From patchwork Tue Mar 18 19:41:09 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 875532 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D787816F8F5; Tue, 18 Mar 2025 19:44:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327055; cv=none; b=CWm3FXcelWjWWmGb8dwlY9J9nwb+BL+7d989X0H/6CWb3CaIWlHbp1dD9XlSZwlP9Y/b3dOf05zu+4R6Wq/AEHUXy+SYZC11OlEGR/gve54yERH2ueoZLBTJLv8W4LRpQWqbIaA0stovZZ1s26QU9oV7VLXBrncCy+BcjG78/MI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327055; c=relaxed/simple; bh=BACGuoqehswM9fmxKSuC7MPf9JKTlGy7hJSvI8vEnys=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=B/8/0P6vgZh2LYcbKeDriIXM6/6Gt76W3w+e/FeG2JrdrpdC3+FMm6kCIG8fE+oz3IClMuOs5boeE8ZFS85ZvCdxo9kt6EZfkdCzRT4XCASp2b8RGOwochbbw1ZCvJ+LowchmNBTEz0dARYD6fnzXltF66Tdvr4N8QlAspGnHnM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by lamorak.hansenpartnership.com (Postfix) with ESMTP id 6D92E1C005E; Tue, 18 Mar 2025 15:44:12 -0400 (EDT) From: James Bottomley To: linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Ard Biesheuvel , Christian Brauner , Al Viro Subject: [RFC PATCH 1/3] libfs: rework dcache_readdir to use an internal function with callback Date: Tue, 18 Mar 2025 15:41:09 -0400 Message-ID: <20250318194111.19419-2-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> References: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 No functional change. Preparatory to using the internal function to iterate a directory with just a dentry not a file. Signed-off-by: James Bottomley --- fs/libfs.c | 41 +++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index 8444f5cc4064..816bfe6c0430 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -189,28 +189,21 @@ EXPORT_SYMBOL(dcache_dir_lseek); * for ramfs-type trees they can't go away without unlink() or rmdir(), * both impossible due to the lock on directory. */ - -int dcache_readdir(struct file *file, struct dir_context *ctx) +static void internal_readdir(struct dentry *dentry, struct dentry *cursor, + void *data, bool start, + bool (*callback)(void *, struct dentry *)) { - struct dentry *dentry = file->f_path.dentry; - struct dentry *cursor = file->private_data; struct dentry *next = NULL; struct hlist_node **p; - if (!dir_emit_dots(file, ctx)) - return 0; - - if (ctx->pos == 2) + if (start) p = &dentry->d_children.first; else p = &cursor->d_sib.next; while ((next = scan_positives(cursor, p, 1, next)) != NULL) { - if (!dir_emit(ctx, next->d_name.name, next->d_name.len, - d_inode(next)->i_ino, - fs_umode_to_dtype(d_inode(next)->i_mode))) + if (!callback(data, next)) break; - ctx->pos++; p = &next->d_sib.next; } spin_lock(&dentry->d_lock); @@ -219,6 +212,30 @@ int dcache_readdir(struct file *file, struct dir_context *ctx) hlist_add_before(&cursor->d_sib, &next->d_sib); spin_unlock(&dentry->d_lock); dput(next); +} + +static bool dcache_readdir_callback(void *data, struct dentry *entry) +{ + struct dir_context *ctx = data; + + if (!dir_emit(ctx, entry->d_name.name, entry->d_name.len, + d_inode(entry)->i_ino, + fs_umode_to_dtype(d_inode(entry)->i_mode))) + return false; + ctx->pos++; + return true; +} + +int dcache_readdir(struct file *file, struct dir_context *ctx) +{ + struct dentry *dentry = file->f_path.dentry; + struct dentry *cursor = file->private_data; + + if (!dir_emit_dots(file, ctx)) + return 0; + + internal_readdir(dentry, cursor, ctx, ctx->pos == 2, + dcache_readdir_callback); return 0; } From patchwork Tue Mar 18 19:41:10 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 874523 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DF5E1684A4; Tue, 18 Mar 2025 19:45:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327158; cv=none; b=W3UYCFsrcMhnhIW/WLGA8XFy1qQn9XfHbY2xcD1aaRrE7cYnaLE+Zc1ICpvClSCmwz12l2mLVKtiK3ezFWDIWnNdCfTkhE6Ohn7fdgJiFus705Xuh64WbZqGyuk7F3FS5kZPZHyd3SEycnmDWg45Yq2LmpHT80tXdxEiilenQJs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327158; c=relaxed/simple; bh=PbsM4F3AQtYmg7+7YvqmfgEnNlaqSZw+r4NRK5QJdvY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hhMhSxO4d0P2Vykf51OGjwho7AyfWDv+vRAMgYlCh7SDDzIIjK9am2QmGHY5ncTn8UoOjJj99LUxpLhyysOPkypto2K3xHdSorStzADIAMTuFgsuk7ADdmJIQOq3mS2B28ky+15wiyeQs57QgiNgM7Qv0eto/l86z/HHGitTmwQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by lamorak.hansenpartnership.com (Postfix) with ESMTP id B02AE1C00FB; Tue, 18 Mar 2025 15:45:51 -0400 (EDT) From: James Bottomley To: linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Ard Biesheuvel , Christian Brauner , Al Viro Subject: [RFC PATCH 2/3] libfs: add simple directory iteration function with callback Date: Tue, 18 Mar 2025 15:41:10 -0400 Message-ID: <20250318194111.19419-3-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> References: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The current iterate_dir() infrastructure is somewhat cumbersome to use from within the kernel. Introduce a lighter weight simple_iterate_dir() function that directly iterates the directory and executes a callback for each positive dentry. Signed-off-by: James Bottomley --- fs/libfs.c | 33 +++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 2 files changed, 35 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index 816bfe6c0430..37da5fe25242 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -214,6 +214,39 @@ static void internal_readdir(struct dentry *dentry, struct dentry *cursor, dput(next); } +/** + * generic_iterate_call - iterate all entries executing @callback + * + * @dir: directory to iterate over + * @data: data passed to callback + * @callback: callback to call + * + * Iterates over all positive dentries that are direct children of + * @dir (so doesn't include . and ..) and executes the callback for + * each of them. Note that because there's no struct *mnt, the caller + * is responsible for pinning the filesystem. + * + * If the @callback returns true, the iteration will continue and if + * it returns @false, it will stop (note that since the cursor is + * destroyed the next invocation will go back to the beginning again). + * + */ +int simple_iterate_call(struct dentry *dir, void *data, + bool (*callback)(void *, struct dentry *)) +{ + struct dentry *cursor = d_alloc_cursor(dir); + + if (!cursor) + return -ENOMEM; + + internal_readdir(dir, cursor, data, true, callback); + + dput(cursor); + + return 0; +} +EXPORT_SYMBOL(simple_iterate_call); + static bool dcache_readdir_callback(void *data, struct dentry *entry) { struct dir_context *ctx = data; diff --git a/include/linux/fs.h b/include/linux/fs.h index 2788df98080f..a84896f0b2d1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3531,6 +3531,8 @@ extern int simple_rename(struct mnt_idmap *, struct inode *, unsigned int); extern void simple_recursive_removal(struct dentry *, void (*callback)(struct dentry *)); +extern int simple_iterate_call(struct dentry *dir, void *data, + bool (*callback)(void *, struct dentry *)); extern int noop_fsync(struct file *, loff_t, loff_t, int); extern ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter); extern int simple_empty(struct dentry *); From patchwork Tue Mar 18 19:41:11 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 875531 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 285A617A30B; Tue, 18 Mar 2025 19:45:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327159; cv=none; b=KARsLbOHxG4UxJPZb2/9z1gUASditZ3CL0MkthSZQwylagJzCTwJBS28Vg3OzRB7vh+22VpLH2MugQeQ+wOpA4B01HMpiDsW3t1IM3QRv6gCAePavs0JS45hgvdjhGMVOJNP0BT14RGRI+RMnGummu0NmoTfBviHHP+gaNtqd0E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742327159; c=relaxed/simple; bh=mjgUYd2kEKX4/RMlqt+MrH5193XPf2wi4ZI0Gx2Y5vs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qs4NGDEmDc88iv66ZVub1ekvlpgBZRFFPodn51sVbcu/KdPOwBHUhN+8CnKgXlARohJJ63vjG/iPBzPs9oMHE91EZu7OpGDY6Ssuu28bSdVj+bn68DkWUqZPWEsf8mLsitZPlsLNRkgn3CwpVKLn+u/3MktqdqbqeDPfZsqD0Es= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Received: from lingrow.int.hansenpartnership.com (unknown [153.66.160.227]) by lamorak.hansenpartnership.com (Postfix) with ESMTP id E0BDE1C0105; Tue, 18 Mar 2025 15:45:55 -0400 (EDT) From: James Bottomley To: linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Ard Biesheuvel , Christian Brauner , Al Viro Subject: [RFC PATCH 3/3] efivarfs: replace iterate_dir with libfs function simple_iterate_call Date: Tue, 18 Mar 2025 15:41:11 -0400 Message-ID: <20250318194111.19419-4-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> References: <20250318194111.19419-1-James.Bottomley@HansenPartnership.com> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This relieves us of the requirement to have a struct path and use file operations, which greatly simplifies the code. The superblock is now pinned by the blocking notifier (which is why deregistration moves above kill_litter_super). Signed-off-by: James Bottomley --- fs/efivarfs/super.c | 103 +++----------------------------------------- 1 file changed, 7 insertions(+), 96 deletions(-) diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c index 81b3c6b7e100..135b0bb9b4b5 100644 --- a/fs/efivarfs/super.c +++ b/fs/efivarfs/super.c @@ -393,29 +393,13 @@ static const struct fs_context_operations efivarfs_context_ops = { .reconfigure = efivarfs_reconfigure, }; -struct efivarfs_ctx { - struct dir_context ctx; - struct super_block *sb; - struct dentry *dentry; -}; - -static bool efivarfs_actor(struct dir_context *ctx, const char *name, int len, - loff_t offset, u64 ino, unsigned mode) +static bool efivarfs_iterate_callback(void *data, struct dentry *dentry) { unsigned long size; - struct efivarfs_ctx *ectx = container_of(ctx, struct efivarfs_ctx, ctx); - struct qstr qstr = { .name = name, .len = len }; - struct dentry *dentry = d_hash_and_lookup(ectx->sb->s_root, &qstr); - struct inode *inode; - struct efivar_entry *entry; + struct inode *inode = d_inode(dentry); + struct efivar_entry *entry = efivar_entry(inode); int err; - if (IS_ERR_OR_NULL(dentry)) - return true; - - inode = d_inode(dentry); - entry = efivar_entry(inode); - err = efivar_entry_size(entry, &size); size += sizeof(__u32); /* attributes */ if (err) @@ -426,12 +410,10 @@ static bool efivarfs_actor(struct dir_context *ctx, const char *name, int len, inode_unlock(inode); if (!size) { - ectx->dentry = dentry; - return false; + pr_info("efivarfs: removing variable %pd\n", dentry); + simple_recursive_removal(dentry, NULL); } - dput(dentry); - return true; } @@ -474,33 +456,11 @@ static int efivarfs_check_missing(efi_char16_t *name16, efi_guid_t vendor, return err; } -static void efivarfs_deactivate_super_work(struct work_struct *work) -{ - struct super_block *s = container_of(work, struct super_block, - destroy_work); - /* - * note: here s->destroy_work is free for reuse (which - * will happen in deactivate_super) - */ - deactivate_super(s); -} - -static struct file_system_type efivarfs_type; - static int efivarfs_pm_notify(struct notifier_block *nb, unsigned long action, void *ptr) { struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, pm_nb); - struct path path; - struct efivarfs_ctx ectx = { - .ctx = { - .actor = efivarfs_actor, - }, - .sb = sfi->sb, - }; - struct file *file; - struct super_block *s = sfi->sb; static bool rescan_done = true; if (action == PM_HIBERNATION_PREPARE) { @@ -513,64 +473,15 @@ static int efivarfs_pm_notify(struct notifier_block *nb, unsigned long action, if (rescan_done) return NOTIFY_DONE; - /* ensure single superblock is alive and pin it */ - if (!atomic_inc_not_zero(&s->s_active)) - return NOTIFY_DONE; - pr_info("efivarfs: resyncing variable state\n"); - path.dentry = sfi->sb->s_root; - - /* - * do not add SB_KERNMOUNT which a single superblock could - * expose to userspace and which also causes MNT_INTERNAL, see - * below - */ - path.mnt = vfs_kern_mount(&efivarfs_type, 0, - efivarfs_type.name, NULL); - if (IS_ERR(path.mnt)) { - pr_err("efivarfs: internal mount failed\n"); - /* - * We may be the last pinner of the superblock but - * calling efivarfs_kill_sb from within the notifier - * here would deadlock trying to unregister it - */ - INIT_WORK(&s->destroy_work, efivarfs_deactivate_super_work); - schedule_work(&s->destroy_work); - return PTR_ERR(path.mnt); - } - - /* path.mnt now has pin on superblock, so this must be above one */ - atomic_dec(&s->s_active); - - file = kernel_file_open(&path, O_RDONLY | O_DIRECTORY | O_NOATIME, - current_cred()); - /* - * safe even if last put because no MNT_INTERNAL means this - * will do delayed deactivate_super and not deadlock - */ - mntput(path.mnt); - if (IS_ERR(file)) - return NOTIFY_DONE; - rescan_done = true; /* * First loop over the directory and verify each entry exists, * removing it if it doesn't */ - file->f_pos = 2; /* skip . and .. */ - do { - ectx.dentry = NULL; - iterate_dir(file, &ectx.ctx); - if (ectx.dentry) { - pr_info("efivarfs: removing variable %pd\n", - ectx.dentry); - simple_recursive_removal(ectx.dentry, NULL); - dput(ectx.dentry); - } - } while (ectx.dentry); - fput(file); + simple_iterate_call(sfi->sb->s_root, NULL, efivarfs_iterate_callback); /* * then loop over variables, creating them if there's no matching @@ -609,8 +520,8 @@ static void efivarfs_kill_sb(struct super_block *sb) struct efivarfs_fs_info *sfi = sb->s_fs_info; blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb); - kill_litter_super(sb); unregister_pm_notifier(&sfi->pm_nb); + kill_litter_super(sb); kfree(sfi); }