From 262c5e86fec7cfd59754732001a9ff5b13eba501 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Mon, 12 Dec 2016 16:45:50 -0800 Subject: [PATCH] printk/btrfs: handle more message headers Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") allows to define more message headers for a single message. The motivation is that continuous lines might get mixed. Therefore it make sense to define the right log level for every piece of a cont line. The current btrfs_printk() macros do not support continuous lines at the moment. But better be prepared for a custom messages and avoid potential "lvl" buffer overflow. This patch iterates over the entire message header. It is interested only into the message level like the original code. This patch also introduces PRINTK_MAX_SINGLE_HEADER_LEN. Three bytes are enough for the message level header at the moment. But it used to be three, see the commit 04d2c8c83d0e ("printk: convert the format for KERN_ to a 2 byte pattern"). Also I fixed the default ratelimit level. It looked very strange when it was different from the default log level. [pmladek@suse.com: Fix a check of the valid message level] Link: http://lkml.kernel.org/r/20161111183236.GD2145@dhcp128.suse.cz Link: http://lkml.kernel.org/r/1478695291-12169-4-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek Acked-by: David Sterba Cc: Joe Perches Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Jason Wessel Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Chris Mason Cc: Josef Bacik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/btrfs/super.c | 26 +++++++++++++++----------- include/linux/printk.h | 2 ++ 2 files changed, 17 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 74ed5aae6cea..180f910339f4 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -202,27 +202,31 @@ static struct ratelimit_state printk_limits[] = { void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...) { struct super_block *sb = fs_info->sb; - char lvl[4]; + char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1]; struct va_format vaf; va_list args; - const char *type = logtypes[4]; + const char *type = NULL; int kern_level; struct ratelimit_state *ratelimit; va_start(args, fmt); - kern_level = printk_get_level(fmt); - if (kern_level) { + while ((kern_level = printk_get_level(fmt)) != 0) { size_t size = printk_skip_level(fmt) - fmt; - memcpy(lvl, fmt, size); - lvl[size] = '\0'; + + if (kern_level >= '0' && kern_level <= '7') { + memcpy(lvl, fmt, size); + lvl[size] = '\0'; + type = logtypes[kern_level - '0']; + ratelimit = &printk_limits[kern_level - '0']; + } fmt += size; - type = logtypes[kern_level - '0']; - ratelimit = &printk_limits[kern_level - '0']; - } else { + } + + if (!type) { *lvl = '\0'; - /* Default to debug output */ - ratelimit = &printk_limits[7]; + type = logtypes[4]; + ratelimit = &printk_limits[4]; } vaf.fmt = fmt; diff --git a/include/linux/printk.h b/include/linux/printk.h index a0859e169bc3..afe8ccec1672 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -10,6 +10,8 @@ extern const char linux_banner[]; extern const char linux_proc_banner[]; +#define PRINTK_MAX_SINGLE_HEADER_LEN 2 + static inline int printk_get_level(const char *buffer) { if (buffer[0] == KERN_SOH_ASCII && buffer[1]) {