![Dave Chinner](/assets/img/avatar_default.png)
In converting the buffer lru lists to use the generic code, the locking for marking the buffers as on the dispose list was lost. This results in confusion in LRU buffer tracking and acocunting, resulting in reference counts being mucked up and filesystem beig unmountable. To fix this, introduce an internal buffer spinlock to protect the state field that holds the dispose list information. Because there is now locking needed around xfs_buf_lru_add/del, and they are used in exactly one place each two lines apart, get rid of the wrappers and code the logic directly in place. Further, the LRU emptying code used on unmount is less than optimal. Convert it to use a dispose list as per a normal shrinker walk, and repeat the walk that fills the dispose list until the LRU is empty. Thi avoids needing to drop and regain the LRU lock for every item being freed, and allows the same logic as the shrinker isolate call to be used. Simpler, easier to understand. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
368 lines
12 KiB
C
368 lines
12 KiB
C
/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_BUF_H__
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#define __XFS_BUF_H__
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/uio.h>
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#include <linux/list_lru.h>
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/*
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* Base types
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*/
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#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
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typedef enum {
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XBRW_READ = 1, /* transfer into target memory */
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XBRW_WRITE = 2, /* transfer from target memory */
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XBRW_ZERO = 3, /* Zero target memory */
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} xfs_buf_rw_t;
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#define XBF_READ (1 << 0) /* buffer intended for reading from device */
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#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
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#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
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#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
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#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
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#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
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/* I/O hints for the BIO layer */
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#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
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#define XBF_FUA (1 << 11)/* force cache write through mode */
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#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
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/* flags used only as arguments to access routines */
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#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
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#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
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/* flags used only internally */
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#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
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#define _XBF_KMEM (1 << 21)/* backed by heap memory */
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#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
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#define _XBF_COMPOUND (1 << 23)/* compound buffer */
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typedef unsigned int xfs_buf_flags_t;
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#define XFS_BUF_FLAGS \
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{ XBF_READ, "READ" }, \
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{ XBF_WRITE, "WRITE" }, \
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{ XBF_READ_AHEAD, "READ_AHEAD" }, \
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{ XBF_ASYNC, "ASYNC" }, \
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{ XBF_DONE, "DONE" }, \
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{ XBF_STALE, "STALE" }, \
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{ XBF_SYNCIO, "SYNCIO" }, \
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{ XBF_FUA, "FUA" }, \
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{ XBF_FLUSH, "FLUSH" }, \
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{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
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{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
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{ _XBF_PAGES, "PAGES" }, \
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{ _XBF_KMEM, "KMEM" }, \
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{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
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{ _XBF_COMPOUND, "COMPOUND" }
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/*
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* Internal state flags.
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*/
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#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
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typedef struct xfs_buftarg {
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dev_t bt_dev;
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struct block_device *bt_bdev;
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struct backing_dev_info *bt_bdi;
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struct xfs_mount *bt_mount;
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unsigned int bt_bsize;
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unsigned int bt_sshift;
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size_t bt_smask;
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/* LRU control structures */
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struct shrinker bt_shrinker;
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struct list_lru bt_lru;
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} xfs_buftarg_t;
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struct xfs_buf;
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typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
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#define XB_PAGES 2
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struct xfs_buf_map {
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xfs_daddr_t bm_bn; /* block number for I/O */
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int bm_len; /* size of I/O */
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};
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#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
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struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
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struct xfs_buf_ops {
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void (*verify_read)(struct xfs_buf *);
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void (*verify_write)(struct xfs_buf *);
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};
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typedef struct xfs_buf {
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/*
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* first cacheline holds all the fields needed for an uncontended cache
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* hit to be fully processed. The semaphore straddles the cacheline
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* boundary, but the counter and lock sits on the first cacheline,
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* which is the only bit that is touched if we hit the semaphore
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* fast-path on locking.
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*/
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struct rb_node b_rbnode; /* rbtree node */
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xfs_daddr_t b_bn; /* block number of buffer */
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int b_length; /* size of buffer in BBs */
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atomic_t b_hold; /* reference count */
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atomic_t b_lru_ref; /* lru reclaim ref count */
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xfs_buf_flags_t b_flags; /* status flags */
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struct semaphore b_sema; /* semaphore for lockables */
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/*
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* concurrent access to b_lru and b_lru_flags are protected by
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* bt_lru_lock and not by b_sema
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*/
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struct list_head b_lru; /* lru list */
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spinlock_t b_lock; /* internal state lock */
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unsigned int b_state; /* internal state flags */
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wait_queue_head_t b_waiters; /* unpin waiters */
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struct list_head b_list;
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struct xfs_perag *b_pag; /* contains rbtree root */
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xfs_buftarg_t *b_target; /* buffer target (device) */
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void *b_addr; /* virtual address of buffer */
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struct work_struct b_iodone_work;
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xfs_buf_iodone_t b_iodone; /* I/O completion function */
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struct completion b_iowait; /* queue for I/O waiters */
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void *b_fspriv;
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struct xfs_trans *b_transp;
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struct page **b_pages; /* array of page pointers */
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struct page *b_page_array[XB_PAGES]; /* inline pages */
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struct xfs_buf_map *b_maps; /* compound buffer map */
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struct xfs_buf_map __b_map; /* inline compound buffer map */
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int b_map_count;
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int b_io_length; /* IO size in BBs */
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atomic_t b_pin_count; /* pin count */
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atomic_t b_io_remaining; /* #outstanding I/O requests */
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unsigned int b_page_count; /* size of page array */
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unsigned int b_offset; /* page offset in first page */
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unsigned short b_error; /* error code on I/O */
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const struct xfs_buf_ops *b_ops;
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#ifdef XFS_BUF_LOCK_TRACKING
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int b_last_holder;
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#endif
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} xfs_buf_t;
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/* Finding and Reading Buffers */
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struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags, struct xfs_buf *new_bp);
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static inline struct xfs_buf *
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xfs_incore(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return _xfs_buf_find(target, &map, 1, flags, NULL);
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}
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struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags);
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static inline struct xfs_buf *
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xfs_buf_alloc(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return _xfs_buf_alloc(target, &map, 1, flags);
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}
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struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags);
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struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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xfs_buf_flags_t flags,
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const struct xfs_buf_ops *ops);
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void xfs_buf_readahead_map(struct xfs_buftarg *target,
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struct xfs_buf_map *map, int nmaps,
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const struct xfs_buf_ops *ops);
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static inline struct xfs_buf *
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xfs_buf_get(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_get_map(target, &map, 1, flags);
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}
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static inline struct xfs_buf *
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xfs_buf_read(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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xfs_buf_flags_t flags,
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const struct xfs_buf_ops *ops)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_read_map(target, &map, 1, flags, ops);
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}
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static inline void
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xfs_buf_readahead(
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struct xfs_buftarg *target,
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xfs_daddr_t blkno,
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size_t numblks,
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const struct xfs_buf_ops *ops)
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{
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DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
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return xfs_buf_readahead_map(target, &map, 1, ops);
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}
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struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
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void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
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int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
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struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
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int flags);
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struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
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xfs_daddr_t daddr, size_t numblks, int flags,
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const struct xfs_buf_ops *ops);
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void xfs_buf_hold(struct xfs_buf *bp);
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/* Releasing Buffers */
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extern void xfs_buf_free(xfs_buf_t *);
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extern void xfs_buf_rele(xfs_buf_t *);
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/* Locking and Unlocking Buffers */
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extern int xfs_buf_trylock(xfs_buf_t *);
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extern void xfs_buf_lock(xfs_buf_t *);
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extern void xfs_buf_unlock(xfs_buf_t *);
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#define xfs_buf_islocked(bp) \
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((bp)->b_sema.count <= 0)
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/* Buffer Read and Write Routines */
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extern int xfs_bwrite(struct xfs_buf *bp);
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extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);
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extern void xfs_buf_ioend(xfs_buf_t *, int);
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extern void xfs_buf_ioerror(xfs_buf_t *, int);
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extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
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extern void xfs_buf_iorequest(xfs_buf_t *);
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extern int xfs_buf_iowait(xfs_buf_t *);
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extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
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xfs_buf_rw_t);
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#define xfs_buf_zero(bp, off, len) \
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xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
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static inline int xfs_buf_geterror(xfs_buf_t *bp)
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{
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return bp ? bp->b_error : ENOMEM;
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}
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/* Buffer Utility Routines */
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extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
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/* Delayed Write Buffer Routines */
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extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
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extern int xfs_buf_delwri_submit(struct list_head *);
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extern int xfs_buf_delwri_submit_nowait(struct list_head *);
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/* Buffer Daemon Setup Routines */
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extern int xfs_buf_init(void);
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extern void xfs_buf_terminate(void);
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#define XFS_BUF_ZEROFLAGS(bp) \
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((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
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XBF_SYNCIO|XBF_FUA|XBF_FLUSH))
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void xfs_buf_stale(struct xfs_buf *bp);
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#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
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#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
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#define XFS_BUF_DONE(bp) ((bp)->b_flags |= XBF_DONE)
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#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
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#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
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#define XFS_BUF_ASYNC(bp) ((bp)->b_flags |= XBF_ASYNC)
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#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
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#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
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#define XFS_BUF_READ(bp) ((bp)->b_flags |= XBF_READ)
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#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
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#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
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#define XFS_BUF_WRITE(bp) ((bp)->b_flags |= XBF_WRITE)
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#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
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#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
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/*
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* These macros use the IO block map rather than b_bn. b_bn is now really
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* just for the buffer cache index for cached buffers. As IO does not use b_bn
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* anymore, uncached buffers do not use b_bn at all and hence must modify the IO
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* map directly. Uncached buffers are not allowed to be discontiguous, so this
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* is safe to do.
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*
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* In future, uncached buffers will pass the block number directly to the io
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* request function and hence these macros will go away at that point.
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*/
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#define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
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#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
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static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
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{
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atomic_set(&bp->b_lru_ref, lru_ref);
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}
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static inline int xfs_buf_ispinned(struct xfs_buf *bp)
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{
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return atomic_read(&bp->b_pin_count);
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}
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static inline void xfs_buf_relse(xfs_buf_t *bp)
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{
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xfs_buf_unlock(bp);
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xfs_buf_rele(bp);
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}
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/*
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* Handling of buftargs.
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*/
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extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
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struct block_device *, int, const char *);
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extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
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extern void xfs_wait_buftarg(xfs_buftarg_t *);
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extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
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#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
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#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
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#endif /* __XFS_BUF_H__ */
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