| Message ID | 20210712123649.1102392-6-dkadashev@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | namei: clean up retry logic in various do_* functions | expand |
On Mon, Jul 12, 2021 at 5:37 AM Dmitry Kadashev <dkadashev@gmail.com> wrote: > > + > +int do_symlinkat(struct filename *from, int newdfd, struct filename *to) > +{ > + int error; > + > + if (IS_ERR(from)) { > + error = PTR_ERR(from); > + goto out; > } > -out_putnames: > + > + error = symlinkat_helper(from, newdfd, to, 0); > + if (retry_estale(error, 0)) > + error = symlinkat_helper(from, newdfd, to, LOOKUP_REVAL); > + > +out: > putname(to); > putname(from); > return error; So here you moved that part that was outside the retry loop into the caller. Except it's very ugly and keeps the goto mess. So I'd suggest either keep it as a nested if - avoiding the goto - or like in the previous patch, do that "we can do this test twice" with a big commit message note about why it's ok. Because it _is_ ok to repeat the test inside the retry_estale, and 'from' won't have changed (and won't have been -ESTALE in the first place). Looking at the pattern of this and the previous one, I think just repeating the test is what generates the cleanest end result. Linus
diff --git a/fs/namei.c b/fs/namei.c index 7bf7a9f38ce2..c9110ac83ccb 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4237,22 +4237,17 @@ int vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir, } EXPORT_SYMBOL(vfs_symlink); -int do_symlinkat(struct filename *from, int newdfd, struct filename *to) +static int symlinkat_helper(struct filename *from, int newdfd, + struct filename *to, unsigned int lookup_flags) { int error; struct dentry *dentry; struct path path; - unsigned int lookup_flags = 0; - if (IS_ERR(from)) { - error = PTR_ERR(from); - goto out_putnames; - } -retry: dentry = __filename_create(newdfd, to, &path, lookup_flags); error = PTR_ERR(dentry); if (IS_ERR(dentry)) - goto out_putnames; + return error; error = security_path_symlink(&path, dentry, from->name); if (!error) { @@ -4263,11 +4258,23 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to) from->name); } done_path_create(&path, dentry); - if (retry_estale(error, lookup_flags)) { - lookup_flags |= LOOKUP_REVAL; - goto retry; + return error; +} + +int do_symlinkat(struct filename *from, int newdfd, struct filename *to) +{ + int error; + + if (IS_ERR(from)) { + error = PTR_ERR(from); + goto out; } -out_putnames: + + error = symlinkat_helper(from, newdfd, to, 0); + if (retry_estale(error, 0)) + error = symlinkat_helper(from, newdfd, to, LOOKUP_REVAL); + +out: putname(to); putname(from); return error;
Moving the main logic to a helper function makes the whole thing much easier to follow. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <christian.brauner@ubuntu.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/io-uring/CAHk-=wiG+sN+2zSoAOggKCGue2kOJvw3rQySvQXsZstRQFTN+g@mail.gmail.com/ Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com> --- fs/namei.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-)