From f8ad850f11e11d10e7de1a16ca53cb193afc9313 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 6 Jun 2010 23:49:18 -0400 Subject: try to get rid of races in hostfs open() In case of mode mismatch, do *not* blindly close the descriptor another openers might be using right now. Open the underlying file with currently sufficient mode, then * if current mode has grown so that it's sufficient for us now, just close our new fd * if current mode has grown and our fd is *not* enough to cover it, close and repeat. * otherwise, install our fd if the file hadn't been opened at all or dup2() our fd over the current one (and close our fd). Critical section is protected by mutex; yes, system-wide. All we do under it is a bunch of comparison and maybe an overwriting dup2() on host. Signed-off-by: Al Viro --- fs/hostfs/hostfs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/hostfs/hostfs.h') diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h index ea87e224ed9..6bbd75c5589 100644 --- a/fs/hostfs/hostfs.h +++ b/fs/hostfs/hostfs.h @@ -74,6 +74,7 @@ extern void *open_dir(char *path, int *err_out); extern char *read_dir(void *stream, unsigned long long *pos, unsigned long long *ino_out, int *len_out); extern void close_file(void *stream); +extern int replace_file(int oldfd, int fd); extern void close_dir(void *stream); extern int read_file(int fd, unsigned long long *offset, char *buf, int len); extern int write_file(int fd, unsigned long long *offset, const char *buf, -- cgit v1.2.3-18-g5258