linux/fs/ocfs2/alloc.h
Changwei Ge 71a3694404 ocfs2: try to reuse extent block in dealloc without meta_alloc
A crash issue was reported by John Lightsey with a call trace as follows:

  ocfs2_split_extent+0x1ad3/0x1b40 [ocfs2]
  ocfs2_change_extent_flag+0x33a/0x470 [ocfs2]
  ocfs2_mark_extent_written+0x172/0x220 [ocfs2]
  ocfs2_dio_end_io+0x62d/0x910 [ocfs2]
  dio_complete+0x19a/0x1a0
  do_blockdev_direct_IO+0x19dd/0x1eb0
  __blockdev_direct_IO+0x43/0x50
  ocfs2_direct_IO+0x8f/0xa0 [ocfs2]
  generic_file_direct_write+0xb2/0x170
  __generic_file_write_iter+0xc3/0x1b0
  ocfs2_file_write_iter+0x4bb/0xca0 [ocfs2]
  __vfs_write+0xae/0xf0
  vfs_write+0xb8/0x1b0
  SyS_write+0x4f/0xb0
  system_call_fastpath+0x16/0x75

The BUG code told that extent tree wants to grow but no metadata was
reserved ahead of time.  From my investigation into this issue, the root
cause it that although enough metadata is not reserved, there should be
enough for following use.  Rightmost extent is merged into its left one
due to a certain times of marking extent written.  Because during
marking extent written, we got many physically continuous extents.  At
last, an empty extent showed up and the rightmost path is removed from
extent tree.

Add a new mechanism to reuse extent block cached in dealloc which were
just unlinked from extent tree to solve this crash issue.

Criteria is that during marking extents *written*, if extent rotation
and merging results in unlinking extent with growing extent tree later
without any metadata reserved ahead of time, try to reuse those extents
in dealloc in which deleted extents are cached.

Also, this patch addresses the issue John reported that ::dw_zero_count
is not calculated properly.

After applying this patch, the issue John reported was gone.  Thanks for
the reproducer provided by John.  And this patch has passed
ocfs2-test(29 cases) suite running by New H3C Group.

[ge.changwei@h3c.com: fix static checker warnning]
  Link: http://lkml.kernel.org/r/63ADC13FD55D6546B7DECE290D39E373F29196AE@H3CMLB12-EX.srv.huawei-3com.com
[akpm@linux-foundation.org: brelse(NULL) is legal]
Link: http://lkml.kernel.org/r/1515479070-32653-2-git-send-email-ge.changwei@h3c.com
Signed-off-by: Changwei Ge <ge.changwei@h3c.com>
Reported-by: John Lightsey <john@nixnuts.net>
Tested-by: John Lightsey <john@nixnuts.net>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:35 -08:00

327 lines
12 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* alloc.h
*
* Function prototypes
*
* Copyright (C) 2002, 2004 Oracle. 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; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will 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 to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef OCFS2_ALLOC_H
#define OCFS2_ALLOC_H
/*
* For xattr tree leaf, we limit the leaf byte size to be 64K.
*/
#define OCFS2_MAX_XATTR_TREE_LEAF_SIZE 65536
/*
* ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
* the b-tree operations in ocfs2. Now all the b-tree operations are not
* limited to ocfs2_dinode only. Any data which need to allocate clusters
* to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
* and operation.
*
* ocfs2_extent_tree becomes the first-class object for extent tree
* manipulation. Callers of the alloc.c code need to fill it via one of
* the ocfs2_init_*_extent_tree() operations below.
*
* ocfs2_extent_tree contains info for the root of the b-tree, it must have a
* root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
* functions. It needs the ocfs2_caching_info structure associated with
* I/O on the tree. With metadata ecc, we now call different journal_access
* functions for each type of metadata, so it must have the
* root_journal_access function.
* ocfs2_extent_tree_operations abstract the normal operations we do for
* the root of extent b-tree.
*/
struct ocfs2_extent_tree_operations;
struct ocfs2_extent_tree {
const struct ocfs2_extent_tree_operations *et_ops;
struct buffer_head *et_root_bh;
struct ocfs2_extent_list *et_root_el;
struct ocfs2_caching_info *et_ci;
ocfs2_journal_access_func et_root_journal_access;
void *et_object;
unsigned int et_max_leaf_clusters;
struct ocfs2_cached_dealloc_ctxt *et_dealloc;
};
/*
* ocfs2_init_*_extent_tree() will fill an ocfs2_extent_tree from the
* specified object buffer.
*/
void ocfs2_init_dinode_extent_tree(struct ocfs2_extent_tree *et,
struct ocfs2_caching_info *ci,
struct buffer_head *bh);
void ocfs2_init_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
struct ocfs2_caching_info *ci,
struct buffer_head *bh);
struct ocfs2_xattr_value_buf;
void ocfs2_init_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
struct ocfs2_caching_info *ci,
struct ocfs2_xattr_value_buf *vb);
void ocfs2_init_dx_root_extent_tree(struct ocfs2_extent_tree *et,
struct ocfs2_caching_info *ci,
struct buffer_head *bh);
void ocfs2_init_refcount_extent_tree(struct ocfs2_extent_tree *et,
struct ocfs2_caching_info *ci,
struct buffer_head *bh);
/*
* Read an extent block into *bh. If *bh is NULL, a bh will be
* allocated. This is a cached read. The extent block will be validated
* with ocfs2_validate_extent_block().
*/
int ocfs2_read_extent_block(struct ocfs2_caching_info *ci, u64 eb_blkno,
struct buffer_head **bh);
struct ocfs2_alloc_context;
int ocfs2_insert_extent(handle_t *handle,
struct ocfs2_extent_tree *et,
u32 cpos,
u64 start_blk,
u32 new_clusters,
u8 flags,
struct ocfs2_alloc_context *meta_ac);
enum ocfs2_alloc_restarted {
RESTART_NONE = 0,
RESTART_TRANS,
RESTART_META
};
int ocfs2_add_clusters_in_btree(handle_t *handle,
struct ocfs2_extent_tree *et,
u32 *logical_offset,
u32 clusters_to_add,
int mark_unwritten,
struct ocfs2_alloc_context *data_ac,
struct ocfs2_alloc_context *meta_ac,
enum ocfs2_alloc_restarted *reason_ret);
struct ocfs2_cached_dealloc_ctxt;
struct ocfs2_path;
int ocfs2_split_extent(handle_t *handle,
struct ocfs2_extent_tree *et,
struct ocfs2_path *path,
int split_index,
struct ocfs2_extent_rec *split_rec,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_mark_extent_written(struct inode *inode,
struct ocfs2_extent_tree *et,
handle_t *handle, u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_change_extent_flag(handle_t *handle,
struct ocfs2_extent_tree *et,
u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc,
int new_flags, int clear_flags);
int ocfs2_remove_extent(handle_t *handle, struct ocfs2_extent_tree *et,
u32 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_remove_btree_range(struct inode *inode,
struct ocfs2_extent_tree *et,
u32 cpos, u32 phys_cpos, u32 len, int flags,
struct ocfs2_cached_dealloc_ctxt *dealloc,
u64 refcount_loc, bool refcount_tree_locked);
int ocfs2_num_free_extents(struct ocfs2_extent_tree *et);
/*
* how many new metadata chunks would an allocation need at maximum?
*
* Please note that the caller must make sure that root_el is the root
* of extent tree. So for an inode, it should be &fe->id2.i_list. Otherwise
* the result may be wrong.
*/
static inline int ocfs2_extend_meta_needed(struct ocfs2_extent_list *root_el)
{
/*
* Rather than do all the work of determining how much we need
* (involves a ton of reads and locks), just ask for the
* maximal limit. That's a tree depth shift. So, one block for
* level of the tree (current l_tree_depth), one block for the
* new tree_depth==0 extent_block, and one block at the new
* top-of-the tree.
*/
return le16_to_cpu(root_el->l_tree_depth) + 2;
}
void ocfs2_dinode_new_extent_list(struct inode *inode, struct ocfs2_dinode *di);
void ocfs2_set_inode_data_inline(struct inode *inode, struct ocfs2_dinode *di);
int ocfs2_convert_inline_data_to_extents(struct inode *inode,
struct buffer_head *di_bh);
int ocfs2_truncate_log_init(struct ocfs2_super *osb);
void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb);
void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
int cancel);
int ocfs2_flush_truncate_log(struct ocfs2_super *osb);
int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
int slot_num,
struct ocfs2_dinode **tl_copy);
int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
struct ocfs2_dinode *tl_copy);
int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb);
int ocfs2_truncate_log_append(struct ocfs2_super *osb,
handle_t *handle,
u64 start_blk,
unsigned int num_clusters);
int __ocfs2_flush_truncate_log(struct ocfs2_super *osb);
int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
unsigned int needed);
/*
* Process local structure which describes the block unlinks done
* during an operation. This is populated via
* ocfs2_cache_block_dealloc().
*
* ocfs2_run_deallocs() should be called after the potentially
* de-allocating routines. No journal handles should be open, and most
* locks should have been dropped.
*/
struct ocfs2_cached_dealloc_ctxt {
struct ocfs2_per_slot_free_list *c_first_suballocator;
struct ocfs2_cached_block_free *c_global_allocator;
};
static inline void ocfs2_init_dealloc_ctxt(struct ocfs2_cached_dealloc_ctxt *c)
{
c->c_first_suballocator = NULL;
c->c_global_allocator = NULL;
}
int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
u64 blkno, unsigned int bit);
int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
int type, int slot, u64 suballoc, u64 blkno,
unsigned int bit);
static inline int ocfs2_dealloc_has_cluster(struct ocfs2_cached_dealloc_ctxt *c)
{
return c->c_global_allocator != NULL;
}
int ocfs2_run_deallocs(struct ocfs2_super *osb,
struct ocfs2_cached_dealloc_ctxt *ctxt);
struct ocfs2_truncate_context {
struct ocfs2_cached_dealloc_ctxt tc_dealloc;
int tc_ext_alloc_locked; /* is it cluster locked? */
/* these get destroyed once it's passed to ocfs2_commit_truncate. */
struct buffer_head *tc_last_eb_bh;
};
int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
u64 range_start, u64 range_end);
int ocfs2_commit_truncate(struct ocfs2_super *osb,
struct inode *inode,
struct buffer_head *di_bh);
int ocfs2_truncate_inline(struct inode *inode, struct buffer_head *di_bh,
unsigned int start, unsigned int end, int trunc);
int ocfs2_find_leaf(struct ocfs2_caching_info *ci,
struct ocfs2_extent_list *root_el, u32 cpos,
struct buffer_head **leaf_bh);
int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster);
int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range);
/*
* Helper function to look at the # of clusters in an extent record.
*/
static inline unsigned int ocfs2_rec_clusters(struct ocfs2_extent_list *el,
struct ocfs2_extent_rec *rec)
{
/*
* Cluster count in extent records is slightly different
* between interior nodes and leaf nodes. This is to support
* unwritten extents which need a flags field in leaf node
* records, thus shrinking the available space for a clusters
* field.
*/
if (el->l_tree_depth)
return le32_to_cpu(rec->e_int_clusters);
else
return le16_to_cpu(rec->e_leaf_clusters);
}
/*
* This is only valid for leaf nodes, which are the only ones that can
* have empty extents anyway.
*/
static inline int ocfs2_is_empty_extent(struct ocfs2_extent_rec *rec)
{
return !rec->e_leaf_clusters;
}
int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
struct page **pages, int *num);
void ocfs2_map_and_dirty_page(struct inode *inode, handle_t *handle,
unsigned int from, unsigned int to,
struct page *page, int zero, u64 *phys);
/*
* Structures which describe a path through a btree, and functions to
* manipulate them.
*
* The idea here is to be as generic as possible with the tree
* manipulation code.
*/
struct ocfs2_path_item {
struct buffer_head *bh;
struct ocfs2_extent_list *el;
};
#define OCFS2_MAX_PATH_DEPTH 5
struct ocfs2_path {
int p_tree_depth;
ocfs2_journal_access_func p_root_access;
struct ocfs2_path_item p_node[OCFS2_MAX_PATH_DEPTH];
};
#define path_root_bh(_path) ((_path)->p_node[0].bh)
#define path_root_el(_path) ((_path)->p_node[0].el)
#define path_root_access(_path)((_path)->p_root_access)
#define path_leaf_bh(_path) ((_path)->p_node[(_path)->p_tree_depth].bh)
#define path_leaf_el(_path) ((_path)->p_node[(_path)->p_tree_depth].el)
#define path_num_items(_path) ((_path)->p_tree_depth + 1)
void ocfs2_reinit_path(struct ocfs2_path *path, int keep_root);
void ocfs2_free_path(struct ocfs2_path *path);
int ocfs2_find_path(struct ocfs2_caching_info *ci,
struct ocfs2_path *path,
u32 cpos);
struct ocfs2_path *ocfs2_new_path_from_path(struct ocfs2_path *path);
struct ocfs2_path *ocfs2_new_path_from_et(struct ocfs2_extent_tree *et);
int ocfs2_path_bh_journal_access(handle_t *handle,
struct ocfs2_caching_info *ci,
struct ocfs2_path *path,
int idx);
int ocfs2_journal_access_path(struct ocfs2_caching_info *ci,
handle_t *handle,
struct ocfs2_path *path);
int ocfs2_find_cpos_for_right_leaf(struct super_block *sb,
struct ocfs2_path *path, u32 *cpos);
int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
struct ocfs2_path *path, u32 *cpos);
int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et,
struct ocfs2_path *left,
struct ocfs2_path *right);
#endif /* OCFS2_ALLOC_H */