diff options
Diffstat (limited to 'fs/xfs/linux-2.6/xfs_buf.c')
| -rw-r--r-- | fs/xfs/linux-2.6/xfs_buf.c | 1876 |
1 files changed, 0 insertions, 1876 deletions
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c deleted file mode 100644 index c57836d..0000000 --- a/fs/xfs/linux-2.6/xfs_buf.c +++ /dev/null @@ -1,1876 +0,0 @@ -/* - * 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 |
