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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-04-04 21:04:13 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-04-04 21:04:13 -0400 |
| commit | 9419a3191dcb27f24478d288abaab697228d28e6 (patch) | |
| tree | 7fd926e271483ad1270c5440d4839fc3711e31bb | |
| parent | 79a3aaa7b82e3106be97842dedfd8429248896e6 (diff) | |
| download | linux-9419a3191dcb27f24478d288abaab697228d28e6.tar.bz2 | |
acct_on(): don't mess with freeze protection
What happens there is that we are replacing file->path.mnt of
a file we'd just opened with a clone and we need the write
count contribution to be transferred from original mount to
new one. That's it. We do *NOT* want any kind of freeze
protection for the duration of switchover.
IOW, we should just use __mnt_{want,drop}_write() for that
switchover; no need to bother with mnt_{want,drop}_write()
there.
Tested-by: Amir Goldstein <amir73il@gmail.com>
Reported-by: syzbot+2a73a6ea9507b7112141@syzkaller.appspotmail.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/internal.h | 2 | ||||
| -rw-r--r-- | include/linux/mount.h | 2 | ||||
| -rw-r--r-- | kernel/acct.c | 4 |
3 files changed, 4 insertions, 4 deletions
diff --git a/fs/internal.h b/fs/internal.h index 6a8b71643af4..2e7362837a6e 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -89,9 +89,7 @@ extern int sb_prepare_remount_readonly(struct super_block *); extern void __init mnt_init(void); -extern int __mnt_want_write(struct vfsmount *); extern int __mnt_want_write_file(struct file *); -extern void __mnt_drop_write(struct vfsmount *); extern void __mnt_drop_write_file(struct file *); /* diff --git a/include/linux/mount.h b/include/linux/mount.h index 9197ddbf35fb..bf8cc4108b8f 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -87,6 +87,8 @@ extern bool mnt_may_suid(struct vfsmount *mnt); struct path; extern struct vfsmount *clone_private_mount(const struct path *path); +extern int __mnt_want_write(struct vfsmount *); +extern void __mnt_drop_write(struct vfsmount *); struct file_system_type; extern struct vfsmount *fc_mount(struct fs_context *fc); diff --git a/kernel/acct.c b/kernel/acct.c index addf7732fb56..81f9831a7859 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -227,7 +227,7 @@ static int acct_on(struct filename *pathname) filp_close(file, NULL); return PTR_ERR(internal); } - err = mnt_want_write(internal); + err = __mnt_want_write(internal); if (err) { mntput(internal); kfree(acct); @@ -252,7 +252,7 @@ static int acct_on(struct filename *pathname) old = xchg(&ns->bacct, &acct->pin); mutex_unlock(&acct->lock); pin_kill(old); - mnt_drop_write(mnt); + __mnt_drop_write(mnt); mntput(mnt); return 0; } |