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btrfs: dev-replace: avoid useless lock on error handling path

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The exit sequence in btrfs_dev_replace_start does not allow to simply
add a label to the right place so the error handling after starting
transaction failure jumps there. Currently there's a lock that pairs
with the unlock in the section, which is unnecessary and only raises
questions.  Add a variable to track the locking status and avoid the
extra locking.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba
2018-08-24 17:44:05 +02:00
parent 9f6cbcbb09
commit aa144bfeaa
1 changed files with 6 additions and 1 deletions
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5
fs/btrfs/dev-replace.c
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@@ -400,6 +400,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
int ret; int ret;
struct btrfs_device *tgt_device = NULL; struct btrfs_device *tgt_device = NULL;
struct btrfs_device *src_device = NULL; struct btrfs_device *src_device = NULL;
bool need_unlock;
src_device = btrfs_find_device_by_devspec(fs_info, srcdevid, src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
srcdev_name); srcdev_name);
@@ -424,6 +425,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
return PTR_ERR(trans); return PTR_ERR(trans);
} }
need_unlock = true;
btrfs_dev_replace_write_lock(dev_replace); btrfs_dev_replace_write_lock(dev_replace);
switch (dev_replace->replace_state) { switch (dev_replace->replace_state) {
case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
@@ -463,6 +465,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
atomic64_set(&dev_replace->num_write_errors, 0); atomic64_set(&dev_replace->num_write_errors, 0);
atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0); atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
btrfs_dev_replace_write_unlock(dev_replace); btrfs_dev_replace_write_unlock(dev_replace);
need_unlock = false;
ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device); ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
if (ret) if (ret)
@@ -474,6 +477,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
trans = btrfs_start_transaction(root, 0); trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) { if (IS_ERR(trans)) {
ret = PTR_ERR(trans); ret = PTR_ERR(trans);
need_unlock = true;
btrfs_dev_replace_write_lock(dev_replace); btrfs_dev_replace_write_lock(dev_replace);
dev_replace->replace_state = dev_replace->replace_state =
BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED; BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
@@ -500,6 +504,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
return ret; return ret;
leave: leave:
if (need_unlock)
btrfs_dev_replace_write_unlock(dev_replace); btrfs_dev_replace_write_unlock(dev_replace);
btrfs_destroy_dev_replace_tgtdev(tgt_device); btrfs_destroy_dev_replace_tgtdev(tgt_device);
return ret; return ret;