Skip to main content

Browse the archive

Revision 4860abb91f3d7fbaf8147d54782149bb1fc45892 authored by Steve French on 06 February 2024, 22:34:22 UTC, committed by Steve French on 16 February 2024, 04:19:23 UTC 
smb: Fix regression in writes when non-standard maximum write size negotiated
 
The conversion to netfs in the 6.3 kernel caused a regression when
maximum write size is set by the server to an unexpected value which is
not a multiple of 4096 (similarly if the user overrides the maximum
write size by setting mount parm "wsize", but sets it to a value that
is not a multiple of 4096).  When negotiated write size is not a
multiple of 4096 the netfs code can skip the end of the final
page when doing large sequential writes, causing data corruption.

This section of code is being rewritten/removed due to a large
netfs change, but until that point (ie for the 6.3 kernel until now)
we can not support non-standard maximum write sizes.

Add a warning if a user specifies a wsize on mount that is not
a multiple of 4096 (and round down), also add a change where we
round down the maximum write size if the server negotiates a value
that is not a multiple of 4096 (we also have to check to make sure that
we do not round it down to zero).

Reported-by: R. Diez" <rdiez-2006@rd10.de>
Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Suggested-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Acked-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Tested-by: Matthew Ruffell <matthew.ruffell@canonical.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # v6.3+
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
1 parent 8bde59b
Raw File
bucket_locks.c 
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

/* Allocate an array of spinlocks to be accessed by a hash. Two arguments
 * indicate the number of elements to allocate in the array. max_size
 * gives the maximum number of elements to allocate. cpu_mult gives
 * the number of locks per CPU to allocate. The size is rounded up
 * to a power of 2 to be suitable as a hash table.
 */

int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *locks_mask,
			     size_t max_size, unsigned int cpu_mult, gfp_t gfp,
			     const char *name, struct lock_class_key *key)
{
	spinlock_t *tlocks = NULL;
	unsigned int i, size;
#if defined(CONFIG_PROVE_LOCKING)
	unsigned int nr_pcpus = 2;
#else
	unsigned int nr_pcpus = num_possible_cpus();
#endif

	if (cpu_mult) {
		nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
		size = min_t(unsigned int, nr_pcpus * cpu_mult, max_size);
	} else {
		size = max_size;
	}

	if (sizeof(spinlock_t) != 0) {
		tlocks = kvmalloc_array(size, sizeof(spinlock_t), gfp);
		if (!tlocks)
			return -ENOMEM;
		for (i = 0; i < size; i++) {
			spin_lock_init(&tlocks[i]);
			lockdep_init_map(&tlocks[i].dep_map, name, key, 0);
		}
	}

	*locks = tlocks;
	*locks_mask = size - 1;

	return 0;
}
EXPORT_SYMBOL(__alloc_bucket_spinlocks);

void free_bucket_spinlocks(spinlock_t *locks)
{
	kvfree(locks);
}
EXPORT_SYMBOL(free_bucket_spinlocks);
back to top