X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Fdcache.c;h=0e73aa0a0e8b66a1bf213ed53ad579bbabe7b2f3;hb=80f03e349f06a261a8e980bf6005c61811a0d66a;hp=b5f613932912436da57d062d6ffbe91c2c5e139a;hpb=7baca6ad0ef09c8a78d798c93a3ce25336e8f50f;p=linux-2.6-omap-h63xx.git diff --git a/fs/dcache.c b/fs/dcache.c index b5f61393291..0e73aa0a0e8 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -21,7 +21,6 @@ #include #include #include -#include #include #include #include @@ -121,6 +120,28 @@ static void dentry_iput(struct dentry * dentry) } } +/** + * d_kill - kill dentry and return parent + * @dentry: dentry to kill + * + * Called with dcache_lock and d_lock, releases both. The dentry must + * already be unhashed and removed from the LRU. + * + * If this is the root of the dentry tree, return NULL. + */ +static struct dentry *d_kill(struct dentry *dentry) +{ + struct dentry *parent; + + list_del(&dentry->d_u.d_child); + dentry_stat.nr_dentry--; /* For d_free, below */ + /*drops the locks, at that point nobody can reach this dentry */ + dentry_iput(dentry); + parent = dentry->d_parent; + d_free(dentry); + return dentry == parent ? NULL : parent; +} + /* * This is dput * @@ -189,28 +210,17 @@ repeat: unhash_it: __d_drop(dentry); - -kill_it: { - struct dentry *parent; - - /* If dentry was on d_lru list - * delete it from there - */ - if (!list_empty(&dentry->d_lru)) { - list_del(&dentry->d_lru); - dentry_stat.nr_unused--; - } - list_del(&dentry->d_u.d_child); - dentry_stat.nr_dentry--; /* For d_free, below */ - /*drops the locks, at that point nobody can reach this dentry */ - dentry_iput(dentry); - parent = dentry->d_parent; - d_free(dentry); - if (dentry == parent) - return; - dentry = parent; - goto repeat; +kill_it: + /* If dentry was on d_lru list + * delete it from there + */ + if (!list_empty(&dentry->d_lru)) { + list_del(&dentry->d_lru); + dentry_stat.nr_unused--; } + dentry = d_kill(dentry); + if (dentry) + goto repeat; } /** @@ -371,22 +381,40 @@ restart: * Throw away a dentry - free the inode, dput the parent. This requires that * the LRU list has already been removed. * + * If prune_parents is true, try to prune ancestors as well. + * * Called with dcache_lock, drops it and then regains. * Called with dentry->d_lock held, drops it. */ -static void prune_one_dentry(struct dentry * dentry) +static void prune_one_dentry(struct dentry * dentry, int prune_parents) { - struct dentry * parent; - __d_drop(dentry); - list_del(&dentry->d_u.d_child); - dentry_stat.nr_dentry--; /* For d_free, below */ - dentry_iput(dentry); - parent = dentry->d_parent; - d_free(dentry); - if (parent != dentry) - dput(parent); + dentry = d_kill(dentry); + if (!prune_parents) { + dput(dentry); + spin_lock(&dcache_lock); + return; + } + + /* + * Prune ancestors. Locking is simpler than in dput(), + * because dcache_lock needs to be taken anyway. + */ spin_lock(&dcache_lock); + while (dentry) { + if (!atomic_dec_and_lock(&dentry->d_count, &dentry->d_lock)) + return; + + if (dentry->d_op && dentry->d_op->d_delete) + dentry->d_op->d_delete(dentry); + if (!list_empty(&dentry->d_lru)) { + list_del(&dentry->d_lru); + dentry_stat.nr_unused--; + } + __d_drop(dentry); + dentry = d_kill(dentry); + spin_lock(&dcache_lock); + } } /** @@ -394,6 +422,7 @@ static void prune_one_dentry(struct dentry * dentry) * @count: number of entries to try and free * @sb: if given, ignore dentries for other superblocks * which are being unmounted. + * @prune_parents: if true, try to prune ancestors as well in one go * * Shrink the dcache. This is done when we need * more memory, or simply when we need to unmount @@ -404,7 +433,7 @@ static void prune_one_dentry(struct dentry * dentry) * all the dentries are in use. */ -static void prune_dcache(int count, struct super_block *sb) +static void prune_dcache(int count, struct super_block *sb, int prune_parents) { spin_lock(&dcache_lock); for (; count ; count--) { @@ -464,7 +493,7 @@ static void prune_dcache(int count, struct super_block *sb) * without taking the s_umount lock (I already hold it). */ if (sb && dentry->d_sb == sb) { - prune_one_dentry(dentry); + prune_one_dentry(dentry, prune_parents); continue; } /* @@ -479,7 +508,7 @@ static void prune_dcache(int count, struct super_block *sb) s_umount = &dentry->d_sb->s_umount; if (down_read_trylock(s_umount)) { if (dentry->d_sb->s_root != NULL) { - prune_one_dentry(dentry); + prune_one_dentry(dentry, prune_parents); up_read(s_umount); continue; } @@ -550,7 +579,7 @@ repeat: spin_unlock(&dentry->d_lock); continue; } - prune_one_dentry(dentry); + prune_one_dentry(dentry, 1); cond_resched_lock(&dcache_lock); goto repeat; } @@ -829,7 +858,7 @@ void shrink_dcache_parent(struct dentry * parent) int found; while ((found = select_parent(parent)) != 0) - prune_dcache(found, parent->d_sb); + prune_dcache(found, parent->d_sb, 1); } /* @@ -849,7 +878,7 @@ static int shrink_dcache_memory(int nr, gfp_t gfp_mask) if (nr) { if (!(gfp_mask & __GFP_FS)) return -1; - prune_dcache(nr, NULL); + prune_dcache(nr, NULL, 1); } return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; } @@ -1739,41 +1768,45 @@ shouldnt_be_hashed: * @rootmnt: vfsmnt to which the root dentry belongs * @buffer: buffer to return value in * @buflen: buffer length - * @fail_deleted: what to return for deleted files * - * Convert a dentry into an ASCII path name. If the entry has been deleted, - * then if @fail_deleted is true, ERR_PTR(-ENOENT) is returned. Otherwise, - * the the string " (deleted)" is appended. Note that this is ambiguous. + * Convert a dentry into an ASCII path name. If the entry has been deleted + * the string " (deleted)" is appended. Note that this is ambiguous. + * + * Returns the buffer or an error code if the path was too long. * - * Returns the buffer or an error code. + * "buflen" should be positive. Caller holds the dcache_lock. */ -static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, - struct dentry *root, struct vfsmount *rootmnt, - char *buffer, int buflen, int fail_deleted) +static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt, + struct dentry *root, struct vfsmount *rootmnt, + char *buffer, int buflen) { - int namelen, is_slash; + char * end = buffer+buflen; + char * retval; + int namelen; - if (buflen < 2) - return ERR_PTR(-ENAMETOOLONG); - buffer += --buflen; - *buffer = '\0'; - - spin_lock(&dcache_lock); + *--end = '\0'; + buflen--; if (!IS_ROOT(dentry) && d_unhashed(dentry)) { - if (fail_deleted) { - buffer = ERR_PTR(-ENOENT); - goto out; - } - if (buflen < 10) - goto Elong; buflen -= 10; - buffer -= 10; - memcpy(buffer, " (deleted)", 10); + end -= 10; + if (buflen < 0) + goto Elong; + memcpy(end, " (deleted)", 10); } - while (dentry != root || vfsmnt != rootmnt) { + + if (buflen < 1) + goto Elong; + /* Get '/' right */ + retval = end-1; + *retval = '/'; + + for (;;) { struct dentry * parent; + if (dentry == root && vfsmnt == rootmnt) + break; if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { + /* Global root? */ spin_lock(&vfsmount_lock); if (vfsmnt->mnt_parent == vfsmnt) { spin_unlock(&vfsmount_lock); @@ -1787,75 +1820,81 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, parent = dentry->d_parent; prefetch(parent); namelen = dentry->d_name.len; - if (buflen <= namelen) - goto Elong; buflen -= namelen + 1; - buffer -= namelen; - memcpy(buffer, dentry->d_name.name, namelen); - *--buffer = '/'; + if (buflen < 0) + goto Elong; + end -= namelen; + memcpy(end, dentry->d_name.name, namelen); + *--end = '/'; + retval = end; dentry = parent; } - /* Get '/' right */ - if (*buffer != '/') - *--buffer = '/'; -out: - spin_unlock(&dcache_lock); - return buffer; + return retval; global_root: - /* - * We went past the (vfsmount, dentry) we were looking for and have - * either hit a root dentry, a lazily unmounted dentry, an - * unconnected dentry, or the file is on a pseudo filesystem. - */ namelen = dentry->d_name.len; - is_slash = (namelen == 1 && *dentry->d_name.name == '/'); - if (is_slash || (dentry->d_sb->s_flags & MS_NOUSER)) { - /* - * Make sure we won't return a pathname starting with '/'. - * - * Historically, we also glue together the root dentry and - * remaining name for pseudo filesystems like pipefs, which - * have the MS_NOUSER flag set. This results in pathnames - * like "pipe:[439336]". - */ - if (*buffer == '/') { - buffer++; - buflen++; - } - if (is_slash) - goto out; - } - if (buflen < namelen) + buflen -= namelen; + if (buflen < 0) goto Elong; - buffer -= namelen; - memcpy(buffer, dentry->d_name.name, namelen); - goto out; - + retval -= namelen-1; /* hit the slash */ + memcpy(retval, dentry->d_name.name, namelen); + return retval; Elong: - buffer = ERR_PTR(-ENAMETOOLONG); - goto out; + return ERR_PTR(-ENAMETOOLONG); } /* write full pathname into buffer and return start of pathname */ -char *d_path(struct dentry *dentry, struct vfsmount *vfsmnt, char *buf, - int buflen) +char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, + char *buf, int buflen) { char *res; struct vfsmount *rootmnt; struct dentry *root; + /* + * We have various synthetic filesystems that never get mounted. On + * these filesystems dentries are never used for lookup purposes, and + * thus don't need to be hashed. They also don't need a name until a + * user wants to identify the object in /proc/pid/fd/. The little hack + * below allows us to generate a name for these objects on demand: + */ + if (dentry->d_op && dentry->d_op->d_dname) + return dentry->d_op->d_dname(dentry, buf, buflen); + read_lock(¤t->fs->lock); rootmnt = mntget(current->fs->rootmnt); root = dget(current->fs->root); read_unlock(¤t->fs->lock); - res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen, 0); + spin_lock(&dcache_lock); + res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen); + spin_unlock(&dcache_lock); dput(root); mntput(rootmnt); return res; } +/* + * Helper function for dentry_operations.d_dname() members + */ +char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, + const char *fmt, ...) +{ + va_list args; + char temp[64]; + int sz; + + va_start(args, fmt); + sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; + va_end(args); + + if (sz > sizeof(temp) || sz > buflen) + return ERR_PTR(-ENAMETOOLONG); + + buffer += buflen - sz; + return memcpy(buffer, temp, sz); +} + /* * NOTE! The user-level library version returns a * character pointer. The kernel system call just @@ -1876,10 +1915,10 @@ char *d_path(struct dentry *dentry, struct vfsmount *vfsmnt, char *buf, */ asmlinkage long sys_getcwd(char __user *buf, unsigned long size) { - int error, len; + int error; struct vfsmount *pwdmnt, *rootmnt; struct dentry *pwd, *root; - char *page = (char *) __get_free_page(GFP_USER), *cwd; + char *page = (char *) __get_free_page(GFP_USER); if (!page) return -ENOMEM; @@ -1891,18 +1930,29 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size) root = dget(current->fs->root); read_unlock(¤t->fs->lock); - cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE, 1); - error = PTR_ERR(cwd); - if (IS_ERR(cwd)) - goto out; + error = -ENOENT; + /* Has the current directory has been unlinked? */ + spin_lock(&dcache_lock); + if (pwd->d_parent == pwd || !d_unhashed(pwd)) { + unsigned long len; + char * cwd; - error = -ERANGE; - len = PAGE_SIZE + page - cwd; - if (len <= size) { - error = len; - if (copy_to_user(buf, cwd, len)) - error = -EFAULT; - } + cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE); + spin_unlock(&dcache_lock); + + error = PTR_ERR(cwd); + if (IS_ERR(cwd)) + goto out; + + error = -ERANGE; + len = PAGE_SIZE + page - cwd; + if (len <= size) { + error = len; + if (copy_to_user(buf, cwd, len)) + error = -EFAULT; + } + } else + spin_unlock(&dcache_lock); out: dput(pwd); @@ -2062,12 +2112,8 @@ static void __init dcache_init(unsigned long mempages) * but it is probably not worth it because of the cache nature * of the dcache. */ - dentry_cache = kmem_cache_create("dentry_cache", - sizeof(struct dentry), - 0, - (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| - SLAB_MEM_SPREAD), - NULL, NULL); + dentry_cache = KMEM_CACHE(dentry, + SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory);