diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2018-06-02 07:31:02 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-03 19:58:23 +0200 |
commit | af04fadcaa932d2d804699409d9d96dd5d85ce7f (patch) | |
tree | ad6d262eed4b0e19ee7d43ed27aee8eb22565dfb /fs/open.c | |
parent | fix io_destroy()/aio_complete() race (diff) | |
download | linux-af04fadcaa932d2d804699409d9d96dd5d85ce7f.tar.xz linux-af04fadcaa932d2d804699409d9d96dd5d85ce7f.zip |
Revert "fs: fold open_check_o_direct into do_dentry_open"
This reverts commit cab64df194667dc5d9d786f0a895f647f5501c0d.
Having vfs_open() in some cases drop the reference to
struct file combined with
error = vfs_open(path, f, cred);
if (error) {
put_filp(f);
return ERR_PTR(error);
}
return f;
is flat-out wrong. It used to be
error = vfs_open(path, f, cred);
if (!error) {
/* from now on we need fput() to dispose of f */
error = open_check_o_direct(f);
if (error) {
fput(f);
f = ERR_PTR(error);
}
} else {
put_filp(f);
f = ERR_PTR(error);
}
and sure, having that open_check_o_direct() boilerplate gotten rid of is
nice, but not that way...
Worse, another call chain (via finish_open()) is FUBAR now wrt
FILE_OPENED handling - in that case we get error returned, with file
already hit by fput() *AND* FILE_OPENED not set. Guess what happens in
path_openat(), when it hits
if (!(opened & FILE_OPENED)) {
BUG_ON(!error);
put_filp(file);
}
The root cause of all that crap is that the callers of do_dentry_open()
have no way to tell which way did it fail; while that could be fixed up
(by passing something like int *opened to do_dentry_open() and have it
marked if we'd called ->open()), it's probably much too late in the
cycle to do so right now.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r-- | fs/open.c | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/fs/open.c b/fs/open.c index c5ee7cd60424..d0e955b558ad 100644 --- a/fs/open.c +++ b/fs/open.c @@ -724,6 +724,16 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) return ksys_fchown(fd, user, group); } +int open_check_o_direct(struct file *f) +{ + /* NB: we're sure to have correct a_ops only after f_op->open */ + if (f->f_flags & O_DIRECT) { + if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) + return -EINVAL; + } + return 0; +} + static int do_dentry_open(struct file *f, struct inode *inode, int (*open)(struct inode *, struct file *), @@ -745,7 +755,7 @@ static int do_dentry_open(struct file *f, if (unlikely(f->f_flags & O_PATH)) { f->f_mode = FMODE_PATH; f->f_op = &empty_fops; - goto done; + return 0; } if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { @@ -798,12 +808,7 @@ static int do_dentry_open(struct file *f, f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); -done: - /* NB: we're sure to have correct a_ops only after f_op->open */ - error = -EINVAL; - if ((f->f_flags & O_DIRECT) && - (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)) - goto out_fput; + return 0; cleanup_all: @@ -818,9 +823,6 @@ cleanup_file: f->f_path.dentry = NULL; f->f_inode = NULL; return error; -out_fput: - fput(f); - return error; } /** @@ -918,14 +920,20 @@ struct file *dentry_open(const struct path *path, int flags, BUG_ON(!path->mnt); f = get_empty_filp(); - if (IS_ERR(f)) - return f; - - f->f_flags = flags; - error = vfs_open(path, f, cred); - if (error) { - put_filp(f); - return ERR_PTR(error); + if (!IS_ERR(f)) { + f->f_flags = flags; + error = vfs_open(path, f, cred); + if (!error) { + /* from now on we need fput() to dispose of f */ + error = open_check_o_direct(f); + if (error) { + fput(f); + f = ERR_PTR(error); + } + } else { + put_filp(f); + f = ERR_PTR(error); + } } return f; } |