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authorAl Viro <viro@zeniv.linux.org.uk>2018-06-02 01:31:02 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-03 10:58:23 -0700
commitaf04fadcaa932d2d804699409d9d96dd5d85ce7f (patch)
treead6d262eed4b0e19ee7d43ed27aee8eb22565dfb
parent4faa99965e027cc057c5145ce45fa772caa04e8d (diff)
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>
-rw-r--r--fs/internal.h1
-rw-r--r--fs/namei.c7
-rw-r--r--fs/open.c44
3 files changed, 33 insertions, 19 deletions
diff --git a/fs/internal.h b/fs/internal.h
index e08972db0303..980d005b21b4 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -125,6 +125,7 @@ int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
int flag);
+extern int open_check_o_direct(struct file *f);
extern int vfs_open(const struct path *, struct file *, const struct cred *);
extern struct file *filp_clone_open(struct file *);
diff --git a/fs/namei.c b/fs/namei.c
index 186bd2464fd5..4eb916996345 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3367,7 +3367,9 @@ finish_open_created:
goto out;
*opened |= FILE_OPENED;
opened:
- error = ima_file_check(file, op->acc_mode, *opened);
+ error = open_check_o_direct(file);
+ if (!error)
+ error = ima_file_check(file, op->acc_mode, *opened);
if (!error && will_truncate)
error = handle_truncate(file);
out:
@@ -3447,6 +3449,9 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
error = finish_open(file, child, NULL, opened);
if (error)
goto out2;
+ error = open_check_o_direct(file);
+ if (error)
+ fput(file);
out2:
mnt_drop_write(path.mnt);
out:
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;
}