Commit 092a5345 authored Feb 27, 2017 by Ian Kent Committed by Linus Torvalds Feb 27, 2017

autofs: take more care to not update last_used on path walk

GUI environments seem to be becoming more agressive at scanning
filesystems, to the point where autofs cannot expire mounts at all.

This is one key reason the update of the autofs dentry info last_used
field is done in the expire system when the dentry is seen to be in use.

But somewhere along the way instances of the update has crept back into
the autofs path walk functions which, with the more aggressive file
access patterns, is preventing expiration.

Changing the update in the path walk functions allows autofs to at least
make progress in spite of frequent immediate re-mounts from file
accesses.

Link: http://lkml.kernel.org/r/148577167169.9801.1377050092212016834.stgit@pluto.themaw.net


Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Tomohiro Kusumi <tkusumi@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3bb2fbda

fs/autofs4/root.c

+11 −6

Original line number	Diff line number	Diff line
		@@ -281,8 +281,8 @@ static int autofs4_mount_wait(const struct path *path, bool rcu_walk)
		pr_debug("waiting for mount name=%pd\n", path->dentry);
		status = autofs4_wait(sbi, path, NFY_MOUNT);
		pr_debug("mount wait done status=%d\n", status);
		}
		ino->last_used = jiffies;
		}
		return status;
		}

		@@ -321,17 +321,22 @@ static struct dentry autofs4_mountpoint_changed(struct path path)
		*/
		if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
		struct dentry *parent = dentry->d_parent;
		struct autofs_info *ino;
		struct dentry *new;

		new = d_lookup(parent, &dentry->d_name);
		if (!new)
		return NULL;
		if (new == dentry)
		dput(new);
		else {
		struct autofs_info *ino;

		ino = autofs4_dentry_ino(new);
		ino->last_used = jiffies;
		dput(path->dentry);
		path->dentry = new;
		}
		}
		return path->dentry;
		}

Admin message