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linux_dsm_epyc7002/fs/ufs/truncate.c
Al Viro 724bb09fdc ufs: don't use lock_ufs() for block pointers tree protection 
* stores to block pointers are under per-inode seqlock (meta_lock) and
mutex (truncate_mutex)
* fetches of block pointers are either under truncate_mutex, or wrapped
into seqretry loop on meta_lock
* all changes of ->i_size are under truncate_mutex and i_mutex
* all changes of ->i_lastfrag are under truncate_mutex

It's similar to what ext2 is doing; the main difference is that unlike
ext2 we can't rely upon the atomicity of stores into block pointers -
on UFS2 they are 64bit.  So we can't cut the corner when switching
a pointer from NULL to non-NULL as we could in ext2_splice_branch()
and need to use meta_lock on all modifications.

We use seqlock where ext2 uses rwlock; ext2 could probably also benefit
from such change...

Another non-trivial difference is that with UFS we *cannot* have reader
grab truncate_mutex in case of race - it has to keep retrying.  That
might be possible to change, but not until we lift tail unpacking
several levels up in call chain.

After that commit we do *NOT* hold fs-wide serialization on accesses
to block pointers anymore.  Moreover, lock_ufs() can become a normal
mutex now - it's only used on statfs, remount and sync_fs and none
of those uses are recursive.  As the matter of fact, *now* it can be
collapsed with ->s_lock, and be eventually replaced with saner
per-cylinder-group spinlocks, but that's a separate story.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-07-06 17:39:25 -04:00

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/*
* linux/fs/ufs/truncate.c
*
* Copyright (C) 1998
* Daniel Pirkl <daniel.pirkl@email.cz>
* Charles University, Faculty of Mathematics and Physics
*
* from
*
* linux/fs/ext2/truncate.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/truncate.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
/*
* Real random numbers for secure rm added 94/02/18
* Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
*/
/*
* Adoptation to use page cache and UFS2 write support by
* Evgeniy Dushistov <dushistov@mail.ru>, 2006-2007
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/sched.h>
#include "ufs_fs.h"
#include "ufs.h"
#include "swab.h"
#include "util.h"
/*
* Secure deletion currently doesn't work. It interacts very badly
* with buffers shared with memory mappings, and for that reason
* can't be done in the truncate() routines. It should instead be
* done separately in "release()" before calling the truncate routines
* that will release the actual file blocks.
*
* Linus
*/
#define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
#define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
static int ufs_trunc_direct(struct inode *inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block * sb;
struct ufs_sb_private_info * uspi;
void *p;
u64 frag1, frag2, frag3, frag4, block1, block2;
unsigned frag_to_free, free_count;
unsigned i, tmp;
int retry;
UFSD("ENTER: ino %lu\n", inode->i_ino);
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
frag_to_free = 0;
free_count = 0;
retry = 0;
frag1 = DIRECT_FRAGMENT;
frag4 = min_t(u64, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
frag3 = frag4 & ~uspi->s_fpbmask;
block1 = block2 = 0;
if (frag2 > frag3) {
frag2 = frag4;
frag3 = frag4 = 0;
} else if (frag2 < frag3) {
block1 = ufs_fragstoblks (frag2);
block2 = ufs_fragstoblks (frag3);
}
UFSD("ino %lu, frag1 %llu, frag2 %llu, block1 %llu, block2 %llu,"
" frag3 %llu, frag4 %llu\n", inode->i_ino,
(unsigned long long)frag1, (unsigned long long)frag2,
(unsigned long long)block1, (unsigned long long)block2,
(unsigned long long)frag3, (unsigned long long)frag4);
if (frag1 >= frag2)
goto next1;
/*
* Free first free fragments
*/
p = ufs_get_direct_data_ptr(uspi, ufsi, ufs_fragstoblks(frag1));
tmp = ufs_data_ptr_to_cpu(sb, p);
if (!tmp )
ufs_panic (sb, "ufs_trunc_direct", "internal error");
frag2 -= frag1;
frag1 = ufs_fragnum (frag1);
ufs_free_fragments(inode, tmp + frag1, frag2);
mark_inode_dirty(inode);
frag_to_free = tmp + frag1;
next1:
/*
* Free whole blocks
*/
for (i = block1 ; i < block2; i++) {
p = ufs_get_direct_data_ptr(uspi, ufsi, i);
tmp = ufs_data_ptr_to_cpu(sb, p);
if (!tmp)
continue;
write_seqlock(&ufsi->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&ufsi->meta_lock);
if (free_count == 0) {
frag_to_free = tmp;
free_count = uspi->s_fpb;
} else if (free_count > 0 && frag_to_free == tmp - free_count)
free_count += uspi->s_fpb;
else {
ufs_free_blocks (inode, frag_to_free, free_count);
frag_to_free = tmp;
free_count = uspi->s_fpb;
}
mark_inode_dirty(inode);
}
if (free_count > 0)
ufs_free_blocks (inode, frag_to_free, free_count);
if (frag3 >= frag4)
goto next3;
/*
* Free last free fragments
*/
p = ufs_get_direct_data_ptr(uspi, ufsi, ufs_fragstoblks(frag3));
tmp = ufs_data_ptr_to_cpu(sb, p);
if (!tmp )
ufs_panic(sb, "ufs_truncate_direct", "internal error");
frag4 = ufs_fragnum (frag4);
write_seqlock(&ufsi->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&ufsi->meta_lock);
ufs_free_fragments (inode, tmp, frag4);
mark_inode_dirty(inode);
next3:
UFSD("EXIT: ino %lu\n", inode->i_ino);
return retry;
}
static int ufs_trunc_indirect(struct inode *inode, u64 offset, void *p)
{
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct ufs_buffer_head * ind_ubh;
void *ind;
u64 tmp, indirect_block, i, frag_to_free;
unsigned free_count;
int retry;
UFSD("ENTER: ino %lu, offset %llu, p: %p\n",
inode->i_ino, (unsigned long long)offset, p);
BUG_ON(!p);
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
frag_to_free = 0;
free_count = 0;
retry = 0;
tmp = ufs_data_ptr_to_cpu(sb, p);
if (!tmp)
return 0;
ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
ubh_brelse (ind_ubh);
return 1;
}
if (!ind_ubh) {
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&UFS_I(inode)->meta_lock);
return 0;
}
indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
for (i = indirect_block; i < uspi->s_apb; i++) {
ind = ubh_get_data_ptr(uspi, ind_ubh, i);
tmp = ufs_data_ptr_to_cpu(sb, ind);
if (!tmp)
continue;
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_data_ptr_clear(uspi, ind);
write_sequnlock(&UFS_I(inode)->meta_lock);
ubh_mark_buffer_dirty(ind_ubh);
if (free_count == 0) {
frag_to_free = tmp;
free_count = uspi->s_fpb;
} else if (free_count > 0 && frag_to_free == tmp - free_count)
free_count += uspi->s_fpb;
else {
ufs_free_blocks (inode, frag_to_free, free_count);
frag_to_free = tmp;
free_count = uspi->s_fpb;
}
mark_inode_dirty(inode);
}
if (free_count > 0) {
ufs_free_blocks (inode, frag_to_free, free_count);
}
for (i = 0; i < uspi->s_apb; i++)
if (!ufs_is_data_ptr_zero(uspi,
ubh_get_data_ptr(uspi, ind_ubh, i)))
break;
if (i >= uspi->s_apb) {
tmp = ufs_data_ptr_to_cpu(sb, p);
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&UFS_I(inode)->meta_lock);
ubh_bforget(ind_ubh);
ufs_free_blocks (inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
ind_ubh = NULL;
}
if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh))
ubh_sync_block(ind_ubh);
ubh_brelse (ind_ubh);
UFSD("EXIT: ino %lu\n", inode->i_ino);
return retry;
}
static int ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
{
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct ufs_buffer_head *dind_bh;
u64 i, tmp, dindirect_block;
void *dind;
int retry = 0;
UFSD("ENTER: ino %lu\n", inode->i_ino);
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
dindirect_block = (DIRECT_BLOCK > offset)
? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
retry = 0;
tmp = ufs_data_ptr_to_cpu(sb, p);
if (!tmp)
return 0;
dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
ubh_brelse (dind_bh);
return 1;
}
if (!dind_bh) {
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&UFS_I(inode)->meta_lock);
return 0;
}
for (i = dindirect_block ; i < uspi->s_apb ; i++) {
dind = ubh_get_data_ptr(uspi, dind_bh, i);
tmp = ufs_data_ptr_to_cpu(sb, dind);
if (!tmp)
continue;
retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
ubh_mark_buffer_dirty(dind_bh);
}
for (i = 0; i < uspi->s_apb; i++)
if (!ufs_is_data_ptr_zero(uspi,
ubh_get_data_ptr(uspi, dind_bh, i)))
break;
if (i >= uspi->s_apb) {
tmp = ufs_data_ptr_to_cpu(sb, p);
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&UFS_I(inode)->meta_lock);
ubh_bforget(dind_bh);
ufs_free_blocks(inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
dind_bh = NULL;
}
if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh))
ubh_sync_block(dind_bh);
ubh_brelse (dind_bh);
UFSD("EXIT: ino %lu\n", inode->i_ino);
return retry;
}
static int ufs_trunc_tindirect(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
struct ufs_inode_info *ufsi = UFS_I(inode);
struct ufs_buffer_head * tind_bh;
u64 tindirect_block, tmp, i;
void *tind, *p;
int retry;
UFSD("ENTER: ino %lu\n", inode->i_ino);
retry = 0;
tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
p = ufs_get_direct_data_ptr(uspi, ufsi, UFS_TIND_BLOCK);
if (!(tmp = ufs_data_ptr_to_cpu(sb, p)))
return 0;
tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
ubh_brelse (tind_bh);
return 1;
}
if (!tind_bh) {
write_seqlock(&ufsi->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&ufsi->meta_lock);
return 0;
}
for (i = tindirect_block ; i < uspi->s_apb ; i++) {
tind = ubh_get_data_ptr(uspi, tind_bh, i);
retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
ubh_mark_buffer_dirty(tind_bh);
}
for (i = 0; i < uspi->s_apb; i++)
if (!ufs_is_data_ptr_zero(uspi,
ubh_get_data_ptr(uspi, tind_bh, i)))
break;
if (i >= uspi->s_apb) {
tmp = ufs_data_ptr_to_cpu(sb, p);
write_seqlock(&ufsi->meta_lock);
ufs_data_ptr_clear(uspi, p);
write_sequnlock(&ufsi->meta_lock);
ubh_bforget(tind_bh);
ufs_free_blocks(inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
tind_bh = NULL;
}
if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh))
ubh_sync_block(tind_bh);
ubh_brelse (tind_bh);
UFSD("EXIT: ino %lu\n", inode->i_ino);
return retry;
}
static int ufs_alloc_lastblock(struct inode *inode, loff_t size)
{
int err = 0;
struct super_block *sb = inode->i_sb;
struct address_space *mapping = inode->i_mapping;
struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
unsigned i, end;
sector_t lastfrag;
struct page *lastpage;
struct buffer_head *bh;
u64 phys64;
lastfrag = (size + uspi->s_fsize - 1) >> uspi->s_fshift;
if (!lastfrag)
goto out;
lastfrag--;
lastpage = ufs_get_locked_page(mapping, lastfrag >>
(PAGE_CACHE_SHIFT - inode->i_blkbits));
if (IS_ERR(lastpage)) {
err = -EIO;
goto out;
}
end = lastfrag & ((1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)) - 1);
bh = page_buffers(lastpage);
for (i = 0; i < end; ++i)
bh = bh->b_this_page;
err = ufs_getfrag_block(inode, lastfrag, bh, 1);
if (unlikely(err))
goto out_unlock;
if (buffer_new(bh)) {
clear_buffer_new(bh);
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
/*
* we do not zeroize fragment, because of
* if it maped to hole, it already contains zeroes
*/
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
set_page_dirty(lastpage);
}
if (lastfrag >= UFS_IND_FRAGMENT) {
end = uspi->s_fpb - ufs_fragnum(lastfrag) - 1;
phys64 = bh->b_blocknr + 1;
for (i = 0; i < end; ++i) {
bh = sb_getblk(sb, i + phys64);
lock_buffer(bh);
memset(bh->b_data, 0, sb->s_blocksize);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
unlock_buffer(bh);
sync_dirty_buffer(bh);
brelse(bh);
}
}
out_unlock:
ufs_put_locked_page(lastpage);
out:
return err;
}
static void __ufs_truncate_blocks(struct inode *inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block *sb = inode->i_sb;
struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
int retry;
mutex_lock(&ufsi->truncate_mutex);
while (1) {
retry = ufs_trunc_direct(inode);
retry |= ufs_trunc_indirect(inode, UFS_IND_BLOCK,
ufs_get_direct_data_ptr(uspi, ufsi,
UFS_IND_BLOCK));
retry |= ufs_trunc_dindirect(inode, UFS_IND_BLOCK + uspi->s_apb,
ufs_get_direct_data_ptr(uspi, ufsi,
UFS_DIND_BLOCK));
retry |= ufs_trunc_tindirect (inode);
if (!retry)
break;
if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
ufs_sync_inode (inode);
yield();
}
ufsi->i_lastfrag = DIRECT_FRAGMENT;
mutex_unlock(&ufsi->truncate_mutex);
}
int ufs_truncate(struct inode *inode, loff_t size)
{
int err = 0;
UFSD("ENTER: ino %lu, i_size: %llu, old_i_size: %llu\n",
inode->i_ino, (unsigned long long)size,
(unsigned long long)i_size_read(inode));
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)))
return -EINVAL;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
err = ufs_alloc_lastblock(inode, size);
if (err)
goto out;
block_truncate_page(inode->i_mapping, size, ufs_getfrag_block);
truncate_setsize(inode, size);
__ufs_truncate_blocks(inode);
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
out:
UFSD("EXIT: err %d\n", err);
return err;
}
void ufs_truncate_blocks(struct inode *inode)
{
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)))
return;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
__ufs_truncate_blocks(inode);
}
int ufs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
unsigned int ia_valid = attr->ia_valid;
int error;
error = inode_change_ok(inode, attr);
if (error)
return error;
if (ia_valid & ATTR_SIZE && attr->ia_size != inode->i_size) {
error = ufs_truncate(inode, attr->ia_size);
if (error)
return error;
}
setattr_copy(inode, attr);
mark_inode_dirty(inode);
return 0;
}
const struct inode_operations ufs_file_inode_operations = {
.setattr = ufs_setattr,
};
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