diff options
Diffstat (limited to 'fs/debugfs')
| -rw-r--r-- | fs/debugfs/file.c | 244 | ||||
| -rw-r--r-- | fs/debugfs/inode.c | 452 | ||||
| -rw-r--r-- | fs/debugfs/internal.h | 52 |
3 files changed, 405 insertions, 343 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index c6f4a9a98b85..69e9ddcb113d 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -47,11 +47,17 @@ const struct file_operations debugfs_noop_file_operations = { #define F_DENTRY(filp) ((filp)->f_path.dentry) +const void *debugfs_get_aux(const struct file *file) +{ + return DEBUGFS_I(file_inode(file))->aux; +} +EXPORT_SYMBOL_GPL(debugfs_get_aux); + const struct file_operations *debugfs_real_fops(const struct file *filp) { struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata; - if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) { + if (!fsd) { /* * Urgh, we've been called w/o a protecting * debugfs_file_get(). @@ -64,22 +70,13 @@ const struct file_operations *debugfs_real_fops(const struct file *filp) } EXPORT_SYMBOL_GPL(debugfs_real_fops); -/** - * debugfs_file_get - mark the beginning of file data access - * @dentry: the dentry object whose data is being accessed. - * - * Up to a matching call to debugfs_file_put(), any successive call - * into the file removing functions debugfs_remove() and - * debugfs_remove_recursive() will block. Since associated private - * file data may only get freed after a successful return of any of - * the removal functions, you may safely access it after a successful - * call to debugfs_file_get() without worrying about lifetime issues. - * - * If -%EIO is returned, the file has already been removed and thus, - * it is not safe to access any of its data. If, on the other hand, - * it is allowed to access the file data, zero is returned. - */ -int debugfs_file_get(struct dentry *dentry) +enum dbgfs_get_mode { + DBGFS_GET_ALREADY, + DBGFS_GET_REGULAR, + DBGFS_GET_SHORT, +}; + +static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode) { struct debugfs_fsdata *fsd; void *d_fsd; @@ -93,24 +90,55 @@ int debugfs_file_get(struct dentry *dentry) return -EINVAL; d_fsd = READ_ONCE(dentry->d_fsdata); - if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) { + if (d_fsd) { fsd = d_fsd; } else { + struct inode *inode = dentry->d_inode; + unsigned int methods = 0; + + if (WARN_ON(mode == DBGFS_GET_ALREADY)) + return -EINVAL; + fsd = kmalloc(sizeof(*fsd), GFP_KERNEL); if (!fsd) return -ENOMEM; - fsd->real_fops = (void *)((unsigned long)d_fsd & - ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); + if (mode == DBGFS_GET_SHORT) { + const struct debugfs_short_fops *ops; + ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops; + if (ops->llseek) + methods |= HAS_LSEEK; + if (ops->read) + methods |= HAS_READ; + if (ops->write) + methods |= HAS_WRITE; + fsd->real_fops = NULL; + } else { + const struct file_operations *ops; + ops = fsd->real_fops = DEBUGFS_I(inode)->real_fops; + if (ops->llseek) + methods |= HAS_LSEEK; + if (ops->read) + methods |= HAS_READ; + if (ops->write) + methods |= HAS_WRITE; + if (ops->unlocked_ioctl) + methods |= HAS_IOCTL; + if (ops->poll) + methods |= HAS_POLL; + fsd->short_fops = NULL; + } + fsd->methods = methods; refcount_set(&fsd->active_users, 1); init_completion(&fsd->active_users_drained); INIT_LIST_HEAD(&fsd->cancellations); mutex_init(&fsd->cancellations_mtx); - if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) { + d_fsd = cmpxchg(&dentry->d_fsdata, NULL, fsd); + if (d_fsd) { mutex_destroy(&fsd->cancellations_mtx); kfree(fsd); - fsd = READ_ONCE(dentry->d_fsdata); + fsd = d_fsd; } } @@ -130,6 +158,26 @@ int debugfs_file_get(struct dentry *dentry) return 0; } + +/** + * debugfs_file_get - mark the beginning of file data access + * @dentry: the dentry object whose data is being accessed. + * + * Up to a matching call to debugfs_file_put(), any successive call + * into the file removing functions debugfs_remove() and + * debugfs_remove_recursive() will block. Since associated private + * file data may only get freed after a successful return of any of + * the removal functions, you may safely access it after a successful + * call to debugfs_file_get() without worrying about lifetime issues. + * + * If -%EIO is returned, the file has already been removed and thus, + * it is not safe to access any of its data. If, on the other hand, + * it is allowed to access the file data, zero is returned. + */ +int debugfs_file_get(struct dentry *dentry) +{ + return __debugfs_file_get(dentry, DBGFS_GET_ALREADY); +} EXPORT_SYMBOL_GPL(debugfs_file_get); /** @@ -187,8 +235,7 @@ void debugfs_enter_cancellation(struct file *file, return; fsd = READ_ONCE(dentry->d_fsdata); - if (WARN_ON(!fsd || - ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) + if (WARN_ON(!fsd)) return; mutex_lock(&fsd->cancellations_mtx); @@ -219,8 +266,7 @@ void debugfs_leave_cancellation(struct file *file, return; fsd = READ_ONCE(dentry->d_fsdata); - if (WARN_ON(!fsd || - ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))) + if (WARN_ON(!fsd)) return; mutex_lock(&fsd->cancellations_mtx); @@ -241,9 +287,10 @@ static int debugfs_locked_down(struct inode *inode, { if ((inode->i_mode & 07777 & ~0444) == 0 && !(filp->f_mode & FMODE_WRITE) && - !real_fops->unlocked_ioctl && - !real_fops->compat_ioctl && - !real_fops->mmap) + (!real_fops || + (!real_fops->unlocked_ioctl && + !real_fops->compat_ioctl && + !real_fops->mmap))) return 0; if (security_locked_down(LOCKDOWN_DEBUGFS)) @@ -258,7 +305,7 @@ static int open_proxy_open(struct inode *inode, struct file *filp) const struct file_operations *real_fops = NULL; int r; - r = debugfs_file_get(dentry); + r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR); if (r) return r == -EIO ? -ENOENT : r; @@ -300,13 +347,16 @@ const struct file_operations debugfs_open_proxy_file_operations = { #define PROTO(args...) args #define ARGS(args...) args -#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \ +#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret) \ static ret_type full_proxy_ ## name(proto) \ { \ - struct dentry *dentry = F_DENTRY(filp); \ + struct dentry *dentry = F_DENTRY(filp); \ + struct debugfs_fsdata *fsd = dentry->d_fsdata; \ const struct file_operations *real_fops; \ ret_type r; \ \ + if (!(fsd->methods & bit)) \ + return ret; \ r = debugfs_file_get(dentry); \ if (unlikely(r)) \ return r; \ @@ -316,31 +366,54 @@ static ret_type full_proxy_ ## name(proto) \ return r; \ } -FULL_PROXY_FUNC(llseek, loff_t, filp, - PROTO(struct file *filp, loff_t offset, int whence), - ARGS(filp, offset, whence)); +#define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args, bit, ret) \ +static ret_type full_proxy_ ## name(proto) \ +{ \ + struct dentry *dentry = F_DENTRY(filp); \ + struct debugfs_fsdata *fsd = dentry->d_fsdata; \ + ret_type r; \ + \ + if (!(fsd->methods & bit)) \ + return ret; \ + r = debugfs_file_get(dentry); \ + if (unlikely(r)) \ + return r; \ + if (fsd->real_fops) \ + r = fsd->real_fops->name(args); \ + else \ + r = fsd->short_fops->name(args); \ + debugfs_file_put(dentry); \ + return r; \ +} + +FULL_PROXY_FUNC_BOTH(llseek, loff_t, filp, + PROTO(struct file *filp, loff_t offset, int whence), + ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE); -FULL_PROXY_FUNC(read, ssize_t, filp, - PROTO(struct file *filp, char __user *buf, size_t size, - loff_t *ppos), - ARGS(filp, buf, size, ppos)); +FULL_PROXY_FUNC_BOTH(read, ssize_t, filp, + PROTO(struct file *filp, char __user *buf, size_t size, + loff_t *ppos), + ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL); -FULL_PROXY_FUNC(write, ssize_t, filp, - PROTO(struct file *filp, const char __user *buf, size_t size, - loff_t *ppos), - ARGS(filp, buf, size, ppos)); +FULL_PROXY_FUNC_BOTH(write, ssize_t, filp, + PROTO(struct file *filp, const char __user *buf, + size_t size, loff_t *ppos), + ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL); FULL_PROXY_FUNC(unlocked_ioctl, long, filp, PROTO(struct file *filp, unsigned int cmd, unsigned long arg), - ARGS(filp, cmd, arg)); + ARGS(filp, cmd, arg), HAS_IOCTL, -ENOTTY); static __poll_t full_proxy_poll(struct file *filp, struct poll_table_struct *wait) { struct dentry *dentry = F_DENTRY(filp); + struct debugfs_fsdata *fsd = dentry->d_fsdata; __poll_t r = 0; const struct file_operations *real_fops; + if (!(fsd->methods & HAS_POLL)) + return DEFAULT_POLLMASK; if (debugfs_file_get(dentry)) return EPOLLHUP; @@ -352,9 +425,7 @@ static __poll_t full_proxy_poll(struct file *filp, static int full_proxy_release(struct inode *inode, struct file *filp) { - const struct dentry *dentry = F_DENTRY(filp); const struct file_operations *real_fops = debugfs_real_fops(filp); - const struct file_operations *proxy_fops = filp->f_op; int r = 0; /* @@ -366,41 +437,23 @@ static int full_proxy_release(struct inode *inode, struct file *filp) if (real_fops->release) r = real_fops->release(inode, filp); - replace_fops(filp, d_inode(dentry)->i_fop); - kfree(proxy_fops); fops_put(real_fops); return r; } -static void __full_proxy_fops_init(struct file_operations *proxy_fops, - const struct file_operations *real_fops) -{ - proxy_fops->release = full_proxy_release; - if (real_fops->llseek) - proxy_fops->llseek = full_proxy_llseek; - if (real_fops->read) - proxy_fops->read = full_proxy_read; - if (real_fops->write) - proxy_fops->write = full_proxy_write; - if (real_fops->poll) - proxy_fops->poll = full_proxy_poll; - if (real_fops->unlocked_ioctl) - proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl; -} - -static int full_proxy_open(struct inode *inode, struct file *filp) +static int full_proxy_open_regular(struct inode *inode, struct file *filp) { struct dentry *dentry = F_DENTRY(filp); - const struct file_operations *real_fops = NULL; - struct file_operations *proxy_fops = NULL; + const struct file_operations *real_fops; + struct debugfs_fsdata *fsd; int r; - r = debugfs_file_get(dentry); + r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR); if (r) return r == -EIO ? -ENOENT : r; - real_fops = debugfs_real_fops(filp); - + fsd = dentry->d_fsdata; + real_fops = fsd->real_fops; r = debugfs_locked_down(inode, filp, real_fops); if (r) goto out; @@ -421,38 +474,52 @@ static int full_proxy_open(struct inode *inode, struct file *filp) goto out; } - proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL); - if (!proxy_fops) { - r = -ENOMEM; - goto free_proxy; - } - __full_proxy_fops_init(proxy_fops, real_fops); - replace_fops(filp, proxy_fops); - if (real_fops->open) { r = real_fops->open(inode, filp); if (r) { - replace_fops(filp, d_inode(dentry)->i_fop); - goto free_proxy; - } else if (filp->f_op != proxy_fops) { + fops_put(real_fops); + } else if (filp->f_op != &debugfs_full_proxy_file_operations) { /* No protection against file removal anymore. */ WARN(1, "debugfs file owner replaced proxy fops: %pd", dentry); - goto free_proxy; + fops_put(real_fops); } } - - goto out; -free_proxy: - kfree(proxy_fops); - fops_put(real_fops); out: debugfs_file_put(dentry); return r; } const struct file_operations debugfs_full_proxy_file_operations = { - .open = full_proxy_open, + .open = full_proxy_open_regular, + .release = full_proxy_release, + .llseek = full_proxy_llseek, + .read = full_proxy_read, + .write = full_proxy_write, + .poll = full_proxy_poll, + .unlocked_ioctl = full_proxy_unlocked_ioctl +}; + +static int full_proxy_open_short(struct inode *inode, struct file *filp) +{ + struct dentry *dentry = F_DENTRY(filp); + int r; + + r = __debugfs_file_get(dentry, DBGFS_GET_SHORT); + if (r) + return r == -EIO ? -ENOENT : r; + r = debugfs_locked_down(inode, filp, NULL); + if (!r) + r = simple_open(inode, filp); + debugfs_file_put(dentry); + return r; +} + +const struct file_operations debugfs_full_short_proxy_file_operations = { + .open = full_proxy_open_short, + .llseek = full_proxy_llseek, + .read = full_proxy_read, + .write = full_proxy_write, }; ssize_t debugfs_attr_read(struct file *file, char __user *buf, @@ -1218,7 +1285,6 @@ static const struct file_operations u32_array_fops = { .open = u32_array_open, .release = u32_array_release, .read = u32_array_read, - .llseek = no_llseek, }; /** diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index a40da0065433..30c4944e1862 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -14,7 +14,8 @@ #include <linux/module.h> #include <linux/fs.h> -#include <linux/mount.h> +#include <linux/fs_context.h> +#include <linux/fs_parser.h> #include <linux/pagemap.h> #include <linux/init.h> #include <linux/kobject.h> @@ -23,7 +24,6 @@ #include <linux/fsnotify.h> #include <linux/string.h> #include <linux/seq_file.h> -#include <linux/parser.h> #include <linux/magic.h> #include <linux/slab.h> #include <linux/security.h> @@ -77,7 +77,7 @@ static struct inode *debugfs_get_inode(struct super_block *sb) return inode; } -struct debugfs_mount_opts { +struct debugfs_fs_info { kuid_t uid; kgid_t gid; umode_t mode; @@ -89,68 +89,59 @@ enum { Opt_uid, Opt_gid, Opt_mode, - Opt_err -}; - -static const match_table_t tokens = { - {Opt_uid, "uid=%u"}, - {Opt_gid, "gid=%u"}, - {Opt_mode, "mode=%o"}, - {Opt_err, NULL} + Opt_source, }; -struct debugfs_fs_info { - struct debugfs_mount_opts mount_opts; +static const struct fs_parameter_spec debugfs_param_specs[] = { + fsparam_gid ("gid", Opt_gid), + fsparam_u32oct ("mode", Opt_mode), + fsparam_uid ("uid", Opt_uid), + fsparam_string ("source", Opt_source), + {} }; -static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) +static int debugfs_parse_param(struct fs_context *fc, struct fs_parameter *param) { - substring_t args[MAX_OPT_ARGS]; - int option; - int token; - kuid_t uid; - kgid_t gid; - char *p; - - opts->opts = 0; - opts->mode = DEBUGFS_DEFAULT_MODE; - - while ((p = strsep(&data, ",")) != NULL) { - if (!*p) - continue; - - token = match_token(p, tokens, args); - switch (token) { - case Opt_uid: - if (match_int(&args[0], &option)) - return -EINVAL; - uid = make_kuid(current_user_ns(), option); - if (!uid_valid(uid)) - return -EINVAL; - opts->uid = uid; - break; - case Opt_gid: - if (match_int(&args[0], &option)) - return -EINVAL; - gid = make_kgid(current_user_ns(), option); - if (!gid_valid(gid)) - return -EINVAL; - opts->gid = gid; - break; - case Opt_mode: - if (match_octal(&args[0], &option)) - return -EINVAL; - opts->mode = option & S_IALLUGO; - break; + struct debugfs_fs_info *opts = fc->s_fs_info; + struct fs_parse_result result; + int opt; + + opt = fs_parse(fc, debugfs_param_specs, param, &result); + if (opt < 0) { /* - * We might like to report bad mount options here; - * but traditionally debugfs has ignored all mount options - */ - } + * We might like to report bad mount options here; but + * traditionally debugfs has ignored all mount options + */ + if (opt == -ENOPARAM) + return 0; - opts->opts |= BIT(token); + return opt; } + switch (opt) { + case Opt_uid: + opts->uid = result.uid; + break; + case Opt_gid: + opts->gid = result.gid; + break; + case Opt_mode: + opts->mode = result.uint_32 & S_IALLUGO; + break; + case Opt_source: + if (fc->source) + return invalfc(fc, "Multiple sources specified"); + fc->source = param->string; + param->string = NULL; + break; + /* + * We might like to report bad mount options here; + * but traditionally debugfs has ignored all mount options + */ + } + + opts->opts |= BIT(opt); + return 0; } @@ -158,23 +149,22 @@ static void _debugfs_apply_options(struct super_block *sb, bool remount) { struct debugfs_fs_info *fsi = sb->s_fs_info; struct inode *inode = d_inode(sb->s_root); - struct debugfs_mount_opts *opts = &fsi->mount_opts; /* * On remount, only reset mode/uid/gid if they were provided as mount * options. */ - if (!remount || opts->opts & BIT(Opt_mode)) { + if (!remount || fsi->opts & BIT(Opt_mode)) { inode->i_mode &= ~S_IALLUGO; - inode->i_mode |= opts->mode; + inode->i_mode |= fsi->mode; } - if (!remount || opts->opts & BIT(Opt_uid)) - inode->i_uid = opts->uid; + if (!remount || fsi->opts & BIT(Opt_uid)) + inode->i_uid = fsi->uid; - if (!remount || opts->opts & BIT(Opt_gid)) - inode->i_gid = opts->gid; + if (!remount || fsi->opts & BIT(Opt_gid)) + inode->i_gid = fsi->gid; } static void debugfs_apply_options(struct super_block *sb) @@ -187,50 +177,65 @@ static void debugfs_apply_options_remount(struct super_block *sb) _debugfs_apply_options(sb, true); } -static int debugfs_remount(struct super_block *sb, int *flags, char *data) +static int debugfs_reconfigure(struct fs_context *fc) { - int err; - struct debugfs_fs_info *fsi = sb->s_fs_info; + struct super_block *sb = fc->root->d_sb; + struct debugfs_fs_info *sb_opts = sb->s_fs_info; + struct debugfs_fs_info *new_opts = fc->s_fs_info; sync_filesystem(sb); - err = debugfs_parse_options(data, &fsi->mount_opts); - if (err) - goto fail; + /* structure copy of new mount options to sb */ + *sb_opts = *new_opts; debugfs_apply_options_remount(sb); -fail: - return err; + return 0; } static int debugfs_show_options(struct seq_file *m, struct dentry *root) { struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; - struct debugfs_mount_opts *opts = &fsi->mount_opts; - if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) + if (!uid_eq(fsi->uid, GLOBAL_ROOT_UID)) seq_printf(m, ",uid=%u", - from_kuid_munged(&init_user_ns, opts->uid)); - if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) + from_kuid_munged(&init_user_ns, fsi->uid)); + if (!gid_eq(fsi->gid, GLOBAL_ROOT_GID)) seq_printf(m, ",gid=%u", - from_kgid_munged(&init_user_ns, opts->gid)); - if (opts->mode != DEBUGFS_DEFAULT_MODE) - seq_printf(m, ",mode=%o", opts->mode); + from_kgid_munged(&init_user_ns, fsi->gid)); + if (fsi->mode != DEBUGFS_DEFAULT_MODE) + seq_printf(m, ",mode=%o", fsi->mode); return 0; } +static struct kmem_cache *debugfs_inode_cachep __ro_after_init; + +static void init_once(void *foo) +{ + struct debugfs_inode_info *info = foo; + inode_init_once(&info->vfs_inode); +} + +static struct inode *debugfs_alloc_inode(struct super_block *sb) +{ + struct debugfs_inode_info *info; + info = alloc_inode_sb(sb, debugfs_inode_cachep, GFP_KERNEL); + if (!info) + return NULL; + return &info->vfs_inode; +} + static void debugfs_free_inode(struct inode *inode) { if (S_ISLNK(inode->i_mode)) kfree(inode->i_link); - free_inode_nonrcu(inode); + kmem_cache_free(debugfs_inode_cachep, DEBUGFS_I(inode)); } static const struct super_operations debugfs_super_operations = { .statfs = simple_statfs, - .remount_fs = debugfs_remount, .show_options = debugfs_show_options, + .alloc_inode = debugfs_alloc_inode, .free_inode = debugfs_free_inode, }; @@ -238,23 +243,18 @@ static void debugfs_release_dentry(struct dentry *dentry) { struct debugfs_fsdata *fsd = dentry->d_fsdata; - if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) - return; - - /* check it wasn't a dir (no fsdata) or automount (no real_fops) */ - if (fsd && fsd->real_fops) { + if (fsd) { WARN_ON(!list_empty(&fsd->cancellations)); mutex_destroy(&fsd->cancellations_mtx); } - kfree(fsd); } static struct vfsmount *debugfs_automount(struct path *path) { - struct debugfs_fsdata *fsd = path->dentry->d_fsdata; + struct inode *inode = path->dentry->d_inode; - return fsd->automount(path->dentry, d_inode(path->dentry)->i_private); + return DEBUGFS_I(inode)->automount(path->dentry, inode->i_private); } static const struct dentry_operations debugfs_dops = { @@ -263,26 +263,14 @@ static const struct dentry_operations debugfs_dops = { .d_automount = debugfs_automount, }; -static int debug_fill_super(struct super_block *sb, void *data, int silent) +static int debugfs_fill_super(struct super_block *sb, struct fs_context *fc) { static const struct tree_descr debug_files[] = {{""}}; - struct debugfs_fs_info *fsi; int err; - fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); - sb->s_fs_info = fsi; - if (!fsi) { - err = -ENOMEM; - goto fail; - } - - err = debugfs_parse_options(data, &fsi->mount_opts); - if (err) - goto fail; - - err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); + err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); if (err) - goto fail; + return err; sb->s_op = &debugfs_super_operations; sb->s_d_op = &debugfs_dops; @@ -290,27 +278,48 @@ static int debug_fill_super(struct super_block *sb, void *data, int silent) debugfs_apply_options(sb); return 0; - -fail: - kfree(fsi); - sb->s_fs_info = NULL; - return err; } -static struct dentry *debug_mount(struct file_system_type *fs_type, - int flags, const char *dev_name, - void *data) +static int debugfs_get_tree(struct fs_context *fc) { if (!(debugfs_allow & DEBUGFS_ALLOW_API)) - return ERR_PTR(-EPERM); + return -EPERM; - return mount_single(fs_type, flags, data, debug_fill_super); + return get_tree_single(fc, debugfs_fill_super); +} + +static void debugfs_free_fc(struct fs_context *fc) +{ + kfree(fc->s_fs_info); +} + +static const struct fs_context_operations debugfs_context_ops = { + .free = debugfs_free_fc, + .parse_param = debugfs_parse_param, + .get_tree = debugfs_get_tree, + .reconfigure = debugfs_reconfigure, +}; + +static int debugfs_init_fs_context(struct fs_context *fc) +{ + struct debugfs_fs_info *fsi; + + fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); + if (!fsi) + return -ENOMEM; + + fsi->mode = DEBUGFS_DEFAULT_MODE; + + fc->s_fs_info = fsi; + fc->ops = &debugfs_context_ops; + return 0; } static struct file_system_type debug_fs_type = { .owner = THIS_MODULE, .name = "debugfs", - .mount = debug_mount, + .init_fs_context = debugfs_init_fs_context, + .parameters = debugfs_param_specs, .kill_sb = kill_litter_super, }; MODULE_ALIAS_FS("debugfs"); @@ -337,7 +346,7 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent) if (!parent) parent = debugfs_mount->mnt_root; - dentry = lookup_positive_unlocked(name, parent, strlen(name)); + dentry = lookup_noperm_positive_unlocked(&QSTR(name), parent); if (IS_ERR(dentry)) return NULL; return dentry; @@ -379,7 +388,7 @@ static struct dentry *start_creating(const char *name, struct dentry *parent) if (unlikely(IS_DEADDIR(d_inode(parent)))) dentry = ERR_PTR(-ENOENT); else - dentry = lookup_one_len(name, parent, strlen(name)); + dentry = lookup_noperm(&QSTR(name), parent); if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { if (d_is_dir(dentry)) pr_err("Directory '%s' with parent '%s' already present!\n", @@ -415,8 +424,9 @@ static struct dentry *end_creating(struct dentry *dentry) static struct dentry *__debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, + const void *aux, const struct file_operations *proxy_fops, - const struct file_operations *real_fops) + const void *real_fops) { struct dentry *dentry; struct inode *inode; @@ -445,58 +455,38 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode, inode->i_private = data; inode->i_op = &debugfs_file_inode_operations; + if (!real_fops) + proxy_fops = &debugfs_noop_file_operations; inode->i_fop = proxy_fops; - dentry->d_fsdata = (void *)((unsigned long)real_fops | - DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); + DEBUGFS_I(inode)->raw = real_fops; + DEBUGFS_I(inode)->aux = aux; d_instantiate(dentry, inode); fsnotify_create(d_inode(dentry->d_parent), dentry); return end_creating(dentry); } -/** - * debugfs_create_file - create a file in the debugfs filesystem - * @name: a pointer to a string containing the name of the file to create. - * @mode: the permission that the file should have. - * @parent: a pointer to the parent dentry for this file. This should be a - * directory dentry if set. If this parameter is NULL, then the - * file will be created in the root of the debugfs filesystem. - * @data: a pointer to something that the caller will want to get to later - * on. The inode.i_private pointer will point to this value on - * the open() call. - * @fops: a pointer to a struct file_operations that should be used for - * this file. - * - * This is the basic "create a file" function for debugfs. It allows for a - * wide range of flexibility in creating a file, or a directory (if you want - * to create a directory, the debugfs_create_dir() function is - * recommended to be used instead.) - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the debugfs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be - * returned. - * - * If debugfs is not enabled in the kernel, the value -%ENODEV will be - * returned. - * - * NOTE: it's expected that most callers should _ignore_ the errors returned - * by this function. Other debugfs functions handle the fact that the "dentry" - * passed to them could be an error and they don't crash in that case. - * Drivers should generally work fine even if debugfs fails to init anyway. - */ -struct dentry *debugfs_create_file(const char *name, umode_t mode, - struct dentry *parent, void *data, - const struct file_operations *fops) +struct dentry *debugfs_create_file_full(const char *name, umode_t mode, + struct dentry *parent, void *data, + const void *aux, + const struct file_operations *fops) { + return __debugfs_create_file(name, mode, parent, data, aux, + &debugfs_full_proxy_file_operations, + fops); +} +EXPORT_SYMBOL_GPL(debugfs_create_file_full); - return __debugfs_create_file(name, mode, parent, data, - fops ? &debugfs_full_proxy_file_operations : - &debugfs_noop_file_operations, +struct dentry *debugfs_create_file_short(const char *name, umode_t mode, + struct dentry *parent, void *data, + const void *aux, + const struct debugfs_short_fops *fops) +{ + return __debugfs_create_file(name, mode, parent, data, aux, + &debugfs_full_short_proxy_file_operations, fops); } -EXPORT_SYMBOL_GPL(debugfs_create_file); +EXPORT_SYMBOL_GPL(debugfs_create_file_short); /** * debugfs_create_file_unsafe - create a file in the debugfs filesystem @@ -530,9 +520,8 @@ struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, const struct file_operations *fops) { - return __debugfs_create_file(name, mode, parent, data, - fops ? &debugfs_open_proxy_file_operations : - &debugfs_noop_file_operations, + return __debugfs_create_file(name, mode, parent, data, NULL, + &debugfs_open_proxy_file_operations, fops); } EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); @@ -642,23 +631,13 @@ struct dentry *debugfs_create_automount(const char *name, void *data) { struct dentry *dentry = start_creating(name, parent); - struct debugfs_fsdata *fsd; struct inode *inode; if (IS_ERR(dentry)) return dentry; - fsd = kzalloc(sizeof(*fsd), GFP_KERNEL); - if (!fsd) { - failed_creating(dentry); - return ERR_PTR(-ENOMEM); - } - - fsd->automount = f; - if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { failed_creating(dentry); - kfree(fsd); return ERR_PTR(-EPERM); } @@ -666,14 +645,13 @@ struct dentry *debugfs_create_automount(const char *name, if (unlikely(!inode)) { pr_err("out of free dentries, can not create automount '%s'\n", name); - kfree(fsd); return failed_creating(dentry); } make_empty_dir_inode(inode); inode->i_flags |= S_AUTOMOUNT; inode->i_private = data; - dentry->d_fsdata = fsd; + DEBUGFS_I(inode)->automount = f; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inc_nlink(inode); d_instantiate(dentry, inode); @@ -748,7 +726,7 @@ static void __debugfs_file_removed(struct dentry *dentry) */ smp_mb(); fsd = READ_ONCE(dentry->d_fsdata); - if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) + if (!fsd) return; /* if this was the last reference, we're done */ @@ -852,76 +830,70 @@ void debugfs_lookup_and_remove(const char *name, struct dentry *parent) EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove); /** - * debugfs_rename - rename a file/directory in the debugfs filesystem - * @old_dir: a pointer to the parent dentry for the renamed object. This - * should be a directory dentry. - * @old_dentry: dentry of an object to be renamed. - * @new_dir: a pointer to the parent dentry where the object should be - * moved. This should be a directory dentry. - * @new_name: a pointer to a string containing the target name. + * debugfs_change_name - rename a file/directory in the debugfs filesystem + * @dentry: dentry of an object to be renamed. + * @fmt: format for new name * * This function renames a file/directory in debugfs. The target must not * exist for rename to succeed. * - * This function will return a pointer to old_dentry (which is updated to - * reflect renaming) if it succeeds. If an error occurs, ERR_PTR(-ERROR) - * will be returned. + * This function will return 0 on success and -E... on failure. * * If debugfs is not enabled in the kernel, the value -%ENODEV will be * returned. */ -struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, - struct dentry *new_dir, const char *new_name) +int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, ...) { - int error; - struct dentry *dentry = NULL, *trap; + int error = 0; + const char *new_name; struct name_snapshot old_name; + struct dentry *parent, *target; + struct inode *dir; + va_list ap; - if (IS_ERR(old_dir)) - return old_dir; - if (IS_ERR(new_dir)) - return new_dir; - if (IS_ERR_OR_NULL(old_dentry)) - return old_dentry; - - trap = lock_rename(new_dir, old_dir); - /* Source or destination directories don't exist? */ - if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) - goto exit; - /* Source does not exist, cyclic rename, or mountpoint? */ - if (d_really_is_negative(old_dentry) || old_dentry == trap || - d_mountpoint(old_dentry)) - goto exit; - dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); - /* Lookup failed, cyclic rename or target exists? */ - if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) - goto exit; - - take_dentry_name_snapshot(&old_name, old_dentry); - - error = simple_rename(&nop_mnt_idmap, d_inode(old_dir), old_dentry, - d_inode(new_dir), dentry, 0); - if (error) { - release_dentry_name_snapshot(&old_name); - goto exit; + if (IS_ERR_OR_NULL(dentry)) + return 0; + + va_start(ap, fmt); + new_name = kvasprintf_const(GFP_KERNEL, fmt, ap); + va_end(ap); + if (!new_name) + return -ENOMEM; + + parent = dget_parent(dentry); + dir = d_inode(parent); + inode_lock(dir); + + take_dentry_name_snapshot(&old_name, dentry); + + if (WARN_ON_ONCE(dentry->d_parent != parent)) { + error = -EINVAL; + goto out; + } + if (strcmp(old_name.name.name, new_name) == 0) + goto out; + target = lookup_noperm(&QSTR(new_name), parent); + if (IS_ERR(target)) { + error = PTR_ERR(target); + goto out; } - d_move(old_dentry, dentry); - fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, - d_is_dir(old_dentry), - NULL, old_dentry); + if (d_really_is_positive(target)) { + dput(target); + error = -EINVAL; + goto out; + } + simple_rename_timestamp(dir, dentry, dir, target); + d_move(dentry, target); + dput(target); + fsnotify_move(dir, dir, &old_name.name, d_is_dir(dentry), NULL, dentry); +out: release_dentry_name_snapshot(&old_name); - unlock_rename(new_dir, old_dir); - dput(dentry); - return old_dentry; -exit: - if (dentry && !IS_ERR(dentry)) - dput(dentry); - unlock_rename(new_dir, old_dir); - if (IS_ERR(dentry)) - return dentry; - return ERR_PTR(-EINVAL); + inode_unlock(dir); + dput(parent); + kfree_const(new_name); + return error; } -EXPORT_SYMBOL_GPL(debugfs_rename); +EXPORT_SYMBOL_GPL(debugfs_change_name); /** * debugfs_initialized - Tells whether debugfs has been registered @@ -957,12 +929,22 @@ static int __init debugfs_init(void) if (retval) return retval; - retval = register_filesystem(&debug_fs_type); - if (retval) + debugfs_inode_cachep = kmem_cache_create("debugfs_inode_cache", + sizeof(struct debugfs_inode_info), 0, + SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, + init_once); + if (debugfs_inode_cachep == NULL) { sysfs_remove_mount_point(kernel_kobj, "debug"); - else - debugfs_registered = true; + return -ENOMEM; + } - return retval; + retval = register_filesystem(&debug_fs_type); + if (retval) { // Really not going to happen + sysfs_remove_mount_point(kernel_kobj, "debug"); + kmem_cache_destroy(debugfs_inode_cachep); + return retval; + } + debugfs_registered = true; + return 0; } core_initcall(debugfs_init); diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h index dae80c2a469e..93483fe84425 100644 --- a/fs/debugfs/internal.h +++ b/fs/debugfs/internal.h @@ -11,36 +11,50 @@ struct file_operations; +struct debugfs_inode_info { + struct inode vfs_inode; + union { + const void *raw; + const struct file_operations *real_fops; + const struct debugfs_short_fops *short_fops; + debugfs_automount_t automount; + }; + const void *aux; +}; + +static inline struct debugfs_inode_info *DEBUGFS_I(struct inode *inode) +{ + return container_of(inode, struct debugfs_inode_info, vfs_inode); +} + /* declared over in file.c */ extern const struct file_operations debugfs_noop_file_operations; extern const struct file_operations debugfs_open_proxy_file_operations; extern const struct file_operations debugfs_full_proxy_file_operations; +extern const struct file_operations debugfs_full_short_proxy_file_operations; struct debugfs_fsdata { const struct file_operations *real_fops; - union { - /* automount_fn is used when real_fops is NULL */ - debugfs_automount_t automount; - struct { - refcount_t active_users; - struct completion active_users_drained; - - /* protect cancellations */ - struct mutex cancellations_mtx; - struct list_head cancellations; - }; + const struct debugfs_short_fops *short_fops; + struct { + refcount_t active_users; + struct completion active_users_drained; + + /* protect cancellations */ + struct mutex cancellations_mtx; + struct list_head cancellations; + unsigned int methods; }; }; -/* - * A dentry's ->d_fsdata either points to the real fops or to a - * dynamically allocated debugfs_fsdata instance. - * In order to distinguish between these two cases, a real fops - * pointer gets its lowest bit set. - */ -#define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0) +enum { + HAS_READ = 1, + HAS_WRITE = 2, + HAS_LSEEK = 4, + HAS_POLL = 8, + HAS_IOCTL = 16 +}; -/* Access BITS */ #define DEBUGFS_ALLOW_API BIT(0) #define DEBUGFS_ALLOW_MOUNT BIT(1) |