From 18e2663db3e18d4506b6fe583ad93fc83235fca9 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 4 Jul 2014 15:29:17 +0800 Subject: btrfs-progs: Add minimum device size check Btrfs has global block reservation, so even mkfs.btrfs can execute without problem, there is still a possibility that the filesystem can't be mounted. For example when mkfs.btrfs on a 8M file on x86_64 platform, kernel will refuse to mount due to ENOSPC, since system block group takes 4M and mixed block group takes 4M, and global block reservation will takes all the 4M from mixed block group, which makes btrfs unable to create uuid tree. This patch will add minimum device size check before actually mkfs. The minimum size calculation uses a simplified one: minimum_size_for_each_dev = 2 * (system block group + global block rsv) and global block rsv = leafsize << 10 Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- mkfs.c | 30 ++++++++++++++++++++++++++++++ utils.c | 20 ++++++++++++++++++++ utils.h | 22 ++++++++++++++++++++++ 3 files changed, 72 insertions(+) diff --git a/mkfs.c b/mkfs.c index 7695c015..52b9a8d2 100644 --- a/mkfs.c +++ b/mkfs.c @@ -1451,6 +1451,36 @@ int main(int ac, char **av) } } + /* Check device/block_count after the leafsize is determined */ + if (block_count && block_count < btrfs_min_dev_size(leafsize)) { + fprintf(stderr, + "Size '%llu' is too small to make a usable filesystem\n", + block_count); + fprintf(stderr, + "Minimum size for btrfs filesystem is %llu\n", + btrfs_min_dev_size(leafsize)); + exit(1); + } + for (i = saved_optind; i < saved_optind + dev_cnt; i++) { + char *path; + + path = av[i]; + ret = test_minimum_size(path, leafsize); + if (ret < 0) { + fprintf(stderr, "Failed to check size for '%s': %s\n", + path, strerror(-ret)); + exit (1); + } + if (ret > 0) { + fprintf(stderr, + "'%s' is too small to make a usable filesystem\n", + path); + fprintf(stderr, + "Minimum size for each btrfs device is %llu.\n", + btrfs_min_dev_size(leafsize)); + exit(1); + } + } ret = test_num_disk_vs_raid(metadata_profile, data_profile, dev_cnt, mixed, estr); if (ret) { diff --git a/utils.c b/utils.c index 46c3a431..c139eb2e 100644 --- a/utils.c +++ b/utils.c @@ -2344,3 +2344,23 @@ int find_mount_root(const char *path, char **mount_root) free(longest_match); return ret; } + +int test_minimum_size(const char *file, u32 leafsize) +{ + int fd; + struct stat statbuf; + + fd = open(file, O_RDONLY); + if (fd < 0) + return -errno; + if (stat(file, &statbuf) < 0) { + close(fd); + return -errno; + } + if (btrfs_device_size(fd, &statbuf) < btrfs_min_dev_size(leafsize)) { + close(fd); + return 1; + } + close(fd); + return 0; +} diff --git a/utils.h b/utils.h index 37fe1ba0..6599ee4d 100644 --- a/utils.h +++ b/utils.h @@ -105,4 +105,26 @@ int get_device_info(int fd, u64 devid, struct btrfs_ioctl_dev_info_args *di_args); int test_uuid_unique(char *fs_uuid); +int test_minimum_size(const char *file, u32 leafsize); + +/* + * Btrfs minimum size calculation is complicated, it should include at least: + * 1. system group size + * 2. minimum global block reserve + * 3. metadata used at mkfs + * 4. space reservation to create uuid for first mount. + * Also, raid factor should also be taken into consideration. + * To avoid the overkill calculation, (system group + global block rsv) * 2 + * for *EACH* device should be good enough. + */ +static inline u64 btrfs_min_global_blk_rsv_size(u32 leafsize) +{ + return leafsize << 10; +} +static inline u64 btrfs_min_dev_size(u32 leafsize) +{ + return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE + + btrfs_min_global_blk_rsv_size(leafsize)); +} + #endif -- cgit v1.2.3