[GFS2] Tidy up error handling in gfs2_releasepage()
[pandora-kernel.git] / fs / gfs2 / ops_address.c
index 3fd8c6e..4872042 100644 (file)
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
 #include <linux/completion.h>
 #include <linux/buffer_head.h>
 #include <linux/pagemap.h>
+#include <linux/pagevec.h>
 #include <linux/mpage.h>
 #include <linux/fs.h>
 #include <linux/gfs2_ondisk.h>
-#include <asm/semaphore.h>
 
 #include "gfs2.h"
 #include "lm_interface.h"
 #include "log.h"
 #include "meta_io.h"
 #include "ops_address.h"
-#include "page.h"
 #include "quota.h"
 #include "trans.h"
 #include "rgrp.h"
 #include "ops_file.h"
 #include "util.h"
+#include "glops.h"
+
+
+static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
+                                  unsigned int from, unsigned int to)
+{
+       struct buffer_head *head = page_buffers(page);
+       unsigned int bsize = head->b_size;
+       struct buffer_head *bh;
+       unsigned int start, end;
+
+       for (bh = head, start = 0; bh != head || !start;
+            bh = bh->b_this_page, start = end) {
+               end = start + bsize;
+               if (end <= from || start >= to)
+                       continue;
+               gfs2_trans_add_bh(ip->i_gl, bh, 0);
+       }
+}
 
 /**
  * gfs2_get_block - Fills in a buffer head with details about a block
 int gfs2_get_block(struct inode *inode, sector_t lblock,
                   struct buffer_head *bh_result, int create)
 {
-       struct gfs2_inode *ip = inode->u.generic_ip;
        int new = create;
        uint64_t dblock;
        int error;
+       int boundary;
 
-       error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
+       error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
        if (error)
                return error;
 
@@ -62,6 +80,8 @@ int gfs2_get_block(struct inode *inode, sector_t lblock,
        map_bh(bh_result, inode->i_sb, dblock);
        if (new)
                set_buffer_new(bh_result);
+       if (boundary)
+               set_buffer_boundary(bh_result);
 
        return 0;
 }
@@ -79,19 +99,21 @@ int gfs2_get_block(struct inode *inode, sector_t lblock,
 static int get_block_noalloc(struct inode *inode, sector_t lblock,
                             struct buffer_head *bh_result, int create)
 {
-       struct gfs2_inode *ip = inode->u.generic_ip;
        int new = 0;
        uint64_t dblock;
        int error;
+       int boundary;
 
-       error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
+       error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
        if (error)
                return error;
 
        if (dblock)
                map_bh(bh_result, inode->i_sb, dblock);
-       else if (gfs2_assert_withdraw(ip->i_sbd, !create))
+       else if (gfs2_assert_withdraw(GFS2_SB(inode), !create))
                error = -EIO;
+       if (boundary)
+               set_buffer_boundary(bh_result);
 
        return error;
 }
@@ -109,8 +131,8 @@ static int get_block_noalloc(struct inode *inode, sector_t lblock,
 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 {
        struct inode *inode = page->mapping->host;
-       struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
-       struct gfs2_sbd *sdp = ip->i_sbd;
+       struct gfs2_inode *ip = GFS2_I(inode);
+       struct gfs2_sbd *sdp = GFS2_SB(inode);
        loff_t i_size = i_size_read(inode);
        pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
        unsigned offset;
@@ -126,7 +148,7 @@ static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 
        /* Is the page fully outside i_size? (truncate in progress) */
         offset = i_size & (PAGE_CACHE_SIZE-1);
-       if (page->index >= end_index+1 || !offset) {
+       if (page->index > end_index || (page->index == end_index && !offset)) {
                page->mapping->a_ops->invalidatepage(page, 0);
                unlock_page(page);
                return 0; /* don't care */
@@ -136,6 +158,10 @@ static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
                error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
                if (error)
                        goto out_ignore;
+               if (!page_has_buffers(page)) {
+                       create_empty_buffers(page, inode->i_sb->s_blocksize,
+                                            (1 << BH_Dirty)|(1 << BH_Uptodate));
+               }
                gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
                done_trans = 1;
        }
@@ -151,6 +177,19 @@ out_ignore:
        return 0;
 }
 
+static int zero_readpage(struct page *page)
+{
+       void *kaddr;
+
+       kaddr = kmap_atomic(page, KM_USER0);
+       memset(kaddr, 0, PAGE_CACHE_SIZE);
+       kunmap_atomic(page, KM_USER0);
+
+       SetPageUptodate(page);
+
+       return 0;
+}
+
 /**
  * stuffed_readpage - Fill in a Linux page with stuffed file data
  * @ip: the inode
@@ -165,17 +204,18 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
        void *kaddr;
        int error;
 
+       /* Only the first page of a stuffed file might contain data */
+       if (unlikely(page->index))
+               return zero_readpage(page);
+
        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (error)
                return error;
 
        kaddr = kmap_atomic(page, KM_USER0);
-       memcpy((char *)kaddr,
-              dibh->b_data + sizeof(struct gfs2_dinode),
+       memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
               ip->i_di.di_size);
-       memset((char *)kaddr + ip->i_di.di_size,
-              0,
-              PAGE_CACHE_SIZE - ip->i_di.di_size);
+       memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
        kunmap_atomic(page, KM_USER0);
 
        brelse(dibh);
@@ -185,19 +225,6 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
        return 0;
 }
 
-static int zero_readpage(struct page *page)
-{
-       void *kaddr;
-
-       kaddr = kmap_atomic(page, KM_USER0);
-       memset(kaddr, 0, PAGE_CACHE_SIZE);
-       kunmap_atomic(page, KM_USER0);
-
-       SetPageUptodate(page);
-       unlock_page(page);
-
-       return 0;
-}
 
 /**
  * gfs2_readpage - readpage with locking
@@ -210,24 +237,29 @@ static int zero_readpage(struct page *page)
 
 static int gfs2_readpage(struct file *file, struct page *page)
 {
-       struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
-       struct gfs2_sbd *sdp = ip->i_sbd;
+       struct gfs2_inode *ip = GFS2_I(page->mapping->host);
+       struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
        struct gfs2_holder gh;
        int error;
+       int do_unlock = 0;
 
-       if (file != &gfs2_internal_file_sentinal) {
-               gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
+       if (likely(file != &gfs2_internal_file_sentinal)) {
+               if (file) {
+                       struct gfs2_file *gf = file->private_data;
+                       if (test_bit(GFF_EXLOCK, &gf->f_flags))
+                               goto skip_lock;
+               }
+               gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
+               do_unlock = 1;
                error = gfs2_glock_nq_m_atime(1, &gh);
-               if (error)
+               if (unlikely(error))
                        goto out_unlock;
        }
 
+skip_lock:
        if (gfs2_is_stuffed(ip)) {
-               if (!page->index) {
-                       error = stuffed_readpage(ip, page);
-                       unlock_page(page);
-               } else
-                       error = zero_readpage(page);
+               error = stuffed_readpage(ip, page);
+               unlock_page(page);
        } else
                error = mpage_readpage(page, gfs2_get_block);
 
@@ -242,6 +274,97 @@ out:
        return error;
 out_unlock:
        unlock_page(page);
+       if (do_unlock)
+               gfs2_holder_uninit(&gh);
+       goto out;
+}
+
+/**
+ * gfs2_readpages - Read a bunch of pages at once
+ *
+ * Some notes:
+ * 1. This is only for readahead, so we can simply ignore any things
+ *    which are slightly inconvenient (such as locking conflicts between
+ *    the page lock and the glock) and return having done no I/O. Its
+ *    obviously not something we'd want to do on too regular a basis.
+ *    Any I/O we ignore at this time will be done via readpage later.
+ * 2. We have to handle stuffed files here too.
+ * 3. mpage_readpages() does most of the heavy lifting in the common case.
+ * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
+ * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
+ *    well as read-ahead.
+ */
+static int gfs2_readpages(struct file *file, struct address_space *mapping,
+                         struct list_head *pages, unsigned nr_pages)
+{
+       struct inode *inode = mapping->host;
+       struct gfs2_inode *ip = GFS2_I(inode);
+       struct gfs2_sbd *sdp = GFS2_SB(inode);
+       struct gfs2_holder gh;
+       unsigned page_idx;
+       int ret;
+       int do_unlock = 0;
+
+       if (likely(file != &gfs2_internal_file_sentinal)) {
+               if (file) {
+                       struct gfs2_file *gf = file->private_data;
+                       if (test_bit(GFF_EXLOCK, &gf->f_flags))
+                               goto skip_lock;
+               }
+               gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
+                                LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
+               do_unlock = 1;
+               ret = gfs2_glock_nq_m_atime(1, &gh);
+               if (ret == GLR_TRYFAILED) 
+                       goto out_noerror;
+               if (unlikely(ret))
+                       goto out_unlock;
+       }
+skip_lock:
+       if (gfs2_is_stuffed(ip)) {
+               struct pagevec lru_pvec;
+               pagevec_init(&lru_pvec, 0);
+               for (page_idx = 0; page_idx < nr_pages; page_idx++) {
+                       struct page *page = list_entry(pages->prev, struct page, lru);
+                       prefetchw(&page->flags);
+                       list_del(&page->lru);
+                       if (!add_to_page_cache(page, mapping,
+                                              page->index, GFP_KERNEL)) {
+                               ret = stuffed_readpage(ip, page);
+                               unlock_page(page);
+                               if (!pagevec_add(&lru_pvec, page))
+                                        __pagevec_lru_add(&lru_pvec);
+                       } else {
+                               page_cache_release(page);
+                       }
+               }
+               pagevec_lru_add(&lru_pvec);
+               ret = 0;
+       } else {
+               /* What we really want to do .... */
+               ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
+       }
+
+       if (do_unlock) {
+               gfs2_glock_dq_m(1, &gh);
+               gfs2_holder_uninit(&gh);
+       }
+out:
+       if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+               ret = -EIO;
+       return ret;
+out_noerror:
+       ret = 0;
+out_unlock:
+       /* unlock all pages, we can't do any I/O right now */
+       for (page_idx = 0; page_idx < nr_pages; page_idx++) {
+               struct page *page = list_entry(pages->prev, struct page, lru);
+               list_del(&page->lru);
+               unlock_page(page);
+               page_cache_release(page);
+       }
+       if (do_unlock)
+               gfs2_holder_uninit(&gh);
        goto out;
 }
 
@@ -258,8 +381,8 @@ out_unlock:
 static int gfs2_prepare_write(struct file *file, struct page *page,
                              unsigned from, unsigned to)
 {
-       struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
-       struct gfs2_sbd *sdp = ip->i_sbd;
+       struct gfs2_inode *ip = GFS2_I(page->mapping->host);
+       struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
        unsigned int data_blocks, ind_blocks, rblocks;
        int alloc_required;
        int error = 0;
@@ -267,7 +390,7 @@ static int gfs2_prepare_write(struct file *file, struct page *page,
        loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
        struct gfs2_alloc *al;
 
-       gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
+       gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
        error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
        if (error)
                goto out_uninit;
@@ -308,8 +431,7 @@ static int gfs2_prepare_write(struct file *file, struct page *page,
 
        if (gfs2_is_stuffed(ip)) {
                if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
-                       error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
-                                                   page);
+                       error = gfs2_unstuff_dinode(ip, page);
                        if (error == 0)
                                goto prepare_write;
                } else if (!PageUptodate(page))
@@ -353,8 +475,8 @@ static int gfs2_commit_write(struct file *file, struct page *page,
                             unsigned from, unsigned to)
 {
        struct inode *inode = page->mapping->host;
-       struct gfs2_inode *ip = inode->u.generic_ip;
-       struct gfs2_sbd *sdp = ip->i_sbd;
+       struct gfs2_inode *ip = GFS2_I(inode);
+       struct gfs2_sbd *sdp = GFS2_SB(inode);
        int error = -EOPNOTSUPP;
        struct buffer_head *dibh;
        struct gfs2_alloc *al = &ip->i_alloc;;
@@ -433,7 +555,7 @@ fail_nounlock:
 
 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 {
-       struct gfs2_inode *ip = mapping->host->u.generic_ip;
+       struct gfs2_inode *ip = GFS2_I(mapping->host);
        struct gfs2_holder i_gh;
        sector_t dblock = 0;
        int error;
@@ -459,10 +581,8 @@ static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
        if (bd) {
                bd->bd_bh = NULL;
                bh->b_private = NULL;
-               gfs2_log_unlock(sdp);
-               brelse(bh);
-       } else
-               gfs2_log_unlock(sdp);
+       }
+       gfs2_log_unlock(sdp);
 
        lock_buffer(bh);
        clear_buffer_dirty(bh);
@@ -476,7 +596,7 @@ static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 
 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 {
-       struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
+       struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
        struct buffer_head *head, *bh, *next;
        unsigned int curr_off = 0;
 
@@ -502,17 +622,20 @@ static void gfs2_invalidatepage(struct page *page, unsigned long offset)
        return;
 }
 
-static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
-                                   loff_t offset, unsigned long nr_segs)
+static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
+                             const struct iovec *iov, loff_t offset,
+                             unsigned long nr_segs)
 {
        struct file *file = iocb->ki_filp;
        struct inode *inode = file->f_mapping->host;
-       struct gfs2_inode *ip = inode->u.generic_ip;
+       struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_holder gh;
        int rv;
 
+       if (rw == READ)
+               mutex_lock(&inode->i_mutex);
        /*
-        * Shared lock, even though its write, since we do no allocation
+        * Shared lock, even if its a write, since we do no allocation
         * on this path. All we need change is atime.
         */
        gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
@@ -520,6 +643,9 @@ static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
        if (rv)
                goto out;
 
+       if (offset > i_size_read(inode))
+               goto out;
+
        /*
         * Should we return an error here? I can't see that O_DIRECT for
         * a journaled file makes any sense. For now we'll silently fall
@@ -532,51 +658,137 @@ static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
        if (gfs2_is_stuffed(ip))
                goto out;
 
-       rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
-                                 iov, offset, nr_segs, gfs2_get_block,
-                                 NULL, DIO_OWN_LOCKING);
+       rv = blockdev_direct_IO_own_locking(rw, iocb, inode,
+                                           inode->i_sb->s_bdev,
+                                           iov, offset, nr_segs,
+                                           gfs2_get_block, NULL);
 out:
        gfs2_glock_dq_m(1, &gh);
        gfs2_holder_uninit(&gh);
+       if (rw == READ)
+               mutex_unlock(&inode->i_mutex);
 
        return rv;
 }
 
 /**
- * gfs2_direct_IO
+ * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
+ * @bh: the buffer we're stuck on
  *
- * This is called with a shared lock already held for the read path.
- * Currently, no locks are held when the write path is called.
  */
-static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
-                             const struct iovec *iov, loff_t offset,
-                             unsigned long nr_segs)
+
+static void stuck_releasepage(struct buffer_head *bh)
 {
-       struct file *file = iocb->ki_filp;
-       struct inode *inode = file->f_mapping->host;
-       struct gfs2_inode *ip = inode->u.generic_ip;
-       struct gfs2_sbd *sdp = ip->i_sbd;
+       struct inode *inode = bh->b_page->mapping->host;
+       struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
+       struct gfs2_bufdata *bd = bh->b_private;
+       struct gfs2_glock *gl;
+static unsigned limit = 0;
+
+       if (limit++ > 3)
+               return;
+
+       fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
+       fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
+               (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
+       fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
+       fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
+
+       if (!bd)
+               return;
+
+       gl = bd->bd_gl;
+
+       fs_warn(sdp, "gl = (%u, %llu)\n", 
+               gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 
-       if (rw == WRITE)
-               return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
+       fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
+               (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
+               (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 
-       if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
-           gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
-               return -EINVAL;
+       if (gl->gl_ops == &gfs2_inode_glops) {
+               struct gfs2_inode *ip = gl->gl_object;
+               unsigned int x;
 
-       return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
-                                   offset, nr_segs, gfs2_get_block, NULL,
-                                   DIO_OWN_LOCKING);
+               if (!ip)
+                       return;
+
+               fs_warn(sdp, "ip = %llu %llu\n",
+                       (unsigned long long)ip->i_num.no_formal_ino,
+                       (unsigned long long)ip->i_num.no_addr);
+
+               for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
+                       fs_warn(sdp, "ip->i_cache[%u] = %s\n",
+                               x, (ip->i_cache[x]) ? "!NULL" : "NULL");
+       }
+}
+
+/**
+ * gfs2_aspace_releasepage - free the metadata associated with a page
+ * @page: the page that's being released
+ * @gfp_mask: passed from Linux VFS, ignored by us
+ *
+ * Call try_to_free_buffers() if the buffers in this page can be
+ * released.
+ *
+ * Returns: 0
+ */
+
+int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
+{
+       struct inode *aspace = page->mapping->host;
+       struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
+       struct buffer_head *bh, *head;
+       struct gfs2_bufdata *bd;
+       unsigned long t = jiffies + gfs2_tune_get(sdp, gt_stall_secs) * HZ;
+
+       if (!page_has_buffers(page))
+               goto out;
+
+       head = bh = page_buffers(page);
+       do {
+               while (atomic_read(&bh->b_count)) {
+                       if (!atomic_read(&aspace->i_writecount))
+                               return 0;
+
+                       if (time_after_eq(jiffies, t)) {
+                               stuck_releasepage(bh);
+                               /* should we withdraw here? */
+                               return 0;
+                       }
+
+                       yield();
+               }
+
+               gfs2_assert_warn(sdp, !buffer_pinned(bh));
+
+               bd = bh->b_private;
+               if (bd) {
+                       gfs2_assert_warn(sdp, bd->bd_bh == bh);
+                       gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
+                       gfs2_assert_warn(sdp, list_empty(&bd->bd_le.le_list));
+                       gfs2_assert_warn(sdp, !bd->bd_ail);
+                       kmem_cache_free(gfs2_bufdata_cachep, bd);
+                       bh->b_private = NULL;
+               }
+
+               bh = bh->b_this_page;
+       } while (bh != head);
+
+out:
+       return try_to_free_buffers(page);
 }
 
-struct address_space_operations gfs2_file_aops = {
+const struct address_space_operations gfs2_file_aops = {
        .writepage = gfs2_writepage,
        .readpage = gfs2_readpage,
+       .readpages = gfs2_readpages,
        .sync_page = block_sync_page,
        .prepare_write = gfs2_prepare_write,
        .commit_write = gfs2_commit_write,
        .bmap = gfs2_bmap,
        .invalidatepage = gfs2_invalidatepage,
+       .releasepage = gfs2_releasepage,
        .direct_IO = gfs2_direct_IO,
 };