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-rw-r--r--fs/ocfs2/refcounttree.c814
1 files changed, 814 insertions, 0 deletions
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index e72dbdd..4e7df8b 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -31,6 +31,27 @@
#include "sysfile.h"
#include "dlmglue.h"
#include "extent_map.h"
+#include "aops.h"
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/swap.h>
+
+struct ocfs2_cow_context {
+ struct inode *inode;
+ u32 cow_start;
+ u32 cow_len;
+ struct ocfs2_extent_tree di_et;
+ struct ocfs2_caching_info *ref_ci;
+ struct buffer_head *ref_root_bh;
+ struct ocfs2_alloc_context *meta_ac;
+ struct ocfs2_alloc_context *data_ac;
+ struct ocfs2_cached_dealloc_ctxt dealloc;
+};
static inline struct ocfs2_refcount_tree *
cache_info_to_refcount(struct ocfs2_caching_info *ci)
@@ -2404,3 +2425,796 @@ out:
brelse(ref_root_bh);
return ret;
}
+
+#define MAX_CONTIG_BYTES 1048576
+
+static inline unsigned int ocfs2_cow_contig_clusters(struct super_block *sb)
+{
+ return ocfs2_clusters_for_bytes(sb, MAX_CONTIG_BYTES);
+}
+
+static inline unsigned int ocfs2_cow_contig_mask(struct super_block *sb)
+{
+ return ~(ocfs2_cow_contig_clusters(sb) - 1);
+}
+
+/*
+ * Given an extent that starts at 'start' and an I/O that starts at 'cpos',
+ * find an offset (start + (n * contig_clusters)) that is closest to cpos
+ * while still being less than or equal to it.
+ *
+ * The goal is to break the extent at a multiple of contig_clusters.
+ */
+static inline unsigned int ocfs2_cow_align_start(struct super_block *sb,
+ unsigned int start,
+ unsigned int cpos)
+{
+ BUG_ON(start > cpos);
+
+ return start + ((cpos - start) & ocfs2_cow_contig_mask(sb));
+}
+
+/*
+ * Given a cluster count of len, pad it out so that it is a multiple
+ * of contig_clusters.
+ */
+static inline unsigned int ocfs2_cow_align_length(struct super_block *sb,
+ unsigned int len)
+{
+ unsigned int padded =
+ (len + (ocfs2_cow_contig_clusters(sb) - 1)) &
+ ocfs2_cow_contig_mask(sb);
+
+ /* Did we wrap? */
+ if (padded < len)
+ padded = UINT_MAX;
+
+ return padded;
+}
+
+/*
+ * Calculate out the start and number of virtual clusters we need to to CoW.
+ *
+ * cpos is vitual start cluster position we want to do CoW in a
+ * file and write_len is the cluster length.
+ *
+ * Normal we will start CoW from the beginning of extent record cotaining cpos.
+ * We try to break up extents on boundaries of MAX_CONTIG_BYTES so that we
+ * get good I/O from the resulting extent tree.
+ */
+static int ocfs2_refcount_cal_cow_clusters(struct inode *inode,
+ struct buffer_head *di_bh,
+ u32 cpos,
+ u32 write_len,
+ u32 *cow_start,
+ u32 *cow_len)
+{
+ int ret = 0;
+ struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
+ struct ocfs2_extent_list *el = &di->id2.i_list;
+ int tree_height = le16_to_cpu(el->l_tree_depth), i;
+ struct buffer_head *eb_bh = NULL;
+ struct ocfs2_extent_block *eb = NULL;
+ struct ocfs2_extent_rec *rec;
+ unsigned int want_clusters, rec_end = 0;
+ int contig_clusters = ocfs2_cow_contig_clusters(inode->i_sb);
+ int leaf_clusters;
+
+ if (tree_height > 0) {
+ ret = ocfs2_find_leaf(INODE_CACHE(inode), el, cpos, &eb_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+ el = &eb->h_list;
+
+ if (el->l_tree_depth) {
+ ocfs2_error(inode->i_sb,
+ "Inode %lu has non zero tree depth in "
+ "leaf block %llu\n", inode->i_ino,
+ (unsigned long long)eb_bh->b_blocknr);
+ ret = -EROFS;
+ goto out;
+ }
+ }
+
+ *cow_len = 0;
+ for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+ rec = &el->l_recs[i];
+
+ if (ocfs2_is_empty_extent(rec)) {
+ mlog_bug_on_msg(i != 0, "Inode %lu has empty record in "
+ "index %d\n", inode->i_ino, i);
+ continue;
+ }
+
+ if (le32_to_cpu(rec->e_cpos) +
+ le16_to_cpu(rec->e_leaf_clusters) <= cpos)
+ continue;
+
+ if (*cow_len == 0) {
+ /*
+ * We should find a refcounted record in the
+ * first pass.
+ */
+ BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED));
+ *cow_start = le32_to_cpu(rec->e_cpos);
+ }
+
+ /*
+ * If we encounter a hole or a non-refcounted record,
+ * stop the search.
+ */
+ if ((!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) ||
+ (*cow_len && rec_end != le32_to_cpu(rec->e_cpos)))
+ break;
+
+ leaf_clusters = le16_to_cpu(rec->e_leaf_clusters);
+ rec_end = le32_to_cpu(rec->e_cpos) + leaf_clusters;
+
+ /*
+ * How many clusters do we actually need from
+ * this extent? First we see how many we actually
+ * need to complete the write. If that's smaller
+ * than contig_clusters, we try for contig_clusters.
+ */
+ if (!*cow_len)
+ want_clusters = write_len;
+ else
+ want_clusters = (cpos + write_len) -
+ (*cow_start + *cow_len);
+ if (want_clusters < contig_clusters)
+ want_clusters = contig_clusters;
+
+ /*
+ * If the write does not cover the whole extent, we
+ * need to calculate how we're going to split the extent.
+ * We try to do it on contig_clusters boundaries.
+ *
+ * Any extent smaller than contig_clusters will be
+ * CoWed in its entirety.
+ */
+ if (leaf_clusters <= contig_clusters)
+ *cow_len += leaf_clusters;
+ else if (*cow_len || (*cow_start == cpos)) {
+ /*
+ * This extent needs to be CoW'd from its
+ * beginning, so all we have to do is compute
+ * how many clusters to grab. We align
+ * want_clusters to the edge of contig_clusters
+ * to get better I/O.
+ */
+ want_clusters = ocfs2_cow_align_length(inode->i_sb,
+ want_clusters);
+
+ if (leaf_clusters < want_clusters)
+ *cow_len += leaf_clusters;
+ else
+ *cow_len += want_clusters;
+ } else if ((*cow_start + contig_clusters) >=
+ (cpos + write_len)) {
+ /*
+ * Breaking off contig_clusters at the front
+ * of the extent will cover our write. That's
+ * easy.
+ */
+ *cow_len = contig_clusters;
+ } else if ((rec_end - cpos) <= contig_clusters) {
+ /*
+ * Breaking off contig_clusters at the tail of
+ * this extent will cover cpos.
+ */
+ *cow_start = rec_end - contig_clusters;
+ *cow_len = contig_clusters;
+ } else if ((rec_end - cpos) <= want_clusters) {
+ /*
+ * While we can't fit the entire write in this
+ * extent, we know that the write goes from cpos
+ * to the end of the extent. Break that off.
+ * We try to break it at some multiple of
+ * contig_clusters from the front of the extent.
+ * Failing that (ie, cpos is within
+ * contig_clusters of the front), we'll CoW the
+ * entire extent.
+ */
+ *cow_start = ocfs2_cow_align_start(inode->i_sb,
+ *cow_start, cpos);
+ *cow_len = rec_end - *cow_start;
+ } else {
+ /*
+ * Ok, the entire write lives in the middle of
+ * this extent. Let's try to slice the extent up
+ * nicely. Optimally, our CoW region starts at
+ * m*contig_clusters from the beginning of the
+ * extent and goes for n*contig_clusters,
+ * covering the entire write.
+ */
+ *cow_start = ocfs2_cow_align_start(inode->i_sb,
+ *cow_start, cpos);
+
+ want_clusters = (cpos + write_len) - *cow_start;
+ want_clusters = ocfs2_cow_align_length(inode->i_sb,
+ want_clusters);
+ if (*cow_start + want_clusters <= rec_end)
+ *cow_len = want_clusters;
+ else
+ *cow_len = rec_end - *cow_start;
+ }
+
+ /* Have we covered our entire write yet? */
+ if ((*cow_start + *cow_len) >= (cpos + write_len))
+ break;
+
+ /*
+ * If we reach the end of the extent block and don't get enough
+ * clusters, continue with the next extent block if possible.
+ */
+ if (i + 1 == le16_to_cpu(el->l_next_free_rec) &&
+ eb && eb->h_next_leaf_blk) {
+ brelse(eb_bh);
+ eb_bh = NULL;
+
+ ret = ocfs2_read_extent_block(INODE_CACHE(inode),
+ le64_to_cpu(eb->h_next_leaf_blk),
+ &eb_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+ el = &eb->h_list;
+ i = -1;
+ }
+ }
+
+out:
+ brelse(eb_bh);
+ return ret;
+}
+
+/*
+ * Prepare meta_ac, data_ac and calculate credits when we want to add some
+ * num_clusters in data_tree "et" and change the refcount for the old
+ * clusters(starting form p_cluster) in the refcount tree.
+ *
+ * Note:
+ * 1. since we may split the old tree, so we at most will need num_clusters + 2
+ * more new leaf records.
+ * 2. In some case, we may not need to reserve new clusters(e.g, reflink), so
+ * just give data_ac = NULL.
+ */
+static int ocfs2_lock_refcount_allocators(struct super_block *sb,
+ u32 p_cluster, u32 num_clusters,
+ struct ocfs2_extent_tree *et,
+ struct ocfs2_caching_info *ref_ci,
+ struct buffer_head *ref_root_bh,
+ struct ocfs2_alloc_context **meta_ac,
+ struct ocfs2_alloc_context **data_ac,
+ int *credits)
+{
+ int ret = 0, meta_add = 0;
+ int num_free_extents = ocfs2_num_free_extents(OCFS2_SB(sb), et);
+
+ if (num_free_extents < 0) {
+ ret = num_free_extents;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (num_free_extents < num_clusters + 2)
+ meta_add =
+ ocfs2_extend_meta_needed(et->et_root_el);
+
+ *credits += ocfs2_calc_extend_credits(sb, et->et_root_el,
+ num_clusters + 2);
+
+ ret = ocfs2_calc_refcount_meta_credits(sb, ref_ci, ref_root_bh,
+ p_cluster, num_clusters,
+ &meta_add, credits);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ mlog(0, "reserve new metadata %d, clusters %u, credits = %d\n",
+ meta_add, num_clusters, *credits);
+ ret = ocfs2_reserve_new_metadata_blocks(OCFS2_SB(sb), meta_add,
+ meta_ac);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (data_ac) {
+ ret = ocfs2_reserve_clusters(OCFS2_SB(sb), num_clusters,
+ data_ac);
+ if (ret)
+ mlog_errno(ret);
+ }
+
+out:
+ if (ret) {
+ if (*meta_ac) {
+ ocfs2_free_alloc_context(*meta_ac);
+ *meta_ac = NULL;
+ }
+ }
+
+ return ret;
+}
+
+static int ocfs2_clear_cow_buffer(handle_t *handle, struct buffer_head *bh)
+{
+ BUG_ON(buffer_dirty(bh));
+
+ clear_buffer_mapped(bh);
+
+ return 0;
+}
+
+static int ocfs2_duplicate_clusters(handle_t *handle,
+ struct ocfs2_cow_context *context,
+ u32 cpos, u32 old_cluster,
+ u32 new_cluster, u32 new_len)
+{
+ int ret = 0, partial;
+ struct ocfs2_caching_info *ci = context->di_et.et_ci;
+ struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
+ u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
+ struct page *page;
+ pgoff_t page_index;
+ unsigned int from, to;
+ loff_t offset, end, map_end;
+ struct address_space *mapping = context->inode->i_mapping;
+
+ mlog(0, "old_cluster %u, new %u, len %u at offset %u\n", old_cluster,
+ new_cluster, new_len, cpos);
+
+ offset = ((loff_t)cpos) << OCFS2_SB(sb)->s_clustersize_bits;
+ end = offset + (new_len << OCFS2_SB(sb)->s_clustersize_bits);
+
+ while (offset < end) {
+ page_index = offset >> PAGE_CACHE_SHIFT;
+ map_end = (page_index + 1) << PAGE_CACHE_SHIFT;
+ if (map_end > end)
+ map_end = end;
+
+ /* from, to is the offset within the page. */
+ from = offset & (PAGE_CACHE_SIZE - 1);
+ to = PAGE_CACHE_SIZE;
+ if (map_end & (PAGE_CACHE_SIZE - 1))
+ to = map_end & (PAGE_CACHE_SIZE - 1);
+
+ page = grab_cache_page(mapping, page_index);
+
+ /* This page can't be dirtied before we CoW it out. */
+ BUG_ON(PageDirty(page));
+
+ if (!PageUptodate(page)) {
+ ret = block_read_full_page(page, ocfs2_get_block);
+ if (ret) {
+ mlog_errno(ret);
+ goto unlock;
+ }
+ lock_page(page);
+ }
+
+ if (page_has_buffers(page)) {
+ ret = walk_page_buffers(handle, page_buffers(page),
+ from, to, &partial,
+ ocfs2_clear_cow_buffer);
+ if (ret) {
+ mlog_errno(ret);
+ goto unlock;
+ }
+ }
+
+ ocfs2_map_and_dirty_page(context->inode,
+ handle, from, to,
+ page, 0, &new_block);
+ mark_page_accessed(page);
+unlock:
+ unlock_page(page);
+ page_cache_release(page);
+ page = NULL;
+ offset = map_end;
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int ocfs2_clear_ext_refcount(handle_t *handle,
+ struct ocfs2_extent_tree *et,
+ u32 cpos, u32 p_cluster, u32 len,
+ unsigned int ext_flags,
+ struct ocfs2_alloc_context *meta_ac,
+ struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+ int ret, index;
+ struct ocfs2_extent_rec replace_rec;
+ struct ocfs2_path *path = NULL;
+ struct ocfs2_extent_list *el;
+ struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
+ u64 ino = ocfs2_metadata_cache_owner(et->et_ci);
+
+ mlog(0, "inode %llu cpos %u, len %u, p_cluster %u, ext_flags %u\n",
+ (unsigned long long)ino, cpos, len, p_cluster, ext_flags);
+
+ memset(&replace_rec, 0, sizeof(replace_rec));
+ replace_rec.e_cpos = cpu_to_le32(cpos);
+ replace_rec.e_leaf_clusters = cpu_to_le16(len);
+ replace_rec.e_blkno = cpu_to_le64(ocfs2_clusters_to_blocks(sb,
+ p_cluster));
+ replace_rec.e_flags = ext_flags;
+ replace_rec.e_flags &= ~OCFS2_EXT_REFCOUNTED;
+
+ path = ocfs2_new_path_from_et(et);
+ if (!path) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_find_path(et->et_ci, path, cpos);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ el = path_leaf_el(path);
+
+ index = ocfs2_search_extent_list(el, cpos);
+ if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+ ocfs2_error(sb,
+ "Inode %llu has an extent at cpos %u which can no "
+ "longer be found.\n",
+ (unsigned long long)ino, cpos);
+ ret = -EROFS;
+ goto out;
+ }
+
+ ret = ocfs2_split_extent(handle, et, path, index,
+ &replace_rec, meta_ac, dealloc);
+ if (ret)
+ mlog_errno(ret);
+
+out:
+ ocfs2_free_path(path);
+ return ret;
+}
+
+static int ocfs2_replace_clusters(handle_t *handle,
+ struct ocfs2_cow_context *context,
+ u32 cpos, u32 old,
+ u32 new, u32 len,
+ unsigned int ext_flags)
+{
+ int ret;
+ struct ocfs2_caching_info *ci = context->di_et.et_ci;
+ u64 ino = ocfs2_metadata_cache_owner(ci);
+
+ mlog(0, "inode %llu, cpos %u, old %u, new %u, len %u, ext_flags %u\n",
+ (unsigned long long)ino, cpos, old, new, len, ext_flags);
+
+ /*If the old clusters is unwritten, no need to duplicate. */
+ if (!(ext_flags & OCFS2_EXT_UNWRITTEN)) {
+ ret = ocfs2_duplicate_clusters(handle, context, cpos,
+ old, new, len);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ ret = ocfs2_clear_ext_refcount(handle, &context->di_et,
+ cpos, new, len, ext_flags,
+ context->meta_ac, &context->dealloc);
+ if (ret)
+ mlog_errno(ret);
+out:
+ return ret;
+}
+
+static int ocfs2_cow_sync_writeback(struct super_block *sb,
+ struct ocfs2_cow_context *context,
+ u32 cpos, u32 num_clusters)
+{
+ int ret = 0;
+ loff_t offset, end, map_end;
+ pgoff_t page_index;
+ struct page *page;
+
+ if (ocfs2_should_order_data(context->inode))
+ return 0;
+
+ offset = ((loff_t)cpos) << OCFS2_SB(sb)->s_clustersize_bits;
+ end = offset + (num_clusters << OCFS2_SB(sb)->s_clustersize_bits);
+
+ ret = filemap_fdatawrite_range(context->inode->i_mapping,
+ offset, end - 1);
+ if (ret < 0) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ while (offset < end) {
+ page_index = offset >> PAGE_CACHE_SHIFT;
+ map_end = (page_index + 1) << PAGE_CACHE_SHIFT;
+ if (map_end > end)
+ map_end = end;
+
+ page = grab_cache_page(context->inode->i_mapping, page_index);
+ BUG_ON(!page);
+
+ wait_on_page_writeback(page);
+ if (PageError(page)) {
+ ret = -EIO;
+ mlog_errno(ret);
+ } else
+ mark_page_accessed(page);
+
+ unlock_page(page);
+ page_cache_release(page);
+ page = NULL;
+ offset = map_end;
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int ocfs2_make_clusters_writable(struct super_block *sb,
+ struct ocfs2_cow_context *context,
+ u32 cpos, u32 p_cluster,
+ u32 num_clusters, unsigned int e_flags)
+{
+ int ret, credits = 0;
+ u32 new_bit, new_len;
+ struct ocfs2_super *osb = OCFS2_SB(sb);
+ handle_t *handle;
+
+ ret = ocfs2_lock_refcount_allocators(sb, p_cluster, num_clusters,
+ &context->di_et,
+ context->ref_ci,
+ context->ref_root_bh,
+ &context->meta_ac,
+ &context->data_ac, &credits);
+ if (ret) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ handle = ocfs2_start_trans(osb, credits);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ mlog_errno(ret);
+ goto out;
+ }
+
+ while (num_clusters) {
+ ret = __ocfs2_claim_clusters(osb, handle, context->data_ac,
+ 1, num_clusters,
+ &new_bit, &new_len);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+
+ ret = ocfs2_replace_clusters(handle, context,
+ cpos, p_cluster, new_bit,
+ new_len, e_flags);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+
+ cpos += new_len;
+ p_cluster += new_len;
+ num_clusters -= new_len;
+ }
+
+ ret = __ocfs2_decrease_refcount(handle, context->ref_ci,
+ context->ref_root_bh,
+ p_cluster, num_clusters,
+ context->meta_ac,
+ &context->dealloc);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+
+ /*
+ * Here we should write the new page out first if we are
+ * in write-back mode.
+ */
+ ret = ocfs2_cow_sync_writeback(sb, context, cpos, num_clusters);
+ if (ret)
+ mlog_errno(ret);
+
+out_commit:
+ ocfs2_commit_trans(osb, handle);
+
+out:
+ if (context->data_ac) {
+ ocfs2_free_alloc_context(context->data_ac);
+ context->data_ac = NULL;
+ }
+ if (context->meta_ac) {
+ ocfs2_free_alloc_context(context->meta_ac);
+ context->meta_ac = NULL;
+ }
+
+ return ret;
+}
+
+static int ocfs2_replace_cow(struct inode *inode,
+ struct buffer_head *di_bh,
+ struct buffer_head *ref_root_bh,
+ struct ocfs2_caching_info *ref_ci,
+ u32 cow_start, u32 cow_len)
+{
+ int ret = 0;
+ u32 p_cluster, num_clusters, start = cow_start;
+ unsigned int ext_flags;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ struct ocfs2_cow_context *context;
+
+ if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb))) {
+ ocfs2_error(inode->i_sb, "Inode %lu want to use refcount "
+ "tree, but the feature bit is not set in the "
+ "super block.", inode->i_ino);
+ return -EROFS;
+ }
+
+ context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
+ if (!context) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ return ret;
+ }
+
+ context->inode = inode;
+ context->cow_start = cow_start;
+ context->cow_len = cow_len;
+ context->ref_ci = ref_ci;
+ context->ref_root_bh = ref_root_bh;
+
+ ocfs2_init_dealloc_ctxt(&context->dealloc);
+ ocfs2_init_dinode_extent_tree(&context->di_et,
+ INODE_CACHE(inode), di_bh);
+
+ while (cow_len) {
+ ret = ocfs2_get_clusters(inode, cow_start, &p_cluster,
+ &num_clusters, &ext_flags);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+
+ BUG_ON(!(ext_flags & OCFS2_EXT_REFCOUNTED));
+
+ if (cow_len < num_clusters)
+ num_clusters = cow_len;
+
+ ret = ocfs2_make_clusters_writable(inode->i_sb, context,
+ cow_start, p_cluster,
+ num_clusters, ext_flags);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+
+ cow_len -= num_clusters;
+ cow_start += num_clusters;
+ }
+
+
+ /*
+ * truncate the extent map here since no matter whether we meet with
+ * any error during the action, we shouldn't trust cached extent map
+ * any more.
+ */
+ ocfs2_extent_map_trunc(inode, start);
+
+ if (ocfs2_dealloc_has_cluster(&context->dealloc)) {
+ ocfs2_schedule_truncate_log_flush(osb, 1);
+ ocfs2_run_deallocs(osb, &context->dealloc);
+ }
+
+ kfree(context);
+ return ret;
+}
+
+/*
+ * Starting at cpos, try to CoW write_len clusters.
+ * This will stop when it runs into a hole or an unrefcounted extent.
+ */
+static int ocfs2_refcount_cow_hunk(struct inode *inode,
+ struct buffer_head *di_bh,
+ u32 cpos, u32 write_len)
+{
+ int ret;
+ u32 cow_start = 0, cow_len = 0;
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+ struct buffer_head *ref_root_bh = NULL;
+ struct ocfs2_refcount_tree *ref_tree;
+
+ BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
+
+ ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh, cpos, write_len,
+ &cow_start, &cow_len);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ mlog(0, "CoW inode %lu, cpos %u, write_len %u, cow_start %u, "
+ "cow_len %u\n", inode->i_ino,
+ cpos, write_len, cow_start, cow_len);
+
+ BUG_ON(cow_len == 0);
+
+ ret = ocfs2_lock_refcount_tree(osb, le64_to_cpu(di->i_refcount_loc),
+ 1, &ref_tree, &ref_root_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_replace_cow(inode, di_bh, ref_root_bh, &ref_tree->rf_ci,
+ cow_start, cow_len);
+ if (ret)
+ mlog_errno(ret);
+
+ ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
+ brelse(ref_root_bh);
+out:
+ return ret;
+}
+
+/*
+ * CoW any and all clusters between cpos and cpos+write_len.
+ * If this returns successfully, all clusters between cpos and
+ * cpos+write_len are safe to modify.
+ */
+int ocfs2_refcount_cow(struct inode *inode,
+ struct buffer_head *di_bh,
+ u32 cpos, u32 write_len)
+{
+ int ret = 0;
+ u32 p_cluster, num_clusters;
+ unsigned int ext_flags;
+
+ while (write_len) {
+ ret = ocfs2_get_clusters(inode, cpos, &p_cluster,
+ &num_clusters, &ext_flags);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+
+ if (write_len < num_clusters)
+ num_clusters = write_len;
+
+ if (ext_flags & OCFS2_EXT_REFCOUNTED) {
+ ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,
+ num_clusters);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+ }
+
+ write_len -= num_clusters;
+ cpos += num_clusters;
+ }
+
+ return ret;
+}
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