diff options
| -rw-r--r-- | Documentation/filesystems/ext3.txt | 15 | ||||
| -rw-r--r-- | fs/ext3/super.c | 33 |
2 files changed, 39 insertions, 9 deletions
diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt index 867c5b50cb4..272f80d5f96 100644 --- a/Documentation/filesystems/ext3.txt +++ b/Documentation/filesystems/ext3.txt @@ -59,8 +59,19 @@ commit=nrsec (*) Ext3 can be told to sync all its data and metadata Setting it to very large values will improve performance. -barrier=1 This enables/disables barriers. barrier=0 disables - it, barrier=1 enables it. +barrier=<0(*)|1> This enables/disables the use of write barriers in +barrier the jbd code. barrier=0 disables, barrier=1 enables. +nobarrier (*) This also requires an IO stack which can support + barriers, and if jbd gets an error on a barrier + write, it will disable again with a warning. + Write barriers enforce proper on-disk ordering + of journal commits, making volatile disk write caches + safe to use, at some performance penalty. If + your disks are battery-backed in one way or another, + disabling barriers may safely improve performance. + The mount options "barrier" and "nobarrier" can + also be used to enable or disable barriers, for + consistency with other ext3 mount options. orlov (*) This enables the new Orlov block allocator. It is enabled by default. diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 6b6e49de091..0fc1293d0e9 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -653,8 +653,12 @@ static int ext3_show_options(struct seq_file *seq, struct vfsmount *vfs) seq_printf(seq, ",commit=%u", (unsigned) (sbi->s_commit_interval / HZ)); } - if (test_opt(sb, BARRIER)) - seq_puts(seq, ",barrier=1"); + + /* + * Always display barrier state so it's clear what the status is. + */ + seq_puts(seq, ",barrier="); + seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0"); if (test_opt(sb, NOBH)) seq_puts(seq, ",nobh"); @@ -810,8 +814,8 @@ enum { Opt_data_err_abort, Opt_data_err_ignore, Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota, Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota, - Opt_noquota, Opt_ignore, Opt_barrier, Opt_err, Opt_resize, - Opt_usrquota, Opt_grpquota + Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err, + Opt_resize, Opt_usrquota, Opt_grpquota }; static const match_table_t tokens = { @@ -865,6 +869,8 @@ static const match_table_t tokens = { {Opt_quota, "quota"}, {Opt_usrquota, "usrquota"}, {Opt_barrier, "barrier=%u"}, + {Opt_barrier, "barrier"}, + {Opt_nobarrier, "nobarrier"}, {Opt_resize, "resize"}, {Opt_err, NULL}, }; @@ -967,7 +973,11 @@ static int parse_options (char *options, struct super_block *sb, int token; if (!*p) continue; - + /* + * Initialize args struct so we know whether arg was + * found; some options take optional arguments. + */ + args[0].to = args[0].from = 0; token = match_token(p, tokens, args); switch (token) { case Opt_bsd_df: @@ -1215,9 +1225,15 @@ set_qf_format: case Opt_abort: set_opt(sbi->s_mount_opt, ABORT); break; + case Opt_nobarrier: + clear_opt(sbi->s_mount_opt, BARRIER); + break; case Opt_barrier: - if (match_int(&args[0], &option)) - return 0; + if (args[0].from) { + if (match_int(&args[0], &option)) + return 0; + } else + option = 1; /* No argument, default to 1 */ if (option) set_opt(sbi->s_mount_opt, BARRIER); else @@ -2276,6 +2292,9 @@ static int ext3_load_journal(struct super_block *sb, return -EINVAL; } + if (!(journal->j_flags & JFS_BARRIER)) + printk(KERN_INFO "EXT3-fs: barriers not enabled\n"); + if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) { err = journal_update_format(journal); if (err) { |