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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [gfs2/] [meta_io.c] - Blame information for rev 62

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 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
 * of the GNU General Public License version 2.
 */
 
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/delay.h>
#include <linux/bio.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>
 
#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"
#include "ops_address.h"
 
static int aspace_get_block(struct inode *inode, sector_t lblock,
                            struct buffer_head *bh_result, int create)
{
        gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
        return -EOPNOTSUPP;
}
 
static int gfs2_aspace_writepage(struct page *page,
                                 struct writeback_control *wbc)
{
        return block_write_full_page(page, aspace_get_block, wbc);
}
 
static const struct address_space_operations aspace_aops = {
        .writepage = gfs2_aspace_writepage,
        .releasepage = gfs2_releasepage,
};
 
/**
 * gfs2_aspace_get - Create and initialize a struct inode structure
 * @sdp: the filesystem the aspace is in
 *
 * Right now a struct inode is just a struct inode.  Maybe Linux
 * will supply a more lightweight address space construct (that works)
 * in the future.
 *
 * Make sure pages/buffers in this aspace aren't in high memory.
 *
 * Returns: the aspace
 */
 
struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
{
        struct inode *aspace;
 
        aspace = new_inode(sdp->sd_vfs);
        if (aspace) {
                mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
                aspace->i_mapping->a_ops = &aspace_aops;
                aspace->i_size = ~0ULL;
                aspace->i_private = NULL;
                insert_inode_hash(aspace);
        }
        return aspace;
}
 
void gfs2_aspace_put(struct inode *aspace)
{
        remove_inode_hash(aspace);
        iput(aspace);
}
 
/**
 * gfs2_meta_inval - Invalidate all buffers associated with a glock
 * @gl: the glock
 *
 */
 
void gfs2_meta_inval(struct gfs2_glock *gl)
{
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct inode *aspace = gl->gl_aspace;
        struct address_space *mapping = gl->gl_aspace->i_mapping;
 
        gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 
        atomic_inc(&aspace->i_writecount);
        truncate_inode_pages(mapping, 0);
        atomic_dec(&aspace->i_writecount);
 
        gfs2_assert_withdraw(sdp, !mapping->nrpages);
}
 
/**
 * gfs2_meta_sync - Sync all buffers associated with a glock
 * @gl: The glock
 *
 */
 
void gfs2_meta_sync(struct gfs2_glock *gl)
{
        struct address_space *mapping = gl->gl_aspace->i_mapping;
        int error;
 
        filemap_fdatawrite(mapping);
        error = filemap_fdatawait(mapping);
 
        if (error)
                gfs2_io_error(gl->gl_sbd);
}
 
/**
 * getbuf - Get a buffer with a given address space
 * @gl: the glock
 * @blkno: the block number (filesystem scope)
 * @create: 1 if the buffer should be created
 *
 * Returns: the buffer
 */
 
static struct buffer_head *getbuf(struct gfs2_glock *gl, u64 blkno, int create)
{
        struct address_space *mapping = gl->gl_aspace->i_mapping;
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct page *page;
        struct buffer_head *bh;
        unsigned int shift;
        unsigned long index;
        unsigned int bufnum;
 
        shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
        index = blkno >> shift;             /* convert block to page */
        bufnum = blkno - (index << shift);  /* block buf index within page */
 
        if (create) {
                for (;;) {
                        page = grab_cache_page(mapping, index);
                        if (page)
                                break;
                        yield();
                }
        } else {
                page = find_lock_page(mapping, index);
                if (!page)
                        return NULL;
        }
 
        if (!page_has_buffers(page))
                create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 
        /* Locate header for our buffer within our page */
        for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
                /* Do nothing */;
        get_bh(bh);
 
        if (!buffer_mapped(bh))
                map_bh(bh, sdp->sd_vfs, blkno);
 
        unlock_page(page);
        mark_page_accessed(page);
        page_cache_release(page);
 
        return bh;
}
 
static void meta_prep_new(struct buffer_head *bh)
{
        struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 
        lock_buffer(bh);
        clear_buffer_dirty(bh);
        set_buffer_uptodate(bh);
        unlock_buffer(bh);
 
        mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
}
 
/**
 * gfs2_meta_new - Get a block
 * @gl: The glock associated with this block
 * @blkno: The block number
 *
 * Returns: The buffer
 */
 
struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
{
        struct buffer_head *bh;
        bh = getbuf(gl, blkno, CREATE);
        meta_prep_new(bh);
        return bh;
}
 
/**
 * gfs2_meta_read - Read a block from disk
 * @gl: The glock covering the block
 * @blkno: The block number
 * @flags: flags
 * @bhp: the place where the buffer is returned (NULL on failure)
 *
 * Returns: errno
 */
 
int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
                   struct buffer_head **bhp)
{
        *bhp = getbuf(gl, blkno, CREATE);
        if (!buffer_uptodate(*bhp))
                ll_rw_block(READ_META, 1, bhp);
        if (flags & DIO_WAIT) {
                int error = gfs2_meta_wait(gl->gl_sbd, *bhp);
                if (error) {
                        brelse(*bhp);
                        return error;
                }
        }
 
        return 0;
}
 
/**
 * gfs2_meta_wait - Reread a block from disk
 * @sdp: the filesystem
 * @bh: The block to wait for
 *
 * Returns: errno
 */
 
int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
                return -EIO;
 
        wait_on_buffer(bh);
 
        if (!buffer_uptodate(bh)) {
                struct gfs2_trans *tr = current->journal_info;
                if (tr && tr->tr_touched)
                        gfs2_io_error_bh(sdp, bh);
                return -EIO;
        }
        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
                return -EIO;
 
        return 0;
}
 
/**
 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 * @gl: the glock the buffer belongs to
 * @bh: The buffer to be attached to
 * @meta: Flag to indicate whether its metadata or not
 */
 
void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
                         int meta)
{
        struct gfs2_bufdata *bd;
 
        if (meta)
                lock_page(bh->b_page);
 
        if (bh->b_private) {
                if (meta)
                        unlock_page(bh->b_page);
                return;
        }
 
        bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
        bd->bd_bh = bh;
        bd->bd_gl = gl;
 
        INIT_LIST_HEAD(&bd->bd_list_tr);
        if (meta)
                lops_init_le(&bd->bd_le, &gfs2_buf_lops);
        else
                lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
        bh->b_private = bd;
 
        if (meta)
                unlock_page(bh->b_page);
}
 
void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
{
        struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);
        struct gfs2_bufdata *bd = bh->b_private;
        if (test_clear_buffer_pinned(bh)) {
                list_del_init(&bd->bd_le.le_list);
                if (meta) {
                        gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
                        sdp->sd_log_num_buf--;
                        tr->tr_num_buf_rm++;
                } else {
                        gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
                        sdp->sd_log_num_databuf--;
                        tr->tr_num_databuf_rm++;
                }
                tr->tr_touched = 1;
                brelse(bh);
        }
        if (bd) {
                if (bd->bd_ail) {
                        gfs2_remove_from_ail(NULL, bd);
                        bh->b_private = NULL;
                        bd->bd_bh = NULL;
                        bd->bd_blkno = bh->b_blocknr;
                        gfs2_trans_add_revoke(sdp, bd);
                }
        }
        clear_buffer_dirty(bh);
        clear_buffer_uptodate(bh);
}
 
/**
 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 * @ip: the inode who owns the buffers
 * @bstart: the first buffer in the run
 * @blen: the number of buffers in the run
 *
 */
 
void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head *bh;
 
        while (blen) {
                bh = getbuf(ip->i_gl, bstart, NO_CREATE);
                if (bh) {
                        lock_buffer(bh);
                        gfs2_log_lock(sdp);
                        gfs2_remove_from_journal(bh, current->journal_info, 1);
                        gfs2_log_unlock(sdp);
                        unlock_buffer(bh);
                        brelse(bh);
                }
 
                bstart++;
                blen--;
        }
}
 
/**
 * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
 * @ip: The GFS2 inode
 *
 * This releases buffers that are in the most-recently-used array of
 * blocks used for indirect block addressing for this inode.
 */
 
void gfs2_meta_cache_flush(struct gfs2_inode *ip)
{
        struct buffer_head **bh_slot;
        unsigned int x;
 
        spin_lock(&ip->i_spin);
 
        for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
                bh_slot = &ip->i_cache[x];
                if (*bh_slot) {
                        brelse(*bh_slot);
                        *bh_slot = NULL;
                }
        }
 
        spin_unlock(&ip->i_spin);
}
 
/**
 * gfs2_meta_indirect_buffer - Get a metadata buffer
 * @ip: The GFS2 inode
 * @height: The level of this buf in the metadata (indir addr) tree (if any)
 * @num: The block number (device relative) of the buffer
 * @new: Non-zero if we may create a new buffer
 * @bhp: the buffer is returned here
 *
 * Try to use the gfs2_inode's MRU metadata tree cache.
 *
 * Returns: errno
 */
 
int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
                              int new, struct buffer_head **bhp)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_glock *gl = ip->i_gl;
        struct buffer_head *bh = NULL, **bh_slot = ip->i_cache + height;
        int in_cache = 0;
 
        BUG_ON(!gl);
        BUG_ON(!sdp);
 
        spin_lock(&ip->i_spin);
        if (*bh_slot && (*bh_slot)->b_blocknr == num) {
                bh = *bh_slot;
                get_bh(bh);
                in_cache = 1;
        }
        spin_unlock(&ip->i_spin);
 
        if (!bh)
                bh = getbuf(gl, num, CREATE);
 
        if (!bh)
                return -ENOBUFS;
 
        if (new) {
                if (gfs2_assert_warn(sdp, height))
                        goto err;
                meta_prep_new(bh);
                gfs2_trans_add_bh(ip->i_gl, bh, 1);
                gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
                gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
        } else {
                u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
                if (!buffer_uptodate(bh)) {
                        ll_rw_block(READ_META, 1, &bh);
                        if (gfs2_meta_wait(sdp, bh))
                                goto err;
                }
                if (gfs2_metatype_check(sdp, bh, mtype))
                        goto err;
        }
 
        if (!in_cache) {
                spin_lock(&ip->i_spin);
                if (*bh_slot)
                        brelse(*bh_slot);
                *bh_slot = bh;
                get_bh(bh);
                spin_unlock(&ip->i_spin);
        }
 
        *bhp = bh;
        return 0;
err:
        brelse(bh);
        return -EIO;
}
 
/**
 * gfs2_meta_ra - start readahead on an extent of a file
 * @gl: the glock the blocks belong to
 * @dblock: the starting disk block
 * @extlen: the number of blocks in the extent
 *
 * returns: the first buffer in the extent
 */
 
struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
{
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct buffer_head *first_bh, *bh;
        u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
                          sdp->sd_sb.sb_bsize_shift;
 
        BUG_ON(!extlen);
 
        if (max_ra < 1)
                max_ra = 1;
        if (extlen > max_ra)
                extlen = max_ra;
 
        first_bh = getbuf(gl, dblock, CREATE);
 
        if (buffer_uptodate(first_bh))
                goto out;
        if (!buffer_locked(first_bh))
                ll_rw_block(READ_META, 1, &first_bh);
 
        dblock++;
        extlen--;
 
        while (extlen) {
                bh = getbuf(gl, dblock, CREATE);
 
                if (!buffer_uptodate(bh) && !buffer_locked(bh))
                        ll_rw_block(READA, 1, &bh);
                brelse(bh);
                dblock++;
                extlen--;
                if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
                        goto out;
        }
 
        wait_on_buffer(first_bh);
out:
        return first_bh;
}
 

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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [gfs2/] [meta_io.c] - Blame information for rev 62

Line No.	Rev	Author	Line
1	62	marcus.erl	`/*`
2			`* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.`
3			`* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.`
4			`*`
5			`* This copyrighted material is made available to anyone wishing to use,`
6			`* modify, copy, or redistribute it subject to the terms and conditions`
7			`* of the GNU General Public License version 2.`
8			`*/`
9
10			`#include <linux/sched.h>`
11			`#include <linux/slab.h>`
12			`#include <linux/spinlock.h>`
13			`#include <linux/completion.h>`
14			`#include <linux/buffer_head.h>`
15			`#include <linux/mm.h>`
16			`#include <linux/pagemap.h>`
17			`#include <linux/writeback.h>`
18			`#include <linux/swap.h>`
19			`#include <linux/delay.h>`
20			`#include <linux/bio.h>`
21			`#include <linux/gfs2_ondisk.h>`
22			`#include <linux/lm_interface.h>`
23
24			`#include "gfs2.h"`
25			`#include "incore.h"`
26			`#include "glock.h"`
27			`#include "glops.h"`
28			`#include "inode.h"`
29			`#include "log.h"`
30			`#include "lops.h"`
31			`#include "meta_io.h"`
32			`#include "rgrp.h"`
33			`#include "trans.h"`
34			`#include "util.h"`
35			`#include "ops_address.h"`
36
37			`static int aspace_get_block(struct inode *inode, sector_t lblock,`
38			`struct buffer_head *bh_result, int create)`
39			`{`
40			`gfs2_assert_warn(inode->i_sb->s_fs_info, 0);`
41			`return -EOPNOTSUPP;`
42			`}`
43
44			`static int gfs2_aspace_writepage(struct page *page,`
45			`struct writeback_control *wbc)`
46			`{`
47			`return block_write_full_page(page, aspace_get_block, wbc);`
48			`}`
49
50			`static const struct address_space_operations aspace_aops = {`
51			`.writepage = gfs2_aspace_writepage,`
52			`.releasepage = gfs2_releasepage,`
53			`};`
54
55			`/**`
56			`* gfs2_aspace_get - Create and initialize a struct inode structure`
57			`* @sdp: the filesystem the aspace is in`
58			`*`
59			`* Right now a struct inode is just a struct inode. Maybe Linux`
60			`* will supply a more lightweight address space construct (that works)`
61			`* in the future.`
62			`*`
63			`* Make sure pages/buffers in this aspace aren't in high memory.`
64			`*`
65			`* Returns: the aspace`
66			`*/`
67
68			`struct inode gfs2_aspace_get(struct gfs2_sbd sdp)`
69			`{`
70			`struct inode *aspace;`
71
72			`aspace = new_inode(sdp->sd_vfs);`
73			`if (aspace) {`
74			`mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);`
75			`aspace->i_mapping->a_ops = &aspace_aops;`
76			`aspace->i_size = ~0ULL;`
77			`aspace->i_private = NULL;`
78			`insert_inode_hash(aspace);`
79			`}`
80			`return aspace;`
81			`}`
82
83			`void gfs2_aspace_put(struct inode *aspace)`
84			`{`
85			`remove_inode_hash(aspace);`
86			`iput(aspace);`
87			`}`
88
89			`/**`
90			`* gfs2_meta_inval - Invalidate all buffers associated with a glock`
91			`* @gl: the glock`
92			`*`
93			`*/`
94
95			`void gfs2_meta_inval(struct gfs2_glock *gl)`
96			`{`
97			`struct gfs2_sbd *sdp = gl->gl_sbd;`
98			`struct inode *aspace = gl->gl_aspace;`
99			`struct address_space *mapping = gl->gl_aspace->i_mapping;`
100
101			`gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));`
102
103			`atomic_inc(&aspace->i_writecount);`
104			`truncate_inode_pages(mapping, 0);`
105			`atomic_dec(&aspace->i_writecount);`
106
107			`gfs2_assert_withdraw(sdp, !mapping->nrpages);`
108			`}`
109
110			`/**`
111			`* gfs2_meta_sync - Sync all buffers associated with a glock`
112			`* @gl: The glock`
113			`*`
114			`*/`
115
116			`void gfs2_meta_sync(struct gfs2_glock *gl)`
117			`{`
118			`struct address_space *mapping = gl->gl_aspace->i_mapping;`
119			`int error;`
120
121			`filemap_fdatawrite(mapping);`
122			`error = filemap_fdatawait(mapping);`
123
124			`if (error)`
125			`gfs2_io_error(gl->gl_sbd);`
126			`}`
127
128			`/**`
129			`* getbuf - Get a buffer with a given address space`
130			`* @gl: the glock`
131			`* @blkno: the block number (filesystem scope)`
132			`* @create: 1 if the buffer should be created`
133			`*`
134			`* Returns: the buffer`
135			`*/`
136
137			`static struct buffer_head getbuf(struct gfs2_glock gl, u64 blkno, int create)`
138			`{`
139			`struct address_space *mapping = gl->gl_aspace->i_mapping;`
140			`struct gfs2_sbd *sdp = gl->gl_sbd;`
141			`struct page *page;`
142			`struct buffer_head *bh;`
143			`unsigned int shift;`
144			`unsigned long index;`
145			`unsigned int bufnum;`
146
147			`shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;`
148			`index = blkno >> shift; /* convert block to page */`
149			`bufnum = blkno - (index << shift); /* block buf index within page */`
150
151			`if (create) {`
152			`for (;;) {`
153			`page = grab_cache_page(mapping, index);`
154			`if (page)`
155			`break;`
156			`yield();`
157			`}`
158			`} else {`
159			`page = find_lock_page(mapping, index);`
160			`if (!page)`
161			`return NULL;`
162			`}`
163
164			`if (!page_has_buffers(page))`
165			`create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);`
166
167			`/* Locate header for our buffer within our page */`
168			`for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)`
169			`/* Do nothing */;`
170			`get_bh(bh);`
171
172			`if (!buffer_mapped(bh))`
173			`map_bh(bh, sdp->sd_vfs, blkno);`
174
175			`unlock_page(page);`
176			`mark_page_accessed(page);`
177			`page_cache_release(page);`
178
179			`return bh;`
180			`}`
181
182			`static void meta_prep_new(struct buffer_head *bh)`
183			`{`
184			`struct gfs2_meta_header mh = (struct gfs2_meta_header )bh->b_data;`
185
186			`lock_buffer(bh);`
187			`clear_buffer_dirty(bh);`
188			`set_buffer_uptodate(bh);`
189			`unlock_buffer(bh);`
190
191			`mh->mh_magic = cpu_to_be32(GFS2_MAGIC);`
192			`}`
193
194			`/**`
195			`* gfs2_meta_new - Get a block`
196			`* @gl: The glock associated with this block`
197			`* @blkno: The block number`
198			`*`
199			`* Returns: The buffer`
200			`*/`
201
202			`struct buffer_head gfs2_meta_new(struct gfs2_glock gl, u64 blkno)`
203			`{`
204			`struct buffer_head *bh;`
205			`bh = getbuf(gl, blkno, CREATE);`
206			`meta_prep_new(bh);`
207			`return bh;`
208			`}`
209
210			`/**`
211			`* gfs2_meta_read - Read a block from disk`
212			`* @gl: The glock covering the block`
213			`* @blkno: The block number`
214			`* @flags: flags`
215			`* @bhp: the place where the buffer is returned (NULL on failure)`
216			`*`
217			`* Returns: errno`
218			`*/`
219
220			`int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,`
221			`struct buffer_head **bhp)`
222			`{`
223			`*bhp = getbuf(gl, blkno, CREATE);`
224			`if (!buffer_uptodate(*bhp))`
225			`ll_rw_block(READ_META, 1, bhp);`
226			`if (flags & DIO_WAIT) {`
227			`int error = gfs2_meta_wait(gl->gl_sbd, *bhp);`
228			`if (error) {`
229			`brelse(*bhp);`
230			`return error;`
231			`}`
232			`}`
233
234			`return 0;`
235			`}`
236
237			`/**`
238			`* gfs2_meta_wait - Reread a block from disk`
239			`* @sdp: the filesystem`
240			`* @bh: The block to wait for`
241			`*`
242			`* Returns: errno`
243			`*/`
244
245			`int gfs2_meta_wait(struct gfs2_sbd sdp, struct buffer_head bh)`
246			`{`
247			`if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))`
248			`return -EIO;`
249
250			`wait_on_buffer(bh);`
251
252			`if (!buffer_uptodate(bh)) {`
253			`struct gfs2_trans *tr = current->journal_info;`
254			`if (tr && tr->tr_touched)`
255			`gfs2_io_error_bh(sdp, bh);`
256			`return -EIO;`
257			`}`
258			`if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))`
259			`return -EIO;`
260
261			`return 0;`
262			`}`
263
264			`/**`
265			`* gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer`
266			`* @gl: the glock the buffer belongs to`
267			`* @bh: The buffer to be attached to`
268			`* @meta: Flag to indicate whether its metadata or not`
269			`*/`
270
271			`void gfs2_attach_bufdata(struct gfs2_glock gl, struct buffer_head bh,`
272			`int meta)`
273			`{`
274			`struct gfs2_bufdata *bd;`
275
276			`if (meta)`
277			`lock_page(bh->b_page);`
278
279			`if (bh->b_private) {`
280			`if (meta)`
281			`unlock_page(bh->b_page);`
282			`return;`
283			`}`
284
285			`bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS \| __GFP_NOFAIL),`
286			`bd->bd_bh = bh;`
287			`bd->bd_gl = gl;`
288
289			`INIT_LIST_HEAD(&bd->bd_list_tr);`
290			`if (meta)`
291			`lops_init_le(&bd->bd_le, &gfs2_buf_lops);`
292			`else`
293			`lops_init_le(&bd->bd_le, &gfs2_databuf_lops);`
294			`bh->b_private = bd;`
295
296			`if (meta)`
297			`unlock_page(bh->b_page);`
298			`}`
299
300			`void gfs2_remove_from_journal(struct buffer_head bh, struct gfs2_trans tr, int meta)`
301			`{`
302			`struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);`
303			`struct gfs2_bufdata *bd = bh->b_private;`
304			`if (test_clear_buffer_pinned(bh)) {`
305			`list_del_init(&bd->bd_le.le_list);`
306			`if (meta) {`
307			`gfs2_assert_warn(sdp, sdp->sd_log_num_buf);`
308			`sdp->sd_log_num_buf--;`
309			`tr->tr_num_buf_rm++;`
310			`} else {`
311			`gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);`
312			`sdp->sd_log_num_databuf--;`
313			`tr->tr_num_databuf_rm++;`
314			`}`
315			`tr->tr_touched = 1;`
316			`brelse(bh);`
317			`}`
318			`if (bd) {`
319			`if (bd->bd_ail) {`
320			`gfs2_remove_from_ail(NULL, bd);`
321			`bh->b_private = NULL;`
322			`bd->bd_bh = NULL;`
323			`bd->bd_blkno = bh->b_blocknr;`
324			`gfs2_trans_add_revoke(sdp, bd);`
325			`}`
326			`}`
327			`clear_buffer_dirty(bh);`
328			`clear_buffer_uptodate(bh);`
329			`}`
330
331			`/**`
332			`* gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore`
333			`* @ip: the inode who owns the buffers`
334			`* @bstart: the first buffer in the run`
335			`* @blen: the number of buffers in the run`
336			`*`
337			`*/`
338
339			`void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)`
340			`{`
341			`struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);`
342			`struct buffer_head *bh;`
343
344			`while (blen) {`
345			`bh = getbuf(ip->i_gl, bstart, NO_CREATE);`
346			`if (bh) {`
347			`lock_buffer(bh);`
348			`gfs2_log_lock(sdp);`
349			`gfs2_remove_from_journal(bh, current->journal_info, 1);`
350			`gfs2_log_unlock(sdp);`
351			`unlock_buffer(bh);`
352			`brelse(bh);`
353			`}`
354
355			`bstart++;`
356			`blen--;`
357			`}`
358			`}`
359
360			`/**`
361			`* gfs2_meta_cache_flush - get rid of any references on buffers for this inode`
362			`* @ip: The GFS2 inode`
363			`*`
364			`* This releases buffers that are in the most-recently-used array of`
365			`* blocks used for indirect block addressing for this inode.`
366			`*/`
367
368			`void gfs2_meta_cache_flush(struct gfs2_inode *ip)`
369			`{`
370			`struct buffer_head **bh_slot;`
371			`unsigned int x;`
372
373			`spin_lock(&ip->i_spin);`
374
375			`for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {`
376			`bh_slot = &ip->i_cache[x];`
377			`if (*bh_slot) {`
378			`brelse(*bh_slot);`
379			`*bh_slot = NULL;`
380			`}`
381			`}`
382
383			`spin_unlock(&ip->i_spin);`
384			`}`
385
386			`/**`
387			`* gfs2_meta_indirect_buffer - Get a metadata buffer`
388			`* @ip: The GFS2 inode`
389			`* @height: The level of this buf in the metadata (indir addr) tree (if any)`
390			`* @num: The block number (device relative) of the buffer`
391			`* @new: Non-zero if we may create a new buffer`
392			`* @bhp: the buffer is returned here`
393			`*`
394			`* Try to use the gfs2_inode's MRU metadata tree cache.`
395			`*`
396			`* Returns: errno`
397			`*/`
398
399			`int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,`
400			`int new, struct buffer_head **bhp)`
401			`{`
402			`struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);`
403			`struct gfs2_glock *gl = ip->i_gl;`
404			`struct buffer_head bh = NULL, *bh_slot = ip->i_cache + height;`
405			`int in_cache = 0;`
406
407			`BUG_ON(!gl);`
408			`BUG_ON(!sdp);`
409
410			`spin_lock(&ip->i_spin);`
411			`if (bh_slot && (bh_slot)->b_blocknr == num) {`
412			`bh = *bh_slot;`
413			`get_bh(bh);`
414			`in_cache = 1;`
415			`}`
416			`spin_unlock(&ip->i_spin);`
417
418			`if (!bh)`
419			`bh = getbuf(gl, num, CREATE);`
420
421			`if (!bh)`
422			`return -ENOBUFS;`
423
424			`if (new) {`
425			`if (gfs2_assert_warn(sdp, height))`
426			`goto err;`
427			`meta_prep_new(bh);`
428			`gfs2_trans_add_bh(ip->i_gl, bh, 1);`
429			`gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);`
430			`gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));`
431			`} else {`
432			`u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;`
433			`if (!buffer_uptodate(bh)) {`
434			`ll_rw_block(READ_META, 1, &bh);`
435			`if (gfs2_meta_wait(sdp, bh))`
436			`goto err;`
437			`}`
438			`if (gfs2_metatype_check(sdp, bh, mtype))`
439			`goto err;`
440			`}`
441
442			`if (!in_cache) {`
443			`spin_lock(&ip->i_spin);`
444			`if (*bh_slot)`
445			`brelse(*bh_slot);`
446			`*bh_slot = bh;`
447			`get_bh(bh);`
448			`spin_unlock(&ip->i_spin);`
449			`}`
450
451			`*bhp = bh;`
452			`return 0;`
453			`err:`
454			`brelse(bh);`
455			`return -EIO;`
456			`}`
457
458			`/**`
459			`* gfs2_meta_ra - start readahead on an extent of a file`
460			`* @gl: the glock the blocks belong to`
461			`* @dblock: the starting disk block`
462			`* @extlen: the number of blocks in the extent`
463			`*`
464			`* returns: the first buffer in the extent`
465			`*/`
466
467			`struct buffer_head gfs2_meta_ra(struct gfs2_glock gl, u64 dblock, u32 extlen)`
468			`{`
469			`struct gfs2_sbd *sdp = gl->gl_sbd;`
470			`struct buffer_head first_bh, bh;`
471			`u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>`
472			`sdp->sd_sb.sb_bsize_shift;`
473
474			`BUG_ON(!extlen);`
475
476			`if (max_ra < 1)`
477			`max_ra = 1;`
478			`if (extlen > max_ra)`
479			`extlen = max_ra;`
480
481			`first_bh = getbuf(gl, dblock, CREATE);`
482
483			`if (buffer_uptodate(first_bh))`
484			`goto out;`
485			`if (!buffer_locked(first_bh))`
486			`ll_rw_block(READ_META, 1, &first_bh);`
487
488			`dblock++;`
489			`extlen--;`
490
491			`while (extlen) {`
492			`bh = getbuf(gl, dblock, CREATE);`
493
494			`if (!buffer_uptodate(bh) && !buffer_locked(bh))`
495			`ll_rw_block(READA, 1, &bh);`
496			`brelse(bh);`
497			`dblock++;`
498			`extlen--;`
499			`if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))`
500			`goto out;`
501			`}`
502
503			`wait_on_buffer(first_bh);`
504			`out:`
505			`return first_bh;`
506			`}`
507