return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
}
-/*
- * Page Region interfaces.
- *
- * For pages in filesystems where the blocksize is smaller than the
- * pagesize, we use the page->private field (long) to hold a bitmap
- * of uptodate regions within the page.
- *
- * Each such region is "bytes per page / bits per long" bytes long.
- *
- * NBPPR == number-of-bytes-per-page-region
- * BTOPR == bytes-to-page-region (rounded up)
- * BTOPRT == bytes-to-page-region-truncated (rounded down)
- */
-#if (BITS_PER_LONG == 32)
-#define PRSHIFT (PAGE_CACHE_SHIFT - 5) /* (32 == 1<<5) */
-#elif (BITS_PER_LONG == 64)
-#define PRSHIFT (PAGE_CACHE_SHIFT - 6) /* (64 == 1<<6) */
-#else
-#error BITS_PER_LONG must be 32 or 64
-#endif
-#define NBPPR (PAGE_CACHE_SIZE/BITS_PER_LONG)
-#define BTOPR(b) (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT)
-#define BTOPRT(b) (((unsigned int)(b) >> PRSHIFT))
-
-STATIC unsigned long
-page_region_mask(
- size_t offset,
- size_t length)
-{
- unsigned long mask;
- int first, final;
-
- first = BTOPR(offset);
- final = BTOPRT(offset + length - 1);
- first = min(first, final);
-
- mask = ~0UL;
- mask <<= BITS_PER_LONG - (final - first);
- mask >>= BITS_PER_LONG - (final);
-
- ASSERT(offset + length <= PAGE_CACHE_SIZE);
- ASSERT((final - first) < BITS_PER_LONG && (final - first) >= 0);
-
- return mask;
-}
-
-STATIC void
-set_page_region(
- struct page *page,
- size_t offset,
- size_t length)
-{
- set_page_private(page,
- page_private(page) | page_region_mask(offset, length));
- if (page_private(page) == ~0UL)
- SetPageUptodate(page);
-}
-
-STATIC int
-test_page_region(
- struct page *page,
- size_t offset,
- size_t length)
-{
- unsigned long mask = page_region_mask(offset, length);
-
- return (mask && (page_private(page) & mask) == mask);
-}
-
/*
* xfs_buf_lru_add - add a buffer to the LRU.
*
ASSERT(list_empty(&bp->b_lru));
- if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) {
+ if (bp->b_flags & _XBF_PAGES) {
uint i;
if (xfs_buf_is_vmapped(bp))
for (i = 0; i < bp->b_page_count; i++) {
struct page *page = bp->b_pages[i];
- if (bp->b_flags & _XBF_PAGE_CACHE)
- ASSERT(!PagePrivate(page));
- page_cache_release(page);
+ __free_page(page);
}
- }
+ } else if (bp->b_flags & _XBF_KMEM)
+ kmem_free(bp->b_addr);
_xfs_buf_free_pages(bp);
xfs_buf_deallocate(bp);
}
/*
- * Finds all pages for buffer in question and builds it's page list.
+ * Allocates all the pages for buffer in question and builds it's page list.
*/
STATIC int
-_xfs_buf_lookup_pages(
+xfs_buf_allocate_memory(
xfs_buf_t *bp,
uint flags)
{
- struct address_space *mapping = bp->b_target->bt_mapping;
- size_t blocksize = bp->b_target->bt_bsize;
size_t size = bp->b_count_desired;
size_t nbytes, offset;
gfp_t gfp_mask = xb_to_gfp(flags);
xfs_off_t end;
int error;
+ /*
+ * for buffers that are contained within a single page, just allocate
+ * the memory from the heap - there's no need for the complexity of
+ * page arrays to keep allocation down to order 0.
+ */
+ if (bp->b_buffer_length < PAGE_SIZE) {
+ bp->b_addr = kmem_alloc(bp->b_buffer_length, xb_to_km(flags));
+ if (!bp->b_addr) {
+ /* low memory - use alloc_page loop instead */
+ goto use_alloc_page;
+ }
+
+ if (((unsigned long)(bp->b_addr + bp->b_buffer_length - 1) &
+ PAGE_MASK) !=
+ ((unsigned long)bp->b_addr & PAGE_MASK)) {
+ /* b_addr spans two pages - use alloc_page instead */
+ kmem_free(bp->b_addr);
+ bp->b_addr = NULL;
+ goto use_alloc_page;
+ }
+ bp->b_offset = offset_in_page(bp->b_addr);
+ bp->b_pages = bp->b_page_array;
+ bp->b_pages[0] = virt_to_page(bp->b_addr);
+ bp->b_page_count = 1;
+ bp->b_flags |= XBF_MAPPED | _XBF_KMEM;
+ return 0;
+ }
+
+use_alloc_page:
end = bp->b_file_offset + bp->b_buffer_length;
page_count = xfs_buf_btoc(end) - xfs_buf_btoct(bp->b_file_offset);
-
error = _xfs_buf_get_pages(bp, page_count, flags);
if (unlikely(error))
return error;
- bp->b_flags |= _XBF_PAGE_CACHE;
offset = bp->b_offset;
- first = bp->b_file_offset >> PAGE_CACHE_SHIFT;
+ first = bp->b_file_offset >> PAGE_SHIFT;
+ bp->b_flags |= _XBF_PAGES;
for (i = 0; i < bp->b_page_count; i++) {
struct page *page;
uint retries = 0;
-
- retry:
- page = find_or_create_page(mapping, first + i, gfp_mask);
+retry:
+ page = alloc_page(gfp_mask);
if (unlikely(page == NULL)) {
if (flags & XBF_READ_AHEAD) {
bp->b_page_count = i;
- for (i = 0; i < bp->b_page_count; i++)
- unlock_page(bp->b_pages[i]);
- return -ENOMEM;
+ error = ENOMEM;
+ goto out_free_pages;
}
/*
XFS_STATS_INC(xb_page_found);
- nbytes = min_t(size_t, size, PAGE_CACHE_SIZE - offset);
+ nbytes = min_t(size_t, size, PAGE_SIZE - offset);
size -= nbytes;
-
- ASSERT(!PagePrivate(page));
- if (!PageUptodate(page)) {
- page_count--;
- if (blocksize >= PAGE_CACHE_SIZE) {
- if (flags & XBF_READ)
- bp->b_flags |= _XBF_PAGE_LOCKED;
- } else if (!PagePrivate(page)) {
- if (test_page_region(page, offset, nbytes))
- page_count++;
- }
- }
-
bp->b_pages[i] = page;
offset = 0;
}
+ return 0;
- if (!(bp->b_flags & _XBF_PAGE_LOCKED)) {
- for (i = 0; i < bp->b_page_count; i++)
- unlock_page(bp->b_pages[i]);
- }
-
- if (page_count == bp->b_page_count)
- bp->b_flags |= XBF_DONE;
-
+out_free_pages:
+ for (i = 0; i < bp->b_page_count; i++)
+ __free_page(bp->b_pages[i]);
return error;
}
xfs_buf_t *bp,
uint flags)
{
- /* A single page buffer is always mappable */
+ ASSERT(bp->b_flags & _XBF_PAGES);
if (bp->b_page_count == 1) {
+ /* A single page buffer is always mappable */
bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
bp->b_flags |= XBF_MAPPED;
} else if (flags & XBF_MAPPED) {
- bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
- -1, PAGE_KERNEL);
- if (unlikely(bp->b_addr == NULL))
+ int retried = 0;
+
+ do {
+ bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
+ -1, PAGE_KERNEL);
+ if (bp->b_addr)
+ break;
+ vm_unmap_aliases();
+ } while (retried++ <= 1);
+
+ if (!bp->b_addr)
return -ENOMEM;
bp->b_addr += bp->b_offset;
bp->b_flags |= XBF_MAPPED;
}
}
+ /*
+ * if the buffer is stale, clear all the external state associated with
+ * it. We need to keep flags such as how we allocated the buffer memory
+ * intact here.
+ */
if (bp->b_flags & XBF_STALE) {
ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
- bp->b_flags &= XBF_MAPPED;
+ bp->b_flags &= XBF_MAPPED | _XBF_KMEM | _XBF_PAGES;
}
trace_xfs_buf_find(bp, flags, _RET_IP_);
xfs_buf_flags_t flags)
{
xfs_buf_t *bp, *new_bp;
- int error = 0, i;
+ int error = 0;
new_bp = xfs_buf_allocate(flags);
if (unlikely(!new_bp))
bp = _xfs_buf_find(target, ioff, isize, flags, new_bp);
if (bp == new_bp) {
- error = _xfs_buf_lookup_pages(bp, flags);
+ error = xfs_buf_allocate_memory(bp, flags);
if (error)
goto no_buffer;
} else {
return NULL;
}
- for (i = 0; i < bp->b_page_count; i++)
- mark_page_accessed(bp->b_pages[i]);
-
if (!(bp->b_flags & XBF_MAPPED)) {
error = _xfs_buf_map_pages(bp, flags);
if (unlikely(error)) {
{
struct backing_dev_info *bdi;
- bdi = target->bt_mapping->backing_dev_info;
- if (bdi_read_congested(bdi))
+ if (bdi_read_congested(target->bt_bdi))
return;
xfs_buf_read(target, ioff, isize,
size_t buflen;
int page_count;
- pageaddr = (unsigned long)mem & PAGE_CACHE_MASK;
+ pageaddr = (unsigned long)mem & PAGE_MASK;
offset = (unsigned long)mem - pageaddr;
- buflen = PAGE_CACHE_ALIGN(len + offset);
- page_count = buflen >> PAGE_CACHE_SHIFT;
+ buflen = PAGE_ALIGN(len + offset);
+ page_count = buflen >> PAGE_SHIFT;
/* Free any previous set of page pointers */
if (bp->b_pages)
for (i = 0; i < bp->b_page_count; i++) {
bp->b_pages[i] = mem_to_page((void *)pageaddr);
- pageaddr += PAGE_CACHE_SIZE;
+ pageaddr += PAGE_SIZE;
}
bp->b_count_desired = len;
bp->b_buffer_length = buflen;
bp->b_flags |= XBF_MAPPED;
- bp->b_flags &= ~_XBF_PAGE_LOCKED;
return 0;
}
/*
- * Mutual exclusion on buffers. Locking model:
- *
- * Buffers associated with inodes for which buffer locking
- * is not enabled are not protected by semaphores, and are
- * assumed to be exclusively owned by the caller. There is a
- * spinlock in the buffer, used by the caller when concurrent
- * access is possible.
- */
-
-/*
- * Locks a buffer object, if it is not already locked. Note that this in
- * no way locks the underlying pages, so it is only useful for
- * synchronizing concurrent use of buffer objects, not for synchronizing
- * independent access to the underlying pages.
+ * Lock a buffer object, if it is not already locked.
*
* If we come across a stale, pinned, locked buffer, we know that we are
* being asked to lock a buffer that has been reallocated. Because it is
}
/*
- * Locks a buffer object.
- * Note that this in no way locks the underlying pages, so it is only
- * useful for synchronizing concurrent use of buffer objects, not for
- * synchronizing independent access to the underlying pages.
+ * Lock a buffer object.
*
* If we come across a stale, pinned, locked buffer, we know that we
* are being asked to lock a buffer that has been reallocated. Because
xfs_buf_t *bp,
int schedule)
{
- if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
- bp->b_flags &= ~_XBF_PAGE_LOCKED;
+ if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
xfs_buf_ioend(bp, schedule);
- }
}
STATIC void
int error)
{
xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private;
- unsigned int blocksize = bp->b_target->bt_bsize;
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
xfs_buf_ioerror(bp, -error);
if (!error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
- do {
- struct page *page = bvec->bv_page;
-
- ASSERT(!PagePrivate(page));
- if (unlikely(bp->b_error)) {
- if (bp->b_flags & XBF_READ)
- ClearPageUptodate(page);
- } else if (blocksize >= PAGE_CACHE_SIZE) {
- SetPageUptodate(page);
- } else if (!PagePrivate(page) &&
- (bp->b_flags & _XBF_PAGE_CACHE)) {
- set_page_region(page, bvec->bv_offset, bvec->bv_len);
- }
-
- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
-
- if (bp->b_flags & _XBF_PAGE_LOCKED)
- unlock_page(page);
- } while (bvec >= bio->bi_io_vec);
-
_xfs_buf_ioend(bp, 1);
bio_put(bio);
}
int offset = bp->b_offset;
int size = bp->b_count_desired;
sector_t sector = bp->b_bn;
- unsigned int blocksize = bp->b_target->bt_bsize;
total_nr_pages = bp->b_page_count;
map_i = 0;
(bp->b_flags & XBF_READ_AHEAD) ? READA : READ;
}
- /* Special code path for reading a sub page size buffer in --
- * we populate up the whole page, and hence the other metadata
- * in the same page. This optimization is only valid when the
- * filesystem block size is not smaller than the page size.
- */
- if ((bp->b_buffer_length < PAGE_CACHE_SIZE) &&
- ((bp->b_flags & (XBF_READ|_XBF_PAGE_LOCKED)) ==
- (XBF_READ|_XBF_PAGE_LOCKED)) &&
- (blocksize >= PAGE_CACHE_SIZE)) {
- bio = bio_alloc(GFP_NOIO, 1);
-
- bio->bi_bdev = bp->b_target->bt_bdev;
- bio->bi_sector = sector - (offset >> BBSHIFT);
- bio->bi_end_io = xfs_buf_bio_end_io;
- bio->bi_private = bp;
-
- bio_add_page(bio, bp->b_pages[0], PAGE_CACHE_SIZE, 0);
- size = 0;
-
- atomic_inc(&bp->b_io_remaining);
-
- goto submit_io;
- }
next_chunk:
atomic_inc(&bp->b_io_remaining);
bio->bi_end_io = xfs_buf_bio_end_io;
bio->bi_private = bp;
+
for (; size && nr_pages; nr_pages--, map_i++) {
- int rbytes, nbytes = PAGE_CACHE_SIZE - offset;
+ int rbytes, nbytes = PAGE_SIZE - offset;
if (nbytes > size)
nbytes = size;
total_nr_pages--;
}
-submit_io:
if (likely(bio->bi_size)) {
if (xfs_buf_is_vmapped(bp)) {
flush_kernel_vmap_range(bp->b_addr,
if (size)
goto next_chunk;
} else {
- /*
- * if we get here, no pages were added to the bio. However,
- * we can't just error out here - if the pages are locked then
- * we have to unlock them otherwise we can hang on a later
- * access to the page.
- */
xfs_buf_ioerror(bp, EIO);
- if (bp->b_flags & _XBF_PAGE_LOCKED) {
- int i;
- for (i = 0; i < bp->b_page_count; i++)
- unlock_page(bp->b_pages[i]);
- }
bio_put(bio);
}
}
return XFS_BUF_PTR(bp) + offset;
offset += bp->b_offset;
- page = bp->b_pages[offset >> PAGE_CACHE_SHIFT];
- return (xfs_caddr_t)page_address(page) + (offset & (PAGE_CACHE_SIZE-1));
+ page = bp->b_pages[offset >> PAGE_SHIFT];
+ return (xfs_caddr_t)page_address(page) + (offset & (PAGE_SIZE-1));
}
/*
page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)];
cpoff = xfs_buf_poff(boff + bp->b_offset);
csize = min_t(size_t,
- PAGE_CACHE_SIZE-cpoff, bp->b_count_desired-boff);
+ PAGE_SIZE-cpoff, bp->b_count_desired-boff);
- ASSERT(((csize + cpoff) <= PAGE_CACHE_SIZE));
+ ASSERT(((csize + cpoff) <= PAGE_SIZE));
switch (mode) {
case XBRW_ZERO:
xfs_flush_buftarg(btp, 1);
if (mp->m_flags & XFS_MOUNT_BARRIER)
xfs_blkdev_issue_flush(btp);
- iput(btp->bt_mapping->host);
kthread_stop(btp->bt_task);
kmem_free(btp);
return EINVAL;
}
- if (verbose &&
- (PAGE_CACHE_SIZE / BITS_PER_LONG) > sectorsize) {
- printk(KERN_WARNING
- "XFS: %u byte sectors in use on device %s. "
- "This is suboptimal; %u or greater is ideal.\n",
- sectorsize, XFS_BUFTARG_NAME(btp),
- (unsigned int)PAGE_CACHE_SIZE / BITS_PER_LONG);
- }
-
return 0;
}
struct block_device *bdev)
{
return xfs_setsize_buftarg_flags(btp,
- PAGE_CACHE_SIZE, bdev_logical_block_size(bdev), 0);
+ PAGE_SIZE, bdev_logical_block_size(bdev), 0);
}
int
return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1);
}
-STATIC int
-xfs_mapping_buftarg(
- xfs_buftarg_t *btp,
- struct block_device *bdev)
-{
- struct backing_dev_info *bdi;
- struct inode *inode;
- struct address_space *mapping;
- static const struct address_space_operations mapping_aops = {
- .migratepage = fail_migrate_page,
- };
-
- inode = new_inode(bdev->bd_inode->i_sb);
- if (!inode) {
- printk(KERN_WARNING
- "XFS: Cannot allocate mapping inode for device %s\n",
- XFS_BUFTARG_NAME(btp));
- return ENOMEM;
- }
- inode->i_ino = get_next_ino();
- inode->i_mode = S_IFBLK;
- inode->i_bdev = bdev;
- inode->i_rdev = bdev->bd_dev;
- bdi = blk_get_backing_dev_info(bdev);
- if (!bdi)
- bdi = &default_backing_dev_info;
- mapping = &inode->i_data;
- mapping->a_ops = &mapping_aops;
- mapping->backing_dev_info = bdi;
- mapping_set_gfp_mask(mapping, GFP_NOFS);
- btp->bt_mapping = mapping;
- return 0;
-}
-
STATIC int
xfs_alloc_delwrite_queue(
xfs_buftarg_t *btp,
btp->bt_mount = mp;
btp->bt_dev = bdev->bd_dev;
btp->bt_bdev = bdev;
+ btp->bt_bdi = blk_get_backing_dev_info(bdev);
+ if (!btp->bt_bdi)
+ goto error;
+
INIT_LIST_HEAD(&btp->bt_lru);
spin_lock_init(&btp->bt_lru_lock);
if (xfs_setsize_buftarg_early(btp, bdev))
goto error;
- if (xfs_mapping_buftarg(btp, bdev))
- goto error;
if (xfs_alloc_delwrite_queue(btp, fsname))
goto error;
btp->bt_shrinker.shrink = xfs_buftarg_shrink;
git.openpandora.org / pandora-kernel.git / commitdiff