From 4f43aaf4aac13cc0d52302ff294c49e3b43f0e62 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Thu, 4 Jun 2015 15:54:22 +0200 Subject: btrfs-progs: doc: update btrfs-rescue page and drop btrfs-zero-log - fix page title - update zero-log text - delete btrfs-zero-log.asciidoc as page is not shipped anymore Signed-off-by: David Sterba --- Documentation/btrfs-rescue.asciidoc | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'Documentation/btrfs-rescue.asciidoc') diff --git a/Documentation/btrfs-rescue.asciidoc b/Documentation/btrfs-rescue.asciidoc index 32d8a927..42aca645 100644 --- a/Documentation/btrfs-rescue.asciidoc +++ b/Documentation/btrfs-rescue.asciidoc @@ -1,4 +1,4 @@ -btrfs-check(8) +btrfs-rescue(8) ============== NAME @@ -41,15 +41,21 @@ assume an answer of 'yes' to all questions. verbose mode. *zero-log* :: -clear out log tree +clear the filesystem log tree -*btrfs rescue zero-log* will remove the log tree if log tree is corrupt, which -will allow you to mount the filesystem again. +This command will clear the filesystem log tree. This may fix a specific +set of problem when the filesystem mount fails due to the log replay. See below +for sample stacktraces that may show up in system log. The common case where this happens has been fixed a long time ago, -so it is unlikely that you will see this particular problem. +so it is unlikely that you will see this particular problem, but the utility is +kept around. -One can determine whether *btrfs-zero-log* is needed according to the kernel +NOTE: clearing the log may lead to loss of changes that were made since the +last transaction commit. This may be up to 30 seconds (default commit period) +or less if the commit was implied by other filesystem activity. + +One can determine whether *zero-log* is needed according to the kernel backtrace: ---- ? replay_one_dir_item+0xb5/0xb5 [btrfs] @@ -61,8 +67,10 @@ backtrace: ? open_ctree+0xff6/0x132c [btrfs] ---- -If the errors are like above, then *zero-log* could be used to clear -the log and the filesystem may be mounted normally again. +If the errors are like above, then *zero-log* should be used to clear +the log and the filesystem may be mounted normally again. The keywords to look +for are 'open_ctree' which says that it's during mount and function names +that contain 'replay', 'recover' or 'log_tree'. EXIT STATUS ----------- -- cgit v1.2.3