From 59e96e65833e05a9410327627d91ccef39392a25 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 26 Jan 2020 10:22:24 -0500 Subject: do_last(): don't bother with keeping got_write in FMODE_OPENED case it's easier to drop it right after lookup_open() and regain if needed (i.e. if we will need to truncate). On the non-FMODE_OPENED path we do that anyway. In case of FMODE_CREATED we won't be needing it. And it's easier to prove correctness that way, especially since the initial failure to get write access is not always fatal; proving that we'll never end up truncating in that case is rather convoluted. Signed-off-by: Al Viro --- fs/namei.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 2f8a5d3be784..2eef41f505db 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3191,11 +3191,14 @@ static const char *do_last(struct nameidata *nd, else inode_unlock_shared(dir->d_inode); - if (IS_ERR(dentry)) { - error = PTR_ERR(dentry); - goto out; + if (got_write) { + mnt_drop_write(nd->path.mnt); + got_write = false; } + if (IS_ERR(dentry)) + return ERR_CAST(dentry); + if (file->f_mode & FMODE_OPENED) { if (file->f_mode & FMODE_CREATED) { open_flag &= ~O_TRUNC; @@ -3220,16 +3223,6 @@ static const char *do_last(struct nameidata *nd, goto finish_open_created; } - /* - * If atomic_open() acquired write access it is dropped now due to - * possible mount and symlink following (this might be optimized away if - * necessary...) - */ - if (got_write) { - mnt_drop_write(nd->path.mnt); - got_write = false; - } - finish_lookup: if (nd->depth) put_link(nd); @@ -3250,27 +3243,25 @@ finish_open: return ERR_PTR(error); audit_inode(nd->name, nd->path.dentry, 0); if (open_flag & O_CREAT) { - error = -EISDIR; if (d_is_dir(nd->path.dentry)) - goto out; + return ERR_PTR(-EISDIR); error = may_create_in_sticky(dir_mode, dir_uid, d_backing_inode(nd->path.dentry)); if (unlikely(error)) - goto out; + return ERR_PTR(error); } - error = -ENOTDIR; if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry)) - goto out; + return ERR_PTR(-ENOTDIR); if (!d_is_reg(nd->path.dentry)) will_truncate = false; +finish_open_created: if (will_truncate) { error = mnt_want_write(nd->path.mnt); if (error) - goto out; + return ERR_PTR(error); got_write = true; } -finish_open_created: error = may_open(&nd->path, acc_mode, open_flag); if (error) goto out; -- cgit v1.2.3