From fdf7f35d3ed4ced6c27222ec99a8306f93cd1009 Mon Sep 17 00:00:00 2001 From: Goffredo Baroncelli Date: Thu, 4 Jan 2024 21:41:42 +0100 Subject: [PATCH] btrfs-progs: fi usage: wrong values in case of raid56 and not root In case of a raid5/6 filesystem 'btrfs fi us' returns wrong values without the root capabilities: $ sudo btrfs fi us /tmp/raid5fs # as root Overall: Device size: 3.00GiB Device allocated: 1.51GiB <--- OK Device unallocated: 1.49GiB <--- OK Device missing: 0.00B Device slack: 0.00B Used: 769.03MiB <--- OK Free (estimated): 1.32GiB (min: 1.32GiB) <-OK Free (statfs, df): 1.32GiB Data ratio: 1.50 <--- OK Metadata ratio: 1.50 <--- OK Global reserve: 5.50MiB (used: 0.00B) Multiple profiles: no [...] $ btrfs fi us /tmp/raid5fs # as user WARNING: cannot read detailed chunk info, per-device usage will not be shown, run as root Overall: Device size: 3.00GiB Device allocated: 0.00B <--- WRONG Device unallocated: 3.00GiB <--- WRONG Device missing: 0.00B Device slack: 0.00B Used: 0.00B <--- WRONG Free (estimated): 0.00B (min: 8.00EiB) <- WRONG Free (statfs, df): 1.32GiB Data ratio: 0.00 <--- WRONG Metadata ratio: 0.00 <--- WRONG Global reserve: 5.50MiB (used: 0.00B) Multiple profiles: no [...] The reason is that the BTRFS_IOC_SPACE_INFO ioctl doesn't return enough information. To bypass it a scan of the chunks is required when a raid5/6 profile is present. To avoid providing wrong information, in case of a raid5/6 filesystem without the root capabilities the "btrfs fi us" is not executed at all and a warning with a suggestion to run it as root is printed. $ ./btrfs fi us /tmp/t/ WARNING: cannot read detailed chunk info, per-device usage will not be shown, run as root WARNING: due to the presence of a raid5/raid6 profile, we cannots compute some values; WARNING: run as root instead. Signed-off-by: Goffredo Baroncelli Signed-off-by: David Sterba --- cmds/filesystem-usage.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/cmds/filesystem-usage.c b/cmds/filesystem-usage.c index 4c4467ee..52e552dc 100644 --- a/cmds/filesystem-usage.c +++ b/cmds/filesystem-usage.c @@ -478,6 +478,8 @@ static int print_filesystem_usage_overall(int fd, const struct array *chunkinfos bool mixed = false; struct statvfs statvfs_buf; struct btrfs_ioctl_feature_flags feature_flags; + bool raid56 = false; + bool unreliable_allocated = false; sargs = load_space_info(fd, path); if (!sargs) { @@ -518,8 +520,10 @@ static int print_filesystem_usage_overall(int fd, const struct array *chunkinfos * computed separately. Setting ratio to 0 will not account * the chunks in this loop. */ - if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) + if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) { ratio = 0; + raid56 = true; + } if (ratio > max_data_ratio) max_data_ratio = ratio; @@ -610,6 +614,18 @@ static int print_filesystem_usage_overall(int fd, const struct array *chunkinfos ret = 0; } + /* + * If we don't have any chunk information (e.g. due to missing + * privileges) and there's a raid56 profile, the computation of + * "unallocated", "data/metadata ratio", "free estimated" are wrong. + */ + unreliable_allocated = (raid56 && chunkinfos->length == 0); + if (unreliable_allocated) { + warning("radid56 found, we cannots compute some values, run as root if needed"); + ret = 1; + goto exit; + } + pr_verbose(LOG_DEFAULT, "Overall:\n"); pr_verbose(LOG_DEFAULT, " Device size:\t\t%*s\n", width,