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author | David Howells <dhowells@redhat.com> | 2011-01-14 19:10:03 (GMT) |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-01-16 01:07:48 (GMT) |
commit | ea5b778a8b98c85a87d66bf844904f9c3802b869 (patch) | |
tree | baa56cbe1a907d76341f2cad53e16569cc1d3288 /fs/afs/mntpt.c | |
parent | ab90911ff90cdab59b31c045c3f0ae480d14f29d (diff) | |
download | linux-fsl-qoriq-ea5b778a8b98c85a87d66bf844904f9c3802b869.tar.xz |
Unexport do_add_mount() and add in follow_automount(), not ->d_automount()
Unexport do_add_mount() and make ->d_automount() return the vfsmount to be
added rather than calling do_add_mount() itself. follow_automount() will then
do the addition.
This slightly complicates things as ->d_automount() normally wants to add the
new vfsmount to an expiration list and start an expiration timer. The problem
with that is that the vfsmount will be deleted if it has a refcount of 1 and
the timer will not repeat if the expiration list is empty.
To this end, we require the vfsmount to be returned from d_automount() with a
refcount of (at least) 2. One of these refs will be dropped unconditionally.
In addition, follow_automount() must get a 3rd ref around the call to
do_add_mount() lest it eat a ref and return an error, leaving the mount we
have open to being expired as we would otherwise have only 1 ref on it.
d_automount() should also add the the vfsmount to the expiration list (by
calling mnt_set_expiry()) and start the expiration timer before returning, if
this mechanism is to be used. The vfsmount will be unlinked from the
expiration list by follow_automount() if do_add_mount() fails.
This patch also fixes the call to do_add_mount() for AFS to propagate the mount
flags from the parent vfsmount.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/afs/mntpt.c')
-rw-r--r-- | fs/afs/mntpt.c | 25 |
1 files changed, 6 insertions, 19 deletions
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c index d23b2e3..aa59184 100644 --- a/fs/afs/mntpt.c +++ b/fs/afs/mntpt.c @@ -241,7 +241,6 @@ error_no_devname: struct vfsmount *afs_d_automount(struct path *path) { struct vfsmount *newmnt; - int err; _enter("{%s,%s}", path->mnt->mnt_devname, path->dentry->d_name.name); @@ -249,24 +248,12 @@ struct vfsmount *afs_d_automount(struct path *path) if (IS_ERR(newmnt)) return newmnt; - mntget(newmnt); - err = do_add_mount(newmnt, path, MNT_SHRINKABLE, &afs_vfsmounts); - switch (err) { - case 0: - queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, - afs_mntpt_expiry_timeout * HZ); - _leave(" = %p {%s}", newmnt, newmnt->mnt_devname); - return newmnt; - case -EBUSY: - /* someone else made a mount here whilst we were busy */ - mntput(newmnt); - _leave(" = NULL [EBUSY]"); - return NULL; - default: - mntput(newmnt); - _leave(" = %d", err); - return ERR_PTR(err); - } + mntget(newmnt); /* prevent immediate expiration */ + mnt_set_expiry(newmnt, &afs_vfsmounts); + queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, + afs_mntpt_expiry_timeout * HZ); + _leave(" = %p {%s}", newmnt, newmnt->mnt_devname); + return newmnt; } /* |