/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "xfs_sb.h" #include "xfs_inum.h" #include "xfs_ag.h" #include "xfs_dmapi.h" #include "xfs_mount.h" #include "xfs_trace.h" static kmem_zone_t *xfs_buf_zone; STATIC int xfsbufd(void *); STATIC int xfsbufd_wakeup(int, gfp_t); STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int); static struct shrinker xfs_buf_shake = { .shrink = xfsbufd_wakeup, .seeks = DEFAULT_SEEKS, }; 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; } /* * 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); } /* * Internal xfs_buf_t object manipulation */ 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); init_completion(&bp->b_iowait); INIT_LIST_HEAD(&bp->b_list); INIT_LIST_HEAD(&bp->b_hash_list); init_MUTEX_LOCKED(&bp->b_sema); /* 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_hash_list)); if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) { uint i; if (xfs_buf_is_vmapped(bp)) vunmap(bp->b_addr - bp->b_offset); 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); } } _xfs_buf_free_pages(bp); xfs_buf_deallocate(bp); } /* * Finds all pages for buffer in question and builds it's page list. */ STATIC int _xfs_buf_lookup_pages( 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); unsigned short page_count, i; pgoff_t first; xfs_off_t end; int error; 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; 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); 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; } /* * 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)) printk(KERN_ERR "XFS: possible memory allocation " "deadlock in %s (mode:0x%x)\n", __func__, gfp_mask); XFS_STATS_INC(xb_page_retries); xfsbufd_wakeup(0, gfp_mask); congestion_wait(BLK_RW_ASYNC, HZ/50); goto retry; } XFS_STATS_INC(xb_page_found); nbytes = min_t(size_t, size, PAGE_CACHE_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; } 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; return error; } /* * Map buffer into kernel address-space if nessecary. */ STATIC int _xfs_buf_map_pages( xfs_buf_t *bp, uint flags) { /* A single page buffer is always mappable */ if (bp->b_page_count == 1) { 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 = vmap(bp->b_pages, bp->b_page_count, VM_MAP, PAGE_KERNEL); if (unlikely(bp->b_addr == NULL)) 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; xfs_bufhash_t *hash; xfs_buf_t *bp, *n; 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)); hash = &btp->bt_hash[hash_long((unsigned long)ioff, btp->bt_hashshift)]; spin_lock(&hash->bh_lock); list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) { ASSERT(btp == bp->b_target); if (bp->b_file_offset == range_base && bp->b_buffer_length == range_length) { /* * If we look at something, bring it to the * front of the list for next time. */ atomic_inc(&bp->b_hold); list_move(&bp->b_hash_list, &hash->bh_list); goto found; } } /* No match found */ if (new_bp) { _xfs_buf_initialize(new_bp, btp, range_base, range_length, flags); new_bp->b_hash = hash; list_add(&new_bp->b_hash_list, &hash->bh_list); } else { XFS_STATS_INC(xb_miss_locked); } spin_unlock(&hash->bh_lock); return new_bp; found: spin_unlock(&hash->bh_lock); /* Attempt to get the semaphore without sleeping, * if this does not work then we need to drop the * spinlock and do a hard attempt on the semaphore. */ if (down_trylock(&bp->b_sema)) { if (!(flags & XBF_TRYLOCK)) { /* wait for buffer ownership */ xfs_buf_lock(bp); XFS_STATS_INC(xb_get_locked_waited); } else { /* We asked for a trylock and failed, no need * to look at file offset and length here, we * know that this buffer at least overlaps our * buffer and is locked, therefore our buffer * either does not exist, or is this buffer. */ xfs_buf_rele(bp); XFS_STATS_INC(xb_busy_locked); return NULL; } } else { /* trylock worked */ XB_SET_OWNER(bp); } if (bp->b_flags & XBF_STALE) { ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0); bp->b_flags &= XBF_MAPPED; } 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, i; 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_lookup_pages(bp, flags); if (error) goto no_buffer; } else { xfs_buf_deallocate(new_bp); if (unlikely(bp == NULL)) 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)) { printk(KERN_WARNING "%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 | _XBF_RUN_QUEUES); bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | \ XBF_READ_AHEAD | _XBF_RUN_QUEUES); status = xfs_buf_iorequest(bp); if (!status && !(flags & XBF_ASYNC)) status = xfs_buf_iowait(bp); return status; } 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, xfs_buf_flags_t flags) { struct backing_dev_info *bdi; bdi = target->bt_mapping->backing_dev_info; if (bdi_read_congested(bdi)) return; flags |= (XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD); xfs_buf_read(target, ioff, isize, flags); } 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; } 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_CACHE_MASK; offset = (unsigned long)mem - pageaddr; buflen = PAGE_CACHE_ALIGN(len + offset); page_count = buflen >> PAGE_CACHE_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_CACHE_SIZE; } bp->b_count_desired = len; bp->b_buffer_length = buflen; bp->b_flags |= XBF_MAPPED; bp->b_flags &= ~_XBF_PAGE_LOCKED; return 0; } xfs_buf_t * xfs_buf_get_noaddr( size_t len, xfs_buftarg_t *target) { 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(GFP_KERNEL); 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)) { printk(KERN_WARNING "%s: failed to map pages\n", __func__); goto fail_free_mem; } xfs_buf_unlock(bp); trace_xfs_buf_get_noaddr(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) { xfs_bufhash_t *hash = bp->b_hash; trace_xfs_buf_rele(bp, _RET_IP_); if (unlikely(!hash)) { ASSERT(!bp->b_relse); if (atomic_dec_and_test(&bp->b_hold)) xfs_buf_free(bp); return; } ASSERT(atomic_read(&bp->b_hold) > 0); if (atomic_dec_and_lock(&bp->b_hold, &hash->bh_lock)) { if (bp->b_relse) { atomic_inc(&bp->b_hold); spin_unlock(&hash->bh_lock); (*(bp->b_relse)) (bp); } else if (bp->b_flags & XBF_FS_MANAGED) { spin_unlock(&hash->bh_lock); } else { ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q))); list_del_init(&bp->b_hash_list); spin_unlock(&hash->bh_lock); xfs_buf_free(bp); } } } /* * 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. */ int xfs_buf_cond_lock( xfs_buf_t *bp) { int locked; locked = down_trylock(&bp->b_sema) == 0; if (locked) XB_SET_OWNER(bp); trace_xfs_buf_cond_lock(bp, _RET_IP_); return locked ? 0 : -EBUSY; } int xfs_buf_lock_value( xfs_buf_t *bp) { return bp->b_sema.count; } /* * 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. */ void xfs_buf_lock( xfs_buf_t *bp) { trace_xfs_buf_lock(bp, _RET_IP_); if (atomic_read(&bp->b_io_remaining)) blk_run_address_space(bp->b_target->bt_mapping); 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( xfs_buf_t *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_); } /* * Pinning Buffer Storage in Memory * Ensure that no attempt to force a buffer to disk will succeed. */ void xfs_buf_pin( xfs_buf_t *bp) { trace_xfs_buf_pin(bp, _RET_IP_); atomic_inc(&bp->b_pin_count); } void xfs_buf_unpin( xfs_buf_t *bp) { trace_xfs_buf_unpin(bp, _RET_IP_); if (atomic_dec_and_test(&bp->b_pin_count)) wake_up_all(&bp->b_waiters); } int xfs_buf_ispin( xfs_buf_t *bp) { return atomic_read(&bp->b_pin_count); } 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; if (atomic_read(&bp->b_io_remaining)) blk_run_address_space(bp->b_target->bt_mapping); 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); /* * We can get an EOPNOTSUPP to ordered writes. Here we clear the * ordered flag and reissue them. Because we can't tell the higher * layers directly that they should not issue ordered I/O anymore, they * need to check if the _XFS_BARRIER_FAILED flag was set during I/O completion. */ if ((bp->b_error == EOPNOTSUPP) && (bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) { trace_xfs_buf_ordered_retry(bp, _RET_IP_); bp->b_flags &= ~XBF_ORDERED; bp->b_flags |= _XFS_BARRIER_FAILED; xfs_buf_iorequest(bp); } else 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 iowait = (bp->b_flags & XBF_ASYNC) == 0; int error = 0; bp->b_strat = xfs_bdstrat_cb; bp->b_mount = mp; bp->b_flags |= XBF_WRITE; if (!iowait) bp->b_flags |= _XBF_RUN_QUEUES; xfs_buf_delwri_dequeue(bp); xfs_buf_iostrategy(bp); if (iowait) { 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_strat = xfs_bdstrat_cb; bp->b_mount = mp; 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 biodone * 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_ERROR(bp, EIO); /* * We're calling biodone, so delete XBF_DONE flag. */ XFS_BUF_UNREAD(bp); XFS_BUF_UNDELAYWRITE(bp); XFS_BUF_UNDONE(bp); XFS_BUF_STALE(bp); XFS_BUF_CLR_BDSTRAT_FUNC(bp); xfs_biodone(bp); return EIO; } /* * Same as xfs_bioerror, except that we are releasing the buffer * here ourselves, and avoiding the biodone 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 = XFS_BUF_BFLAGS(bp); /* * 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); XFS_BUF_CLR_IODONE_FUNC(bp); XFS_BUF_CLR_BDSTRAT_FUNC(bp); 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_ERROR(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_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) { bp->b_flags &= ~_XBF_PAGE_LOCKED; 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; 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); } 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; unsigned int blocksize = bp->b_target->bt_bsize; total_nr_pages = bp->b_page_count; map_i = 0; if (bp->b_flags & XBF_ORDERED) { ASSERT(!(bp->b_flags & XBF_READ)); rw = WRITE_BARRIER; } else if (bp->b_flags & XBF_LOG_BUFFER) { ASSERT(!(bp->b_flags & XBF_READ_AHEAD)); bp->b_flags &= ~_XBF_RUN_QUEUES; rw = (bp->b_flags & XBF_WRITE) ? WRITE_SYNC : READ_SYNC; } else if (bp->b_flags & _XBF_RUN_QUEUES) { ASSERT(!(bp->b_flags & XBF_READ_AHEAD)); bp->b_flags &= ~_XBF_RUN_QUEUES; rw = (bp->b_flags & XBF_WRITE) ? WRITE_META : READ_META; } else { rw = (bp->b_flags & XBF_WRITE) ? WRITE : (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); 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_CACHE_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--; } submit_io: 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 { bio_put(bio); xfs_buf_ioerror(bp, EIO); } } 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_); if (atomic_read(&bp->b_io_remaining)) blk_run_address_space(bp->b_target->bt_mapping); 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 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)); } /* * 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_CACHE_SIZE-cpoff, bp->b_count_desired-boff); ASSERT(((csize + cpoff) <= PAGE_CACHE_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... walk the hash list for the target. */ void xfs_wait_buftarg( xfs_buftarg_t *btp) { xfs_buf_t *bp, *n; xfs_bufhash_t *hash; uint i; for (i = 0; i < (1 << btp->bt_hashshift); i++) { hash = &btp->bt_hash[i]; again: spin_lock(&hash->bh_lock); list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) { ASSERT(btp == bp->b_target); if (!(bp->b_flags & XBF_FS_MANAGED)) { spin_unlock(&hash->bh_lock); /* * Catch superblock reference count leaks * immediately */ BUG_ON(bp->b_bn == 0); delay(100); goto again; } } spin_unlock(&hash->bh_lock); } } /* * Allocate buffer hash table for a given target. * For devices containing metadata (i.e. not the log/realtime devices) * we need to allocate a much larger hash table. */ STATIC void xfs_alloc_bufhash( xfs_buftarg_t *btp, int external) { unsigned int i; btp->bt_hashshift = external ? 3 : 8; /* 8 or 256 buckets */ btp->bt_hashmask = (1 << btp->bt_hashshift) - 1; btp->bt_hash = kmem_zalloc_large((1 << btp->bt_hashshift) * sizeof(xfs_bufhash_t)); for (i = 0; i < (1 << btp->bt_hashshift); i++) { spin_lock_init(&btp->bt_hash[i].bh_lock); INIT_LIST_HEAD(&btp->bt_hash[i].bh_list); } } STATIC void xfs_free_bufhash( xfs_buftarg_t *btp) { kmem_free_large(btp->bt_hash); btp->bt_hash = NULL; } /* * buftarg list for delwrite queue processing */ static LIST_HEAD(xfs_buftarg_list); static DEFINE_SPINLOCK(xfs_buftarg_lock); STATIC void xfs_register_buftarg( xfs_buftarg_t *btp) { spin_lock(&xfs_buftarg_lock); list_add(&btp->bt_list, &xfs_buftarg_list); spin_unlock(&xfs_buftarg_lock); } STATIC void xfs_unregister_buftarg( xfs_buftarg_t *btp) { spin_lock(&xfs_buftarg_lock); list_del(&btp->bt_list); spin_unlock(&xfs_buftarg_lock); } void xfs_free_buftarg( struct xfs_mount *mp, struct xfs_buftarg *btp) { xfs_flush_buftarg(btp, 1); if (mp->m_flags & XFS_MOUNT_BARRIER) xfs_blkdev_issue_flush(btp); xfs_free_bufhash(btp); iput(btp->bt_mapping->host); /* Unregister the buftarg first so that we don't get a * wakeup finding a non-existent task */ xfs_unregister_buftarg(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)) { printk(KERN_WARNING "XFS: Cannot set_blocksize to %u on device %s\n", sectorsize, XFS_BUFTARG_NAME(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; } /* * 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_CACHE_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_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 = { .sync_page = block_sync_page, .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_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) { int error = 0; INIT_LIST_HEAD(&btp->bt_list); 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"); if (IS_ERR(btp->bt_task)) { error = PTR_ERR(btp->bt_task); goto out_error; } xfs_register_buftarg(btp); out_error: return error; } xfs_buftarg_t * xfs_alloc_buftarg( struct block_device *bdev, int external) { xfs_buftarg_t *btp; btp = kmem_zalloc(sizeof(*btp), KM_SLEEP); btp->bt_dev = bdev->bd_dev; btp->bt_bdev = bdev; if (xfs_setsize_buftarg_early(btp, bdev)) goto error; if (xfs_mapping_buftarg(btp, bdev)) goto error; if (xfs_alloc_delwrite_queue(btp)) goto error; xfs_alloc_bufhash(btp, external); 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); } STATIC int xfsbufd_wakeup( int priority, gfp_t mask) { xfs_buftarg_t *btp; spin_lock(&xfs_buftarg_lock); list_for_each_entry(btp, &xfs_buftarg_list, bt_list) { if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags)) continue; if (list_empty(&btp->bt_delwrite_queue)) continue; set_bit(XBT_FORCE_FLUSH, &btp->bt_flags); wake_up_process(btp->bt_task); } spin_unlock(&xfs_buftarg_lock); return 0; } /* * 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) { trace_xfs_buf_delwri_split(bp, _RET_IP_); ASSERT(bp->b_flags & XBF_DELWRI); if (!xfs_buf_ispin(bp) && !xfs_buf_cond_lock(bp)) { if (!force && time_before(jiffies, bp->b_queuetime + age)) { xfs_buf_unlock(bp); break; } bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q| _XBF_RUN_QUEUES); bp->b_flags |= XBF_WRITE; list_move_tail(&bp->b_list, list); } 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; } void xfs_buf_delwri_sort( xfs_buftarg_t *target, struct list_head *list) { list_sort(NULL, list, xfs_buf_cmp); } 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); int count = 0; struct list_head tmp; 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); 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_buf_iostrategy(bp); count++; } if (count) blk_run_address_space(target->bt_mapping); } 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); 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); 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_buf_iostrategy(bp); } if (wait) { /* Expedite and wait for IO to complete. */ blk_run_address_space(target->bt_mapping); while (!list_empty(&wait_list)) { bp = list_first_entry(&wait_list, struct xfs_buf, b_list); list_del_init(&bp->b_list); xfs_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 = create_workqueue("xfslogd"); if (!xfslogd_workqueue) goto out_free_buf_zone; xfsdatad_workqueue = create_workqueue("xfsdatad"); if (!xfsdatad_workqueue) goto out_destroy_xfslogd_workqueue; xfsconvertd_workqueue = create_workqueue("xfsconvertd"); if (!xfsconvertd_workqueue) goto out_destroy_xfsdatad_workqueue; register_shrinker(&xfs_buf_shake); 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) { unregister_shrinker(&xfs_buf_shake); 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