kernel/linux.git/fs/ext4/resize.c, branch v6.1

ext4: update the backup superblock's at the end of the online resize

2022-10-28T03:21:40+00:00

When expanding a file system using online resize, various fields in the superblock (e.g., s_blocks_count, s_inodes_count, etc.) change. To update the backup superblocks, the online resize uses the function update_backups() in fs/ext4/resize.c. This function was not updating the checksum field in the backup superblocks. This wasn't a big deal previously, because e2fsck didn't care about the checksum field in the backup superblock. (And indeed, update_backups() goes all the way back to the ext3 days, well before we had support for metadata checksums.) However, there is an alternate, more general way of updating superblock fields, ext4_update_primary_sb() in fs/ext4/ioctl.c. This function does check the checksum of the backup superblock, and if it doesn't match will mark the file system as corrupted. That was clearly not the intent, so avoid to aborting the resize when a bad superblock is found. In addition, teach update_backups() to properly update the checksum in the backup superblocks. We will eventually want to unify updapte_backups() with the infrasture in ext4_update_primary_sb(), but that's for another day. Note: The problem has been around for a while; it just didn't really matter until ext4_update_primary_sb() was added by commit bbc605cdb1e1 ("ext4: implement support for get/set fs label"). And it became trivially easy to reproduce after commit 827891a38acc ("ext4: update the s_overhead_clusters in the backup sb's when resizing") in v6.0. Cc: stable@kernel.org # 5.17+ Fixes: bbc605cdb1e1 ("ext4: implement support for get/set fs label") Signed-off-by: Theodore Ts'o

ext4: continue to expand file system when the target size doesn't reach

2022-09-27T20:40:30+00:00

When expanding a file system from (16TiB-2MiB) to 18TiB, the operation exits early which leads to result inconsistency between resize2fs and Ext4 kernel driver. === before === ○ → resize2fs /dev/mapper/thin resize2fs 1.45.5 (07-Jan-2020) Filesystem at /dev/mapper/thin is mounted on /mnt/test; on-line resizing required old_desc_blocks = 2048, new_desc_blocks = 2304 The filesystem on /dev/mapper/thin is now 4831837696 (4k) blocks long. [ 865.186308] EXT4-fs (dm-5): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none. [ 912.091502] dm-4: detected capacity change from 34359738368 to 38654705664 [ 970.030550] dm-5: detected capacity change from 34359734272 to 38654701568 [ 1000.012751] EXT4-fs (dm-5): resizing filesystem from 4294966784 to 4831837696 blocks [ 1000.012878] EXT4-fs (dm-5): resized filesystem to 4294967296 === after === [ 129.104898] EXT4-fs (dm-5): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none. [ 143.773630] dm-4: detected capacity change from 34359738368 to 38654705664 [ 198.203246] dm-5: detected capacity change from 34359734272 to 38654701568 [ 207.918603] EXT4-fs (dm-5): resizing filesystem from 4294966784 to 4831837696 blocks [ 207.918754] EXT4-fs (dm-5): resizing filesystem from 4294967296 to 4831837696 blocks [ 207.918758] EXT4-fs (dm-5): Converting file system to meta_bg [ 207.918790] EXT4-fs (dm-5): resizing filesystem from 4294967296 to 4831837696 blocks [ 221.454050] EXT4-fs (dm-5): resized to 4658298880 blocks [ 227.634613] EXT4-fs (dm-5): resized filesystem to 4831837696 Signed-off-by: Jerry Lee Link: https://lore.kernel.org/r/PU1PR04MB22635E739BD21150DC182AC6A18C9@PU1PR04MB2263.apcprd04.prod.outlook.com Signed-off-by: Theodore Ts'o

ext4: avoid resizing to a partial cluster size

2022-08-03T03:56:26+00:00

This patch avoids an attempt to resize the filesystem to an unaligned cluster boundary. An online resize to a size that is not integral to cluster size results in the last iteration attempting to grow the fs by a negative amount, which trips a BUG_ON and leaves the fs with a corrupted in-memory superblock. Signed-off-by: Oleg Kiselev Link: https://lore.kernel.org/r/0E92A0AB-4F16-4F1A-94B7-702CC6504FDE@amazon.com Signed-off-by: Theodore Ts'o

ext4: reduce computation of overhead during resize

2022-08-03T03:56:25+00:00

This patch avoids doing an O(n**2)-complexity walk through every flex group. Instead, it uses the already computed overhead information for the newly allocated space, and simply adds it to the previously calculated overhead stored in the superblock. This drastically reduces the time taken to resize very large bigalloc filesystems (from 3+ hours for a 64TB fs down to milliseconds). Signed-off-by: Oleg Kiselev Link: https://lore.kernel.org/r/CE4F359F-4779-45E6-B6A9-8D67FDFF5AE2@amazon.com Signed-off-by: Theodore Ts'o

ext4: update the s_overhead_clusters in the backup sb's when resizing

2022-08-03T03:52:19+00:00

When the EXT4_IOC_RESIZE_FS ioctl is complete, update the backup superblocks. We don't do this for the old-style resize ioctls since they are quite ancient, and only used by very old versions of resize2fs --- and we don't want to update the backup superblocks every time EXT4_IOC_GROUP_ADD is called, since it might get called a lot. Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20220629040026.112371-2-tytso@mit.edu Signed-off-by: Theodore Ts'o

ext4: update s_overhead_clusters in the superblock during an on-line resize

2022-08-03T03:52:19+00:00

When doing an online resize, the on-disk superblock on-disk wasn't updated. This means that when the file system is unmounted and remounted, and the on-disk overhead value is non-zero, this would result in the results of statfs(2) to be incorrect. This was partially fixed by Commits 10b01ee92df5 ("ext4: fix overhead calculation to account for the reserved gdt blocks"), 85d825dbf489 ("ext4: force overhead calculation if the s_overhead_cluster makes no sense"), and eb7054212eac ("ext4: update the cached overhead value in the superblock"). However, since it was too expensive to forcibly recalculate the overhead for bigalloc file systems at every mount, this didn't fix the problem for bigalloc file systems. This commit should address the problem when resizing file systems with the bigalloc feature enabled. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20220629040026.112371-1-tytso@mit.edu Signed-off-by: Theodore Ts'o

ext4: add reserved GDT blocks check

2022-06-18T23:36:08+00:00

We capture a NULL pointer issue when resizing a corrupt ext4 image which is freshly clear resize_inode feature (not run e2fsck). It could be simply reproduced by following steps. The problem is because of the resize_inode feature was cleared, and it will convert the filesystem to meta_bg mode in ext4_resize_fs(), but the es->s_reserved_gdt_blocks was not reduced to zero, so could we mistakenly call reserve_backup_gdb() and passing an uninitialized resize_inode to it when adding new group descriptors. mkfs.ext4 /dev/sda 3G tune2fs -O ^resize_inode /dev/sda #forget to run requested e2fsck mount /dev/sda /mnt resize2fs /dev/sda 8G ======== BUG: kernel NULL pointer dereference, address: 0000000000000028 CPU: 19 PID: 3243 Comm: resize2fs Not tainted 5.18.0-rc7-00001-gfde086c5ebfd #748 ... RIP: 0010:ext4_flex_group_add+0xe08/0x2570 ... Call Trace: ext4_resize_fs+0xbec/0x1660 __ext4_ioctl+0x1749/0x24e0 ext4_ioctl+0x12/0x20 __x64_sys_ioctl+0xa6/0x110 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2dd739617b ======== The fix is simple, add a check in ext4_resize_begin() to make sure that the es->s_reserved_gdt_blocks is zero when the resize_inode feature is disabled. Cc: stable@kernel.org Signed-off-by: Zhang Yi Reviewed-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220601092717.763694-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o

ext4: use time_is_before_jiffies() instead of open coding it

2022-03-03T04:50:02+00:00

Use the helper function time_is_{before,after}_jiffies() to improve code readability. Signed-off-by: Wang Qing Link: https://lore.kernel.org/r/1646018120-61462-1-git-send-email-wangqing@vivo.com Signed-off-by: Theodore Ts'o

ext4: rename ext4_set_bits to mb_set_bits

2022-02-26T02:34:56+00:00

ext4_set_bits() should actually be mb_set_bits() for uniform API naming convention. This is via below cmd - grep -nr "ext4_set_bits" fs/ext4/ | cut -d ":" -f 1 | xargs sed -i 's/ext4_set_bits/mb_set_bits/g' Signed-off-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/f1f6ece1405b76a7a987e9145d1adfaf71e30695.1644992610.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o

ext4: implement support for get/set fs label

2022-01-10T18:25:55+00:00

Implement support for FS_IOC_GETFSLABEL and FS_IOC_SETFSLABEL ioctls for online reading and setting of file system label. ext4_ioctl_getlabel() is simple, just get the label from the primary superblock. This might not be the first sb on the file system if 'sb=' mount option is used. In ext4_ioctl_setlabel() we update what ext4 currently views as a primary superblock and then proceed to update backup superblocks. There are two caveats: - the primary superblock might not be the first superblock and so it might not be the one used by userspace tools if read directly off the disk. - because the primary superblock might not be the first superblock we potentialy have to update it as part of backup superblock update. However the first sb location is a bit more complicated than the rest so we have to account for that. The superblock modification is created generic enough so the infrastructure can be used for other potential superblock modification operations, such as chaning UUID. Tested with generic/492 with various configurations. I also checked the behavior with 'sb=' mount options, including very large file systems with and without sparse_super/sparse_super2. Signed-off-by: Lukas Czerner Link: https://lore.kernel.org/r/20211213135618.43303-1-lczerner@redhat.com Signed-off-by: Theodore Ts'o