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25294d8c37
linux_dsm_epyc7002/fs/nilfs2/the_nilfs.c
Ryusuke Konishi 25294d8c37 nilfs2: use checkpoint number instead of timestamp to select super block 
Nilfs maintains two super blocks, and selects the new one on mount
time if they both have valid checksums and their timestamps differ.

However, this has potential for mis-selection since the system clock
may be rewinded and the resolution of the timestamps is not high.

Usually this doesn't become an issue because both super blocks are
updated at the same time when the file system is unmounted.  Even if
the file system wasn't unmounted cleanly, the roll-forward recovery
will find the proper log which stores the latest super root.  Thus,
the issue can appear only if update of one super block fails and the
clock happens to be rewinded.

This fixes the issue by using checkpoint numbers instead of timestamps
to pick the super block storing the location of the latest log.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-05-10 11:32:32 +09:00

790 lines
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/*
* the_nilfs.c - the_nilfs shared structure.
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Written by Ryusuke Konishi <ryusuke@osrg.net>
*
*/
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/crc32.h>
#include "nilfs.h"
#include "segment.h"
#include "alloc.h"
#include "cpfile.h"
#include "sufile.h"
#include "dat.h"
#include "segbuf.h"
static LIST_HEAD(nilfs_objects);
static DEFINE_SPINLOCK(nilfs_lock);
void nilfs_set_last_segment(struct the_nilfs *nilfs,
sector_t start_blocknr, u64 seq, __u64 cno)
{
spin_lock(&nilfs->ns_last_segment_lock);
nilfs->ns_last_pseg = start_blocknr;
nilfs->ns_last_seq = seq;
nilfs->ns_last_cno = cno;
spin_unlock(&nilfs->ns_last_segment_lock);
}
/**
* alloc_nilfs - allocate the_nilfs structure
* @bdev: block device to which the_nilfs is related
*
* alloc_nilfs() allocates memory for the_nilfs and
* initializes its reference count and locks.
*
* Return Value: On success, pointer to the_nilfs is returned.
* On error, NULL is returned.
*/
static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
{
struct the_nilfs *nilfs;
nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
if (!nilfs)
return NULL;
nilfs->ns_bdev = bdev;
atomic_set(&nilfs->ns_count, 1);
atomic_set(&nilfs->ns_ndirtyblks, 0);
init_rwsem(&nilfs->ns_sem);
init_rwsem(&nilfs->ns_super_sem);
mutex_init(&nilfs->ns_mount_mutex);
init_rwsem(&nilfs->ns_writer_sem);
INIT_LIST_HEAD(&nilfs->ns_list);
INIT_LIST_HEAD(&nilfs->ns_supers);
spin_lock_init(&nilfs->ns_last_segment_lock);
nilfs->ns_gc_inodes_h = NULL;
init_rwsem(&nilfs->ns_segctor_sem);
return nilfs;
}
/**
* find_or_create_nilfs - find or create nilfs object
* @bdev: block device to which the_nilfs is related
*
* find_nilfs() looks up an existent nilfs object created on the
* device and gets the reference count of the object. If no nilfs object
* is found on the device, a new nilfs object is allocated.
*
* Return Value: On success, pointer to the nilfs object is returned.
* On error, NULL is returned.
*/
struct the_nilfs *find_or_create_nilfs(struct block_device *bdev)
{
struct the_nilfs *nilfs, *new = NULL;
retry:
spin_lock(&nilfs_lock);
list_for_each_entry(nilfs, &nilfs_objects, ns_list) {
if (nilfs->ns_bdev == bdev) {
get_nilfs(nilfs);
spin_unlock(&nilfs_lock);
if (new)
put_nilfs(new);
return nilfs; /* existing object */
}
}
if (new) {
list_add_tail(&new->ns_list, &nilfs_objects);
spin_unlock(&nilfs_lock);
return new; /* new object */
}
spin_unlock(&nilfs_lock);
new = alloc_nilfs(bdev);
if (new)
goto retry;
return NULL; /* insufficient memory */
}
/**
* put_nilfs - release a reference to the_nilfs
* @nilfs: the_nilfs structure to be released
*
* put_nilfs() decrements a reference counter of the_nilfs.
* If the reference count reaches zero, the_nilfs is freed.
*/
void put_nilfs(struct the_nilfs *nilfs)
{
spin_lock(&nilfs_lock);
if (!atomic_dec_and_test(&nilfs->ns_count)) {
spin_unlock(&nilfs_lock);
return;
}
list_del_init(&nilfs->ns_list);
spin_unlock(&nilfs_lock);
/*
* Increment of ns_count never occurs below because the caller
* of get_nilfs() holds at least one reference to the_nilfs.
* Thus its exclusion control is not required here.
*/
might_sleep();
if (nilfs_loaded(nilfs)) {
nilfs_mdt_destroy(nilfs->ns_sufile);
nilfs_mdt_destroy(nilfs->ns_cpfile);
nilfs_mdt_destroy(nilfs->ns_dat);
nilfs_mdt_destroy(nilfs->ns_gc_dat);
}
if (nilfs_init(nilfs)) {
nilfs_destroy_gccache(nilfs);
brelse(nilfs->ns_sbh[0]);
brelse(nilfs->ns_sbh[1]);
}
kfree(nilfs);
}
static int nilfs_load_super_root(struct the_nilfs *nilfs,
struct nilfs_sb_info *sbi, sector_t sr_block)
{
struct buffer_head *bh_sr;
struct nilfs_super_root *raw_sr;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
unsigned dat_entry_size, segment_usage_size, checkpoint_size;
unsigned inode_size;
int err;
err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
if (unlikely(err))
return err;
down_read(&nilfs->ns_sem);
dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
up_read(&nilfs->ns_sem);
inode_size = nilfs->ns_inode_size;
err = -ENOMEM;
nilfs->ns_dat = nilfs_dat_new(nilfs, dat_entry_size);
if (unlikely(!nilfs->ns_dat))
goto failed;
nilfs->ns_gc_dat = nilfs_dat_new(nilfs, dat_entry_size);
if (unlikely(!nilfs->ns_gc_dat))
goto failed_dat;
nilfs->ns_cpfile = nilfs_cpfile_new(nilfs, checkpoint_size);
if (unlikely(!nilfs->ns_cpfile))
goto failed_gc_dat;
nilfs->ns_sufile = nilfs_sufile_new(nilfs, segment_usage_size);
if (unlikely(!nilfs->ns_sufile))
goto failed_cpfile;
nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
err = nilfs_dat_read(nilfs->ns_dat, (void *)bh_sr->b_data +
NILFS_SR_DAT_OFFSET(inode_size));
if (unlikely(err))
goto failed_sufile;
err = nilfs_cpfile_read(nilfs->ns_cpfile, (void *)bh_sr->b_data +
NILFS_SR_CPFILE_OFFSET(inode_size));
if (unlikely(err))
goto failed_sufile;
err = nilfs_sufile_read(nilfs->ns_sufile, (void *)bh_sr->b_data +
NILFS_SR_SUFILE_OFFSET(inode_size));
if (unlikely(err))
goto failed_sufile;
raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
failed:
brelse(bh_sr);
return err;
failed_sufile:
nilfs_mdt_destroy(nilfs->ns_sufile);
failed_cpfile:
nilfs_mdt_destroy(nilfs->ns_cpfile);
failed_gc_dat:
nilfs_mdt_destroy(nilfs->ns_gc_dat);
failed_dat:
nilfs_mdt_destroy(nilfs->ns_dat);
goto failed;
}
static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
{
memset(ri, 0, sizeof(*ri));
INIT_LIST_HEAD(&ri->ri_used_segments);
}
static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
{
nilfs_dispose_segment_list(&ri->ri_used_segments);
}
/**
* load_nilfs - load and recover the nilfs
* @nilfs: the_nilfs structure to be released
* @sbi: nilfs_sb_info used to recover past segment
*
* load_nilfs() searches and load the latest super root,
* attaches the last segment, and does recovery if needed.
* The caller must call this exclusively for simultaneous mounts.
*/
int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
{
struct nilfs_recovery_info ri;
unsigned int s_flags = sbi->s_super->s_flags;
int really_read_only = bdev_read_only(nilfs->ns_bdev);
int valid_fs = nilfs_valid_fs(nilfs);
int err;
if (nilfs_loaded(nilfs)) {
if (valid_fs ||
((s_flags & MS_RDONLY) && nilfs_test_opt(sbi, NORECOVERY)))
return 0;
printk(KERN_ERR "NILFS: the filesystem is in an incomplete "
"recovery state.\n");
return -EINVAL;
}
if (!valid_fs) {
printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
if (s_flags & MS_RDONLY) {
printk(KERN_INFO "NILFS: INFO: recovery "
"required for readonly filesystem.\n");
printk(KERN_INFO "NILFS: write access will "
"be enabled during recovery.\n");
}
}
nilfs_init_recovery_info(&ri);
err = nilfs_search_super_root(nilfs, sbi, &ri);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: error searching super root.\n");
goto failed;
}
err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: error loading super root.\n");
goto failed;
}
if (valid_fs)
goto skip_recovery;
if (s_flags & MS_RDONLY) {
if (nilfs_test_opt(sbi, NORECOVERY)) {
printk(KERN_INFO "NILFS: norecovery option specified. "
"skipping roll-forward recovery\n");
goto skip_recovery;
}
if (really_read_only) {
printk(KERN_ERR "NILFS: write access "
"unavailable, cannot proceed.\n");
err = -EROFS;
goto failed_unload;
}
sbi->s_super->s_flags &= ~MS_RDONLY;
} else if (nilfs_test_opt(sbi, NORECOVERY)) {
printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
"option was specified for a read/write mount\n");
err = -EINVAL;
goto failed_unload;
}
err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
if (err)
goto failed_unload;
down_write(&nilfs->ns_sem);
nilfs->ns_mount_state |= NILFS_VALID_FS;
nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
err = nilfs_commit_super(sbi, 1);
up_write(&nilfs->ns_sem);
if (err) {
printk(KERN_ERR "NILFS: failed to update super block. "
"recovery unfinished.\n");
goto failed_unload;
}
printk(KERN_INFO "NILFS: recovery complete.\n");
skip_recovery:
set_nilfs_loaded(nilfs);
nilfs_clear_recovery_info(&ri);
sbi->s_super->s_flags = s_flags;
return 0;
failed_unload:
nilfs_mdt_destroy(nilfs->ns_cpfile);
nilfs_mdt_destroy(nilfs->ns_sufile);
nilfs_mdt_destroy(nilfs->ns_dat);
failed:
nilfs_clear_recovery_info(&ri);
sbi->s_super->s_flags = s_flags;
return err;
}
static unsigned long long nilfs_max_size(unsigned int blkbits)
{
unsigned int max_bits;
unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
if (max_bits < 64)
res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
return res;
}
static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
struct nilfs_super_block *sbp)
{
if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
printk(KERN_ERR "NILFS: revision mismatch "
"(superblock rev.=%d.%d, current rev.=%d.%d). "
"Please check the version of mkfs.nilfs.\n",
le32_to_cpu(sbp->s_rev_level),
le16_to_cpu(sbp->s_minor_rev_level),
NILFS_CURRENT_REV, NILFS_MINOR_REV);
return -EINVAL;
}
nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
if (nilfs->ns_sbsize > BLOCK_SIZE)
return -EINVAL;
nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
printk(KERN_ERR "NILFS: too short segment.\n");
return -EINVAL;
}
nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
nilfs->ns_r_segments_percentage =
le32_to_cpu(sbp->s_r_segments_percentage);
nilfs->ns_nrsvsegs =
max_t(unsigned long, NILFS_MIN_NRSVSEGS,
DIV_ROUND_UP(nilfs->ns_nsegments *
nilfs->ns_r_segments_percentage, 100));
nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
return 0;
}
static int nilfs_valid_sb(struct nilfs_super_block *sbp)
{
static unsigned char sum[4];
const int sumoff = offsetof(struct nilfs_super_block, s_sum);
size_t bytes;
u32 crc;
if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
return 0;
bytes = le16_to_cpu(sbp->s_bytes);
if (bytes > BLOCK_SIZE)
return 0;
crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
sumoff);
crc = crc32_le(crc, sum, 4);
crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
bytes - sumoff - 4);
return crc == le32_to_cpu(sbp->s_sum);
}
static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
{
return offset < ((le64_to_cpu(sbp->s_nsegments) *
le32_to_cpu(sbp->s_blocks_per_segment)) <<
(le32_to_cpu(sbp->s_log_block_size) + 10));
}
static void nilfs_release_super_block(struct the_nilfs *nilfs)
{
int i;
for (i = 0; i < 2; i++) {
if (nilfs->ns_sbp[i]) {
brelse(nilfs->ns_sbh[i]);
nilfs->ns_sbh[i] = NULL;
nilfs->ns_sbp[i] = NULL;
}
}
}
void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
{
brelse(nilfs->ns_sbh[0]);
nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
nilfs->ns_sbh[1] = NULL;
nilfs->ns_sbp[1] = NULL;
}
void nilfs_swap_super_block(struct the_nilfs *nilfs)
{
struct buffer_head *tsbh = nilfs->ns_sbh[0];
struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
nilfs->ns_sbh[1] = tsbh;
nilfs->ns_sbp[1] = tsbp;
}
static int nilfs_load_super_block(struct the_nilfs *nilfs,
struct super_block *sb, int blocksize,
struct nilfs_super_block **sbpp)
{
struct nilfs_super_block **sbp = nilfs->ns_sbp;
struct buffer_head **sbh = nilfs->ns_sbh;
u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
int valid[2], swp = 0;
sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
&sbh[0]);
sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
if (!sbp[0]) {
if (!sbp[1]) {
printk(KERN_ERR "NILFS: unable to read superblock\n");
return -EIO;
}
printk(KERN_WARNING
"NILFS warning: unable to read primary superblock\n");
} else if (!sbp[1])
printk(KERN_WARNING
"NILFS warning: unable to read secondary superblock\n");
/*
* Compare two super blocks and set 1 in swp if the secondary
* super block is valid and newer. Otherwise, set 0 in swp.
*/
valid[0] = nilfs_valid_sb(sbp[0]);
valid[1] = nilfs_valid_sb(sbp[1]);
swp = valid[1] && (!valid[0] ||
le64_to_cpu(sbp[1]->s_last_cno) >
le64_to_cpu(sbp[0]->s_last_cno));
if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
brelse(sbh[1]);
sbh[1] = NULL;
sbp[1] = NULL;
swp = 0;
}
if (!valid[swp]) {
nilfs_release_super_block(nilfs);
printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
sb->s_id);
return -EINVAL;
}
if (swp) {
printk(KERN_WARNING "NILFS warning: broken superblock. "
"using spare superblock.\n");
nilfs_swap_super_block(nilfs);
}
nilfs->ns_sbwtime[0] = le64_to_cpu(sbp[0]->s_wtime);
nilfs->ns_sbwtime[1] = valid[!swp] ? le64_to_cpu(sbp[1]->s_wtime) : 0;
nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
*sbpp = sbp[0];
return 0;
}
/**
* init_nilfs - initialize a NILFS instance.
* @nilfs: the_nilfs structure
* @sbi: nilfs_sb_info
* @sb: super block
* @data: mount options
*
* init_nilfs() performs common initialization per block device (e.g.
* reading the super block, getting disk layout information, initializing
* shared fields in the_nilfs). It takes on some portion of the jobs
* typically done by a fill_super() routine. This division arises from
* the nature that multiple NILFS instances may be simultaneously
* mounted on a device.
* For multiple mounts on the same device, only the first mount
* invokes these tasks.
*
* Return Value: On success, 0 is returned. On error, a negative error
* code is returned.
*/
int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
{
struct super_block *sb = sbi->s_super;
struct nilfs_super_block *sbp;
struct backing_dev_info *bdi;
int blocksize;
int err;
down_write(&nilfs->ns_sem);
if (nilfs_init(nilfs)) {
/* Load values from existing the_nilfs */
sbp = nilfs->ns_sbp[0];
err = nilfs_store_magic_and_option(sb, sbp, data);
if (err)
goto out;
blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
if (sb->s_blocksize != blocksize &&
!sb_set_blocksize(sb, blocksize)) {
printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
blocksize);
err = -EINVAL;
}
sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
goto out;
}
blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
if (!blocksize) {
printk(KERN_ERR "NILFS: unable to set blocksize\n");
err = -EINVAL;
goto out;
}
err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
if (err)
goto out;
err = nilfs_store_magic_and_option(sb, sbp, data);
if (err)
goto failed_sbh;
blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
if (sb->s_blocksize != blocksize) {
int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
if (blocksize < hw_blocksize) {
printk(KERN_ERR
"NILFS: blocksize %d too small for device "
"(sector-size = %d).\n",
blocksize, hw_blocksize);
err = -EINVAL;
goto failed_sbh;
}
nilfs_release_super_block(nilfs);
sb_set_blocksize(sb, blocksize);
err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
if (err)
goto out;
/* not failed_sbh; sbh is released automatically
when reloading fails. */
}
nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
err = nilfs_store_disk_layout(nilfs, sbp);
if (err)
goto failed_sbh;
sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
/* Finding last segment */
nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
nilfs->ns_seg_seq = nilfs->ns_last_seq;
nilfs->ns_segnum =
nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
nilfs->ns_cno = nilfs->ns_last_cno + 1;
if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
printk(KERN_ERR "NILFS invalid last segment number.\n");
err = -EINVAL;
goto failed_sbh;
}
/* Dummy values */
nilfs->ns_free_segments_count =
nilfs->ns_nsegments - (nilfs->ns_segnum + 1);
/* Initialize gcinode cache */
err = nilfs_init_gccache(nilfs);
if (err)
goto failed_sbh;
set_nilfs_init(nilfs);
err = 0;
out:
up_write(&nilfs->ns_sem);
return err;
failed_sbh:
nilfs_release_super_block(nilfs);
goto out;
}
int nilfs_discard_segments(struct the_nilfs *nilfs, __u64 *segnump,
size_t nsegs)
{
sector_t seg_start, seg_end;
sector_t start = 0, nblocks = 0;
unsigned int sects_per_block;
__u64 *sn;
int ret = 0;
sects_per_block = (1 << nilfs->ns_blocksize_bits) /
bdev_logical_block_size(nilfs->ns_bdev);
for (sn = segnump; sn < segnump + nsegs; sn++) {
nilfs_get_segment_range(nilfs, *sn, &seg_start, &seg_end);
if (!nblocks) {
start = seg_start;
nblocks = seg_end - seg_start + 1;
} else if (start + nblocks == seg_start) {
nblocks += seg_end - seg_start + 1;
} else {
ret = blkdev_issue_discard(nilfs->ns_bdev,
start * sects_per_block,
nblocks * sects_per_block,
GFP_NOFS,
DISCARD_FL_BARRIER);
if (ret < 0)
return ret;
nblocks = 0;
}
}
if (nblocks)
ret = blkdev_issue_discard(nilfs->ns_bdev,
start * sects_per_block,
nblocks * sects_per_block,
GFP_NOFS, DISCARD_FL_BARRIER);
return ret;
}
int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
{
struct inode *dat = nilfs_dat_inode(nilfs);
unsigned long ncleansegs;
down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
*nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
return 0;
}
int nilfs_near_disk_full(struct the_nilfs *nilfs)
{
unsigned long ncleansegs, nincsegs;
ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
nilfs->ns_blocks_per_segment + 1;
return ncleansegs <= nilfs->ns_nrsvsegs + nincsegs;
}
/**
* nilfs_find_sbinfo - find existing nilfs_sb_info structure
* @nilfs: nilfs object
* @rw_mount: mount type (non-zero value for read/write mount)
* @cno: checkpoint number (zero for read-only mount)
*
* nilfs_find_sbinfo() returns the nilfs_sb_info structure which
* @rw_mount and @cno (in case of snapshots) matched. If no instance
* was found, NULL is returned. Although the super block instance can
* be unmounted after this function returns, the nilfs_sb_info struct
* is kept on memory until nilfs_put_sbinfo() is called.
*/
struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs,
int rw_mount, __u64 cno)
{
struct nilfs_sb_info *sbi;
down_read(&nilfs->ns_super_sem);
/*
* The SNAPSHOT flag and sb->s_flags are supposed to be
* protected with nilfs->ns_super_sem.
*/
sbi = nilfs->ns_current;
if (rw_mount) {
if (sbi && !(sbi->s_super->s_flags & MS_RDONLY))
goto found; /* read/write mount */
else
goto out;
} else if (cno == 0) {
if (sbi && (sbi->s_super->s_flags & MS_RDONLY))
goto found; /* read-only mount */
else
goto out;
}
list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
if (nilfs_test_opt(sbi, SNAPSHOT) &&
sbi->s_snapshot_cno == cno)
goto found; /* snapshot mount */
}
out:
up_read(&nilfs->ns_super_sem);
return NULL;
found:
atomic_inc(&sbi->s_count);
up_read(&nilfs->ns_super_sem);
return sbi;
}
int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
int snapshot_mount)
{
struct nilfs_sb_info *sbi;
int ret = 0;
down_read(&nilfs->ns_super_sem);
if (cno == 0 || cno > nilfs->ns_cno)
goto out_unlock;
list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
if (sbi->s_snapshot_cno == cno &&
(!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
/* exclude read-only mounts */
ret++;
break;
}
}
/* for protecting recent checkpoints */
if (cno >= nilfs_last_cno(nilfs))
ret++;
out_unlock:
up_read(&nilfs->ns_super_sem);
return ret;
}
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