kernel.git/fs/cifs/misc.c, branch linux-4.12.y

CIFS: check if pages is null rather than bv for a failed allocation

2017-06-21T00:11:35Z

pages is being allocated however a null check on bv is being used to see if the allocation failed. Fix this by checking if pages is null. Detected by CoverityScan, CID#1432974 ("Logically dead code") Fixes: ccf7f4088af2dd ("CIFS: Add asynchronous context to support kernel AIO") Signed-off-by: Colin Ian King Reviewed-by: Pavel Shilovsky Signed-off-by: Steve French

CIFS: fix oplock break deadlocks

2017-05-03T15:10:10Z

When the final cifsFileInfo_put() is called from cifsiod and an oplock break work is queued, lockdep complains loudly: ============================================= [ INFO: possible recursive locking detected ] 4.11.0+ #21 Not tainted --------------------------------------------- kworker/0:2/78 is trying to acquire lock: ("cifsiod"){++++.+}, at: flush_work+0x215/0x350 but task is already holding lock: ("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock("cifsiod"); lock("cifsiod"); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by kworker/0:2/78: #0: ("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0 #1: ((&wdata->work)){+.+...}, at: process_one_work+0x255/0x8e0 stack backtrace: CPU: 0 PID: 78 Comm: kworker/0:2 Not tainted 4.11.0+ #21 Workqueue: cifsiod cifs_writev_complete Call Trace: dump_stack+0x85/0xc2 __lock_acquire+0x17dd/0x2260 ? match_held_lock+0x20/0x2b0 ? trace_hardirqs_off_caller+0x86/0x130 ? mark_lock+0xa6/0x920 lock_acquire+0xcc/0x260 ? lock_acquire+0xcc/0x260 ? flush_work+0x215/0x350 flush_work+0x236/0x350 ? flush_work+0x215/0x350 ? destroy_worker+0x170/0x170 __cancel_work_timer+0x17d/0x210 ? ___preempt_schedule+0x16/0x18 cancel_work_sync+0x10/0x20 cifsFileInfo_put+0x338/0x7f0 cifs_writedata_release+0x2a/0x40 ? cifs_writedata_release+0x2a/0x40 cifs_writev_complete+0x29d/0x850 ? preempt_count_sub+0x18/0xd0 process_one_work+0x304/0x8e0 worker_thread+0x9b/0x6a0 kthread+0x1b2/0x200 ? process_one_work+0x8e0/0x8e0 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x31/0x40 This is a real warning. Since the oplock is queued on the same workqueue this can deadlock if there is only one worker thread active for the workqueue (which will be the case during memory pressure when the rescuer thread is handling it). Furthermore, there is at least one other kind of hang possible due to the oplock break handling if there is only worker. (This can be reproduced without introducing memory pressure by having passing 1 for the max_active parameter of cifsiod.) cifs_oplock_break() can wait indefintely in the filemap_fdatawait() while the cifs_writev_complete() work is blocked: sysrq: SysRq : Show Blocked State task PC stack pid father kworker/0:1 D 0 16 2 0x00000000 Workqueue: cifsiod cifs_oplock_break Call Trace: __schedule+0x562/0xf40 ? mark_held_locks+0x4a/0xb0 schedule+0x57/0xe0 io_schedule+0x21/0x50 wait_on_page_bit+0x143/0x190 ? add_to_page_cache_lru+0x150/0x150 __filemap_fdatawait_range+0x134/0x190 ? do_writepages+0x51/0x70 filemap_fdatawait_range+0x14/0x30 filemap_fdatawait+0x3b/0x40 cifs_oplock_break+0x651/0x710 ? preempt_count_sub+0x18/0xd0 process_one_work+0x304/0x8e0 worker_thread+0x9b/0x6a0 kthread+0x1b2/0x200 ? process_one_work+0x8e0/0x8e0 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x31/0x40 dd D 0 683 171 0x00000000 Call Trace: __schedule+0x562/0xf40 ? mark_held_locks+0x29/0xb0 schedule+0x57/0xe0 io_schedule+0x21/0x50 wait_on_page_bit+0x143/0x190 ? add_to_page_cache_lru+0x150/0x150 __filemap_fdatawait_range+0x134/0x190 ? do_writepages+0x51/0x70 filemap_fdatawait_range+0x14/0x30 filemap_fdatawait+0x3b/0x40 filemap_write_and_wait+0x4e/0x70 cifs_flush+0x6a/0xb0 filp_close+0x52/0xa0 __close_fd+0xdc/0x150 SyS_close+0x33/0x60 entry_SYSCALL_64_fastpath+0x1f/0xbe Showing all locks held in the system: 2 locks held by kworker/0:1/16: #0: ("cifsiod"){.+.+.+}, at: process_one_work+0x255/0x8e0 #1: ((&cfile->oplock_break)){+.+.+.}, at: process_one_work+0x255/0x8e0 Showing busy workqueues and worker pools: workqueue cifsiod: flags=0xc pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1 in-flight: 16:cifs_oplock_break delayed: cifs_writev_complete, cifs_echo_request pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 750 3 Fix these problems by creating a a new workqueue (with a rescuer) for the oplock break work. Signed-off-by: Rabin Vincent Signed-off-by: Steve French CC: Stable

CIFS: Add asynchronous context to support kernel AIO

2017-05-02T19:57:34Z

Currently the code doesn't recognize asynchronous calls passed by io_submit() and processes all calls synchronously. This is not what kernel AIO expects. This patch introduces a new async context that keeps track of all issued i/o requests and moves a response collecting procedure to a separate thread. This allows to return to a caller immediately for async calls and call iocb->ki_complete() once all requests are completed. For sync calls the current thread simply waits until all requests are completed. Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French

cifs: don't check for failure from mempool_alloc()

2017-04-28T12:56:33Z

mempool_alloc() cannot fail if the gfp flags allow it to sleep, and both GFP_FS allows for sleeping. So these tests of the return value from mempool_alloc() cannot be needed. Signed-off-by: NeilBrown Signed-off-by: Steve French

CIFS: move DFS response parsing out of SMB1 code

2017-03-02T04:26:10Z

since the DFS payload is not tied to the SMB version we can: * isolate the DFS payload in its own struct, and include that struct in packet structs * move the function that parses the response to misc.c and make it work on the new DFS payload struct (add payload size and utf16 flag as a result). Signed-off-by: Aurelien Aptel Acked-by: Pavel Shilovsky Signed-off-by: Steve French

Clarify locking of cifs file and tcon structures and make more granular

2016-10-12T17:08:32Z

Remove the global file_list_lock to simplify cifs/smb3 locking and have spinlocks that more closely match the information they are protecting. Add new tcon->open_file_lock and file->file_info_lock spinlocks. Locks continue to follow a heirachy, cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file where global tcp_ses_lock still protects socket and cifs_ses, while the the newer locks protect the lower level structure's information (tcon and cifs_file respectively). CC: Stable Signed-off-by: Steve French Signed-off-by: Pavel Shilovsky Reviewed-by: Aurelien Aptel Reviewed-by: Germano Percossi

Prepare for encryption support (first part). Add decryption and encryption key generation. Thanks to Metze for helping with this.

2016-01-14T20:29:42Z

Reviewed-by: Stefan Metzmacher Signed-off-by: Steve French

VFS: normal filesystems (and lustre): d_inode() annotations

2015-04-15T19:06:57Z

that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells Signed-off-by: Al Viro

cifs: convert to print_hex_dump() instead of custom implementation

2014-12-08T04:48:01Z

This patch converts custom dumper to use native print_hex_dump() instead. The cifs_dump_mem() will have an offsets per each line which differs it from the original code. In the dump_smb() we may use native print_hex_dump() as well. It will show slightly different output in ASCII part when character is unprintable, otherwise it keeps same structure. Signed-off-by: Andy Shevchenko Signed-off-by: Steve French

cifs: remove unused function cifs_oplock_break_wait

2014-08-11T06:31:03Z

Commit 743162013d40 ("sched: Remove proliferation of wait_on_bit() action functions") has removed the call to cifs_oplock_break_wait, making this function unused; remove it. This fixes the following compilation warning: fs/cifs/misc.c:578:1: warning: ‘cifs_oplock_break_wait’ defined but not used [-Wunused-function] Signed-off-by: Vincent Stehlé Cc: Steve French Signed-off-by: Steve French