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b=Ies4AD/sXBzLiIMnl/ZdC7Ibm2 W2zIpILtpZKpaSMaPC3m/lcGPJwcT/lgcaPI8Wq88cjONY+ioQ0RVXzan5eukyU+dz2VWKHsevmsq FQA8QbUwpVZOqZNx0f8J8g6ACDW7td+o+0um73FBSFXdqeDWCg/p4qAzvQMjgouuUVEqUNNvqg4jj EYLRbcSUgaVdmj293jx4PQqTvZH9+WYM7dJHG70LulPeirJnDb1I617r5HBvwF5GzgVKNjgxW3o5w U4HrwT9VGp9SZuzokv290LBLe83wLWCw5zltOGXTEzB0gLL96JYIRyaymqy+Q7s6ul5EsE3SYVNiB wDxN6HUw==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzsKH-0000000ExN3-2cBU; Sat, 20 Sep 2025 07:48:09 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: torvalds@linux-foundation.org, brauner@kernel.org, jack@suse.cz, raven@themaw.net, miklos@szeredi.hu, a.hindborg@kernel.org, linux-mm@kvack.org, linux-efi@vger.kernel.org, ocfs2-devel@lists.linux.dev, kees@kernel.org, rostedt@goodmis.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, paul@paul-moore.com, casey@schaufler-ca.com, linuxppc-dev@lists.ozlabs.org, borntraeger@linux.ibm.com Subject: [PATCH 36/39] hypfs: don't pin dentries twice Date: Sat, 20 Sep 2025 08:47:55 +0100 Message-ID: <20250920074759.3564072-36-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250920074759.3564072-1-viro@zeniv.linux.org.uk> References: <20250920074156.GK39973@ZenIV> <20250920074759.3564072-1-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 62BE7140007 X-Stat-Signature: jiu5qi5abwzff1b7n5igfx8ukckoyag8 X-Rspam-User: X-HE-Tag: 1758354493-929359 X-HE-Meta: U2FsdGVkX1+1A8M0FcTwvmP5fQqvp+HrCdGy5TVll27Zn0+lEB2kBkI3IA7EC5OvrgjR53ktRllgGZ7vwlkgodzJEeAfo1pGKs5vBKMiT7TI0+aoiNFutg6pK9EKScCZunO2fC6qUN3ZXARwwcXhsFIPmRj2FWyGR1JtQWdh+BN0ABmxn3HCVS6rXK+HZw0rOMeE1DIKa/bqyrKhW1yvtK3TqsacYOG0R9QhTp+u8LTQvMPYDXxsmTD4CzBmmsKOJaFVCym7iNDOf5ZnpMU9tw6rWbrNa4trY7/JBxDsFIbiUQXC2789o82N4e6Z7PthWAC1pIXZQL9tfJsFshmoA8elit3xN0xIFi7DnAdC0AoG3TCdGpYTJZkzQbdwLv7jJBd+gFZZwYSc7rm6iFBeSIOceTji3OEd12XKMubqvFJjcInaTfEuyur7n+PFHv4/c1kIMB6GIY8dmjhdqYDiXeNGu54Tn0Fv5yzmmLWlj+3hminHrFopZJEk9o/qzdkDw/qWR8ZcjzYnIZ7ijkKxpeusSrJFOzF7zwEl75n0KQvU+ZTJw33K2i887UKVA8CO4amXNclLw4PmOw5S3mIzaK8AhQ95BPK389mIv+2obR+QwHZCDHaT5hRNpL1dQyXhladU6SLQar9bJhUXUHxL6o6RGN5m0clhe8QrRHxXbpoZLCCTFOyOyI1WXSje6WdF+J71uwrSiU0VN/pVA7yeyfD67plNtgMxNuvUVhv4Mpk0UmoLM1ShtnO4QKZNaWkYWOEKrIjHW69N/4Vc8wtyJm04vSkPuPGXJb8ZLCdDvQQCsXpiHoULbe25+RcLftTjJZVstnCgRHpvTTBqve+Ct42xPbJocU518an2j/mrKqlKbevGOM2wBZXTmK5FrWrbMVPCxjU5IeWF2EBxfsfpVvbnzSlnB8OvuFB8W8m31YVfAkIV26mEp72OZSmd5FpGN+c+Rc0zxl1tPAkHLA0 aGn0Ifk5 ltAbJJf6OGKaQTsWVp0+t56ntJeYvH68G/XL4x7R+tMbKoA9I1R54DOUuH4tiD66MD2KXTCaPvwOIZrWWi9wtQh8KAJQo5iZ32kfdPv1Uj0HJssizFYTdii4QeZuV7lx4CilmZ8Y59nVVU7RPgdP9w2khwjqXktzr7203F1IQo1yULACK73zzVgK2IMn2SJKcXpnyKCKgt9YbuEX+8nkjZSxsqPVJ4vlN7hwCpzgfpSMeJgU5NGyLe2d9B4UmGMmdqMJSBSZwYK8xmE0ocoNzXTvk6DGez6vdyl4Act3pvmpejJv7HfvoJn/uJdVU3EI+IfkfyCJqq51HRKnng8Hs6kFBPio3luXEUGQfTU0E1N+NFR/mqc3J8/mrcuHGMgrM39qOucKtmD0EKbz2XNgWGFESTJF5uwRS4P5N X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: hypfs dentries end up with refcount 2 when they are not busy. Refcount 1 is enough to keep them pinned, and going that way allows to simplify things nicely: * don't need to drop an extra reference before the call of kill_litter_super() in ->kill_sb(); all we need there is to reset the cleanup list - everything on it will be taken out automatically. * we can make use of simple_recursive_removal() on tree rebuilds; just make sure that only children of root end up in the cleanup list and hypfs_delete_tree() becomes much simpler Signed-off-by: Al Viro --- arch/s390/hypfs/inode.c | 41 ++++++++++------------------------------- 1 file changed, 10 insertions(+), 31 deletions(-) diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c index 96409573c75d..a4dc8e13d999 100644 --- a/arch/s390/hypfs/inode.c +++ b/arch/s390/hypfs/inode.c @@ -61,33 +61,17 @@ static void hypfs_update_update(struct super_block *sb) static void hypfs_add_dentry(struct dentry *dentry) { - dentry->d_fsdata = hypfs_last_dentry; - hypfs_last_dentry = dentry; -} - -static void hypfs_remove(struct dentry *dentry) -{ - struct dentry *parent; - - parent = dentry->d_parent; - inode_lock(d_inode(parent)); - if (simple_positive(dentry)) { - if (d_is_dir(dentry)) - simple_rmdir(d_inode(parent), dentry); - else - simple_unlink(d_inode(parent), dentry); + if (IS_ROOT(dentry->d_parent)) { + dentry->d_fsdata = hypfs_last_dentry; + hypfs_last_dentry = dentry; } - d_drop(dentry); - dput(dentry); - inode_unlock(d_inode(parent)); } -static void hypfs_delete_tree(struct dentry *root) +static void hypfs_delete_tree(void) { while (hypfs_last_dentry) { - struct dentry *next_dentry; - next_dentry = hypfs_last_dentry->d_fsdata; - hypfs_remove(hypfs_last_dentry); + struct dentry *next_dentry = hypfs_last_dentry->d_fsdata; + simple_recursive_removal(hypfs_last_dentry, NULL); hypfs_last_dentry = next_dentry; } } @@ -184,14 +168,14 @@ static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) rc = -EBUSY; goto out; } - hypfs_delete_tree(sb->s_root); + hypfs_delete_tree(); if (machine_is_vm()) rc = hypfs_vm_create_files(sb->s_root); else rc = hypfs_diag_create_files(sb->s_root); if (rc) { pr_err("Updating the hypfs tree failed\n"); - hypfs_delete_tree(sb->s_root); + hypfs_delete_tree(); goto out; } hypfs_update_update(sb); @@ -326,13 +310,9 @@ static void hypfs_kill_super(struct super_block *sb) { struct hypfs_sb_info *sb_info = sb->s_fs_info; - if (sb->s_root) - hypfs_delete_tree(sb->s_root); - if (sb_info && sb_info->update_file) - hypfs_remove(sb_info->update_file); - kfree(sb->s_fs_info); - sb->s_fs_info = NULL; + hypfs_last_dentry = NULL; kill_litter_super(sb); + kfree(sb_info); } static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, @@ -367,7 +347,6 @@ static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, BUG(); inode->i_private = data; d_instantiate(dentry, inode); - dget(dentry); fail: inode_unlock(d_inode(parent)); return dentry; -- 2.47.3