } if (dentry->d_inode != NULL) { /* NFSd runs find_fh_dentry which instantiates disconnected * dentries which are then connected without a lookup(). * So it is possible to have connected dentries that do not * have d_fsdata set. So we walk the list trying to find * an alias which has its d_fsdata set and then use that * for all the other dentries as well. * - SHP,Vinny. */ /* If there is an alias with d_fsdata use it. */ if ((dd = presto_try_find_alias_with_dd (dentry))) { presto_set_alias_dd (dentry, dd); EXIT; goto out_unlock; } } else { /* Negative dentry */ CDEBUG(D_FSDATA,"negative dentry %p: %*s\n", dentry, dentry->d_name.len, dentry->d_name.name); } /* No pre-existing d_fsdata, we need to construct one. * First, we must walk up the tree to find the fileset * If a fileset can't be found, we leave a null fsdata * and return EROFS to indicate that we can't journal * updates. */ fset = presto_try_find_fset (dentry, &is_under_d_izo); if (!fset) { #ifdef PRESTO_NO_NFS CERROR("No fileset for dentry %p: %*s\n", dentry, dentry->d_name.len, dentry->d_name.name); #endif error = -EROFS; EXIT; goto out_unlock; } dentry->d_fsdata = izo_alloc_ddata(); if (!presto_d2d(dentry)) { CERROR ("InterMezzo: out of memory allocating d_fsdata\n"); error = -ENOMEM; goto out_unlock; } presto_d2d(dentry)->dd_fset = fset; if (is_under_d_izo) presto_d2d(dentry)->dd_flags |= PRESTO_DONT_JOURNAL; EXIT; out_unlock: CDEBUG(D_FSDATA,"presto_set_dd dentry %p: %*s, d_fsdata %p\n", dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_fsdata); unlock_kernel(); return error; } int presto_init_ddata_cache(void) { ENTRY; presto_dentry_slab = kmem_cache_create("presto_cache", sizeof(struct presto_dentry_data), 0, SLAB_HWCACHE_ALIGN, NULL, NULL); EXIT; return (presto_dentry_slab != NULL); } void presto_cleanup_ddata_cache(void) { kmem_cache_destroy(presto_dentry_slab); }
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