wireguard-linux/fs/btrfs/sysfs.c, branch jd/unified-crypt-queue

btrfs: sysfs: Use scnprintf() instead of snprintf()

2020-03-23T17:14:47Z

snprintf() is a hard-to-use function, and it's especially difficult to use it properly for concatenating substrings in a buffer with a limited size. Since snprintf() returns the would-be-output size, not the actual size, the subsequent use of snprintf() may point to the incorrect position easily. Also, returning the value from snprintf() directly to sysfs show function would pass a bogus value that is higher than the actually truncated string. That said, although the current code doesn't actually overflow the buffer with PAGE_SIZE, it's a usage that shouldn't be done. Or it's worse; this gives a wrong confidence as if it were doing safe operations. This patch replaces such snprintf() calls with a safer version, scnprintf(). It returns the actual output size, hence it's more intuitive and the code does what's expected. Signed-off-by: Takashi Iwai Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, unify handler name of devinfo/missing

2020-03-23T16:01:36Z

The devinfo attribute handlers were added in 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and device attributes") and the name should contain _devinfo_, there's one that does not conform, so unify it with the rest. Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, rename device_link add/remove functions

2020-03-23T16:01:35Z

Since commit 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and device attributes"), the functions btrfs_sysfs_add_device_link() and btrfs_sysfs_rm_device_link() do more than just adding and removing the device link as its name indicated. Rename them to be more specific that's about the directory with the attirbutes Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, use btrfs_sysfs_remove_fsid to celanup errors in add_fsid

2020-03-23T16:01:35Z

We have one simple function btrfs_sysfs_remove_fsid() to undo btrfs_sysfs_add_fsid(), which also does proper checks before releasing objects. One difference, if btrfs_sysfs_remove_fsid is used that now we also call kobject_del() which was missing before. This was tested (with kobject debug turned on) and no change in behaviour was found. This is a cleanup patch. Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, move device id directories to UUID/devinfo

2020-02-12T17:28:22Z

Originally it was planned to create device id directories under UUID/devinfo, but it got under UUID/devices by mistake. We really want it under definfo so the bare device node names are not mixed with device ids and are easy to enumerate. Fixes: 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and device attributes") Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, add UUID/devinfo kobject

2020-02-12T17:28:18Z

Create directory /sys/fs/btrfs/UUID/devinfo to hold devices directories by the id (unlike /devices). Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sysfs, add devid/dev_state kobject and device attributes

2020-01-23T16:24:36Z

New sysfs attributes that track the filesystem status of devices, stored in the per-filesystem directory in /sys/fs/btrfs/FSID/devinfo . There's a directory for each device, with name corresponding to the numerical device id. in_fs_metadata - device is in the list of fs metadata missing - device is missing (no device node or block device) replace_target - device is target of replace writeable - writes from fs are allowed These attributes reflect the state of the device::dev_state and created at mount time. Sample output: $ pwd /sys/fs/btrfs/6e1961f1-5918-4ecc-a22f-948897b409f7/devinfo/1/ $ ls in_fs_metadata missing replace_target writeable $ cat missing 0 The output from these attributes are 0 or 1. 0 indicates unset and 1 indicates set. These attributes are readonly. It is observed that the device delete thread and sysfs read thread will not race because the delete thread calls sysfs kobject_put() which in turn waits for existing sysfs read to complete. Note for device replace devid swap: During the replace the target device temporarily assumes devid 0 before assigning the devid of the soruce device. In btrfs_dev_replace_finishing() we remove source sysfs devid using the function btrfs_sysfs_remove_devices_attr(), so after that call kobject_rename() to update the devid in the sysfs. This adds and calls btrfs_sysfs_update_devid() helper function to update the device id. Signed-off-by: Anand Jain Reviewed-by: David Sterba [ update changelog ] Signed-off-by: David Sterba

btrfs: keep track of discard reuse stats

2020-01-20T15:41:00Z

Keep track of how much we are discarding and how often we are reusing with async discard. The discard_*_bytes values don't need any special protection because the work item provides the single threaded access. Reviewed-by: Josef Bacik Signed-off-by: Dennis Zhou Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: make max async discard size tunable

2020-01-20T15:40:59Z

Expose max_discard_size as a tunable via sysfs and switch the current fixed maximum to the default value. Signed-off-by: Dennis Zhou Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add kbps discard rate limit for async discard

2020-01-20T15:40:59Z

Provide the ability to rate limit based on kbps in addition to iops as additional guides for the target discard rate. The delay used ends up being max(kbps_delay, iops_delay). Signed-off-by: Dennis Zhou Reviewed-by: David Sterba Signed-off-by: David Sterba