Anand Jain (4): btrfs: convert latest_bdev type to btrfs_device and rename btrfs: use latest_dev in btrfs_show_devname btrfs: update latest_dev when we create a sprout device btrfs: remove stale comment about the btrfs_show_devname
fs/btrfs/volumes.h | 6 +++++- fs/btrfs/disk-io.c | 6 +++--- fs/btrfs/extent_io.c | 2 +- fs/btrfs/inode.c | 2 +- fs/btrfs/super.c | 26 ++++++-------------------- fs/btrfs/volumes.c | 19 +++++++------------ 6 files changed, 23 insertions(+), 38 deletions(-)
From: Anand Jain anand.jain@oracle.com
mainline inclusion from mainline-v5.16-rc1 commit d24fa5c1da08026be9959baca309fa0adf8708bf category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA77UW CVE: CVE-2021-47599
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
In preparation to fix a bug in btrfs_show_devname().
Convert fs_devices::latest_bdev type from struct block_device to struct btrfs_device and, rename the member to fs_devices::latest_dev. So that btrfs_show_devname() can use fs_devices::latest_dev::name.
Tested-by: Su Yue l@damenly.su Signed-off-by: Anand Jain anand.jain@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Conflicts: fs/btrfs/inode.c fs/btrfs/disk-io.c fs/btrfs/extent_io.c fs/btrfs/volumes.c [Resolve conflicts due to several refactor patches not merged.] Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/volumes.h | 6 +++++- fs/btrfs/disk-io.c | 6 +++--- fs/btrfs/extent_io.c | 2 +- fs/btrfs/inode.c | 2 +- fs/btrfs/super.c | 2 +- fs/btrfs/volumes.c | 10 +++++----- 6 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index f2177263748e..51e66abe314d 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -228,7 +228,11 @@ struct btrfs_fs_devices { /* Highest generation number of seen devices */ u64 latest_generation;
- struct block_device *latest_bdev; + /* + * The mount device or a device with highest generation after removal + * or replace. + */ + struct btrfs_device *latest_dev;
/* all of the devices in the FS, protected by a mutex * so we can safely walk it to write out the supers without diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 59ecab2c6f0e..b9a3bdacdede 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2953,12 +2953,12 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS); btrfs_init_btree_inode(fs_info);
- invalidate_bdev(fs_devices->latest_bdev); + invalidate_bdev(fs_devices->latest_dev->bdev);
/* * Read super block and check the signature bytes only */ - disk_super = btrfs_read_dev_super(fs_devices->latest_bdev); + disk_super = btrfs_read_dev_super(fs_devices->latest_dev->bdev); if (IS_ERR(disk_super)) { err = PTR_ERR(disk_super); goto fail_alloc; @@ -3182,7 +3182,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device */ btrfs_free_extra_devids(fs_devices, 0);
- if (!fs_devices->latest_bdev) { + if (!fs_devices->latest_dev->bdev) { btrfs_err(fs_info, "failed to read devices"); goto fail_tree_roots; } diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 5fc65a780f83..60704b23a8e2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3080,7 +3080,7 @@ static int submit_extent_page(unsigned int opf, if (wbc) { struct block_device *bdev;
- bdev = BTRFS_I(page->mapping->host)->root->fs_info->fs_devices->latest_bdev; + bdev = BTRFS_I(page->mapping->host)->root->fs_info->fs_devices->latest_dev->bdev; bio_set_dev(bio, bdev); wbc_init_bio(wbc, bio); wbc_account_cgroup_owner(wbc, page, page_size); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0445811787b7..ff876a4626cb 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7560,7 +7560,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start, iomap->type = IOMAP_MAPPED; } iomap->offset = start; - iomap->bdev = fs_info->fs_devices->latest_bdev; + iomap->bdev = fs_info->fs_devices->latest_dev->bdev; iomap->length = len;
free_extent_map(em); diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 8bf8cdb62a3a..0e81a99ce7eb 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1676,7 +1676,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, goto error_close_devices; }
- bdev = fs_devices->latest_bdev; + bdev = fs_devices->latest_dev->bdev; s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC, fs_info); if (IS_ERR(s)) { diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index cf9a6d75a484..d38d5d7aecd4 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1133,7 +1133,7 @@ void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step) list_for_each_entry(seed_dev, &fs_devices->seed_list, seed_list) __btrfs_free_extra_devids(seed_dev, step, &latest_dev);
- fs_devices->latest_bdev = latest_dev->bdev; + fs_devices->latest_dev = latest_dev;
mutex_unlock(&uuid_mutex); } @@ -1265,7 +1265,7 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices, return -EINVAL;
fs_devices->opened = 1; - fs_devices->latest_bdev = latest_dev->bdev; + fs_devices->latest_dev = latest_dev; fs_devices->total_rw_bytes = 0; fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_REGULAR;
@@ -2014,7 +2014,7 @@ static struct btrfs_device * btrfs_find_next_active_device( }
/* - * Helper function to check if the given device is part of s_bdev / latest_bdev + * Helper function to check if the given device is part of s_bdev / latest_dev * and replace it with the provided or the next active device, in the context * where this function called, there should be always be another device (or * this_dev) which is active. @@ -2033,8 +2033,8 @@ void __cold btrfs_assign_next_active_device(struct btrfs_device *device, (fs_info->sb->s_bdev == device->bdev)) fs_info->sb->s_bdev = next_device->bdev;
- if (fs_info->fs_devices->latest_bdev == device->bdev) - fs_info->fs_devices->latest_bdev = next_device->bdev; + if (fs_info->fs_devices->latest_dev->bdev == device->bdev) + fs_info->fs_devices->latest_dev = next_device; }
/*
From: Anand Jain anand.jain@oracle.com
mainline inclusion from mainline-v5.16-rc1 commit 6605fd2f394bba0a0059df2b6cfc87b0b6d393a2 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA77UW CVE: CVE-2021-47599
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
The test case btrfs/238 reports the warning below:
WARNING: CPU: 3 PID: 481 at fs/btrfs/super.c:2509 btrfs_show_devname+0x104/0x1e8 [btrfs] CPU: 2 PID: 1 Comm: systemd Tainted: G W O 5.14.0-rc1-custom #72 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: btrfs_show_devname+0x108/0x1b4 [btrfs] show_mountinfo+0x234/0x2c4 m_show+0x28/0x34 seq_read_iter+0x12c/0x3c4 vfs_read+0x29c/0x2c8 ksys_read+0x80/0xec __arm64_sys_read+0x28/0x34 invoke_syscall+0x50/0xf8 do_el0_svc+0x88/0x138 el0_svc+0x2c/0x8c el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x198/0x19c
Reason: While btrfs_prepare_sprout() moves the fs_devices::devices into fs_devices::seed_list, the btrfs_show_devname() searches for the devices and found none, leading to the warning as in above.
Fix: latest_dev is updated according to the changes to the device list. That means we could use the latest_dev->name to show the device name in /proc/self/mounts, the pointer will be always valid as it's assigned before the device is deleted from the list in remove or replace. The RCU protection is sufficient as the device structure is freed after synchronization.
Reported-by: Su Yue l@damenly.su Tested-by: Su Yue l@damenly.su Signed-off-by: Anand Jain anand.jain@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/super.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 0e81a99ce7eb..3c8c9a032002 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2411,30 +2411,16 @@ static int btrfs_unfreeze(struct super_block *sb) static int btrfs_show_devname(struct seq_file *m, struct dentry *root) { struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); - struct btrfs_device *dev, *first_dev = NULL;
/* - * Lightweight locking of the devices. We should not need - * device_list_mutex here as we only read the device data and the list - * is protected by RCU. Even if a device is deleted during the list - * traversals, we'll get valid data, the freeing callback will wait at - * least until the rcu_read_unlock. + * There should be always a valid pointer in latest_dev, it may be stale + * for a short moment in case it's being deleted but still valid until + * the end of RCU grace period. */ rcu_read_lock(); - list_for_each_entry_rcu(dev, &fs_info->fs_devices->devices, dev_list) { - if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) - continue; - if (!dev->name) - continue; - if (!first_dev || dev->devid < first_dev->devid) - first_dev = dev; - } - - if (first_dev) - seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\"); - else - WARN_ON(1); + seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), " \t\n\"); rcu_read_unlock(); + return 0; }
From: Anand Jain anand.jain@oracle.com
mainline inclusion from mainline-v5.16-rc1 commit b7cb29e666fe79dda5dbe5f57fb7c92413bf161c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA77UW CVE: CVE-2021-47599
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
When we add a device to the seed filesystem (sprouting) it is a new filesystem (and fsid) on the device added. Update the latest_dev so that /proc/self/mounts shows the correct device.
Example:
$ btrfstune -S1 /dev/vg/seed $ mount /dev/vg/seed /btrfs mount: /btrfs: WARNING: device write-protected, mounted read-only.
$ cat /proc/self/mounts | grep btrfs /dev/mapper/vg-seed /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0
$ btrfs dev add -f /dev/vg/new /btrfs
Before:
$ cat /proc/self/mounts | grep btrfs /dev/mapper/vg-seed /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0
After:
$ cat /proc/self/mounts | grep btrfs /dev/mapper/vg-new /btrfs btrfs ro,relatime,space_cache,subvolid=5,subvol=/ 0 0
Tested-by: Su Yue l@damenly.su Signed-off-by: Anand Jain anand.jain@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d38d5d7aecd4..2e7a8c1f6db4 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2629,6 +2629,8 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path btrfs_abort_transaction(trans, ret); goto error_trans; } + btrfs_assign_next_active_device(fs_info->fs_devices->latest_dev, + device); }
device->fs_devices = fs_devices;
From: Anand Jain anand.jain@oracle.com
mainline inclusion from mainline-v5.16-rc1 commit cdccc03a8a369b59cff5e7ea3292511cfa551120 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA77UW CVE: CVE-2021-47599
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
There were few lockdep warnings because btrfs_show_devname() was using device_list_mutex as recorded in the commits:
0ccd05285e7f ("btrfs: fix a possible umount deadlock") 779bf3fefa83 ("btrfs: fix lock dep warning, move scratch dev out of device_list_mutex and uuid_mutex")
And finally, commit 88c14590cdd6 ("btrfs: use RCU in btrfs_show_devname for device list traversal") removed the device_list_mutex from btrfs_show_devname for performance reasons.
This patch removes a stale comment about the function btrfs_show_devname and device_list_mutex.
Signed-off-by: Anand Jain anand.jain@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/volumes.c | 7 ------- 1 file changed, 7 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 2e7a8c1f6db4..20784a3ade38 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2317,13 +2317,6 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev)
mutex_unlock(&fs_devices->device_list_mutex);
- /* - * The update_dev_time() with in btrfs_scratch_superblocks() - * may lead to a call to btrfs_show_devname() which will try - * to hold device_list_mutex. And here this device - * is already out of device list, so we don't have to hold - * the device_list_mutex lock. - */ btrfs_scratch_superblocks(tgtdev->fs_info, tgtdev->bdev, tgtdev->name->str);
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