Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=9700382c3c9ff3e673e587084d76eedb3ba88668
Commit: 9700382c3c9ff3e673e587084d76eedb3ba88668
Parent: 937472b00b666ecbf1464502f857ec63b024af72
Author: david m. richter <[EMAIL PROTECTED]>
AuthorDate: Tue Jul 31 00:39:12 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Jul 31 15:39:42 2007 -0700
VFS: fix a race in lease-breaking during truncate
It is possible that another process could acquire a new file lease right
after break_lease() is called during a truncate, but before lease-granting
is disabled by the subsequent get_write_access(). Merely switching the
order of the break_lease() and get_write_access() calls prevents this race.
Signed-off-by: David M. Richter <[EMAIL PROTECTED]>
Signed-off-by: "J. Bruce Fields" <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/open.c | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/open.c b/fs/open.c
index e27c205..1d9e5e9 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -256,24 +256,26 @@ static long do_sys_truncate(const char __user * path,
loff_t length)
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
goto dput_and_out;
- /*
- * Make sure that there are no leases.
- */
- error = break_lease(inode, FMODE_WRITE);
+ error = get_write_access(inode);
if (error)
goto dput_and_out;
- error = get_write_access(inode);
+ /*
+ * Make sure that there are no leases. get_write_access() protects
+ * against the truncate racing with a lease-granting setlease().
+ */
+ error = break_lease(inode, FMODE_WRITE);
if (error)
- goto dput_and_out;
+ goto put_write_and_out;
error = locks_verify_truncate(inode, NULL, length);
if (!error) {
DQUOT_INIT(inode);
error = do_truncate(nd.dentry, length, 0, NULL);
}
- put_write_access(inode);
+put_write_and_out:
+ put_write_access(inode);
dput_and_out:
path_release(&nd);
out:
-
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