diff options
| author | J. Bruce Fields <bfields@redhat.com> | 2011-09-21 14:58:13 (GMT) |
|---|---|---|
| committer | root <root@serles.lst.de> | 2011-10-28 12:59:00 (GMT) |
| commit | f3c7691e8d30d88899b514675c7c86d19057b5fd (patch) | |
| tree | 0065bcc05b19a99d8785ce523f992a48fe573e79 | |
| parent | 79835a710d6ff811659c8de46f89c7577c3b8cc6 (diff) | |
| download | linux-f3c7691e8d30d88899b514675c7c86d19057b5fd.tar.xz | |
leases: fix write-open/read-lease race
In setlease, we use i_writecount to decide whether we can give out a
read lease.
In open, we break leases before incrementing i_writecount.
There is therefore a window between the break lease and the i_writecount
increment when setlease could add a new read lease.
This would leave us with a simultaneous write open and read lease, which
shouldn't happen.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | fs/namei.c | 5 | ||||
| -rw-r--r-- | fs/open.c | 4 |
2 files changed, 5 insertions, 4 deletions
@@ -2035,10 +2035,7 @@ static int may_open(struct path *path, int acc_mode, int flag) if (flag & O_NOATIME && !inode_owner_or_capable(inode)) return -EPERM; - /* - * Ensure there are no outstanding leases on the file. - */ - return break_lease(inode, flag); + return 0; } static int handle_truncate(struct file *filp) @@ -685,6 +685,10 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, if (error) goto cleanup_all; + error = break_lease(inode, f->f_flags); + if (error) + goto cleanup_all; + if (!open && f->f_op) open = f->f_op->open; if (open) { |