Fix autofs_expire()

mnt should remain the same for all iterations through the list;
as it is, if we have a busy mount, mnt follows into it and isn't
restored for the next iteration.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-04-18 11:19:26 -04:00
parent 24b6f16ecf
commit 117aff744a

View file

@ -39,10 +39,12 @@ struct autofs_dir_ent *autofs_expire(struct super_block *sb,
{
struct autofs_dirhash *dh = &sbi->dirhash;
struct autofs_dir_ent *ent;
struct dentry *dentry;
unsigned long timeout = sbi->exp_timeout;
while (1) {
struct path path;
int umount_ok;
if ( list_empty(&dh->expiry_head) || sbi->catatonic )
return NULL; /* No entries */
/* We keep the list sorted by last_usage and want old stuff */
@ -57,17 +59,17 @@ struct autofs_dir_ent *autofs_expire(struct super_block *sb,
return ent; /* Symlinks are always expirable */
/* Get the dentry for the autofs subdirectory */
dentry = ent->dentry;
path.dentry = ent->dentry;
if ( !dentry ) {
if (!path.dentry) {
/* Should only happen in catatonic mode */
printk("autofs: dentry == NULL but inode range is directory, entry %s\n", ent->name);
autofs_delete_usage(ent);
continue;
}
if ( !dentry->d_inode ) {
dput(dentry);
if (!path.dentry->d_inode) {
dput(path.dentry);
printk("autofs: negative dentry on expiry queue: %s\n",
ent->name);
autofs_delete_usage(ent);
@ -76,29 +78,29 @@ struct autofs_dir_ent *autofs_expire(struct super_block *sb,
/* Make sure entry is mounted and unused; note that dentry will
point to the mounted-on-top root. */
if (!S_ISDIR(dentry->d_inode->i_mode)||!d_mountpoint(dentry)) {
if (!S_ISDIR(path.dentry->d_inode->i_mode) ||
!d_mountpoint(path.dentry)) {
DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
continue;
}
mntget(mnt);
dget(dentry);
if (!follow_down(&mnt, &dentry)) {
dput(dentry);
mntput(mnt);
path.mnt = mnt;
path_get(&path);
if (!follow_down(&path.mnt, &path.dentry)) {
path_put(&path);
DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name));
continue;
}
while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))
while (d_mountpoint(path.dentry) &&
follow_down(&path.mnt, &path.dentry))
;
dput(dentry);
umount_ok = may_umount(path.mnt);
path_put(&path);
if ( may_umount(mnt) ) {
mntput(mnt);
if (umount_ok) {
DPRINTK(("autofs: signaling expire on %s\n", ent->name));
return ent; /* Expirable! */
}
DPRINTK(("autofs: didn't expire due to may_umount: %s\n", ent->name));
mntput(mnt);
}
return NULL; /* No expirable entries */
}