bbac58698a
[BUG] There is a report that a btrfs has a bad super block num devices. This makes btrfs to reject the fs completely. BTRFS error (device sdd3): super_num_devices 3 mismatch with num_devices 2 found here BTRFS error (device sdd3): failed to read chunk tree: -22 BTRFS error (device sdd3): open_ctree failed [CAUSE] During btrfs device removal, chunk tree and super block num devs are updated in two different transactions: btrfs_rm_device() |- btrfs_rm_dev_item(device) | |- trans = btrfs_start_transaction() | | Now we got transaction X | | | |- btrfs_del_item() | | Now device item is removed from chunk tree | | | |- btrfs_commit_transaction() | Transaction X got committed, super num devs untouched, | but device item removed from chunk tree. | (AKA, super num devs is already incorrect) | |- cur_devices->num_devices--; |- cur_devices->total_devices--; |- btrfs_set_super_num_devices() All those operations are not in transaction X, thus it will only be written back to disk in next transaction. So after the transaction X in btrfs_rm_dev_item() committed, but before transaction X+1 (which can be minutes away), a power loss happen, then we got the super num mismatch. [FIX] Instead of starting and committing a transaction inside btrfs_rm_dev_item(), start a transaction in side btrfs_rm_device() and pass it to btrfs_rm_dev_item(). And only commit the transaction after everything is done. Reported-by: Luca Béla Palkovics <luca.bela.palkovics@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CA+8xDSpvdm_U0QLBAnrH=zqDq_cWCOH5TiV46CKmp3igr44okQ@mail.gmail.com/ CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.