From e123ace58e2c574cd2eb50ec28f8fe616f9ca69d Mon Sep 17 00:00:00 2001 From: Marc Dionne Date: Mon, 6 Jul 2015 11:00:13 -0300 Subject: [PATCH 3/6] Linux 4.2: total_link_count is no longer accessible The value is now stored in the nameidata structure which is private to fs/namei.c, so we can't modify it here. The effect is that using a path that contains 40+ directories may fail with ELOOP, depending on which directories in the path were previously used. After a directory is accessed once its D_AUTOMOUNT flag is reset and it will no longer count against the symlink limit in later path lookups. Reviewed-on: http://gerrit.openafs.org/11926 Tested-by: BuildBot Reviewed-by: Jeffrey Altman (cherry picked from commit 89aeb71a3e23c944f58cfa9572e9eae4d2130d37) Change-Id: Ib6282f3029c4112c510217eacf270a56d679fccd Reviewed-on: http://gerrit.openafs.org/11949 Tested-by: BuildBot Reviewed-by: Benjamin Kaduk Reviewed-by: Stephan Wiesand (cherry picked from commit 2e5ba7e16c6797a39323173ce17a1db698526c2c) --- acinclude.m4 | 1 + src/afs/LINUX/osi_vnodeops.c | 12 ++++++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/acinclude.m4 b/acinclude.m4 index a99592a..c924d90 100644 --- a/acinclude.m4 +++ b/acinclude.m4 @@ -902,6 +902,7 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*) AC_CHECK_LINUX_STRUCT([task_struct], [sigmask_lock], [sched.h]) AC_CHECK_LINUX_STRUCT([task_struct], [tgid], [sched.h]) AC_CHECK_LINUX_STRUCT([task_struct], [thread_info], [sched.h]) + AC_CHECK_LINUX_STRUCT([task_struct], [total_link_count], [sched.h]) LINUX_SCHED_STRUCT_TASK_STRUCT_HAS_SIGNAL_RLIM dnl Check for typed structure elements diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c index a8f0074..a878eb4 100644 --- a/src/afs/LINUX/osi_vnodeops.c +++ b/src/afs/LINUX/osi_vnodeops.c @@ -1385,9 +1385,17 @@ afs_dentry_automount(afs_linux_path_t *path) { struct dentry *target; - /* avoid symlink resolution limits when resolving; we cannot contribute to - * an infinite symlink loop */ + /* + * Avoid symlink resolution limits when resolving; we cannot contribute to + * an infinite symlink loop. + * + * On newer kernels the field has moved to the private nameidata structure + * so we can't adjust it here. This may cause ELOOP when using a path with + * 40 or more directories that are not already in the dentry cache. + */ +#if defined(STRUCT_TASK_STRUCT_HAS_TOTAL_LINK_COUNT) current->total_link_count--; +#endif target = canonical_dentry(path->dentry->d_inode); -- 2.5.1