From: Vasily Averin Date: Wed, 11 Oct 2006 08:21:50 +0000 (-0700) Subject: [PATCH] ext2: errors behaviour fix X-Git-Tag: v2.6.19-rc2~77 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=5a2b4062f5adf2218b9b021e1c33f374bf142cb2;p=linux-2.6-omap-h63xx.git [PATCH] ext2: errors behaviour fix Current error behaviour for ext2 and ext3 filesystems does not fully correspond to the documentation and should be fixed. According to man 8 mount, ext2 and ext3 file systems allow to set one of 3 different on-errors behaviours: ---- start of quote man 8 mount ---- errors=continue / errors=remount-ro / errors=panic Define the behaviour when an error is encountered. (Either ignore errors and just mark the file system erroneous and continue, or remount the file system read-only, or panic and halt the system.) The default is set in the filesystem superblock, and can be changed using tune2fs(8). ---- end of quote ---- However EXT3_ERRORS_CONTINUE is not read from the superblock, and thus ERRORS_CONT is not saved on the sbi->s_mount_opt. It leads to the incorrect handle of errors on ext3. Then we've checked corresponding code in ext2 and discovered that it is buggy as well: - EXT2_ERRORS_CONTINUE is not read from the superblock (the same); - parse_option() does not clean the alternative values and thus something like (ERRORS_CONT|ERRORS_RO) can be set; - if options are omitted, parse_option() does not set any of these options. Therefore it is possible to set any combination of these options on the ext2: - none of them may be set: EXT2_ERRORS_CONTINUE on superblock / empty mount options; - any of them may be set using mount options; - 2 any options may be set: by using EXT2_ERRORS_RO/EXT2_ERRORS_PANIC on the superblock and other value in mount options; - and finally all three options may be set by adding third option in remount. Currently ext2 uses these values only in ext2_error() and it is not leading to any noticeable troubles. However somebody may be discouraged when he will try to workaround EXT2_ERRORS_PANIC on the superblock by using errors=continue in mount options. This patch: EXT2_ERRORS_CONTINUE should be read from the superblock as default value for error behaviour. parse_option() should clean the alternative options and should not change default value taken from the superblock. Signed-off-by: Vasily Averin Acked-by: Kirill Korotaev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 513cd421ac0..d8b9abd95d0 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -364,7 +364,6 @@ static int parse_options (char * options, { char * p; substring_t args[MAX_OPT_ARGS]; - unsigned long kind = EXT2_MOUNT_ERRORS_CONT; int option; if (!options) @@ -404,13 +403,19 @@ static int parse_options (char * options, /* *sb_block = match_int(&args[0]); */ break; case Opt_err_panic: - kind = EXT2_MOUNT_ERRORS_PANIC; + clear_opt (sbi->s_mount_opt, ERRORS_CONT); + clear_opt (sbi->s_mount_opt, ERRORS_RO); + set_opt (sbi->s_mount_opt, ERRORS_PANIC); break; case Opt_err_ro: - kind = EXT2_MOUNT_ERRORS_RO; + clear_opt (sbi->s_mount_opt, ERRORS_CONT); + clear_opt (sbi->s_mount_opt, ERRORS_PANIC); + set_opt (sbi->s_mount_opt, ERRORS_RO); break; case Opt_err_cont: - kind = EXT2_MOUNT_ERRORS_CONT; + clear_opt (sbi->s_mount_opt, ERRORS_RO); + clear_opt (sbi->s_mount_opt, ERRORS_PANIC); + set_opt (sbi->s_mount_opt, ERRORS_CONT); break; case Opt_nouid32: set_opt (sbi->s_mount_opt, NO_UID32); @@ -489,7 +494,6 @@ static int parse_options (char * options, return 0; } } - sbi->s_mount_opt |= kind; return 1; } @@ -715,6 +719,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) set_opt(sbi->s_mount_opt, ERRORS_PANIC); else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO) set_opt(sbi->s_mount_opt, ERRORS_RO); + else + set_opt(sbi->s_mount_opt, ERRORS_CONT); sbi->s_resuid = le16_to_cpu(es->s_def_resuid); sbi->s_resgid = le16_to_cpu(es->s_def_resgid);