- 28 May, 2018 40 commits
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David Sterba authored
The parameter controls locking of the stats part but we can lock it unconditionally, as this only happens once when balance starts. This is not performance critical. Add the prefix for an exported function. Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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David Sterba authored
Balance cannot be started on a read-only filesystem and will have to finish/exit before eg. going to read-only via remount. In case the filesystem is forcibly set to read-only after an error, balance will finish anyway and if the cancel call is too fast it will just wait for that to happen. The last case is when the balance is paused after mount but it's read-only and cancelling would want to delete the item. The test is moved after the check if balance is running at all, as it looks more logical to report "no balance running" instead of "read-only filesystem". Reviewed-by:
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David Sterba authored
Currently fs_info::balance_running is 0 or 1 and does not use the semantics of atomics. The pause and cancel check for 0, that can happen only after __btrfs_balance exits for whatever reason. Parallel calls to balance ioctl may enter btrfs_ioctl_balance multiple times but will block on the balance_mutex that protects the fs_info::flags bit. Reviewed-by:
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David Sterba authored
Mutual exclusion of device add/rm and balance was done by the volume mutex up to version 3.7. The commit 5ac00add ("Btrfs: disallow mutually exclusive admin operations from user mode") added a bit that essentially tracked the same information. The status bit has an advantage over a mutex that it can be set without restrictions of function context, so it started to be used in the mount-time resuming of balance or device replace. But we don't really need to track the same information in two ways. 1) After the previous cleanups, the main ioctl handlers for add/del/resize copy the EXCL_OP bit next to the volume mutex, here it's clearly safe. 2) Resuming balance during mount or after rw remount will set only the EXCL_OP bit and the volume_mutex is held in the kernel thread that calls btrfs_balance. 3) Resuming device replace during mount or after rw remount is done after balance and is excluded by the EXCL_OP bit. It does not take the volume_mutex at all and completely relies on the EXCL_OP bit. 4) The resuming of balance and dev-replace cannot hapen at the same time as the ioctls cannot be started in parallel. Nevertheless, a crafted image could trigger that and a warning is printed. 5) Balance is normally excluded by EXCL_OP and also uses own mutex to protect against concurrent access to its status data. There's some trickery to maintain the right lock nesting in case we need to reexamine the status in btrfs_ioctl_balance. The volume_mutex is removed and the unlock/lock sequence is left in place as we might expect other waiters to proceed. 6) Similar to 5, the unlock/lock sequence is kept in btrfs_cancel_balance to allow waiters to continue. Reviewed-by:
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David Sterba authored
The volume mutex does not protect against anything in this case, the comment about scrub is right but not related to locking and looks confusing. The comment in btrfs_find_device_missing_or_by_path is wrong and confusing too. The device_list_mutex is not held here to protect device lookup, but in this case device replace cannot run in parallel with device removal (due to exclusive op protection), so we don't need further locking here. Reviewed-by:
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David Sterba authored
The function __cancel_balance name is confusing with the cancel operation of balance and it really resets the state of balance back to zero. The unset_balance_control helper is called only from one place and simple enough to be inlined. Reviewed-by:
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David Sterba authored
Replace a WARN_ON with a proper check and message in case something goes really wrong and resumed balance cannot set up its exclusive status. The check is a user friendly assertion, I don't expect to ever happen under normal circumstances. Also document that the paused balance starts here and owns the exclusive op status. Reviewed-by:
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David Sterba authored
The device replace is paused by unmount or read only remount, and resumed on next mount or write remount. The exclusive status should be checked properly as it's a global invariant and we must not allow 2 operations run. In this case, the balance can be also paused and resumed under same conditions. It's always checked first so dev-replace could see the EXCL_OP already taken, BUT, the ioctl would never let start both at the same time. Replace the WARN_ON with message and return 0, indicating no error as this is purely theoretical and the user will be informed. Resolving that manually should be possible by waiting for the other operation to finish or cancel the paused state. Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Signed-off-by:
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David Sterba authored
Make the clearning visible in the callers so we can pair it with the test_and_set part. Signed-off-by: -
David Sterba authored
Move locking and unlocking next to the BTRFS_FS_EXCL_OP bit manipulation so it's obvious that the two happen at the same time. Reviewed-by:
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David Sterba authored
The function logically belongs there and there's only a single caller, no need to export it. No code changes. Reviewed-by:
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David Sterba authored
The function will be used outside of volumes.c, the allocation btrfs_alloc_device is also exported. Reviewed-by:
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David Sterba authored
This is a preparatory cleanup that will make clear that the only successful way out of btrfs_init_dev_replace_tgtdev will also set the device_out to a valid pointer. With this guarantee, the callers can be simplified. Reviewed-by:
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David Sterba authored
The function is called once and is fairly small, we can merge it with the caller. Reviewed-by:
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Anand Jain authored
This function uses fs_info::fs_devices number of time, however we declare and use it only at the end, instead do it in the beginning of the function and use it. Signed-off-by:
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Anand Jain authored
find_device() declares struct list_head *head pointer and used only once, instead just use it directly. Signed-off-by:
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Anand Jain authored
__btrfs_open_devices() is un-exported drop __ prefix and rename it to open_fs_devices(). Signed-off-by:
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Anand Jain authored
__btrfs_close_devices() is un-exported, drop the __ prefix and rename it to close_fs_devices(). Signed-off-by:
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Anand Jain authored
__btrfs_open_devices() declares struct list_head *head, however head is used only once, instead use btrfs_fs_devices::devices directly. Signed-off-by:
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Anand Jain authored
btrfs_fs_devices::list is the list of BTRFS fsid in the kernel, a generic name 'list' makes it's search very difficult, rename it to fs_list. Signed-off-by:
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Nikolay Borisov authored
It's provided by the transaction handle. Signed-off-by:
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Nikolay Borisov authored
It's provided by the transaction handle. Signed-off-by:
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Nikolay Borisov authored
It's provided by the transaction handle. Signed-off-by:
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Nikolay Borisov authored
This function is called from only 1 place and is effectively a wrapper over wait_completion/kfree. It doesn't really bring any value having those two calls in a separate function. Just open code it and remove it. No functional changes. Signed-off-by:
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Nikolay Borisov authored
It can be directly referenced from the passed address_space so do that. No functional changes. Signed-off-by:
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Nikolay Borisov authored
list_empty_careful usually is a signal of something tricky going on. Its usage in btrfs is actually not needed since both lists it's used on are local to a function and cannot be modified concurrently. So switch to plain list_empty. No functional changes. Signed-off-by:
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Nikolay Borisov authored
This function is called only from btrfs_readpage and is already passed the mapping. Simplify its signature by moving the code obtaining reference to the extent tree in the function. No functional changes. Signed-off-by:
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Nikolay Borisov authored
It's not used in the function so just remove it. No functional changes. Signed-off-by:
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Nikolay Borisov authored
This function already gets the page from which the two extent trees are referenced. Simplify its signature by moving the code getting the trees inside the function. No functional changes. Signed-off-by:
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Misono Tomohiro authored
Change the behavior of rmdir(2) and allow it to delete an empty subvolume by using btrfs_delete_subvolume() which is used by btrfs_ioctl_snap_destroy(). This is a change in behaviour and has been requested by users. Deleting the subvolume by ioctl requires root permissions while the rmdir way does works with standard tools and syscalls for all users that can access the subvolume. The main usecase is to allow 'rm -rf /path/with/subvols' to simply work. We were not able to find any nasty usability surprises, the intention is to do the destructive rm. Without allowing rmdir, this would have to be followed by the ioctl subvolume deletion, which is more of an annoyance. Implementation details: The required lock for @dir and inode of @dentry is already acquired in vfs layer. We need some check before deleting a subvolume. Permission check is done in vfs layer, emptiness check is in btrfs_rmdir() and additional check (i.e. neither the subvolume is a default subvolume nor send is in progress) is in btrfs_delete_subvolume(). Note that in btrfs_ioctl_snap_destroy(), d_delete() is called after btrfs_delete_subvolume(). For rmdir(2), d_delete() is called in vfs layer later. Tested-by:
Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by:
Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> Reviewed-by:
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Misono Tomohiro authored
Factor out the second half of btrfs_ioctl_snap_destroy() as btrfs_delete_subvolume(), which performs some subvolume specific checks before deletion: 1. send is not in progress 2. the subvolume is not the default subvolume 3. the subvolume does not contain other subvolumes and actual deletion process. btrfs_delete_subvolume() requires inode_lock for both @dir and inode of @dentry. The remaining part of btrfs_ioctl_snap_destroy() is mainly permission checks. Note that call of d_delete() is not included in btrfs_delete_subvolume() as this function will also be used by btrfs_rmdir() to delete an empty subvolume and in that case d_delete() is called in VFS layer. As a result, btrfs_unlink_subvol() and may_destroy_subvol() become static functions. No functional changes. Signed-off-by:
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Misono Tomohiro authored
This is a preparation work to refactor btrfs_ioctl_snap_destroy() and to allow rmdir(2) to delete an empty subvolume. Signed-off-by:
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Howard McLauchlan authored
With commit b18253ec57c0 ("btrfs: optimize free space tree bitmap conversion"), there are no more callers to le_test_bit(). This patch removes le_test_bit(). Signed-off-by:Howard McLauchlan <hmclauchlan@fb.com> Signed-off-by:
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Howard McLauchlan authored
Presently, convert_free_space_to_extents() does a linear scan of the bitmap. We can speed this up with find_next_{bit,zero_bit}_le(). This patch replaces the linear scan with find_next_{bit,zero_bit}_le(). Testing shows a 20-33% decrease in execution time for convert_free_space_to_extents(). Since we change bitmap to be unsigned long, we have to do some casting for the bitmap cursor. In le_bitmap_set() it makes sense to use u8, as we are doing bit operations. Everywhere else, we're just using it for pointer arithmetic and not directly accessing it, so char seems more appropriate. Suggested-by:Omar Sandoval <osandov@osandov.com> Signed-off-by:
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Howard McLauchlan authored
le_bitmap_set() is only used by free-space-tree, so move it there and make it static. le_bitmap_clear() is not used, so remove it. Signed-off-by:
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David Sterba authored
We really want to know to which filesystem the extent map events belong, but as it cannot be reached from the extent_map pointers, we need to pass it down the callchain. Reviewed-by:
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David Sterba authored
Preparatory work to pass fs_info to btrfs_add_extent_mapping so we can get a better tracepoint message. Extent maps do not need fs_info for anything so we only add a dummy one without any other initialization. Reviewed-by:
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David Sterba authored
Most of the strings are prefixed by the UUID of the filesystem that generates the message, however there are a few events that still opencode the macro magic and can be converted to the common macros. Reviewed-by:
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David Sterba authored
The preferred style is to avoid spaces between key and value and no commas between key=values. Reviewed-by:
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David Sterba authored
The (unsigned long long) casts are not necessary since long ago. Reviewed-by:
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