summaryrefslogtreecommitdiffstats
path: root/fs/xfs/xfs_buf.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/xfs/xfs_buf.c')
-rw-r--r--fs/xfs/xfs_buf.c1876
1 files changed, 1876 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
new file mode 100644
index 000000000000..c57836dc778f
--- /dev/null
+++ b/fs/xfs/xfs_buf.c
@@ -0,0 +1,1876 @@
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "xfs.h"
+#include <linux/stddef.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/vmalloc.h>
+#include <linux/bio.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
+#include <linux/workqueue.h>
+#include <linux/percpu.h>
+#include <linux/blkdev.h>
+#include <linux/hash.h>
+#include <linux/kthread.h>
+#include <linux/migrate.h>
+#include <linux/backing-dev.h>
+#include <linux/freezer.h>
+
+#include "xfs_sb.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_trace.h"
+
+static kmem_zone_t *xfs_buf_zone;
+STATIC int xfsbufd(void *);
+STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
+
+static struct workqueue_struct *xfslogd_workqueue;
+struct workqueue_struct *xfsdatad_workqueue;
+struct workqueue_struct *xfsconvertd_workqueue;
+
+#ifdef XFS_BUF_LOCK_TRACKING
+# define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid)
+# define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1)
+# define XB_GET_OWNER(bp) ((bp)->b_last_holder)
+#else
+# define XB_SET_OWNER(bp) do { } while (0)
+# define XB_CLEAR_OWNER(bp) do { } while (0)
+# define XB_GET_OWNER(bp) do { } while (0)
+#endif
+
+#define xb_to_gfp(flags) \
+ ((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : \
+ ((flags) & XBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)
+
+#define xb_to_km(flags) \
+ (((flags) & XBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
+
+#define xfs_buf_allocate(flags) \
+ kmem_zone_alloc(xfs_buf_zone, xb_to_km(flags))
+#define xfs_buf_deallocate(bp) \
+ kmem_zone_free(xfs_buf_zone, (bp));
+
+static inline int
+xfs_buf_is_vmapped(
+ struct xfs_buf *bp)
+{
+ /*
+ * Return true if the buffer is vmapped.
+ *
+ * The XBF_MAPPED flag is set if the buffer should be mapped, but the
+ * code is clever enough to know it doesn't have to map a single page,
+ * so the check has to be both for XBF_MAPPED and bp->b_page_count > 1.
+ */
+ return (bp->b_flags & XBF_MAPPED) && bp->b_page_count > 1;
+}
+
+static inline int
+xfs_buf_vmap_len(
+ struct xfs_buf *bp)
+{
+ return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
+}
+
+/*
+ * xfs_buf_lru_add - add a buffer to the LRU.
+ *
+ * The LRU takes a new reference to the buffer so that it will only be freed
+ * once the shrinker takes the buffer off the LRU.
+ */
+STATIC void
+xfs_buf_lru_add(
+ struct xfs_buf *bp)
+{
+ struct xfs_buftarg *btp = bp->b_target;
+
+ spin_lock(&btp->bt_lru_lock);
+ if (list_empty(&bp->b_lru)) {
+ atomic_inc(&bp->b_hold);
+ list_add_tail(&bp->b_lru, &btp->bt_lru);
+ btp->bt_lru_nr++;
+ }
+ spin_unlock(&btp->bt_lru_lock);
+}
+
+/*
+ * xfs_buf_lru_del - remove a buffer from the LRU
+ *
+ * The unlocked check is safe here because it only occurs when there are not
+ * b_lru_ref counts left on the inode under the pag->pag_buf_lock. it is there
+ * to optimise the shrinker removing the buffer from the LRU and calling
+ * xfs_buf_free(). i.e. it removes an unnecessary round trip on the
+ * bt_lru_lock.
+ */
+STATIC void
+xfs_buf_lru_del(
+ struct xfs_buf *bp)
+{
+ struct xfs_buftarg *btp = bp->b_target;
+
+ if (list_empty(&bp->b_lru))
+ return;
+
+ spin_lock(&btp->bt_lru_lock);
+ if (!list_empty(&bp->b_lru)) {
+ list_del_init(&bp->b_lru);
+ btp->bt_lru_nr--;
+ }
+ spin_unlock(&btp->bt_lru_lock);
+}
+
+/*
+ * When we mark a buffer stale, we remove the buffer from the LRU and clear the
+ * b_lru_ref count so that the buffer is freed immediately when the buffer
+ * reference count falls to zero. If the buffer is already on the LRU, we need
+ * to remove the reference that LRU holds on the buffer.
+ *
+ * This prevents build-up of stale buffers on the LRU.
+ */
+void
+xfs_buf_stale(
+ struct xfs_buf *bp)
+{
+ bp->b_flags |= XBF_STALE;
+ atomic_set(&(bp)->b_lru_ref, 0);
+ if (!list_empty(&bp->b_lru)) {
+ struct xfs_buftarg *btp = bp->b_target;
+
+ spin_lock(&btp->bt_lru_lock);
+ if (!list_empty(&bp->b_lru)) {
+ list_del_init(&bp->b_lru);
+ btp->bt_lru_nr--;
+ atomic_dec(&bp->b_hold);
+ }
+ spin_unlock(&btp->bt_lru_lock);
+ }
+ ASSERT(atomic_read(&bp->b_hold) >= 1);
+}
+
+STATIC void
+_xfs_buf_initialize(
+ xfs_buf_t *bp,
+ xfs_buftarg_t *target,
+ xfs_off_t range_base,
+ size_t range_length,
+ xfs_buf_flags_t flags)
+{
+ /*
+ * We don't want certain flags to appear in b_flags.
+ */
+ flags &= ~(XBF_LOCK|XBF_MAPPED|XBF_DONT_BLOCK|XBF_READ_AHEAD);
+
+ memset(bp, 0, sizeof(xfs_buf_t));
+ atomic_set(&bp->b_hold, 1);
+ atomic_set(&bp->b_lru_ref, 1);
+ init_completion(&bp->b_iowait);
+ INIT_LIST_HEAD(&bp->b_lru);
+ INIT_LIST_HEAD(&bp->b_list);
+ RB_CLEAR_NODE(&bp->b_rbnode);
+ sema_init(&bp->b_sema, 0); /* held, no waiters */
+ XB_SET_OWNER(bp);
+ bp->b_target = target;
+ bp->b_file_offset = range_base;
+ /*
+ * Set buffer_length and count_desired to the same value initially.
+ * I/O routines should use count_desired, which will be the same in
+ * most cases but may be reset (e.g. XFS recovery).
+ */
+ bp->b_buffer_length = bp->b_count_desired = range_length;
+ bp->b_flags = flags;
+ bp->b_bn = XFS_BUF_DADDR_NULL;
+ atomic_set(&bp->b_pin_count, 0);
+ init_waitqueue_head(&bp->b_waiters);
+
+ XFS_STATS_INC(xb_create);
+
+ trace_xfs_buf_init(bp, _RET_IP_);
+}
+
+/*
+ * Allocate a page array capable of holding a specified number
+ * of pages, and point the page buf at it.
+ */
+STATIC int
+_xfs_buf_get_pages(
+ xfs_buf_t *bp,
+ int page_count,
+ xfs_buf_flags_t flags)
+{
+ /* Make sure that we have a page list */
+ if (bp->b_pages == NULL) {
+ bp->b_offset = xfs_buf_poff(bp->b_file_offset);
+ bp->b_page_count = page_count;
+ if (page_count <= XB_PAGES) {
+ bp->b_pages = bp->b_page_array;
+ } else {
+ bp->b_pages = kmem_alloc(sizeof(struct page *) *
+ page_count, xb_to_km(flags));
+ if (bp->b_pages == NULL)
+ return -ENOMEM;
+ }
+ memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
+ }
+ return 0;
+}
+
+/*
+ * Frees b_pages if it was allocated.
+ */
+STATIC void
+_xfs_buf_free_pages(
+ xfs_buf_t *bp)
+{
+ if (bp->b_pages != bp->b_page_array) {
+ kmem_free(bp->b_pages);
+ bp->b_pages = NULL;
+ }
+}
+
+/*
+ * Releases the specified buffer.
+ *
+ * The modification state of any associated pages is left unchanged.
+ * The buffer most not be on any hash - use xfs_buf_rele instead for
+ * hashed and refcounted buffers
+ */
+void
+xfs_buf_free(
+ xfs_buf_t *bp)
+{
+ trace_xfs_buf_free(bp, _RET_IP_);
+
+ ASSERT(list_empty(&bp->b_lru));
+
+ if (bp->b_flags & _XBF_PAGES) {
+ uint i;
+
+ if (xfs_buf_is_vmapped(bp))
+ vm_unmap_ram(bp->b_addr - bp->b_offset,
+ bp->b_page_count);
+
+ for (i = 0; i < bp->b_page_count; i++) {
+ struct page *page = bp->b_pages[i];
+
+ __free_page(page);
+ }
+ } else if (bp->b_flags & _XBF_KMEM)
+ kmem_free(bp->b_addr);
+ _xfs_buf_free_pages(bp);
+ xfs_buf_deallocate(bp);
+}
+
+/*
+ * Allocates all the pages for buffer in question and builds it's page list.
+ */
+STATIC int
+xfs_buf_allocate_memory(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ size_t size = bp->b_count_desired;
+ size_t nbytes, offset;
+ gfp_t gfp_mask = xb_to_gfp(flags);
+ unsigned short page_count, i;
+ 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;
+
+ offset = bp->b_offset;
+ bp->b_flags |= _XBF_PAGES;
+
+ for (i = 0; i < bp->b_page_count; i++) {
+ struct page *page;
+ uint retries = 0;
+retry:
+ page = alloc_page(gfp_mask);
+ if (unlikely(page == NULL)) {
+ if (flags & XBF_READ_AHEAD) {
+ bp->b_page_count = i;
+ error = ENOMEM;
+ goto out_free_pages;
+ }
+
+ /*
+ * This could deadlock.
+ *
+ * But until all the XFS lowlevel code is revamped to
+ * handle buffer allocation failures we can't do much.
+ */
+ if (!(++retries % 100))
+ xfs_err(NULL,
+ "possible memory allocation deadlock in %s (mode:0x%x)",
+ __func__, gfp_mask);
+
+ XFS_STATS_INC(xb_page_retries);
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ goto retry;
+ }
+
+ XFS_STATS_INC(xb_page_found);
+
+ nbytes = min_t(size_t, size, PAGE_SIZE - offset);
+ size -= nbytes;
+ bp->b_pages[i] = page;
+ offset = 0;
+ }
+ return 0;
+
+out_free_pages:
+ for (i = 0; i < bp->b_page_count; i++)
+ __free_page(bp->b_pages[i]);
+ return error;
+}
+
+/*
+ * Map buffer into kernel address-space if necessary.
+ */
+STATIC int
+_xfs_buf_map_pages(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ 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) {
+ 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;
+ }
+
+ return 0;
+}
+
+/*
+ * Finding and Reading Buffers
+ */
+
+/*
+ * Look up, and creates if absent, a lockable buffer for
+ * a given range of an inode. The buffer is returned
+ * locked. If other overlapping buffers exist, they are
+ * released before the new buffer is created and locked,
+ * which may imply that this call will block until those buffers
+ * are unlocked. No I/O is implied by this call.
+ */
+xfs_buf_t *
+_xfs_buf_find(
+ xfs_buftarg_t *btp, /* block device target */
+ xfs_off_t ioff, /* starting offset of range */
+ size_t isize, /* length of range */
+ xfs_buf_flags_t flags,
+ xfs_buf_t *new_bp)
+{
+ xfs_off_t range_base;
+ size_t range_length;
+ struct xfs_perag *pag;
+ struct rb_node **rbp;
+ struct rb_node *parent;
+ xfs_buf_t *bp;
+
+ range_base = (ioff << BBSHIFT);
+ range_length = (isize << BBSHIFT);
+
+ /* Check for IOs smaller than the sector size / not sector aligned */
+ ASSERT(!(range_length < (1 << btp->bt_sshift)));
+ ASSERT(!(range_base & (xfs_off_t)btp->bt_smask));
+
+ /* get tree root */
+ pag = xfs_perag_get(btp->bt_mount,
+ xfs_daddr_to_agno(btp->bt_mount, ioff));
+
+ /* walk tree */
+ spin_lock(&pag->pag_buf_lock);
+ rbp = &pag->pag_buf_tree.rb_node;
+ parent = NULL;
+ bp = NULL;
+ while (*rbp) {
+ parent = *rbp;
+ bp = rb_entry(parent, struct xfs_buf, b_rbnode);
+
+ if (range_base < bp->b_file_offset)
+ rbp = &(*rbp)->rb_left;
+ else if (range_base > bp->b_file_offset)
+ rbp = &(*rbp)->rb_right;
+ else {
+ /*
+ * found a block offset match. If the range doesn't
+ * match, the only way this is allowed is if the buffer
+ * in the cache is stale and the transaction that made
+ * it stale has not yet committed. i.e. we are
+ * reallocating a busy extent. Skip this buffer and
+ * continue searching to the right for an exact match.
+ */
+ if (bp->b_buffer_length != range_length) {
+ ASSERT(bp->b_flags & XBF_STALE);
+ rbp = &(*rbp)->rb_right;
+ continue;
+ }
+ atomic_inc(&bp->b_hold);
+ goto found;
+ }
+ }
+
+ /* No match found */
+ if (new_bp) {
+ _xfs_buf_initialize(new_bp, btp, range_base,
+ range_length, flags);
+ rb_link_node(&new_bp->b_rbnode, parent, rbp);
+ rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree);
+ /* the buffer keeps the perag reference until it is freed */
+ new_bp->b_pag = pag;
+ spin_unlock(&pag->pag_buf_lock);
+ } else {
+ XFS_STATS_INC(xb_miss_locked);
+ spin_unlock(&pag->pag_buf_lock);
+ xfs_perag_put(pag);
+ }
+ return new_bp;
+
+found:
+ spin_unlock(&pag->pag_buf_lock);
+ xfs_perag_put(pag);
+
+ if (!xfs_buf_trylock(bp)) {
+ if (flags & XBF_TRYLOCK) {
+ xfs_buf_rele(bp);
+ XFS_STATS_INC(xb_busy_locked);
+ return NULL;
+ }
+ xfs_buf_lock(bp);
+ XFS_STATS_INC(xb_get_locked_waited);
+ }
+
+ /*
+ * 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 | _XBF_KMEM | _XBF_PAGES;
+ }
+
+ trace_xfs_buf_find(bp, flags, _RET_IP_);
+ XFS_STATS_INC(xb_get_locked);
+ return bp;
+}
+
+/*
+ * Assembles a buffer covering the specified range.
+ * Storage in memory for all portions of the buffer will be allocated,
+ * although backing storage may not be.
+ */
+xfs_buf_t *
+xfs_buf_get(
+ xfs_buftarg_t *target,/* target for buffer */
+ xfs_off_t ioff, /* starting offset of range */
+ size_t isize, /* length of range */
+ xfs_buf_flags_t flags)
+{
+ xfs_buf_t *bp, *new_bp;
+ int error = 0;
+
+ new_bp = xfs_buf_allocate(flags);
+ if (unlikely(!new_bp))
+ return NULL;
+
+ bp = _xfs_buf_find(target, ioff, isize, flags, new_bp);
+ if (bp == new_bp) {
+ error = xfs_buf_allocate_memory(bp, flags);
+ if (error)
+ goto no_buffer;
+ } else {
+ xfs_buf_deallocate(new_bp);
+ if (unlikely(bp == NULL))
+ return NULL;
+ }
+
+ if (!(bp->b_flags & XBF_MAPPED)) {
+ error = _xfs_buf_map_pages(bp, flags);
+ if (unlikely(error)) {
+ xfs_warn(target->bt_mount,
+ "%s: failed to map pages\n", __func__);
+ goto no_buffer;
+ }
+ }
+
+ XFS_STATS_INC(xb_get);
+
+ /*
+ * Always fill in the block number now, the mapped cases can do
+ * their own overlay of this later.
+ */
+ bp->b_bn = ioff;
+ bp->b_count_desired = bp->b_buffer_length;
+
+ trace_xfs_buf_get(bp, flags, _RET_IP_);
+ return bp;
+
+ no_buffer:
+ if (flags & (XBF_LOCK | XBF_TRYLOCK))
+ xfs_buf_unlock(bp);
+ xfs_buf_rele(bp);
+ return NULL;
+}
+
+STATIC int
+_xfs_buf_read(
+ xfs_buf_t *bp,
+ xfs_buf_flags_t flags)
+{
+ int status;
+
+ ASSERT(!(flags & (XBF_DELWRI|XBF_WRITE)));
+ ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL);
+
+ bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_DELWRI | XBF_READ_AHEAD);
+ bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
+
+ status = xfs_buf_iorequest(bp);
+ if (status || bp->b_error || (flags & XBF_ASYNC))
+ return status;
+ return xfs_buf_iowait(bp);
+}
+
+xfs_buf_t *
+xfs_buf_read(
+ xfs_buftarg_t *target,
+ xfs_off_t ioff,
+ size_t isize,
+ xfs_buf_flags_t flags)
+{
+ xfs_buf_t *bp;
+
+ flags |= XBF_READ;
+
+ bp = xfs_buf_get(target, ioff, isize, flags);
+ if (bp) {
+ trace_xfs_buf_read(bp, flags, _RET_IP_);
+
+ if (!XFS_BUF_ISDONE(bp)) {
+ XFS_STATS_INC(xb_get_read);
+ _xfs_buf_read(bp, flags);
+ } else if (flags & XBF_ASYNC) {
+ /*
+ * Read ahead call which is already satisfied,
+ * drop the buffer
+ */
+ goto no_buffer;
+ } else {
+ /* We do not want read in the flags */
+ bp->b_flags &= ~XBF_READ;
+ }
+ }
+
+ return bp;
+
+ no_buffer:
+ if (flags & (XBF_LOCK | XBF_TRYLOCK))
+ xfs_buf_unlock(bp);
+ xfs_buf_rele(bp);
+ return NULL;
+}
+
+/*
+ * If we are not low on memory then do the readahead in a deadlock
+ * safe manner.
+ */
+void
+xfs_buf_readahead(
+ xfs_buftarg_t *target,
+ xfs_off_t ioff,
+ size_t isize)
+{
+ if (bdi_read_congested(target->bt_bdi))
+ return;
+
+ xfs_buf_read(target, ioff, isize,
+ XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK);
+}
+
+/*
+ * Read an uncached buffer from disk. Allocates and returns a locked
+ * buffer containing the disk contents or nothing.
+ */
+struct xfs_buf *
+xfs_buf_read_uncached(
+ struct xfs_mount *mp,
+ struct xfs_buftarg *target,
+ xfs_daddr_t daddr,
+ size_t length,
+ int flags)
+{
+ xfs_buf_t *bp;
+ int error;
+
+ bp = xfs_buf_get_uncached(target, length, flags);
+ if (!bp)
+ return NULL;
+
+ /* set up the buffer for a read IO */
+ XFS_BUF_SET_ADDR(bp, daddr);
+ XFS_BUF_READ(bp);
+
+ xfsbdstrat(mp, bp);
+ error = xfs_buf_iowait(bp);
+ if (error || bp->b_error) {
+ xfs_buf_relse(bp);
+ return NULL;
+ }
+ return bp;
+}
+
+xfs_buf_t *
+xfs_buf_get_empty(
+ size_t len,
+ xfs_buftarg_t *target)
+{
+ xfs_buf_t *bp;
+
+ bp = xfs_buf_allocate(0);
+ if (bp)
+ _xfs_buf_initialize(bp, target, 0, len, 0);
+ return bp;
+}
+
+/*
+ * Return a buffer allocated as an empty buffer and associated to external
+ * memory via xfs_buf_associate_memory() back to it's empty state.
+ */
+void
+xfs_buf_set_empty(
+ struct xfs_buf *bp,
+ size_t len)
+{
+ if (bp->b_pages)
+ _xfs_buf_free_pages(bp);
+
+ bp->b_pages = NULL;
+ bp->b_page_count = 0;
+ bp->b_addr = NULL;
+ bp->b_file_offset = 0;
+ bp->b_buffer_length = bp->b_count_desired = len;
+ bp->b_bn = XFS_BUF_DADDR_NULL;
+ bp->b_flags &= ~XBF_MAPPED;
+}
+
+static inline struct page *
+mem_to_page(
+ void *addr)
+{
+ if ((!is_vmalloc_addr(addr))) {
+ return virt_to_page(addr);
+ } else {
+ return vmalloc_to_page(addr);
+ }
+}
+
+int
+xfs_buf_associate_memory(
+ xfs_buf_t *bp,
+ void *mem,
+ size_t len)
+{
+ int rval;
+ int i = 0;
+ unsigned long pageaddr;
+ unsigned long offset;
+ size_t buflen;
+ int page_count;
+
+ pageaddr = (unsigned long)mem & PAGE_MASK;
+ offset = (unsigned long)mem - pageaddr;
+ buflen = PAGE_ALIGN(len + offset);
+ page_count = buflen >> PAGE_SHIFT;
+
+ /* Free any previous set of page pointers */
+ if (bp->b_pages)
+ _xfs_buf_free_pages(bp);
+
+ bp->b_pages = NULL;
+ bp->b_addr = mem;
+
+ rval = _xfs_buf_get_pages(bp, page_count, XBF_DONT_BLOCK);
+ if (rval)
+ return rval;
+
+ bp->b_offset = offset;
+
+ for (i = 0; i < bp->b_page_count; i++) {
+ bp->b_pages[i] = mem_to_page((void *)pageaddr);
+ pageaddr += PAGE_SIZE;
+ }
+
+ bp->b_count_desired = len;
+ bp->b_buffer_length = buflen;
+ bp->b_flags |= XBF_MAPPED;
+
+ return 0;
+}
+
+xfs_buf_t *
+xfs_buf_get_uncached(
+ struct xfs_buftarg *target,
+ size_t len,
+ int flags)
+{
+ unsigned long page_count = PAGE_ALIGN(len) >> PAGE_SHIFT;
+ int error, i;
+ xfs_buf_t *bp;
+
+ bp = xfs_buf_allocate(0);
+ if (unlikely(bp == NULL))
+ goto fail;
+ _xfs_buf_initialize(bp, target, 0, len, 0);
+
+ error = _xfs_buf_get_pages(bp, page_count, 0);
+ if (error)
+ goto fail_free_buf;
+
+ for (i = 0; i < page_count; i++) {
+ bp->b_pages[i] = alloc_page(xb_to_gfp(flags));
+ if (!bp->b_pages[i])
+ goto fail_free_mem;
+ }
+ bp->b_flags |= _XBF_PAGES;
+
+ error = _xfs_buf_map_pages(bp, XBF_MAPPED);
+ if (unlikely(error)) {
+ xfs_warn(target->bt_mount,
+ "%s: failed to map pages\n", __func__);
+ goto fail_free_mem;
+ }
+
+ trace_xfs_buf_get_uncached(bp, _RET_IP_);
+ return bp;
+
+ fail_free_mem:
+ while (--i >= 0)
+ __free_page(bp->b_pages[i]);
+ _xfs_buf_free_pages(bp);
+ fail_free_buf:
+ xfs_buf_deallocate(bp);
+ fail:
+ return NULL;
+}
+
+/*
+ * Increment reference count on buffer, to hold the buffer concurrently
+ * with another thread which may release (free) the buffer asynchronously.
+ * Must hold the buffer already to call this function.
+ */
+void
+xfs_buf_hold(
+ xfs_buf_t *bp)
+{
+ trace_xfs_buf_hold(bp, _RET_IP_);
+ atomic_inc(&bp->b_hold);
+}
+
+/*
+ * Releases a hold on the specified buffer. If the
+ * the hold count is 1, calls xfs_buf_free.
+ */
+void
+xfs_buf_rele(
+ xfs_buf_t *bp)
+{
+ struct xfs_perag *pag = bp->b_pag;
+
+ trace_xfs_buf_rele(bp, _RET_IP_);
+
+ if (!pag) {
+ ASSERT(list_empty(&bp->b_lru));
+ ASSERT(RB_EMPTY_NODE(&bp->b_rbnode));
+ if (atomic_dec_and_test(&bp->b_hold))
+ xfs_buf_free(bp);
+ return;
+ }
+
+ ASSERT(!RB_EMPTY_NODE(&bp->b_rbnode));
+
+ ASSERT(atomic_read(&bp->b_hold) > 0);
+ if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) {
+ if (!(bp->b_flags & XBF_STALE) &&
+ atomic_read(&bp->b_lru_ref)) {
+ xfs_buf_lru_add(bp);
+ spin_unlock(&pag->pag_buf_lock);
+ } else {
+ xfs_buf_lru_del(bp);
+ ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)));
+ rb_erase(&bp->b_rbnode, &pag->pag_buf_tree);
+ spin_unlock(&pag->pag_buf_lock);
+ xfs_perag_put(pag);
+ xfs_buf_free(bp);
+ }
+ }
+}
+
+
+/*
+ * 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
+ * pinned, we know that the log has not been pushed to disk and hence it
+ * will still be locked. Rather than continuing to have trylock attempts
+ * fail until someone else pushes the log, push it ourselves before
+ * returning. This means that the xfsaild will not get stuck trying
+ * to push on stale inode buffers.
+ */
+int
+xfs_buf_trylock(
+ struct xfs_buf *bp)
+{
+ int locked;
+
+ locked = down_trylock(&bp->b_sema) == 0;
+ if (locked)
+ XB_SET_OWNER(bp);
+ else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
+ xfs_log_force(bp->b_target->bt_mount, 0);
+
+ trace_xfs_buf_trylock(bp, _RET_IP_);
+ return locked;
+}
+
+/*
+ * 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
+ * it is pinned, we know that the log has not been pushed to disk and
+ * hence it will still be locked. Rather than sleeping until someone
+ * else pushes the log, push it ourselves before trying to get the lock.
+ */
+void
+xfs_buf_lock(
+ struct xfs_buf *bp)
+{
+ trace_xfs_buf_lock(bp, _RET_IP_);
+
+ if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
+ xfs_log_force(bp->b_target->bt_mount, 0);
+ down(&bp->b_sema);
+ XB_SET_OWNER(bp);
+
+ trace_xfs_buf_lock_done(bp, _RET_IP_);
+}
+
+/*
+ * Releases the lock on the buffer object.
+ * If the buffer is marked delwri but is not queued, do so before we
+ * unlock the buffer as we need to set flags correctly. We also need to
+ * take a reference for the delwri queue because the unlocker is going to
+ * drop their's and they don't know we just queued it.
+ */
+void
+xfs_buf_unlock(
+ struct xfs_buf *bp)
+{
+ if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI) {
+ atomic_inc(&bp->b_hold);
+ bp->b_flags |= XBF_ASYNC;
+ xfs_buf_delwri_queue(bp, 0);
+ }
+
+ XB_CLEAR_OWNER(bp);
+ up(&bp->b_sema);
+
+ trace_xfs_buf_unlock(bp, _RET_IP_);
+}
+
+STATIC void
+xfs_buf_wait_unpin(
+ xfs_buf_t *bp)
+{
+ DECLARE_WAITQUEUE (wait, current);
+
+ if (atomic_read(&bp->b_pin_count) == 0)
+ return;
+
+ add_wait_queue(&bp->b_waiters, &wait);
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&bp->b_pin_count) == 0)
+ break;
+ io_schedule();
+ }
+ remove_wait_queue(&bp->b_waiters, &wait);
+ set_current_state(TASK_RUNNING);
+}
+
+/*
+ * Buffer Utility Routines
+ */
+
+STATIC void
+xfs_buf_iodone_work(
+ struct work_struct *work)
+{
+ xfs_buf_t *bp =
+ container_of(work, xfs_buf_t, b_iodone_work);
+
+ if (bp->b_iodone)
+ (*(bp->b_iodone))(bp);
+ else if (bp->b_flags & XBF_ASYNC)
+ xfs_buf_relse(bp);
+}
+
+void
+xfs_buf_ioend(
+ xfs_buf_t *bp,
+ int schedule)
+{
+ trace_xfs_buf_iodone(bp, _RET_IP_);
+
+ bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
+ if (bp->b_error == 0)
+ bp->b_flags |= XBF_DONE;
+
+ if ((bp->b_iodone) || (bp->b_flags & XBF_ASYNC)) {
+ if (schedule) {
+ INIT_WORK(&bp->b_iodone_work, xfs_buf_iodone_work);
+ queue_work(xfslogd_workqueue, &bp->b_iodone_work);
+ } else {
+ xfs_buf_iodone_work(&bp->b_iodone_work);
+ }
+ } else {
+ complete(&bp->b_iowait);
+ }
+}
+
+void
+xfs_buf_ioerror(
+ xfs_buf_t *bp,
+ int error)
+{
+ ASSERT(error >= 0 && error <= 0xffff);
+ bp->b_error = (unsigned short)error;
+ trace_xfs_buf_ioerror(bp, error, _RET_IP_);
+}
+
+int
+xfs_bwrite(
+ struct xfs_mount *mp,
+ struct xfs_buf *bp)
+{
+ int error;
+
+ bp->b_flags |= XBF_WRITE;
+ bp->b_flags &= ~(XBF_ASYNC | XBF_READ);
+
+ xfs_buf_delwri_dequeue(bp);
+ xfs_bdstrat_cb(bp);
+
+ error = xfs_buf_iowait(bp);
+ if (error)
+ xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
+ xfs_buf_relse(bp);
+ return error;
+}
+
+void
+xfs_bdwrite(
+ void *mp,
+ struct xfs_buf *bp)
+{
+ trace_xfs_buf_bdwrite(bp, _RET_IP_);
+
+ bp->b_flags &= ~XBF_READ;
+ bp->b_flags |= (XBF_DELWRI | XBF_ASYNC);
+
+ xfs_buf_delwri_queue(bp, 1);
+}
+
+/*
+ * Called when we want to stop a buffer from getting written or read.
+ * We attach the EIO error, muck with its flags, and call xfs_buf_ioend
+ * so that the proper iodone callbacks get called.
+ */
+STATIC int
+xfs_bioerror(
+ xfs_buf_t *bp)
+{
+#ifdef XFSERRORDEBUG
+ ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone);
+#endif
+
+ /*
+ * No need to wait until the buffer is unpinned, we aren't flushing it.
+ */
+ xfs_buf_ioerror(bp, EIO);
+
+ /*
+ * We're calling xfs_buf_ioend, so delete XBF_DONE flag.
+ */
+ XFS_BUF_UNREAD(bp);
+ XFS_BUF_UNDELAYWRITE(bp);
+ XFS_BUF_UNDONE(bp);
+ XFS_BUF_STALE(bp);
+
+ xfs_buf_ioend(bp, 0);
+
+ return EIO;
+}
+
+/*
+ * Same as xfs_bioerror, except that we are releasing the buffer
+ * here ourselves, and avoiding the xfs_buf_ioend call.
+ * This is meant for userdata errors; metadata bufs come with
+ * iodone functions attached, so that we can track down errors.
+ */
+STATIC int
+xfs_bioerror_relse(
+ struct xfs_buf *bp)
+{
+ int64_t fl = bp->b_flags;
+ /*
+ * No need to wait until the buffer is unpinned.
+ * We aren't flushing it.
+ *
+ * chunkhold expects B_DONE to be set, whether
+ * we actually finish the I/O or not. We don't want to
+ * change that interface.
+ */
+ XFS_BUF_UNREAD(bp);
+ XFS_BUF_UNDELAYWRITE(bp);
+ XFS_BUF_DONE(bp);
+ XFS_BUF_STALE(bp);
+ bp->b_iodone = NULL;
+ if (!(fl & XBF_ASYNC)) {
+ /*
+ * Mark b_error and B_ERROR _both_.
+ * Lot's of chunkcache code assumes that.
+ * There's no reason to mark error for
+ * ASYNC buffers.
+ */
+ xfs_buf_ioerror(bp, EIO);
+ XFS_BUF_FINISH_IOWAIT(bp);
+ } else {
+ xfs_buf_relse(bp);
+ }
+
+ return EIO;
+}
+
+
+/*
+ * All xfs metadata buffers except log state machine buffers
+ * get this attached as their b_bdstrat callback function.
+ * This is so that we can catch a buffer
+ * after prematurely unpinning it to forcibly shutdown the filesystem.
+ */
+int
+xfs_bdstrat_cb(
+ struct xfs_buf *bp)
+{
+ if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+ trace_xfs_bdstrat_shut(bp, _RET_IP_);
+ /*
+ * Metadata write that didn't get logged but
+ * written delayed anyway. These aren't associated
+ * with a transaction, and can be ignored.
+ */
+ if (!bp->b_iodone && !XFS_BUF_ISREAD(bp))
+ return xfs_bioerror_relse(bp);
+ else
+ return xfs_bioerror(bp);
+ }
+
+ xfs_buf_iorequest(bp);
+ return 0;
+}
+
+/*
+ * Wrapper around bdstrat so that we can stop data from going to disk in case
+ * we are shutting down the filesystem. Typically user data goes thru this
+ * path; one of the exceptions is the superblock.
+ */
+void
+xfsbdstrat(
+ struct xfs_mount *mp,
+ struct xfs_buf *bp)
+{
+ if (XFS_FORCED_SHUTDOWN(mp)) {
+ trace_xfs_bdstrat_shut(bp, _RET_IP_);
+ xfs_bioerror_relse(bp);
+ return;
+ }
+
+ xfs_buf_iorequest(bp);
+}
+
+STATIC void
+_xfs_buf_ioend(
+ xfs_buf_t *bp,
+ int schedule)
+{
+ if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
+ xfs_buf_ioend(bp, schedule);
+}
+
+STATIC void
+xfs_buf_bio_end_io(
+ struct bio *bio,
+ int error)
+{
+ xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private;
+
+ 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));
+
+ _xfs_buf_ioend(bp, 1);
+ bio_put(bio);
+}
+
+STATIC void
+_xfs_buf_ioapply(
+ xfs_buf_t *bp)
+{
+ int rw, map_i, total_nr_pages, nr_pages;
+ struct bio *bio;
+ int offset = bp->b_offset;
+ int size = bp->b_count_desired;
+ sector_t sector = bp->b_bn;
+
+ total_nr_pages = bp->b_page_count;
+ map_i = 0;
+
+ if (bp->b_flags & XBF_WRITE) {
+ if (bp->b_flags & XBF_SYNCIO)
+ rw = WRITE_SYNC;
+ else
+ rw = WRITE;
+ if (bp->b_flags & XBF_FUA)
+ rw |= REQ_FUA;
+ if (bp->b_flags & XBF_FLUSH)
+ rw |= REQ_FLUSH;
+ } else if (bp->b_flags & XBF_READ_AHEAD) {
+ rw = READA;
+ } else {
+ rw = READ;
+ }
+
+ /* we only use the buffer cache for meta-data */
+ rw |= REQ_META;
+
+next_chunk:
+ atomic_inc(&bp->b_io_remaining);
+ nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT);
+ if (nr_pages > total_nr_pages)
+ nr_pages = total_nr_pages;
+
+ bio = bio_alloc(GFP_NOIO, nr_pages);
+ bio->bi_bdev = bp->b_target->bt_bdev;
+ bio->bi_sector = sector;
+ 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_SIZE - offset;
+
+ if (nbytes > size)
+ nbytes = size;
+
+ rbytes = bio_add_page(bio, bp->b_pages[map_i], nbytes, offset);
+ if (rbytes < nbytes)
+ break;
+
+ offset = 0;
+ sector += nbytes >> BBSHIFT;
+ size -= nbytes;
+ total_nr_pages--;
+ }
+
+ if (likely(bio->bi_size)) {
+ if (xfs_buf_is_vmapped(bp)) {
+ flush_kernel_vmap_range(bp->b_addr,
+ xfs_buf_vmap_len(bp));
+ }
+ submit_bio(rw, bio);
+ if (size)
+ goto next_chunk;
+ } else {
+ xfs_buf_ioerror(bp, EIO);
+ bio_put(bio);
+ }
+}
+
+int
+xfs_buf_iorequest(
+ xfs_buf_t *bp)
+{
+ trace_xfs_buf_iorequest(bp, _RET_IP_);
+
+ if (bp->b_flags & XBF_DELWRI) {
+ xfs_buf_delwri_queue(bp, 1);
+ return 0;
+ }
+
+ if (bp->b_flags & XBF_WRITE) {
+ xfs_buf_wait_unpin(bp);
+ }
+
+ xfs_buf_hold(bp);
+
+ /* Set the count to 1 initially, this will stop an I/O
+ * completion callout which happens before we have started
+ * all the I/O from calling xfs_buf_ioend too early.
+ */
+ atomic_set(&bp->b_io_remaining, 1);
+ _xfs_buf_ioapply(bp);
+ _xfs_buf_ioend(bp, 0);
+
+ xfs_buf_rele(bp);
+ return 0;
+}
+
+/*
+ * Waits for I/O to complete on the buffer supplied.
+ * It returns immediately if no I/O is pending.
+ * It returns the I/O error code, if any, or 0 if there was no error.
+ */
+int
+xfs_buf_iowait(
+ xfs_buf_t *bp)
+{
+ trace_xfs_buf_iowait(bp, _RET_IP_);
+
+ wait_for_completion(&bp->b_iowait);
+
+ trace_xfs_buf_iowait_done(bp, _RET_IP_);
+ return bp->b_error;
+}
+
+xfs_caddr_t
+xfs_buf_offset(
+ xfs_buf_t *bp,
+ size_t offset)
+{
+ struct page *page;
+
+ if (bp->b_flags & XBF_MAPPED)
+ return bp->b_addr + offset;
+
+ offset += bp->b_offset;
+ page = bp->b_pages[offset >> PAGE_SHIFT];
+ return (xfs_caddr_t)page_address(page) + (offset & (PAGE_SIZE-1));
+}
+
+/*
+ * Move data into or out of a buffer.
+ */
+void
+xfs_buf_iomove(
+ xfs_buf_t *bp, /* buffer to process */
+ size_t boff, /* starting buffer offset */
+ size_t bsize, /* length to copy */
+ void *data, /* data address */
+ xfs_buf_rw_t mode) /* read/write/zero flag */
+{
+ size_t bend, cpoff, csize;
+ struct page *page;
+
+ bend = boff + bsize;
+ while (boff < bend) {
+ 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_SIZE-cpoff, bp->b_count_desired-boff);
+
+ ASSERT(((csize + cpoff) <= PAGE_SIZE));
+
+ switch (mode) {
+ case XBRW_ZERO:
+ memset(page_address(page) + cpoff, 0, csize);
+ break;
+ case XBRW_READ:
+ memcpy(data, page_address(page) + cpoff, csize);
+ break;
+ case XBRW_WRITE:
+ memcpy(page_address(page) + cpoff, data, csize);
+ }
+
+ boff += csize;
+ data += csize;
+ }
+}
+
+/*
+ * Handling of buffer targets (buftargs).
+ */
+
+/*
+ * Wait for any bufs with callbacks that have been submitted but have not yet
+ * returned. These buffers will have an elevated hold count, so wait on those
+ * while freeing all the buffers only held by the LRU.
+ */
+void
+xfs_wait_buftarg(
+ struct xfs_buftarg *btp)
+{
+ struct xfs_buf *bp;
+
+restart:
+ spin_lock(&btp->bt_lru_lock);
+ while (!list_empty(&btp->bt_lru)) {
+ bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
+ if (atomic_read(&bp->b_hold) > 1) {
+ spin_unlock(&btp->bt_lru_lock);
+ delay(100);
+ goto restart;
+ }
+ /*
+ * clear the LRU reference count so the bufer doesn't get
+ * ignored in xfs_buf_rele().
+ */
+ atomic_set(&bp->b_lru_ref, 0);
+ spin_unlock(&btp->bt_lru_lock);
+ xfs_buf_rele(bp);
+ spin_lock(&btp->bt_lru_lock);
+ }
+ spin_unlock(&btp->bt_lru_lock);
+}
+
+int
+xfs_buftarg_shrink(
+ struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct xfs_buftarg *btp = container_of(shrink,
+ struct xfs_buftarg, bt_shrinker);
+ struct xfs_buf *bp;
+ int nr_to_scan = sc->nr_to_scan;
+ LIST_HEAD(dispose);
+
+ if (!nr_to_scan)
+ return btp->bt_lru_nr;
+
+ spin_lock(&btp->bt_lru_lock);
+ while (!list_empty(&btp->bt_lru)) {
+ if (nr_to_scan-- <= 0)
+ break;
+
+ bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
+
+ /*
+ * Decrement the b_lru_ref count unless the value is already
+ * zero. If the value is already zero, we need to reclaim the
+ * buffer, otherwise it gets another trip through the LRU.
+ */
+ if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
+ list_move_tail(&bp->b_lru, &btp->bt_lru);
+ continue;
+ }
+
+ /*
+ * remove the buffer from the LRU now to avoid needing another
+ * lock round trip inside xfs_buf_rele().
+ */
+ list_move(&bp->b_lru, &dispose);
+ btp->bt_lru_nr--;
+ }
+ spin_unlock(&btp->bt_lru_lock);
+
+ while (!list_empty(&dispose)) {
+ bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
+ list_del_init(&bp->b_lru);
+ xfs_buf_rele(bp);
+ }
+
+ return btp->bt_lru_nr;
+}
+
+void
+xfs_free_buftarg(
+ struct xfs_mount *mp,
+ struct xfs_buftarg *btp)
+{
+ unregister_shrinker(&btp->bt_shrinker);
+
+ xfs_flush_buftarg(btp, 1);
+ if (mp->m_flags & XFS_MOUNT_BARRIER)
+ xfs_blkdev_issue_flush(btp);
+
+ kthread_stop(btp->bt_task);
+ kmem_free(btp);
+}
+
+STATIC int
+xfs_setsize_buftarg_flags(
+ xfs_buftarg_t *btp,
+ unsigned int blocksize,
+ unsigned int sectorsize,
+ int verbose)
+{
+ btp->bt_bsize = blocksize;
+ btp->bt_sshift = ffs(sectorsize) - 1;
+ btp->bt_smask = sectorsize - 1;
+
+ if (set_blocksize(btp->bt_bdev, sectorsize)) {
+ xfs_warn(btp->bt_mount,
+ "Cannot set_blocksize to %u on device %s\n",
+ sectorsize, xfs_buf_target_name(btp));
+ return EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * When allocating the initial buffer target we have not yet
+ * read in the superblock, so don't know what sized sectors
+ * are being used is at this early stage. Play safe.
+ */
+STATIC int
+xfs_setsize_buftarg_early(
+ xfs_buftarg_t *btp,
+ struct block_device *bdev)
+{
+ return xfs_setsize_buftarg_flags(btp,
+ PAGE_SIZE, bdev_logical_block_size(bdev), 0);
+}
+
+int
+xfs_setsize_buftarg(
+ xfs_buftarg_t *btp,
+ unsigned int blocksize,
+ unsigned int sectorsize)
+{
+ return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1);
+}
+
+STATIC int
+xfs_alloc_delwrite_queue(
+ xfs_buftarg_t *btp,
+ const char *fsname)
+{
+ INIT_LIST_HEAD(&btp->bt_delwrite_queue);
+ spin_lock_init(&btp->bt_delwrite_lock);
+ btp->bt_flags = 0;
+ btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
+ if (IS_ERR(btp->bt_task))
+ return PTR_ERR(btp->bt_task);
+ return 0;
+}
+
+xfs_buftarg_t *
+xfs_alloc_buftarg(
+ struct xfs_mount *mp,
+ struct block_device *bdev,
+ int external,
+ const char *fsname)
+{
+ xfs_buftarg_t *btp;
+
+ btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
+
+ 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_alloc_delwrite_queue(btp, fsname))
+ goto error;
+ btp->bt_shrinker.shrink = xfs_buftarg_shrink;
+ btp->bt_shrinker.seeks = DEFAULT_SEEKS;
+ register_shrinker(&btp->bt_shrinker);
+ return btp;
+
+error:
+ kmem_free(btp);
+ return NULL;
+}
+
+
+/*
+ * Delayed write buffer handling
+ */
+STATIC void
+xfs_buf_delwri_queue(
+ xfs_buf_t *bp,
+ int unlock)
+{
+ struct list_head *dwq = &bp->b_target->bt_delwrite_queue;
+ spinlock_t *dwlk = &bp->b_target->bt_delwrite_lock;
+
+ trace_xfs_buf_delwri_queue(bp, _RET_IP_);
+
+ ASSERT((bp->b_flags&(XBF_DELWRI|XBF_ASYNC)) == (XBF_DELWRI|XBF_ASYNC));
+
+ spin_lock(dwlk);
+ /* If already in the queue, dequeue and place at tail */
+ if (!list_empty(&bp->b_list)) {
+ ASSERT(bp->b_flags & _XBF_DELWRI_Q);
+ if (unlock)
+ atomic_dec(&bp->b_hold);
+ list_del(&bp->b_list);
+ }
+
+ if (list_empty(dwq)) {
+ /* start xfsbufd as it is about to have something to do */
+ wake_up_process(bp->b_target->bt_task);
+ }
+
+ bp->b_flags |= _XBF_DELWRI_Q;
+ list_add_tail(&bp->b_list, dwq);
+ bp->b_queuetime = jiffies;
+ spin_unlock(dwlk);
+
+ if (unlock)
+ xfs_buf_unlock(bp);
+}
+
+void
+xfs_buf_delwri_dequeue(
+ xfs_buf_t *bp)
+{
+ spinlock_t *dwlk = &bp->b_target->bt_delwrite_lock;
+ int dequeued = 0;
+
+ spin_lock(dwlk);
+ if ((bp->b_flags & XBF_DELWRI) && !list_empty(&bp->b_list)) {
+ ASSERT(bp->b_flags & _XBF_DELWRI_Q);
+ list_del_init(&bp->b_list);
+ dequeued = 1;
+ }
+ bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q);
+ spin_unlock(dwlk);
+
+ if (dequeued)
+ xfs_buf_rele(bp);
+
+ trace_xfs_buf_delwri_dequeue(bp, _RET_IP_);
+}
+
+/*
+ * If a delwri buffer needs to be pushed before it has aged out, then promote
+ * it to the head of the delwri queue so that it will be flushed on the next
+ * xfsbufd run. We do this by resetting the queuetime of the buffer to be older
+ * than the age currently needed to flush the buffer. Hence the next time the
+ * xfsbufd sees it is guaranteed to be considered old enough to flush.
+ */
+void
+xfs_buf_delwri_promote(
+ struct xfs_buf *bp)
+{
+ struct xfs_buftarg *btp = bp->b_target;
+ long age = xfs_buf_age_centisecs * msecs_to_jiffies(10) + 1;
+
+ ASSERT(bp->b_flags & XBF_DELWRI);
+ ASSERT(bp->b_flags & _XBF_DELWRI_Q);
+
+ /*
+ * Check the buffer age before locking the delayed write queue as we
+ * don't need to promote buffers that are already past the flush age.
+ */
+ if (bp->b_queuetime < jiffies - age)
+ return;
+ bp->b_queuetime = jiffies - age;
+ spin_lock(&btp->bt_delwrite_lock);
+ list_move(&bp->b_list, &btp->bt_delwrite_queue);
+ spin_unlock(&btp->bt_delwrite_lock);
+}
+
+STATIC void
+xfs_buf_runall_queues(
+ struct workqueue_struct *queue)
+{
+ flush_workqueue(queue);
+}
+
+/*
+ * Move as many buffers as specified to the supplied list
+ * idicating if we skipped any buffers to prevent deadlocks.
+ */
+STATIC int
+xfs_buf_delwri_split(
+ xfs_buftarg_t *target,
+ struct list_head *list,
+ unsigned long age)
+{
+ xfs_buf_t *bp, *n;
+ struct list_head *dwq = &target->bt_delwrite_queue;
+ spinlock_t *dwlk = &target->bt_delwrite_lock;
+ int skipped = 0;
+ int force;
+
+ force = test_and_clear_bit(XBT_FORCE_FLUSH, &target->bt_flags);
+ INIT_LIST_HEAD(list);
+ spin_lock(dwlk);
+ list_for_each_entry_safe(bp, n, dwq, b_list) {
+ ASSERT(bp->b_flags & XBF_DELWRI);
+
+ if (!xfs_buf_ispinned(bp) && xfs_buf_trylock(bp)) {
+ if (!force &&
+ time_before(jiffies, bp->b_queuetime + age)) {
+ xfs_buf_unlock(bp);
+ break;
+ }
+
+ bp->b_flags &= ~(XBF_DELWRI | _XBF_DELWRI_Q);
+ bp->b_flags |= XBF_WRITE;
+ list_move_tail(&bp->b_list, list);
+ trace_xfs_buf_delwri_split(bp, _RET_IP_);
+ } else
+ skipped++;
+ }
+ spin_unlock(dwlk);
+
+ return skipped;
+
+}
+
+/*
+ * Compare function is more complex than it needs to be because
+ * the return value is only 32 bits and we are doing comparisons
+ * on 64 bit values
+ */
+static int
+xfs_buf_cmp(
+ void *priv,
+ struct list_head *a,
+ struct list_head *b)
+{
+ struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list);
+ struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list);
+ xfs_daddr_t diff;
+
+ diff = ap->b_bn - bp->b_bn;
+ if (diff < 0)
+ return -1;
+ if (diff > 0)
+ return 1;
+ return 0;
+}
+
+STATIC int
+xfsbufd(
+ void *data)
+{
+ xfs_buftarg_t *target = (xfs_buftarg_t *)data;
+
+ current->flags |= PF_MEMALLOC;
+
+ set_freezable();
+
+ do {
+ long age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+ long tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
+ struct list_head tmp;
+ struct blk_plug plug;
+
+ if (unlikely(freezing(current))) {
+ set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
+ refrigerator();
+ } else {
+ clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
+ }
+
+ /* sleep for a long time if there is nothing to do. */
+ if (list_empty(&target->bt_delwrite_queue))
+ tout = MAX_SCHEDULE_TIMEOUT;
+ schedule_timeout_interruptible(tout);
+
+ xfs_buf_delwri_split(target, &tmp, age);
+ list_sort(NULL, &tmp, xfs_buf_cmp);
+
+ blk_start_plug(&plug);
+ while (!list_empty(&tmp)) {
+ struct xfs_buf *bp;
+ bp = list_first_entry(&tmp, struct xfs_buf, b_list);
+ list_del_init(&bp->b_list);
+ xfs_bdstrat_cb(bp);
+ }
+ blk_finish_plug(&plug);
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+/*
+ * Go through all incore buffers, and release buffers if they belong to
+ * the given device. This is used in filesystem error handling to
+ * preserve the consistency of its metadata.
+ */
+int
+xfs_flush_buftarg(
+ xfs_buftarg_t *target,
+ int wait)
+{
+ xfs_buf_t *bp;
+ int pincount = 0;
+ LIST_HEAD(tmp_list);
+ LIST_HEAD(wait_list);
+ struct blk_plug plug;
+
+ xfs_buf_runall_queues(xfsconvertd_workqueue);
+ xfs_buf_runall_queues(xfsdatad_workqueue);
+ xfs_buf_runall_queues(xfslogd_workqueue);
+
+ set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
+ pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
+
+ /*
+ * Dropped the delayed write list lock, now walk the temporary list.
+ * All I/O is issued async and then if we need to wait for completion
+ * we do that after issuing all the IO.
+ */
+ list_sort(NULL, &tmp_list, xfs_buf_cmp);
+
+ blk_start_plug(&plug);
+ while (!list_empty(&tmp_list)) {
+ bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
+ ASSERT(target == bp->b_target);
+ list_del_init(&bp->b_list);
+ if (wait) {
+ bp->b_flags &= ~XBF_ASYNC;
+ list_add(&bp->b_list, &wait_list);
+ }
+ xfs_bdstrat_cb(bp);
+ }
+ blk_finish_plug(&plug);
+
+ if (wait) {
+ /* Wait for IO to complete. */
+ while (!list_empty(&wait_list)) {
+ bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
+
+ list_del_init(&bp->b_list);
+ xfs_buf_iowait(bp);
+ xfs_buf_relse(bp);
+ }
+ }
+
+ return pincount;
+}
+
+int __init
+xfs_buf_init(void)
+{
+ xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf",
+ KM_ZONE_HWALIGN, NULL);
+ if (!xfs_buf_zone)
+ goto out;
+
+ xfslogd_workqueue = alloc_workqueue("xfslogd",
+ WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
+ if (!xfslogd_workqueue)
+ goto out_free_buf_zone;
+
+ xfsdatad_workqueue = alloc_workqueue("xfsdatad", WQ_MEM_RECLAIM, 1);
+ if (!xfsdatad_workqueue)
+ goto out_destroy_xfslogd_workqueue;
+
+ xfsconvertd_workqueue = alloc_workqueue("xfsconvertd",
+ WQ_MEM_RECLAIM, 1);
+ if (!xfsconvertd_workqueue)
+ goto out_destroy_xfsdatad_workqueue;
+
+ return 0;
+
+ out_destroy_xfsdatad_workqueue:
+ destroy_workqueue(xfsdatad_workqueue);
+ out_destroy_xfslogd_workqueue:
+ destroy_workqueue(xfslogd_workqueue);
+ out_free_buf_zone:
+ kmem_zone_destroy(xfs_buf_zone);
+ out:
+ return -ENOMEM;
+}
+
+void
+xfs_buf_terminate(void)
+{
+ destroy_workqueue(xfsconvertd_workqueue);
+ destroy_workqueue(xfsdatad_workqueue);
+ destroy_workqueue(xfslogd_workqueue);
+ kmem_zone_destroy(xfs_buf_zone);
+}
+
+#ifdef CONFIG_KDB_MODULES
+struct list_head *
+xfs_get_buftarg_list(void)
+{
+ return &xfs_buftarg_list;
+}
+#endif