On Mon, 15 Dec 2014, Jitendra Pawar wrote: > Date: Mon, 15 Dec 2014 19:31:11 +0530 > From: Jitendra Pawar <jitendra.pawar@xxxxxxxxx> > To: linux-ext4@xxxxxxxxxxxxxxx > Subject: Reserved blocks list in ext* filesystem > > Hi, > > Below is snippet of superblock information of one of the block > device(say /dev/sda1) > Which mentions about the reserved blocks- > Reserved block count: 25600 > Does anyone know about how to find out list of blocks which are > reserved(actual block numbers not count). There are no statically reserved blocks. Reserved block count is a number of free block bellow which a non-privileged processes are no more allowed to allocate additional space from the file system. In other words (see man mkfs.ext4): Specify the percentage of the filesystem blocks reserved for the super-user. This avoids fragmentation, and allows root-owned daemons, such as syslogd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. The default percentage is 5%. -Lukas > > ------------------------------------------------- > Filesystem volume name: <none> > Last mounted on: /boot > Filesystem UUID: 99ec51e5-8729-4cab-b2ea-6b55b302aae6 > Filesystem magic number: 0xEF53 > Filesystem revision #: 1 (dynamic) > Filesystem features: has_journal ext_attr resize_inode dir_index > filetype needs_recovery extent flex_bg sparse_super huge_file > uninit_bg dir_nlink extra_isize > Filesystem flags: signed_directory_hash > Default mount options: user_xattr acl > Filesystem state: clean > Errors behavior: Continue > Filesystem OS type: Linux > Inode count: 128016 > Block count: 512000 > Reserved block count: 25600 > Free blocks: 439769 > Free inodes: 127977 > First block: 1 > Block size: 1024 > Fragment size: 1024 > Reserved GDT blocks: 256 > Blocks per group: 8192 > Fragments per group: 8192 > Inodes per group: 2032 > Inode blocks per group: 254 > Flex block group size: 16 > Filesystem created: Thu Aug 8 06:35:16 2013 > Last mount time: Tue Nov 25 18:52:26 2014 > Last write time: Tue Nov 25 18:52:26 2014 > Mount count: 12 > Maximum mount count: -1 > Last checked: Thu Aug 8 06:35:16 2013 > Check interval: 0 (<none>) > Lifetime writes: 105 MB > Reserved blocks uid: 0 (user root) > Reserved blocks gid: 0 (group root) > First inode: 11 > Inode size: 128 > Journal inode: 8 > Default directory hash: half_md4 > Directory Hash Seed: 4c6e20ac-c46d-4bf1-81c1-3c5ae77eaab7 > Journal backup: inode blocks > Journal features: journal_incompat_revoke > Journal size: 8M > Journal length: 8192 > Journal sequence: 0x00000028 > Journal start: 0 > --------------------------------------------- > > Thanks, > -Jitendra > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
