linux/fs/d_path.c, branch v5.14

getcwd(2): clean up error handling

2021-05-19T00:15:58Z

Signed-off-by: Al Viro

d_path: prepend_path() is unlikely to return non-zero

2021-05-19T00:15:58Z

Signed-off-by: Al Viro

d_path: prepend_path(): lift the inner loop into a new helper

2021-05-19T00:15:57Z

... and leave the rename_lock/mount_lock handling in prepend_path() itself Signed-off-by: Al Viro

d_path: prepend_path(): lift resetting b in case when we'd return 3 out of loop

2021-05-19T00:15:56Z

preparation to extracting the loop into helper (next commit) Signed-off-by: Al Viro

d_path: prepend_path(): get rid of vfsmnt

2021-05-19T00:15:56Z

it's kept equal to &mnt->mnt all along. Signed-off-by: Al Viro

d_path: introduce struct prepend_buffer

2021-05-19T00:14:53Z

We've a lot of places where we have pairs of form (pointer to end of buffer, amount of space left in front of that). These sit in pairs of variables located next to each other and usually passed by reference. Turn those into instances of new type (struct prepend_buffer) and pass reference to the pair instead of pairs of references to its fields. Declared and initialized by DECLARE_BUFFER(name, buf, buflen). extract_string(prepend_buffer) returns the buffer contents if no overflow has happened, ERR_PTR(ENAMETOOLONG) otherwise. All places where we used to have that boilerplate converted to use of that helper. Signed-off-by: Al Viro

d_path: make prepend_name() boolean

2021-05-19T00:08:12Z

It returns only 0 or -ENAMETOOLONG and both callers only check if the result is negative. Might as well return true on success and false on failure... Signed-off-by: Al Viro

d_path: lift -ENAMETOOLONG handling into callers of prepend_path()

2021-05-19T00:08:12Z

The only negative value ever returned by prepend_path() is -ENAMETOOLONG and callers can recognize that situation (overflow) by looking at the sign of buflen. Lift that into the callers; we already have the same logics (buf if buflen is non-negative, ERR_PTR(-ENAMETOOLONG) otherwise) in several places and that'll become a new primitive several commits down the road. Make prepend_path() return 0 instead of -ENAMETOOLONG. That makes for saner calling conventions (0/1/2/3/-ENAMETOOLONG is obnoxious) and callers actually get simpler, especially once the aforementioned primitive gets added. In prepend_path() itself we switch prepending the / (in case of empty path) to use of prepend() - no need to open-code that, compiler will do the right thing. It's exactly the same logics as in __dentry_path(). Signed-off-by: Al Viro

d_path: don't bother with return value of prepend()

2021-05-19T00:08:11Z

Only simple_dname() checks it, and there we can simply do those calls and check for overflow (by looking of negative buflen) in the end. Signed-off-by: Al Viro

getcwd(2): saner logics around prepend_path() call

2021-05-19T00:08:11Z

The only negative value that might get returned by prepend_path() is -ENAMETOOLONG, and that happens only on overflow. The same goes for prepend_unreachable(). Overflow is detectable by observing negative buflen, so we can simplify the control flow around the prepend_path() call. Expand prepend_unreachable(), while we are at it - that's the only caller. Signed-off-by: Al Viro