path: root/fs/sysfs/mount.c
diff options
authorEric Sandeen <sandeen@sandeen.net>2007-06-11 14:02:45 +0900
committerGreg Kroah-Hartman <gregkh@suse.de>2007-06-12 16:08:46 -0700
commitdc351252b33f8fede396d6173dba117bcb933607 (patch)
tree282d57855f66119f930eb629ab483bffcc5b6c21 /fs/sysfs/mount.c
parent99f9f3d49cbc7d944476f6fde53a77ec789ab2aa (diff)
sysfs: store sysfs inode nrs in s_ino to avoid readdir oopses
Backport of ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc1/2.6.22-rc1-mm1/broken-out/gregkh-driver-sysfs-allocate-inode-number-using-ida.patch For regular files in sysfs, sysfs_readdir wants to traverse sysfs_dirent->s_dentry->d_inode->i_ino to get to the inode number. But, the dentry can be reclaimed under memory pressure, and there is no synchronization with readdir. This patch follows Tejun's scheme of allocating and storing an inode number in the new s_ino member of a sysfs_dirent, when dirents are created, and retrieving it from there for readdir, so that the pointer chain doesn't have to be traversed. Tejun's upstream patch uses a new-ish "ida" allocator which brings along some extra complexity; this -stable patch has a brain-dead incrementing counter which does not guarantee uniqueness, but because sysfs doesn't hash inodes as iunique expects, uniqueness wasn't guaranteed today anyway. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/mount.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 23a48a38e6a..00ab9125d39 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -33,6 +33,7 @@ static struct sysfs_dirent sysfs_root = {
.s_element = NULL,
.s_type = SYSFS_ROOT,
.s_iattr = NULL,
+ .s_ino = 1,
static void sysfs_clear_inode(struct inode *inode)