vserver 1.9.5.x5
[linux-2.6.git] / fs / buffer.c
index 81f3129..3c40d63 100644 (file)
@@ -20,6 +20,7 @@
 
 #include <linux/config.h>
 #include <linux/kernel.h>
+#include <linux/syscalls.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/percpu.h>
 #include <linux/bio.h>
 #include <linux/notifier.h>
 #include <linux/cpu.h>
-#include <asm/bitops.h>
+#include <linux/bitops.h>
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
 static void invalidate_bh_lrus(void);
 
 #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
 
-struct bh_wait_queue {
-       struct buffer_head *bh;
-       wait_queue_t wait;
-};
-
-#define __DEFINE_BH_WAIT(name, b, f)                                   \
-       struct bh_wait_queue name = {                                   \
-               .bh     = b,                                            \
-               .wait   = {                                             \
-                               .task   = current,                      \
-                               .flags  = f,                            \
-                               .func   = bh_wake_function,             \
-                               .task_list =                            \
-                                       LIST_HEAD_INIT(name.wait.task_list),\
-                       },                                              \
-       }
-#define DEFINE_BH_WAIT(name, bh)       __DEFINE_BH_WAIT(name, bh, 0)
-#define DEFINE_BH_WAIT_EXCLUSIVE(name, bh) \
-               __DEFINE_BH_WAIT(name, bh, WQ_FLAG_EXCLUSIVE)
-
-/*
- * Hashed waitqueue_head's for wait_on_buffer()
- */
-#define BH_WAIT_TABLE_ORDER    7
-static struct bh_wait_queue_head {
-       wait_queue_head_t wqh;
-} ____cacheline_aligned_in_smp bh_wait_queue_heads[1<<BH_WAIT_TABLE_ORDER];
-
 inline void
 init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
 {
@@ -79,63 +52,24 @@ init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
        bh->b_private = private;
 }
 
-/*
- * Return the address of the waitqueue_head to be used for this
- * buffer_head
- */
-wait_queue_head_t *bh_waitq_head(struct buffer_head *bh)
-{
-       return &bh_wait_queue_heads[hash_ptr(bh, BH_WAIT_TABLE_ORDER)].wqh;
-}
-EXPORT_SYMBOL(bh_waitq_head);
-
-void wake_up_buffer(struct buffer_head *bh)
-{
-       wait_queue_head_t *wq = bh_waitq_head(bh);
-
-       smp_mb();
-       if (waitqueue_active(wq))
-               __wake_up(wq, TASK_INTERRUPTIBLE|TASK_UNINTERRUPTIBLE, 1, bh);
-}
-EXPORT_SYMBOL(wake_up_buffer);
-
-static int bh_wake_function(wait_queue_t *wait, unsigned mode,
-                               int sync, void *key)
-{
-       struct buffer_head *bh = key;
-       struct bh_wait_queue *wq;
-
-       wq = container_of(wait, struct bh_wait_queue, wait);
-       if (wq->bh != bh || buffer_locked(bh))
-               return 0;
-       else
-               return autoremove_wake_function(wait, mode, sync, key);
-}
-
-static void sync_buffer(struct buffer_head *bh)
+static int sync_buffer(void *word)
 {
        struct block_device *bd;
+       struct buffer_head *bh
+               = container_of(word, struct buffer_head, b_state);
 
        smp_mb();
        bd = bh->b_bdev;
        if (bd)
                blk_run_address_space(bd->bd_inode->i_mapping);
+       io_schedule();
+       return 0;
 }
 
 void fastcall __lock_buffer(struct buffer_head *bh)
 {
-       wait_queue_head_t *wqh = bh_waitq_head(bh);
-       DEFINE_BH_WAIT_EXCLUSIVE(wait, bh);
-
-       do {
-               prepare_to_wait_exclusive(wqh, &wait.wait,
-                                       TASK_UNINTERRUPTIBLE);
-               if (buffer_locked(bh)) {
-                       sync_buffer(bh);
-                       io_schedule();
-               }
-       } while (test_set_buffer_locked(bh));
-       finish_wait(wqh, &wait.wait);
+       wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer,
+                                                       TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__lock_buffer);
 
@@ -143,7 +77,7 @@ void fastcall unlock_buffer(struct buffer_head *bh)
 {
        clear_buffer_locked(bh);
        smp_mb__after_clear_bit();
-       wake_up_buffer(bh);
+       wake_up_bit(&bh->b_state, BH_Lock);
 }
 
 /*
@@ -153,25 +87,7 @@ void fastcall unlock_buffer(struct buffer_head *bh)
  */
 void __wait_on_buffer(struct buffer_head * bh)
 {
-       wait_queue_head_t *wqh = bh_waitq_head(bh);
-       DEFINE_BH_WAIT(wait, bh);
-
-       do {
-               prepare_to_wait(wqh, &wait.wait, TASK_UNINTERRUPTIBLE);
-               if (buffer_locked(bh)) {
-                       sync_buffer(bh);
-                       io_schedule();
-               }
-       } while (buffer_locked(bh));
-       finish_wait(wqh, &wait.wait);
-}
-
-static void
-__set_page_buffers(struct page *page, struct buffer_head *head)
-{
-       page_cache_get(page);
-       SetPagePrivate(page);
-       page->private = (unsigned long)head;
+       wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE);
 }
 
 static void
@@ -395,10 +311,10 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
 {
        struct inode * inode = dentry->d_inode;
        struct super_block * sb;
-       int ret;
+       int ret, err;
 
        /* sync the inode to buffers */
-       write_inode_now(inode, 0);
+       ret = write_inode_now(inode, 0);
 
        /* sync the superblock to buffers */
        sb = inode->i_sb;
@@ -408,7 +324,9 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
        unlock_super(sb);
 
        /* .. finally sync the buffers to disk */
-       ret = sync_blockdev(sb->s_bdev);
+       err = sync_blockdev(sb->s_bdev);
+       if (!ret)
+               ret = err;
        return ret;
 }
 
@@ -431,18 +349,22 @@ asmlinkage long sys_fsync(unsigned int fd)
                goto out_putf;
        }
 
-       /* We need to protect against concurrent writers.. */
-       down(&mapping->host->i_sem);
        current->flags |= PF_SYNCWRITE;
        ret = filemap_fdatawrite(mapping);
+
+       /*
+        * We need to protect against concurrent writers,
+        * which could cause livelocks in fsync_buffers_list
+        */
+       down(&mapping->host->i_sem);
        err = file->f_op->fsync(file, file->f_dentry, 0);
        if (!ret)
                ret = err;
+       up(&mapping->host->i_sem);
        err = filemap_fdatawait(mapping);
        if (!ret)
                ret = err;
        current->flags &= ~PF_SYNCWRITE;
-       up(&mapping->host->i_sem);
 
 out_putf:
        fput(file);
@@ -467,17 +389,17 @@ asmlinkage long sys_fdatasync(unsigned int fd)
 
        mapping = file->f_mapping;
 
-       down(&mapping->host->i_sem);
        current->flags |= PF_SYNCWRITE;
        ret = filemap_fdatawrite(mapping);
+       down(&mapping->host->i_sem);
        err = file->f_op->fsync(file, file->f_dentry, 1);
        if (!ret)
                ret = err;
+       up(&mapping->host->i_sem);
        err = filemap_fdatawait(mapping);
        if (!ret)
                ret = err;
        current->flags &= ~PF_SYNCWRITE;
-       up(&mapping->host->i_sem);
 
 out_putf:
        fput(file);
@@ -506,6 +428,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block, int unused)
        struct buffer_head *bh;
        struct buffer_head *head;
        struct page *page;
+       int all_mapped = 1;
 
        index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
        page = find_get_page(bd_mapping, index);
@@ -523,14 +446,23 @@ __find_get_block_slow(struct block_device *bdev, sector_t block, int unused)
                        get_bh(bh);
                        goto out_unlock;
                }
+               if (!buffer_mapped(bh))
+                       all_mapped = 0;
                bh = bh->b_this_page;
        } while (bh != head);
 
-       printk("__find_get_block_slow() failed. "
-               "block=%llu, b_blocknr=%llu\n",
-               (unsigned long long)block, (unsigned long long)bh->b_blocknr);
-       printk("b_state=0x%08lx, b_size=%u\n", bh->b_state, bh->b_size);
-       printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits);
+       /* we might be here because some of the buffers on this page are
+        * not mapped.  This is due to various races between
+        * file io on the block device and getblk.  It gets dealt with
+        * elsewhere, don't buffer_error if we had some unmapped buffers
+        */
+       if (all_mapped) {
+               printk("__find_get_block_slow() failed. "
+                       "block=%llu, b_blocknr=%llu\n",
+                       (unsigned long long)block, (unsigned long long)bh->b_blocknr);
+               printk("b_state=0x%08lx, b_size=%u\n", bh->b_state, bh->b_size);
+               printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits);
+       }
 out_unlock:
        spin_unlock(&bd_mapping->private_lock);
        page_cache_release(page);
@@ -605,7 +537,7 @@ static void free_more_memory(void)
  */
 static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
 {
-       static spinlock_t page_uptodate_lock = SPIN_LOCK_UNLOCKED;
+       static DEFINE_SPINLOCK(page_uptodate_lock);
        unsigned long flags;
        struct buffer_head *tmp;
        struct page *page;
@@ -618,7 +550,8 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
                set_buffer_uptodate(bh);
        } else {
                clear_buffer_uptodate(bh);
-               buffer_io_error(bh);
+               if (printk_ratelimit())
+                       buffer_io_error(bh);
                SetPageError(page);
        }
 
@@ -663,7 +596,7 @@ still_busy:
 void end_buffer_async_write(struct buffer_head *bh, int uptodate)
 {
        char b[BDEVNAME_SIZE];
-       static spinlock_t page_uptodate_lock = SPIN_LOCK_UNLOCKED;
+       static DEFINE_SPINLOCK(page_uptodate_lock);
        unsigned long flags;
        struct buffer_head *tmp;
        struct page *page;
@@ -1089,8 +1022,8 @@ int remove_inode_buffers(struct inode *inode)
  * The retry flag is used to differentiate async IO (paging, swapping)
  * which may not fail from ordinary buffer allocations.
  */
-static struct buffer_head *
-create_buffers(struct page * page, unsigned long size, int retry)
+struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
+               int retry)
 {
        struct buffer_head *bh, *head;
        long offset;
@@ -1148,6 +1081,7 @@ no_grow:
        free_more_memory();
        goto try_again;
 }
+EXPORT_SYMBOL_GPL(alloc_page_buffers);
 
 static inline void
 link_dev_buffers(struct page *page, struct buffer_head *head)
@@ -1160,7 +1094,7 @@ link_dev_buffers(struct page *page, struct buffer_head *head)
                bh = bh->b_this_page;
        } while (bh);
        tail->b_this_page = head;
-       __set_page_buffers(page, head);
+       attach_page_buffers(page, head);
 }
 
 /*
@@ -1172,18 +1106,16 @@ init_page_buffers(struct page *page, struct block_device *bdev,
 {
        struct buffer_head *head = page_buffers(page);
        struct buffer_head *bh = head;
-       unsigned int b_state;
-
-       b_state = 1 << BH_Mapped;
-       if (PageUptodate(page))
-               b_state |= 1 << BH_Uptodate;
+       int uptodate = PageUptodate(page);
 
        do {
-               if (!(bh->b_state & (1 << BH_Mapped))) {
+               if (!buffer_mapped(bh)) {
                        init_buffer(bh, NULL, NULL);
                        bh->b_bdev = bdev;
                        bh->b_blocknr = block;
-                       bh->b_state = b_state;
+                       if (uptodate)
+                               set_buffer_uptodate(bh);
+                       set_buffer_mapped(bh);
                }
                block++;
                bh = bh->b_this_page;
@@ -1212,8 +1144,10 @@ grow_dev_page(struct block_device *bdev, sector_t block,
 
        if (page_has_buffers(page)) {
                bh = page_buffers(page);
-               if (bh->b_size == size)
+               if (bh->b_size == size) {
+                       init_page_buffers(page, bdev, block, size);
                        return page;
+               }
                if (!try_to_free_buffers(page))
                        goto failed;
        }
@@ -1221,7 +1155,7 @@ grow_dev_page(struct block_device *bdev, sector_t block,
        /*
         * Allocate some buffers for this page
         */
-       bh = create_buffers(page, size, 0);
+       bh = alloc_page_buffers(page, size, 0);
        if (!bh)
                goto failed;
 
@@ -1727,7 +1661,7 @@ void create_empty_buffers(struct page *page,
 {
        struct buffer_head *bh, *head, *tail;
 
-       head = create_buffers(page, blocksize, 1);
+       head = alloc_page_buffers(page, blocksize, 1);
        bh = head;
        do {
                bh->b_state |= b_state;
@@ -1747,7 +1681,7 @@ void create_empty_buffers(struct page *page,
                        bh = bh->b_this_page;
                } while (bh != head);
        }
-       __set_page_buffers(page, head);
+       attach_page_buffers(page, head);
        spin_unlock(&page->mapping->private_lock);
 }
 EXPORT_SYMBOL(create_empty_buffers);
@@ -2232,7 +2166,7 @@ int generic_cont_expand(struct inode *inode, loff_t size)
        int err;
 
        err = -EFBIG;
-        limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
+        limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
        if (limit != RLIM_INFINITY && size > (loff_t)limit) {
                send_sig(SIGXFSZ, current, 0);
                goto out;
@@ -2307,8 +2241,7 @@ int cont_prepare_write(struct page *page, unsigned offset,
                memset(kaddr+zerofrom, 0, PAGE_CACHE_SIZE-zerofrom);
                flush_dcache_page(new_page);
                kunmap_atomic(kaddr, KM_USER0);
-               __block_commit_write(inode, new_page,
-                               zerofrom, PAGE_CACHE_SIZE);
+               generic_commit_write(NULL, new_page, zerofrom, PAGE_CACHE_SIZE);
                unlock_page(new_page);
                page_cache_release(new_page);
        }
@@ -3122,14 +3055,11 @@ static int buffer_cpu_notify(struct notifier_block *self,
 
 void __init buffer_init(void)
 {
-       int i;
        int nrpages;
 
        bh_cachep = kmem_cache_create("buffer_head",
                        sizeof(struct buffer_head), 0,
                        SLAB_PANIC, init_buffer_head, NULL);
-       for (i = 0; i < ARRAY_SIZE(bh_wait_queue_heads); i++)
-               init_waitqueue_head(&bh_wait_queue_heads[i].wqh);
 
        /*
         * Limit the bh occupancy to 10% of ZONE_NORMAL