Aren/haiku
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

nvme_disk: Protect against simultaneous writes to "rounded" blocks.

Browse Source 
May help with some of the stranger NVMe KDL tickets.
This commit is contained in:
Augustin Cavalier 2020-03-07 17:41:35 -05:00
parent f87a7ab0f7
commit cbdbe1cf43
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/add-ons/kernel/drivers/disk/nvme/nvme_disk.cpp
View File

@ -92,6 +92,8 @@ typedef struct {
uint32 qpair_count;
uint32 next_qpair;
rw_lock rounded_write_lock;
ConditionVariable interrupt;
} nvme_disk_driver_info;
typedef nvme_disk_driver_info::qpair_info qpair_info;
@ -244,6 +246,9 @@ nvme_disk_init_device(void* _info, void** _cookie)
return B_NO_MEMORY;
}
// set up rounded-write lock
rw_lock_init(&info->rounded_write_lock, "nvme rounded writes");
// set up interrupt
if (get_module(B_PCI_X86_MODULE_NAME, (module_info**)&sPCIx86Module)
!= B_OK) {
@ -307,6 +312,8 @@ nvme_disk_uninit_device(void* _cookie)
remove_io_interrupt_handler(info->info.u.h0.interrupt_line,
nvme_interrupt_handler, (void*)info);
rw_lock_destroy(&info->rounded_write_lock);
nvme_ns_close(info->ns);
nvme_ctrlr_close(info->ctrlr);
@ -500,6 +507,15 @@ nvme_disk_write(void* cookie, off_t pos, const void* buffer, size_t* length)
return B_NO_MEMORY;
}
// If we rounded, we must protect against simulaneous writes inside
// the rounded blocks, as otherwise data corruption would occur.
WriteLocker writeLocker;
ReadLocker readLocker;
if (rounded_pos != pos || rounded_len != *length)
writeLocker.SetTo(handle->info->rounded_write_lock, false);
else
readLocker.SetTo(handle->info->rounded_write_lock, false);
// Since we rounded, we need to read in the first and last logical
// blocks before we copy our information to the bounce buffer.
// TODO: This would be faster if we queued both reads at once!
@ -543,6 +559,8 @@ nvme_disk_write(void* cookie, off_t pos, const void* buffer, size_t* length)
return status;
}
ReadLocker _(handle->info->rounded_write_lock);
// If we got here, that means the arguments are already rounded to LBAs,
// so just do the I/O directly.
return do_nvme_io(handle->info, pos, (void*)buffer, length, true);