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linux/fs/ext4/extents.c
Yongqiang Yang 667eff35a1 ext4: reimplement convert and split_unwritten 
Reimplement ext4_ext_convert_to_initialized() and
ext4_split_unwritten_extents() using ext4_split_extent()

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>
2011-05-03 12:25:07 -04:00

3904 lines
102 KiB
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/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*
* Architecture independence:
* Copyright (c) 2005, Bull S.A.
* Written by Pierre Peiffer <pierre.peiffer@bull.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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 Licens
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
/*
* Extents support for EXT4
*
* TODO:
* - ext4*_error() should be used in some situations
* - analyze all BUG()/BUG_ON(), use -EIO where appropriate
* - smart tree reduction
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/jbd2.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/falloc.h>
#include <asm/uaccess.h>
#include <linux/fiemap.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"
#include <trace/events/ext4.h>
static int ext4_ext_truncate_extend_restart(handle_t *handle,
struct inode *inode,
int needed)
{
int err;
if (!ext4_handle_valid(handle))
return 0;
if (handle->h_buffer_credits > needed)
return 0;
err = ext4_journal_extend(handle, needed);
if (err <= 0)
return err;
err = ext4_truncate_restart_trans(handle, inode, needed);
if (err == 0)
err = -EAGAIN;
return err;
}
/*
* could return:
* - EROFS
* - ENOMEM
*/
static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
if (path->p_bh) {
/* path points to block */
return ext4_journal_get_write_access(handle, path->p_bh);
}
/* path points to leaf/index in inode body */
/* we use in-core data, no need to protect them */
return 0;
}
/*
* could return:
* - EROFS
* - ENOMEM
* - EIO
*/
static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
int err;
if (path->p_bh) {
/* path points to block */
err = ext4_handle_dirty_metadata(handle, inode, path->p_bh);
} else {
/* path points to leaf/index in inode body */
err = ext4_mark_inode_dirty(handle, inode);
}
return err;
}
static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t block)
{
struct ext4_inode_info *ei = EXT4_I(inode);
ext4_fsblk_t bg_start;
ext4_fsblk_t last_block;
ext4_grpblk_t colour;
ext4_group_t block_group;
int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
int depth;
if (path) {
struct ext4_extent *ex;
depth = path->p_depth;
/*
* Try to predict block placement assuming that we are
* filling in a file which will eventually be
* non-sparse --- i.e., in the case of libbfd writing
* an ELF object sections out-of-order but in a way
* the eventually results in a contiguous object or
* executable file, or some database extending a table
* space file. However, this is actually somewhat
* non-ideal if we are writing a sparse file such as
* qemu or KVM writing a raw image file that is going
* to stay fairly sparse, since it will end up
* fragmenting the file system's free space. Maybe we
* should have some hueristics or some way to allow
* userspace to pass a hint to file system,
* especially if the latter case turns out to be
* common.
*/
ex = path[depth].p_ext;
if (ex) {
ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
if (block > ext_block)
return ext_pblk + (block - ext_block);
else
return ext_pblk - (ext_block - block);
}
/* it looks like index is empty;
* try to find starting block from index itself */
if (path[depth].p_bh)
return path[depth].p_bh->b_blocknr;
}
/* OK. use inode's group */
block_group = ei->i_block_group;
if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
/*
* If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
* block groups per flexgroup, reserve the first block
* group for directories and special files. Regular
* files will start at the second block group. This
* tends to speed up directory access and improves
* fsck times.
*/
block_group &= ~(flex_size-1);
if (S_ISREG(inode->i_mode))
block_group++;
}
bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
/*
* If we are doing delayed allocation, we don't need take
* colour into account.
*/
if (test_opt(inode->i_sb, DELALLOC))
return bg_start;
if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
colour = (current->pid % 16) *
(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
else
colour = (current->pid % 16) * ((last_block - bg_start) / 16);
return bg_start + colour + block;
}
/*
* Allocation for a meta data block
*/
static ext4_fsblk_t
ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *ex, int *err)
{
ext4_fsblk_t goal, newblock;
goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
return newblock;
}
static inline int ext4_ext_space_block(struct inode *inode, int check)
{
int size;
size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
/ sizeof(struct ext4_extent);
if (!check) {
#ifdef AGGRESSIVE_TEST
if (size > 6)
size = 6;
#endif
}
return size;
}
static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
{
int size;
size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
/ sizeof(struct ext4_extent_idx);
if (!check) {
#ifdef AGGRESSIVE_TEST
if (size > 5)
size = 5;
#endif
}
return size;
}
static inline int ext4_ext_space_root(struct inode *inode, int check)
{
int size;
size = sizeof(EXT4_I(inode)->i_data);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent);
if (!check) {
#ifdef AGGRESSIVE_TEST
if (size > 3)
size = 3;
#endif
}
return size;
}
static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
{
int size;
size = sizeof(EXT4_I(inode)->i_data);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent_idx);
if (!check) {
#ifdef AGGRESSIVE_TEST
if (size > 4)
size = 4;
#endif
}
return size;
}
/*
* Calculate the number of metadata blocks needed
* to allocate @blocks
* Worse case is one block per extent
*/
int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
{
struct ext4_inode_info *ei = EXT4_I(inode);
int idxs, num = 0;
idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
/ sizeof(struct ext4_extent_idx));
/*
* If the new delayed allocation block is contiguous with the
* previous da block, it can share index blocks with the
* previous block, so we only need to allocate a new index
* block every idxs leaf blocks. At ldxs**2 blocks, we need
* an additional index block, and at ldxs**3 blocks, yet
* another index blocks.
*/
if (ei->i_da_metadata_calc_len &&
ei->i_da_metadata_calc_last_lblock+1 == lblock) {
if ((ei->i_da_metadata_calc_len % idxs) == 0)
num++;
if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
num++;
if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
num++;
ei->i_da_metadata_calc_len = 0;
} else
ei->i_da_metadata_calc_len++;
ei->i_da_metadata_calc_last_lblock++;
return num;
}
/*
* In the worst case we need a new set of index blocks at
* every level of the inode's extent tree.
*/
ei->i_da_metadata_calc_len = 1;
ei->i_da_metadata_calc_last_lblock = lblock;
return ext_depth(inode) + 1;
}
static int
ext4_ext_max_entries(struct inode *inode, int depth)
{
int max;
if (depth == ext_depth(inode)) {
if (depth == 0)
max = ext4_ext_space_root(inode, 1);
else
max = ext4_ext_space_root_idx(inode, 1);
} else {
if (depth == 0)
max = ext4_ext_space_block(inode, 1);
else
max = ext4_ext_space_block_idx(inode, 1);
}
return max;
}
static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
{
ext4_fsblk_t block = ext4_ext_pblock(ext);
int len = ext4_ext_get_actual_len(ext);
return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
}
static int ext4_valid_extent_idx(struct inode *inode,
struct ext4_extent_idx *ext_idx)
{
ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
}
static int ext4_valid_extent_entries(struct inode *inode,
struct ext4_extent_header *eh,
int depth)
{
struct ext4_extent *ext;
struct ext4_extent_idx *ext_idx;
unsigned short entries;
if (eh->eh_entries == 0)
return 1;
entries = le16_to_cpu(eh->eh_entries);
if (depth == 0) {
/* leaf entries */
ext = EXT_FIRST_EXTENT(eh);
while (entries) {
if (!ext4_valid_extent(inode, ext))
return 0;
ext++;
entries--;
}
} else {
ext_idx = EXT_FIRST_INDEX(eh);
while (entries) {
if (!ext4_valid_extent_idx(inode, ext_idx))
return 0;
ext_idx++;
entries--;
}
}
return 1;
}
static int __ext4_ext_check(const char *function, unsigned int line,
struct inode *inode, struct ext4_extent_header *eh,
int depth)
{
const char *error_msg;
int max = 0;
if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
error_msg = "invalid magic";
goto corrupted;
}
if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
error_msg = "unexpected eh_depth";
goto corrupted;
}
if (unlikely(eh->eh_max == 0)) {
error_msg = "invalid eh_max";
goto corrupted;
}
max = ext4_ext_max_entries(inode, depth);
if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
error_msg = "too large eh_max";
goto corrupted;
}
if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
error_msg = "invalid eh_entries";
goto corrupted;
}
if (!ext4_valid_extent_entries(inode, eh, depth)) {
error_msg = "invalid extent entries";
goto corrupted;
}
return 0;
corrupted:
ext4_error_inode(inode, function, line, 0,
"bad header/extent: %s - magic %x, "
"entries %u, max %u(%u), depth %u(%u)",
error_msg, le16_to_cpu(eh->eh_magic),
le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
max, le16_to_cpu(eh->eh_depth), depth);
return -EIO;
}
#define ext4_ext_check(inode, eh, depth) \
__ext4_ext_check(__func__, __LINE__, inode, eh, depth)
int ext4_ext_check_inode(struct inode *inode)
{
return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));
}
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
{
int k, l = path->p_depth;
ext_debug("path:");
for (k = 0; k <= l; k++, path++) {
if (path->p_idx) {
ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
ext4_idx_pblock(path->p_idx));
} else if (path->p_ext) {
ext_debug(" %d:[%d]%d:%llu ",
le32_to_cpu(path->p_ext->ee_block),
ext4_ext_is_uninitialized(path->p_ext),
ext4_ext_get_actual_len(path->p_ext),
ext4_ext_pblock(path->p_ext));
} else
ext_debug(" []");
}
ext_debug("\n");
}
static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
{
int depth = ext_depth(inode);
struct ext4_extent_header *eh;
struct ext4_extent *ex;
int i;
if (!path)
return;
eh = path[depth].p_hdr;
ex = EXT_FIRST_EXTENT(eh);
ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
ext4_ext_is_uninitialized(ex),
ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
}
ext_debug("\n");
}
#else
#define ext4_ext_show_path(inode, path)
#define ext4_ext_show_leaf(inode, path)
#endif
void ext4_ext_drop_refs(struct ext4_ext_path *path)
{
int depth = path->p_depth;
int i;
for (i = 0; i <= depth; i++, path++)
if (path->p_bh) {
brelse(path->p_bh);
path->p_bh = NULL;
}
}
/*
* ext4_ext_binsearch_idx:
* binary search for the closest index of the given block
* the header must be checked before calling this
*/
static void
ext4_ext_binsearch_idx(struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent_idx *r, *l, *m;
ext_debug("binsearch for %u(idx): ", block);
l = EXT_FIRST_INDEX(eh) + 1;
r = EXT_LAST_INDEX(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < le32_to_cpu(m->ei_block))
r = m - 1;
else
l = m + 1;
ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
m, le32_to_cpu(m->ei_block),
r, le32_to_cpu(r->ei_block));
}
path->p_idx = l - 1;
ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
ext4_idx_pblock(path->p_idx));
#ifdef CHECK_BINSEARCH
{
struct ext4_extent_idx *chix, *ix;
int k;
chix = ix = EXT_FIRST_INDEX(eh);
for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
if (k != 0 &&
le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
printk(KERN_DEBUG "k=%d, ix=0x%p, "
"first=0x%p\n", k,
ix, EXT_FIRST_INDEX(eh));
printk(KERN_DEBUG "%u <= %u\n",
le32_to_cpu(ix->ei_block),
le32_to_cpu(ix[-1].ei_block));
}
BUG_ON(k && le32_to_cpu(ix->ei_block)
<= le32_to_cpu(ix[-1].ei_block));
if (block < le32_to_cpu(ix->ei_block))
break;
chix = ix;
}
BUG_ON(chix != path->p_idx);
}
#endif
}
/*
* ext4_ext_binsearch:
* binary search for closest extent of the given block
* the header must be checked before calling this
*/
static void
ext4_ext_binsearch(struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent *r, *l, *m;
if (eh->eh_entries == 0) {
/*
* this leaf is empty:
* we get such a leaf in split/add case
*/
return;
}
ext_debug("binsearch for %u: ", block);
l = EXT_FIRST_EXTENT(eh) + 1;
r = EXT_LAST_EXTENT(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < le32_to_cpu(m->ee_block))
r = m - 1;
else
l = m + 1;
ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
m, le32_to_cpu(m->ee_block),
r, le32_to_cpu(r->ee_block));
}
path->p_ext = l - 1;
ext_debug(" -> %d:%llu:[%d]%d ",
le32_to_cpu(path->p_ext->ee_block),
ext4_ext_pblock(path->p_ext),
ext4_ext_is_uninitialized(path->p_ext),
ext4_ext_get_actual_len(path->p_ext));
#ifdef CHECK_BINSEARCH
{
struct ext4_extent *chex, *ex;
int k;
chex = ex = EXT_FIRST_EXTENT(eh);
for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
BUG_ON(k && le32_to_cpu(ex->ee_block)
<= le32_to_cpu(ex[-1].ee_block));
if (block < le32_to_cpu(ex->ee_block))
break;
chex = ex;
}
BUG_ON(chex != path->p_ext);
}
#endif
}
int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
{
struct ext4_extent_header *eh;
eh = ext_inode_hdr(inode);
eh->eh_depth = 0;
eh->eh_entries = 0;
eh->eh_magic = EXT4_EXT_MAGIC;
eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
ext4_mark_inode_dirty(handle, inode);
ext4_ext_invalidate_cache(inode);
return 0;
}
struct ext4_ext_path *
ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
struct ext4_ext_path *path)
{
struct ext4_extent_header *eh;
struct buffer_head *bh;
short int depth, i, ppos = 0, alloc = 0;
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
/* account possible depth increase */
if (!path) {
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
GFP_NOFS);
if (!path)
return ERR_PTR(-ENOMEM);
alloc = 1;
}
path[0].p_hdr = eh;
path[0].p_bh = NULL;
i = depth;
/* walk through the tree */
while (i) {
int need_to_validate = 0;
ext_debug("depth %d: num %d, max %d\n",
ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
ext4_ext_binsearch_idx(inode, path + ppos, block);
path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;
bh = sb_getblk(inode->i_sb, path[ppos].p_block);
if (unlikely(!bh))
goto err;
if (!bh_uptodate_or_lock(bh)) {
trace_ext4_ext_load_extent(inode, block,
path[ppos].p_block);
if (bh_submit_read(bh) < 0) {
put_bh(bh);
goto err;
}
/* validate the extent entries */
need_to_validate = 1;
}
eh = ext_block_hdr(bh);
ppos++;
if (unlikely(ppos > depth)) {
put_bh(bh);
EXT4_ERROR_INODE(inode,
"ppos %d > depth %d", ppos, depth);
goto err;
}
path[ppos].p_bh = bh;
path[ppos].p_hdr = eh;
i--;
if (need_to_validate && ext4_ext_check(inode, eh, i))
goto err;
}
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;
path[ppos].p_idx = NULL;
/* find extent */
ext4_ext_binsearch(inode, path + ppos, block);
/* if not an empty leaf */
if (path[ppos].p_ext)
path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
ext4_ext_show_path(inode, path);
return path;
err:
ext4_ext_drop_refs(path);
if (alloc)
kfree(path);
return ERR_PTR(-EIO);
}
/*
* ext4_ext_insert_index:
* insert new index [@logical;@ptr] into the block at @curp;
* check where to insert: before @curp or after @curp
*/
static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
struct ext4_ext_path *curp,
int logical, ext4_fsblk_t ptr)
{
struct ext4_extent_idx *ix;
int len, err;
err = ext4_ext_get_access(handle, inode, curp);
if (err)
return err;
if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
EXT4_ERROR_INODE(inode,
"logical %d == ei_block %d!",
logical, le32_to_cpu(curp->p_idx->ei_block));
return -EIO;
}
len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
/* insert after */
if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
len = (len - 1) * sizeof(struct ext4_extent_idx);
len = len < 0 ? 0 : len;
ext_debug("insert new index %d after: %llu. "
"move %d from 0x%p to 0x%p\n",
logical, ptr, len,
(curp->p_idx + 1), (curp->p_idx + 2));
memmove(curp->p_idx + 2, curp->p_idx + 1, len);
}
ix = curp->p_idx + 1;
} else {
/* insert before */
len = len * sizeof(struct ext4_extent_idx);
len = len < 0 ? 0 : len;
ext_debug("insert new index %d before: %llu. "
"move %d from 0x%p to 0x%p\n",
logical, ptr, len,
curp->p_idx, (curp->p_idx + 1));
memmove(curp->p_idx + 1, curp->p_idx, len);
ix = curp->p_idx;
}
ix->ei_block = cpu_to_le32(logical);
ext4_idx_store_pblock(ix, ptr);
le16_add_cpu(&curp->p_hdr->eh_entries, 1);
if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
> le16_to_cpu(curp->p_hdr->eh_max))) {
EXT4_ERROR_INODE(inode,
"logical %d == ei_block %d!",
logical, le32_to_cpu(curp->p_idx->ei_block));
return -EIO;
}
if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
return -EIO;
}
err = ext4_ext_dirty(handle, inode, curp);
ext4_std_error(inode->i_sb, err);
return err;
}
/*
* ext4_ext_split:
* inserts new subtree into the path, using free index entry
* at depth @at:
* - allocates all needed blocks (new leaf and all intermediate index blocks)
* - makes decision where to split
* - moves remaining extents and index entries (right to the split point)
* into the newly allocated blocks
* - initializes subtree
*/
static int ext4_ext_split(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext, int at)
{
struct buffer_head *bh = NULL;
int depth = ext_depth(inode);
struct ext4_extent_header *neh;
struct ext4_extent_idx *fidx;
struct ext4_extent *ex;
int i = at, k, m, a;
ext4_fsblk_t newblock, oldblock;
__le32 border;
ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
int err = 0;
/* make decision: where to split? */
/* FIXME: now decision is simplest: at current extent */
/* if current leaf will be split, then we should use
* border from split point */
if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
return -EIO;
}
if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
border = path[depth].p_ext[1].ee_block;
ext_debug("leaf will be split."
" next leaf starts at %d\n",
le32_to_cpu(border));
} else {
border = newext->ee_block;
ext_debug("leaf will be added."
" next leaf starts at %d\n",
le32_to_cpu(border));
}
/*
* If error occurs, then we break processing
* and mark filesystem read-only. index won't
* be inserted and tree will be in consistent
* state. Next mount will repair buffers too.
*/
/*
* Get array to track all allocated blocks.
* We need this to handle errors and free blocks
* upon them.
*/
ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
if (!ablocks)
return -ENOMEM;
/* allocate all needed blocks */
ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
for (a = 0; a < depth - at; a++) {
newblock = ext4_ext_new_meta_block(handle, inode, path,
newext, &err);
if (newblock == 0)
goto cleanup;
ablocks[a] = newblock;
}
/* initialize new leaf */
newblock = ablocks[--a];
if (unlikely(newblock == 0)) {
EXT4_ERROR_INODE(inode, "newblock == 0!");
err = -EIO;
goto cleanup;
}
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
goto cleanup;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err)
goto cleanup;
neh = ext_block_hdr(bh);
neh->eh_entries = 0;
neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
neh->eh_magic = EXT4_EXT_MAGIC;
neh->eh_depth = 0;
ex = EXT_FIRST_EXTENT(neh);
/* move remainder of path[depth] to the new leaf */
if (unlikely(path[depth].p_hdr->eh_entries !=
path[depth].p_hdr->eh_max)) {
EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
path[depth].p_hdr->eh_entries,
path[depth].p_hdr->eh_max);
err = -EIO;
goto cleanup;
}
/* start copy from next extent */
/* TODO: we could do it by single memmove */
m = 0;
path[depth].p_ext++;
while (path[depth].p_ext <=
EXT_MAX_EXTENT(path[depth].p_hdr)) {
ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
le32_to_cpu(path[depth].p_ext->ee_block),
ext4_ext_pblock(path[depth].p_ext),
ext4_ext_is_uninitialized(path[depth].p_ext),
ext4_ext_get_actual_len(path[depth].p_ext),
newblock);
/*memmove(ex++, path[depth].p_ext++,
sizeof(struct ext4_extent));
neh->eh_entries++;*/
path[depth].p_ext++;
m++;
}
if (m) {
memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
le16_add_cpu(&neh->eh_entries, m);
}
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_handle_dirty_metadata(handle, inode, bh);
if (err)
goto cleanup;
brelse(bh);
bh = NULL;
/* correct old leaf */
if (m) {
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto cleanup;
le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
goto cleanup;
}
/* create intermediate indexes */
k = depth - at - 1;
if (unlikely(k < 0)) {
EXT4_ERROR_INODE(inode, "k %d < 0!", k);
err = -EIO;
goto cleanup;
}
if (k)
ext_debug("create %d intermediate indices\n", k);
/* insert new index into current index block */
/* current depth stored in i var */
i = depth - 1;
while (k--) {
oldblock = newblock;
newblock = ablocks[--a];
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
goto cleanup;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err)
goto cleanup;
neh = ext_block_hdr(bh);
neh->eh_entries = cpu_to_le16(1);
neh->eh_magic = EXT4_EXT_MAGIC;
neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
neh->eh_depth = cpu_to_le16(depth - i);
fidx = EXT_FIRST_INDEX(neh);
fidx->ei_block = border;
ext4_idx_store_pblock(fidx, oldblock);
ext_debug("int.index at %d (block %llu): %u -> %llu\n",
i, newblock, le32_to_cpu(border), oldblock);
/* copy indexes */
m = 0;
path[i].p_idx++;
ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
EXT_MAX_INDEX(path[i].p_hdr));
if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
EXT_LAST_INDEX(path[i].p_hdr))) {
EXT4_ERROR_INODE(inode,
"EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
le32_to_cpu(path[i].p_ext->ee_block));
err = -EIO;
goto cleanup;
}
while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
ext_debug("%d: move %d:%llu in new index %llu\n", i,
le32_to_cpu(path[i].p_idx->ei_block),
ext4_idx_pblock(path[i].p_idx),
newblock);
/*memmove(++fidx, path[i].p_idx++,
sizeof(struct ext4_extent_idx));
neh->eh_entries++;
BUG_ON(neh->eh_entries > neh->eh_max);*/
path[i].p_idx++;
m++;
}
if (m) {
memmove(++fidx, path[i].p_idx - m,
sizeof(struct ext4_extent_idx) * m);
le16_add_cpu(&neh->eh_entries, m);
}
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_handle_dirty_metadata(handle, inode, bh);
if (err)
goto cleanup;
brelse(bh);
bh = NULL;
/* correct old index */
if (m) {
err = ext4_ext_get_access(handle, inode, path + i);
if (err)
goto cleanup;
le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
err = ext4_ext_dirty(handle, inode, path + i);
if (err)
goto cleanup;
}
i--;
}
/* insert new index */
err = ext4_ext_insert_index(handle, inode, path + at,
le32_to_cpu(border), newblock);
cleanup:
if (bh) {
if (buffer_locked(bh))
unlock_buffer(bh);
brelse(bh);
}
if (err) {
/* free all allocated blocks in error case */
for (i = 0; i < depth; i++) {
if (!ablocks[i])
continue;
ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
EXT4_FREE_BLOCKS_METADATA);
}
}
kfree(ablocks);
return err;
}
/*
* ext4_ext_grow_indepth:
* implements tree growing procedure:
* - allocates new block
* - moves top-level data (index block or leaf) into the new block
* - initializes new top-level, creating index that points to the
* just created block
*/
static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
struct ext4_ext_path *curp = path;
struct ext4_extent_header *neh;
struct buffer_head *bh;
ext4_fsblk_t newblock;
int err = 0;
newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
if (newblock == 0)
return err;
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
ext4_std_error(inode->i_sb, err);
return err;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err) {
unlock_buffer(bh);
goto out;
}
/* move top-level index/leaf into new block */
memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
/* set size of new block */
neh = ext_block_hdr(bh);
/* old root could have indexes or leaves
* so calculate e_max right way */
if (ext_depth(inode))
neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
else
neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
neh->eh_magic = EXT4_EXT_MAGIC;
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_handle_dirty_metadata(handle, inode, bh);
if (err)
goto out;
/* create index in new top-level index: num,max,pointer */
err = ext4_ext_get_access(handle, inode, curp);
if (err)
goto out;
curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
curp->p_hdr->eh_entries = cpu_to_le16(1);
curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
if (path[0].p_hdr->eh_depth)
curp->p_idx->ei_block =
EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
else
curp->p_idx->ei_block =
EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
ext4_idx_store_pblock(curp->p_idx, newblock);
neh = ext_inode_hdr(inode);
ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
neh->eh_depth = cpu_to_le16(path->p_depth + 1);
err = ext4_ext_dirty(handle, inode, curp);
out:
brelse(bh);
return err;
}
/*
* ext4_ext_create_new_leaf:
* finds empty index and adds new leaf.
* if no free index is found, then it requests in-depth growing.
*/
static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
struct ext4_ext_path *curp;
int depth, i, err = 0;
repeat:
i = depth = ext_depth(inode);
/* walk up to the tree and look for free index entry */
curp = path + depth;
while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
i--;
curp--;
}
/* we use already allocated block for index block,
* so subsequent data blocks should be contiguous */
if (EXT_HAS_FREE_INDEX(curp)) {
/* if we found index with free entry, then use that
* entry: create all needed subtree and add new leaf */
err = ext4_ext_split(handle, inode, path, newext, i);
if (err)
goto out;
/* refill path */
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
path);
if (IS_ERR(path))
err = PTR_ERR(path);
} else {
/* tree is full, time to grow in depth */
err = ext4_ext_grow_indepth(handle, inode, path, newext);
if (err)
goto out;
/* refill path */
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
path);
if (IS_ERR(path)) {
err = PTR_ERR(path);
goto out;
}
/*
* only first (depth 0 -> 1) produces free space;
* in all other cases we have to split the grown tree
*/
depth = ext_depth(inode);
if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
/* now we need to split */
goto repeat;
}
}
out:
return err;
}
/*
* search the closest allocated block to the left for *logical
* and returns it at @logical + it's physical address at @phys
* if *logical is the smallest allocated block, the function
* returns 0 at @phys
* return value contains 0 (success) or error code
*/
static int ext4_ext_search_left(struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t *logical, ext4_fsblk_t *phys)
{
struct ext4_extent_idx *ix;
struct ext4_extent *ex;
int depth, ee_len;
if (unlikely(path == NULL)) {
EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
return -EIO;
}
depth = path->p_depth;
*phys = 0;
if (depth == 0 && path->p_ext == NULL)
return 0;
/* usually extent in the path covers blocks smaller
* then *logical, but it can be that extent is the
* first one in the file */
ex = path[depth].p_ext;
ee_len = ext4_ext_get_actual_len(ex);
if (*logical < le32_to_cpu(ex->ee_block)) {
if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
EXT4_ERROR_INODE(inode,
"EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
*logical, le32_to_cpu(ex->ee_block));
return -EIO;
}
while (--depth >= 0) {
ix = path[depth].p_idx;
if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
EXT4_ERROR_INODE(inode,
"ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
ix != NULL ? ix->ei_block : 0,
EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block : 0,
depth);
return -EIO;
}
}
return 0;
}
if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
EXT4_ERROR_INODE(inode,
"logical %d < ee_block %d + ee_len %d!",
*logical, le32_to_cpu(ex->ee_block), ee_len);
return -EIO;
}
*logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
*phys = ext4_ext_pblock(ex) + ee_len - 1;
return 0;
}
/*
* search the closest allocated block to the right for *logical
* and returns it at @logical + it's physical address at @phys
* if *logical is the smallest allocated block, the function
* returns 0 at @phys
* return value contains 0 (success) or error code
*/
static int ext4_ext_search_right(struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t *logical, ext4_fsblk_t *phys)
{
struct buffer_head *bh = NULL;
struct ext4_extent_header *eh;
struct ext4_extent_idx *ix;
struct ext4_extent *ex;
ext4_fsblk_t block;
int depth; /* Note, NOT eh_depth; depth from top of tree */
int ee_len;
if (unlikely(path == NULL)) {
EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
return -EIO;
}
depth = path->p_depth;
*phys = 0;
if (depth == 0 && path->p_ext == NULL)
return 0;
/* usually extent in the path covers blocks smaller
* then *logical, but it can be that extent is the
* first one in the file */
ex = path[depth].p_ext;
ee_len = ext4_ext_get_actual_len(ex);
if (*logical < le32_to_cpu(ex->ee_block)) {
if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
EXT4_ERROR_INODE(inode,
"first_extent(path[%d].p_hdr) != ex",
depth);
return -EIO;
}
while (--depth >= 0) {
ix = path[depth].p_idx;
if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
EXT4_ERROR_INODE(inode,
"ix != EXT_FIRST_INDEX *logical %d!",
*logical);
return -EIO;
}
}
*logical = le32_to_cpu(ex->ee_block);
*phys = ext4_ext_pblock(ex);
return 0;
}
if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
EXT4_ERROR_INODE(inode,
"logical %d < ee_block %d + ee_len %d!",
*logical, le32_to_cpu(ex->ee_block), ee_len);
return -EIO;
}
if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
/* next allocated block in this leaf */
ex++;
*logical = le32_to_cpu(ex->ee_block);
*phys = ext4_ext_pblock(ex);
return 0;
}
/* go up and search for index to the right */
while (--depth >= 0) {
ix = path[depth].p_idx;
if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
goto got_index;
}
/* we've gone up to the root and found no index to the right */
return 0;
got_index:
/* we've found index to the right, let's
* follow it and find the closest allocated
* block to the right */
ix++;
block = ext4_idx_pblock(ix);
while (++depth < path->p_depth) {
bh = sb_bread(inode->i_sb, block);
if (bh == NULL)
return -EIO;
eh = ext_block_hdr(bh);
/* subtract from p_depth to get proper eh_depth */
if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
put_bh(bh);
return -EIO;
}
ix = EXT_FIRST_INDEX(eh);
block = ext4_idx_pblock(ix);
put_bh(bh);
}
bh = sb_bread(inode->i_sb, block);
if (bh == NULL)
return -EIO;
eh = ext_block_hdr(bh);
if (ext4_ext_check(inode, eh, path->p_depth - depth)) {
put_bh(bh);
return -EIO;
}
ex = EXT_FIRST_EXTENT(eh);
*logical = le32_to_cpu(ex->ee_block);
*phys = ext4_ext_pblock(ex);
put_bh(bh);
return 0;
}
/*
* ext4_ext_next_allocated_block:
* returns allocated block in subsequent extent or EXT_MAX_BLOCK.
* NOTE: it considers block number from index entry as
* allocated block. Thus, index entries have to be consistent
* with leaves.
*/
static ext4_lblk_t
ext4_ext_next_allocated_block(struct ext4_ext_path *path)
{
int depth;
BUG_ON(path == NULL);
depth = path->p_depth;
if (depth == 0 && path->p_ext == NULL)
return EXT_MAX_BLOCK;
while (depth >= 0) {
if (depth == path->p_depth) {
/* leaf */
if (path[depth].p_ext !=
EXT_LAST_EXTENT(path[depth].p_hdr))
return le32_to_cpu(path[depth].p_ext[1].ee_block);
} else {
/* index */
if (path[depth].p_idx !=
EXT_LAST_INDEX(path[depth].p_hdr))
return le32_to_cpu(path[depth].p_idx[1].ei_block);
}
depth--;
}
return EXT_MAX_BLOCK;
}
/*
* ext4_ext_next_leaf_block:
* returns first allocated block from next leaf or EXT_MAX_BLOCK
*/
static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
struct ext4_ext_path *path)
{
int depth;
BUG_ON(path == NULL);
depth = path->p_depth;
/* zero-tree has no leaf blocks at all */
if (depth == 0)
return EXT_MAX_BLOCK;
/* go to index block */
depth--;
while (depth >= 0) {
if (path[depth].p_idx !=
EXT_LAST_INDEX(path[depth].p_hdr))
return (ext4_lblk_t)
le32_to_cpu(path[depth].p_idx[1].ei_block);
depth--;
}
return EXT_MAX_BLOCK;
}
/*
* ext4_ext_correct_indexes:
* if leaf gets modified and modified extent is first in the leaf,
* then we have to correct all indexes above.
* TODO: do we need to correct tree in all cases?
*/
static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
struct ext4_extent_header *eh;
int depth = ext_depth(inode);
struct ext4_extent *ex;
__le32 border;
int k, err = 0;
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
if (unlikely(ex == NULL || eh == NULL)) {
EXT4_ERROR_INODE(inode,
"ex %p == NULL or eh %p == NULL", ex, eh);
return -EIO;
}
if (depth == 0) {
/* there is no tree at all */
return 0;
}
if (ex != EXT_FIRST_EXTENT(eh)) {
/* we correct tree if first leaf got modified only */
return 0;
}
/*
* TODO: we need correction if border is smaller than current one
*/
k = depth - 1;
border = path[depth].p_ext->ee_block;
err = ext4_ext_get_access(handle, inode, path + k);
if (err)
return err;
path[k].p_idx->ei_block = border;
err = ext4_ext_dirty(handle, inode, path + k);
if (err)
return err;
while (k--) {
/* change all left-side indexes */
if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
break;
err = ext4_ext_get_access(handle, inode, path + k);
if (err)
break;
path[k].p_idx->ei_block = border;
err = ext4_ext_dirty(handle, inode, path + k);
if (err)
break;
}
return err;
}
int
ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
struct ext4_extent *ex2)
{
unsigned short ext1_ee_len, ext2_ee_len, max_len;
/*
* Make sure that either both extents are uninitialized, or
* both are _not_.
*/
if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
return 0;
if (ext4_ext_is_uninitialized(ex1))
max_len = EXT_UNINIT_MAX_LEN;
else
max_len = EXT_INIT_MAX_LEN;
ext1_ee_len = ext4_ext_get_actual_len(ex1);
ext2_ee_len = ext4_ext_get_actual_len(ex2);
if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
le32_to_cpu(ex2->ee_block))
return 0;
/*
* To allow future support for preallocated extents to be added
* as an RO_COMPAT feature, refuse to merge to extents if
* this can result in the top bit of ee_len being set.
*/
if (ext1_ee_len + ext2_ee_len > max_len)
return 0;
#ifdef AGGRESSIVE_TEST
if (ext1_ee_len >= 4)
return 0;
#endif
if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
return 1;
return 0;
}
/*
* This function tries to merge the "ex" extent to the next extent in the tree.
* It always tries to merge towards right. If you want to merge towards
* left, pass "ex - 1" as argument instead of "ex".
* Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
* 1 if they got merged.
*/
static int ext4_ext_try_to_merge_right(struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *ex)
{
struct ext4_extent_header *eh;
unsigned int depth, len;
int merge_done = 0;
int uninitialized = 0;
depth = ext_depth(inode);
BUG_ON(path[depth].p_hdr == NULL);
eh = path[depth].p_hdr;
while (ex < EXT_LAST_EXTENT(eh)) {
if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
break;
/* merge with next extent! */
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+ ext4_ext_get_actual_len(ex + 1));
if (uninitialized)
ext4_ext_mark_uninitialized(ex);
if (ex + 1 < EXT_LAST_EXTENT(eh)) {
len = (EXT_LAST_EXTENT(eh) - ex - 1)
* sizeof(struct ext4_extent);
memmove(ex + 1, ex + 2, len);
}
le16_add_cpu(&eh->eh_entries, -1);
merge_done = 1;
WARN_ON(eh->eh_entries == 0);
if (!eh->eh_entries)
EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
}
return merge_done;
}
/*
* This function tries to merge the @ex extent to neighbours in the tree.
* return 1 if merge left else 0.
*/
static int ext4_ext_try_to_merge(struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *ex) {
struct ext4_extent_header *eh;
unsigned int depth;
int merge_done = 0;
int ret = 0;
depth = ext_depth(inode);
BUG_ON(path[depth].p_hdr == NULL);
eh = path[depth].p_hdr;
if (ex > EXT_FIRST_EXTENT(eh))
merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
if (!merge_done)
ret = ext4_ext_try_to_merge_right(inode, path, ex);
return ret;
}
/*
* check if a portion of the "newext" extent overlaps with an
* existing extent.
*
* If there is an overlap discovered, it updates the length of the newext
* such that there will be no overlap, and then returns 1.
* If there is no overlap found, it returns 0.
*/
static unsigned int ext4_ext_check_overlap(struct inode *inode,
struct ext4_extent *newext,
struct ext4_ext_path *path)
{
ext4_lblk_t b1, b2;
unsigned int depth, len1;
unsigned int ret = 0;
b1 = le32_to_cpu(newext->ee_block);
len1 = ext4_ext_get_actual_len(newext);
depth = ext_depth(inode);
if (!path[depth].p_ext)
goto out;
b2 = le32_to_cpu(path[depth].p_ext->ee_block);
/*
* get the next allocated block if the extent in the path
* is before the requested block(s)
*/
if (b2 < b1) {
b2 = ext4_ext_next_allocated_block(path);
if (b2 == EXT_MAX_BLOCK)
goto out;
}
/* check for wrap through zero on extent logical start block*/
if (b1 + len1 < b1) {
len1 = EXT_MAX_BLOCK - b1;
newext->ee_len = cpu_to_le16(len1);
ret = 1;
}
/* check for overlap */
if (b1 + len1 > b2) {
newext->ee_len = cpu_to_le16(b2 - b1);
ret = 1;
}
out:
return ret;
}
/*
* ext4_ext_insert_extent:
* tries to merge requsted extent into the existing extent or
* inserts requested extent as new one into the tree,
* creating new leaf in the no-space case.
*/
int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext, int flag)
{
struct ext4_extent_header *eh;
struct ext4_extent *ex, *fex;
struct ext4_extent *nearex; /* nearest extent */
struct ext4_ext_path *npath = NULL;
int depth, len, err;
ext4_lblk_t next;
unsigned uninitialized = 0;
if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
return -EIO;
}
depth = ext_depth(inode);
ex = path[depth].p_ext;
if (unlikely(path[depth].p_hdr == NULL)) {
EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
return -EIO;
}
/* try to insert block into found extent and return */
if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
&& ext4_can_extents_be_merged(inode, ex, newext)) {
ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
ext4_ext_is_uninitialized(newext),
ext4_ext_get_actual_len(newext),
le32_to_cpu(ex->ee_block),
ext4_ext_is_uninitialized(ex),
ext4_ext_get_actual_len(ex),
ext4_ext_pblock(ex));
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
return err;
/*
* ext4_can_extents_be_merged should have checked that either
* both extents are uninitialized, or both aren't. Thus we
* need to check only one of them here.
*/
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+ ext4_ext_get_actual_len(newext));
if (uninitialized)
ext4_ext_mark_uninitialized(ex);
eh = path[depth].p_hdr;
nearex = ex;
goto merge;
}
repeat:
depth = ext_depth(inode);
eh = path[depth].p_hdr;
if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
goto has_space;
/* probably next leaf has space for us? */
fex = EXT_LAST_EXTENT(eh);
next = ext4_ext_next_leaf_block(inode, path);
if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
&& next != EXT_MAX_BLOCK) {
ext_debug("next leaf block - %d\n", next);
BUG_ON(npath != NULL);
npath = ext4_ext_find_extent(inode, next, NULL);
if (IS_ERR(npath))
return PTR_ERR(npath);
BUG_ON(npath->p_depth != path->p_depth);
eh = npath[depth].p_hdr;
if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
ext_debug("next leaf isn't full(%d)\n",
le16_to_cpu(eh->eh_entries));
path = npath;
goto repeat;
}
ext_debug("next leaf has no free space(%d,%d)\n",
le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
}
/*
* There is no free space in the found leaf.
* We're gonna add a new leaf in the tree.
*/
err = ext4_ext_create_new_leaf(handle, inode, path, newext);
if (err)
goto cleanup;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
has_space:
nearex = path[depth].p_ext;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto cleanup;
if (!nearex) {
/* there is no extent in this leaf, create first one */
ext_debug("first extent in the leaf: %d:%llu:[%d]%d\n",
le32_to_cpu(newext->ee_block),
ext4_ext_pblock(newext),
ext4_ext_is_uninitialized(newext),
ext4_ext_get_actual_len(newext));
path[depth].p_ext = EXT_FIRST_EXTENT(eh);
} else if (le32_to_cpu(newext->ee_block)
> le32_to_cpu(nearex->ee_block)) {
/* BUG_ON(newext->ee_block == nearex->ee_block); */
if (nearex != EXT_LAST_EXTENT(eh)) {
len = EXT_MAX_EXTENT(eh) - nearex;
len = (len - 1) * sizeof(struct ext4_extent);
len = len < 0 ? 0 : len;
ext_debug("insert %d:%llu:[%d]%d after: nearest 0x%p, "
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext4_ext_pblock(newext),
ext4_ext_is_uninitialized(newext),
ext4_ext_get_actual_len(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 2, nearex + 1, len);
}
path[depth].p_ext = nearex + 1;
} else {
BUG_ON(newext->ee_block == nearex->ee_block);
len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
len = len < 0 ? 0 : len;
ext_debug("insert %d:%llu:[%d]%d before: nearest 0x%p, "
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext4_ext_pblock(newext),
ext4_ext_is_uninitialized(newext),
ext4_ext_get_actual_len(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 1, nearex, len);
path[depth].p_ext = nearex;
}
le16_add_cpu(&eh->eh_entries, 1);
nearex = path[depth].p_ext;
nearex->ee_block = newext->ee_block;
ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
nearex->ee_len = newext->ee_len;
merge:
/* try to merge extents to the right */
if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
ext4_ext_try_to_merge(inode, path, nearex);
/* try to merge extents to the left */
/* time to correct all indexes above */
err = ext4_ext_correct_indexes(handle, inode, path);
if (err)
goto cleanup;
err = ext4_ext_dirty(handle, inode, path + depth);
cleanup:
if (npath) {
ext4_ext_drop_refs(npath);
kfree(npath);
}
ext4_ext_invalidate_cache(inode);
return err;
}
static int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block,
ext4_lblk_t num, ext_prepare_callback func,
void *cbdata)
{
struct ext4_ext_path *path = NULL;
struct ext4_ext_cache cbex;
struct ext4_extent *ex;
ext4_lblk_t next, start = 0, end = 0;
ext4_lblk_t last = block + num;
int depth, exists, err = 0;
BUG_ON(func == NULL);
BUG_ON(inode == NULL);
while (block < last && block != EXT_MAX_BLOCK) {
num = last - block;
/* find extent for this block */
down_read(&EXT4_I(inode)->i_data_sem);
path = ext4_ext_find_extent(inode, block, path);
up_read(&EXT4_I(inode)->i_data_sem);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
break;
}
depth = ext_depth(inode);
if (unlikely(path[depth].p_hdr == NULL)) {
EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
err = -EIO;
break;
}
ex = path[depth].p_ext;
next = ext4_ext_next_allocated_block(path);
exists = 0;
if (!ex) {
/* there is no extent yet, so try to allocate
* all requested space */
start = block;
end = block + num;
} else if (le32_to_cpu(ex->ee_block) > block) {
/* need to allocate space before found extent */
start = block;
end = le32_to_cpu(ex->ee_block);
if (block + num < end)
end = block + num;
} else if (block >= le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex)) {
/* need to allocate space after found extent */
start = block;
end = block + num;
if (end >= next)
end = next;
} else if (block >= le32_to_cpu(ex->ee_block)) {
/*
* some part of requested space is covered
* by found extent
*/
start = block;
end = le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex);
if (block + num < end)
end = block + num;
exists = 1;
} else {
BUG();
}
BUG_ON(end <= start);
if (!exists) {
cbex.ec_block = start;
cbex.ec_len = end - start;
cbex.ec_start = 0;
} else {
cbex.ec_block = le32_to_cpu(ex->ee_block);
cbex.ec_len = ext4_ext_get_actual_len(ex);
cbex.ec_start = ext4_ext_pblock(ex);
}
if (unlikely(cbex.ec_len == 0)) {
EXT4_ERROR_INODE(inode, "cbex.ec_len == 0");
err = -EIO;
break;
}
err = func(inode, path, &cbex, ex, cbdata);
ext4_ext_drop_refs(path);
if (err < 0)
break;
if (err == EXT_REPEAT)
continue;
else if (err == EXT_BREAK) {
err = 0;
break;
}
if (ext_depth(inode) != depth) {
/* depth was changed. we have to realloc path */
kfree(path);
path = NULL;
}
block = cbex.ec_block + cbex.ec_len;
}
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
return err;
}
static void
ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
__u32 len, ext4_fsblk_t start)
{
struct ext4_ext_cache *cex;
BUG_ON(len == 0);
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
cex = &EXT4_I(inode)->i_cached_extent;
cex->ec_block = block;
cex->ec_len = len;
cex->ec_start = start;
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}
/*
* ext4_ext_put_gap_in_cache:
* calculate boundaries of the gap that the requested block fits into
* and cache this gap
*/
static void
ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
ext4_lblk_t block)
{
int depth = ext_depth(inode);
unsigned long len;
ext4_lblk_t lblock;
struct ext4_extent *ex;
ex = path[depth].p_ext;
if (ex == NULL) {
/* there is no extent yet, so gap is [0;-] */
lblock = 0;
len = EXT_MAX_BLOCK;
ext_debug("cache gap(whole file):");
} else if (block < le32_to_cpu(ex->ee_block)) {
lblock = block;
len = le32_to_cpu(ex->ee_block) - block;
ext_debug("cache gap(before): %u [%u:%u]",
block,
le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex));
} else if (block >= le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex)) {
ext4_lblk_t next;
lblock = le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex);
next = ext4_ext_next_allocated_block(path);
ext_debug("cache gap(after): [%u:%u] %u",
le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex),
block);
BUG_ON(next == lblock);
len = next - lblock;
} else {
lblock = len = 0;
BUG();
}
ext_debug(" -> %u:%lu\n", lblock, len);
ext4_ext_put_in_cache(inode, lblock, len, 0);
}
/*
* Return 0 if cache is invalid; 1 if the cache is valid
*/
static int
ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
struct ext4_extent *ex)
{
struct ext4_ext_cache *cex;
int ret = 0;
/*
* We borrow i_block_reservation_lock to protect i_cached_extent
*/
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
cex = &EXT4_I(inode)->i_cached_extent;
/* has cache valid data? */
if (cex->ec_len == 0)
goto errout;
if (in_range(block, cex->ec_block, cex->ec_len)) {
ex->ee_block = cpu_to_le32(cex->ec_block);
ext4_ext_store_pblock(ex, cex->ec_start);
ex->ee_len = cpu_to_le16(cex->ec_len);
ext_debug("%u cached by %u:%u:%llu\n",
block,
cex->ec_block, cex->ec_len, cex->ec_start);
ret = 1;
}
errout:
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
return ret;
}
/*
* ext4_ext_rm_idx:
* removes index from the index block.
* It's used in truncate case only, thus all requests are for
* last index in the block only.
*/
static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
int err;
ext4_fsblk_t leaf;
/* free index block */
path--;
leaf = ext4_idx_pblock(path->p_idx);
if (unlikely(path->p_hdr->eh_entries == 0)) {
EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
return -EIO;
}
err = ext4_ext_get_access(handle, inode, path);
if (err)
return err;
le16_add_cpu(&path->p_hdr->eh_entries, -1);
err = ext4_ext_dirty(handle, inode, path);
if (err)
return err;
ext_debug("index is empty, remove it, free block %llu\n", leaf);
ext4_free_blocks(handle, inode, NULL, leaf, 1,
EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
return err;
}
/*
* ext4_ext_calc_credits_for_single_extent:
* This routine returns max. credits that needed to insert an extent
* to the extent tree.
* When pass the actual path, the caller should calculate credits
* under i_data_sem.
*/
int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
struct ext4_ext_path *path)
{
if (path) {
int depth = ext_depth(inode);
int ret = 0;
/* probably there is space in leaf? */
if (le16_to_cpu(path[depth].p_hdr->eh_entries)
< le16_to_cpu(path[depth].p_hdr->eh_max)) {
/*
* There are some space in the leaf tree, no
* need to account for leaf block credit
*
* bitmaps and block group descriptor blocks
* and other metadat blocks still need to be
* accounted.
*/
/* 1 bitmap, 1 block group descriptor */
ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
return ret;
}
}
return ext4_chunk_trans_blocks(inode, nrblocks);
}
/*
* How many index/leaf blocks need to change/allocate to modify nrblocks?
*
* if nrblocks are fit in a single extent (chunk flag is 1), then
* in the worse case, each tree level index/leaf need to be changed
* if the tree split due to insert a new extent, then the old tree
* index/leaf need to be updated too
*
* If the nrblocks are discontiguous, they could cause
* the whole tree split more than once, but this is really rare.
*/
int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
int index;
int depth = ext_depth(inode);
if (chunk)
index = depth * 2;
else
index = depth * 3;
return index;
}
static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
struct ext4_extent *ex,
ext4_lblk_t from, ext4_lblk_t to)
{
unsigned short ee_len = ext4_ext_get_actual_len(ex);
int flags = EXT4_FREE_BLOCKS_FORGET;
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
flags |= EXT4_FREE_BLOCKS_METADATA;
#ifdef EXTENTS_STATS
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
spin_lock(&sbi->s_ext_stats_lock);
sbi->s_ext_blocks += ee_len;
sbi->s_ext_extents++;
if (ee_len < sbi->s_ext_min)
sbi->s_ext_min = ee_len;
if (ee_len > sbi->s_ext_max)
sbi->s_ext_max = ee_len;
if (ext_depth(inode) > sbi->s_depth_max)
sbi->s_depth_max = ext_depth(inode);
spin_unlock(&sbi->s_ext_stats_lock);
}
#endif
if (from >= le32_to_cpu(ex->ee_block)
&& to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
/* tail removal */
ext4_lblk_t num;
ext4_fsblk_t start;
num = le32_to_cpu(ex->ee_block) + ee_len - from;
start = ext4_ext_pblock(ex) + ee_len - num;
ext_debug("free last %u blocks starting %llu\n", num, start);
ext4_free_blocks(handle, inode, NULL, start, num, flags);
} else if (from == le32_to_cpu(ex->ee_block)
&& to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
from, to, le32_to_cpu(ex->ee_block), ee_len);
} else {
printk(KERN_INFO "strange request: removal(2) "
"%u-%u from %u:%u\n",
from, to, le32_to_cpu(ex->ee_block), ee_len);
}
return 0;
}
static int
ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t start)
{
int err = 0, correct_index = 0;
int depth = ext_depth(inode), credits;
struct ext4_extent_header *eh;
ext4_lblk_t a, b, block;
unsigned num;
ext4_lblk_t ex_ee_block;
unsigned short ex_ee_len;
unsigned uninitialized = 0;
struct ext4_extent *ex;
/* the header must be checked already in ext4_ext_remove_space() */
ext_debug("truncate since %u in leaf\n", start);
if (!path[depth].p_hdr)
path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
eh = path[depth].p_hdr;
if (unlikely(path[depth].p_hdr == NULL)) {
EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
return -EIO;
}
/* find where to start removing */
ex = EXT_LAST_EXTENT(eh);
ex_ee_block = le32_to_cpu(ex->ee_block);
ex_ee_len = ext4_ext_get_actual_len(ex);
while (ex >= EXT_FIRST_EXTENT(eh) &&
ex_ee_block + ex_ee_len > start) {
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
else
uninitialized = 0;
ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
uninitialized, ex_ee_len);
path[depth].p_ext = ex;
a = ex_ee_block > start ? ex_ee_block : start;
b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
ext_debug(" border %u:%u\n", a, b);
if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
block = 0;
num = 0;
BUG();
} else if (a != ex_ee_block) {
/* remove tail of the extent */
block = ex_ee_block;
num = a - block;
} else if (b != ex_ee_block + ex_ee_len - 1) {
/* remove head of the extent */
block = a;
num = b - a;
/* there is no "make a hole" API yet */
BUG();
} else {
/* remove whole extent: excellent! */
block = ex_ee_block;
num = 0;
BUG_ON(a != ex_ee_block);
BUG_ON(b != ex_ee_block + ex_ee_len - 1);
}
/*
* 3 for leaf, sb, and inode plus 2 (bmap and group
* descriptor) for each block group; assume two block
* groups plus ex_ee_len/blocks_per_block_group for
* the worst case
*/
credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
if (ex == EXT_FIRST_EXTENT(eh)) {
correct_index = 1;
credits += (ext_depth(inode)) + 1;
}
credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
err = ext4_ext_truncate_extend_restart(handle, inode, credits);
if (err)
goto out;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
err = ext4_remove_blocks(handle, inode, ex, a, b);
if (err)
goto out;
if (num == 0) {
/* this extent is removed; mark slot entirely unused */
ext4_ext_store_pblock(ex, 0);
le16_add_cpu(&eh->eh_entries, -1);
}
ex->ee_block = cpu_to_le32(block);
ex->ee_len = cpu_to_le16(num);
/*
* Do not mark uninitialized if all the blocks in the
* extent have been removed.
*/
if (uninitialized && num)
ext4_ext_mark_uninitialized(ex);
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
goto out;
ext_debug("new extent: %u:%u:%llu\n", block, num,
ext4_ext_pblock(ex));
ex--;
ex_ee_block = le32_to_cpu(ex->ee_block);
ex_ee_len = ext4_ext_get_actual_len(ex);
}
if (correct_index && eh->eh_entries)
err = ext4_ext_correct_indexes(handle, inode, path);
/* if this leaf is free, then we should
* remove it from index block above */
if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
err = ext4_ext_rm_idx(handle, inode, path + depth);
out:
return err;
}
/*
* ext4_ext_more_to_rm:
* returns 1 if current index has to be freed (even partial)
*/
static int
ext4_ext_more_to_rm(struct ext4_ext_path *path)
{
BUG_ON(path->p_idx == NULL);
if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
return 0;
/*
* if truncate on deeper level happened, it wasn't partial,
* so we have to consider current index for truncation
*/
if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
return 0;
return 1;
}
static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
{
struct super_block *sb = inode->i_sb;
int depth = ext_depth(inode);
struct ext4_ext_path *path;
handle_t *handle;
int i, err;
ext_debug("truncate since %u\n", start);
/* probably first extent we're gonna free will be last in block */
handle = ext4_journal_start(inode, depth + 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
again:
ext4_ext_invalidate_cache(inode);
/*
* We start scanning from right side, freeing all the blocks
* after i_size and walking into the tree depth-wise.
*/
depth = ext_depth(inode);
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
if (path == NULL) {
ext4_journal_stop(handle);
return -ENOMEM;
}
path[0].p_depth = depth;
path[0].p_hdr = ext_inode_hdr(inode);
if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
err = -EIO;
goto out;
}
i = err = 0;
while (i >= 0 && err == 0) {
if (i == depth) {
/* this is leaf block */
err = ext4_ext_rm_leaf(handle, inode, path, start);
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);
path[i].p_bh = NULL;
i--;
continue;
}
/* this is index block */
if (!path[i].p_hdr) {
ext_debug("initialize header\n");
path[i].p_hdr = ext_block_hdr(path[i].p_bh);
}
if (!path[i].p_idx) {
/* this level hasn't been touched yet */
path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
ext_debug("init index ptr: hdr 0x%p, num %d\n",
path[i].p_hdr,
le16_to_cpu(path[i].p_hdr->eh_entries));
} else {
/* we were already here, see at next index */
path[i].p_idx--;
}
ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
i, EXT_FIRST_INDEX(path[i].p_hdr),
path[i].p_idx);
if (ext4_ext_more_to_rm(path + i)) {
struct buffer_head *bh;
/* go to the next level */
ext_debug("move to level %d (block %llu)\n",
i + 1, ext4_idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));
if (!bh) {
/* should we reset i_size? */
err = -EIO;
break;
}
if (WARN_ON(i + 1 > depth)) {
err = -EIO;
break;
}
if (ext4_ext_check(inode, ext_block_hdr(bh),
depth - i - 1)) {
err = -EIO;
break;
}
path[i + 1].p_bh = bh;
/* save actual number of indexes since this
* number is changed at the next iteration */
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
i++;
} else {
/* we finished processing this index, go up */
if (path[i].p_hdr->eh_entries == 0 && i > 0) {
/* index is empty, remove it;
* handle must be already prepared by the
* truncatei_leaf() */
err = ext4_ext_rm_idx(handle, inode, path + i);
}
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);
path[i].p_bh = NULL;
i--;
ext_debug("return to level %d\n", i);
}
}
/* TODO: flexible tree reduction should be here */
if (path->p_hdr->eh_entries == 0) {
/*
* truncate to zero freed all the tree,
* so we need to correct eh_depth
*/
err = ext4_ext_get_access(handle, inode, path);
if (err == 0) {
ext_inode_hdr(inode)->eh_depth = 0;
ext_inode_hdr(inode)->eh_max =
cpu_to_le16(ext4_ext_space_root(inode, 0));
err = ext4_ext_dirty(handle, inode, path);
}
}
out:
ext4_ext_drop_refs(path);
kfree(path);
if (err == -EAGAIN)
goto again;
ext4_journal_stop(handle);
return err;
}
/*
* called at mount time
*/
void ext4_ext_init(struct super_block *sb)
{
/*
* possible initialization would be here
*/
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
printk(KERN_INFO "EXT4-fs: file extents enabled");
#ifdef AGGRESSIVE_TEST
printk(", aggressive tests");
#endif
#ifdef CHECK_BINSEARCH
printk(", check binsearch");
#endif
#ifdef EXTENTS_STATS
printk(", stats");
#endif
printk("\n");
#endif
#ifdef EXTENTS_STATS
spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
EXT4_SB(sb)->s_ext_min = 1 << 30;
EXT4_SB(sb)->s_ext_max = 0;
#endif
}
}
/*
* called at umount time
*/
void ext4_ext_release(struct super_block *sb)
{
if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
return;
#ifdef EXTENTS_STATS
if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
sbi->s_ext_blocks, sbi->s_ext_extents,
sbi->s_ext_blocks / sbi->s_ext_extents);
printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
}
#endif
}
/* FIXME!! we need to try to merge to left or right after zero-out */
static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
{
ext4_fsblk_t ee_pblock;
unsigned int ee_len;
int ret;
ee_len = ext4_ext_get_actual_len(ex);
ee_pblock = ext4_ext_pblock(ex);
ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
if (ret > 0)
ret = 0;
return ret;
}
/*
* used by extent splitting.
*/
#define EXT4_EXT_MAY_ZEROOUT 0x1 /* safe to zeroout if split fails \
due to ENOSPC */
#define EXT4_EXT_MARK_UNINIT1 0x2 /* mark first half uninitialized */
#define EXT4_EXT_MARK_UNINIT2 0x4 /* mark second half uninitialized */
/*
* ext4_split_extent_at() splits an extent at given block.
*
* @handle: the journal handle
* @inode: the file inode
* @path: the path to the extent
* @split: the logical block where the extent is splitted.
* @split_flags: indicates if the extent could be zeroout if split fails, and
* the states(init or uninit) of new extents.
* @flags: flags used to insert new extent to extent tree.
*
*
* Splits extent [a, b] into two extents [a, @split) and [@split, b], states
* of which are deterimined by split_flag.
*
* There are two cases:
* a> the extent are splitted into two extent.
* b> split is not needed, and just mark the extent.
*
* return 0 on success.
*/
static int ext4_split_extent_at(handle_t *handle,
struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t split,
int split_flag,
int flags)
{
ext4_fsblk_t newblock;
ext4_lblk_t ee_block;
struct ext4_extent *ex, newex, orig_ex;
struct ext4_extent *ex2 = NULL;
unsigned int ee_len, depth;
int err = 0;
ext_debug("ext4_split_extents_at: inode %lu, logical"
"block %llu\n", inode->i_ino, (unsigned long long)split);
ext4_ext_show_leaf(inode, path);
depth = ext_depth(inode);
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
newblock = split - ee_block + ext4_ext_pblock(ex);
BUG_ON(split < ee_block || split >= (ee_block + ee_len));
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
if (split == ee_block) {
/*
* case b: block @split is the block that the extent begins with
* then we just change the state of the extent, and splitting
* is not needed.
*/
if (split_flag & EXT4_EXT_MARK_UNINIT2)
ext4_ext_mark_uninitialized(ex);
else
ext4_ext_mark_initialized(ex);
if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
ext4_ext_try_to_merge(inode, path, ex);
err = ext4_ext_dirty(handle, inode, path + depth);
goto out;
}
/* case a */
memcpy(&orig_ex, ex, sizeof(orig_ex));
ex->ee_len = cpu_to_le16(split - ee_block);
if (split_flag & EXT4_EXT_MARK_UNINIT1)
ext4_ext_mark_uninitialized(ex);
/*
* path may lead to new leaf, not to original leaf any more
* after ext4_ext_insert_extent() returns,
*/
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
goto fix_extent_len;
ex2 = &newex;
ex2->ee_block = cpu_to_le32(split);
ex2->ee_len = cpu_to_le16(ee_len - (split - ee_block));
ext4_ext_store_pblock(ex2, newblock);
if (split_flag & EXT4_EXT_MARK_UNINIT2)
ext4_ext_mark_uninitialized(ex2);
err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
err = ext4_ext_zeroout(inode, &orig_ex);
if (err)
goto fix_extent_len;
/* update the extent length and mark as initialized */
ex->ee_len = cpu_to_le32(ee_len);
ext4_ext_try_to_merge(inode, path, ex);
err = ext4_ext_dirty(handle, inode, path + depth);
goto out;
} else if (err)
goto fix_extent_len;
out:
ext4_ext_show_leaf(inode, path);
return err;
fix_extent_len:
ex->ee_len = orig_ex.ee_len;
ext4_ext_dirty(handle, inode, path + depth);
return err;
}
/*
* ext4_split_extents() splits an extent and mark extent which is covered
* by @map as split_flags indicates
*
* It may result in splitting the extent into multiple extents (upto three)
* There are three possibilities:
* a> There is no split required
* b> Splits in two extents: Split is happening at either end of the extent
* c> Splits in three extents: Somone is splitting in middle of the extent
*
*/
static int ext4_split_extent(handle_t *handle,
struct inode *inode,
struct ext4_ext_path *path,
struct ext4_map_blocks *map,
int split_flag,
int flags)
{
ext4_lblk_t ee_block;
struct ext4_extent *ex;
unsigned int ee_len, depth;
int err = 0;
int uninitialized;
int split_flag1, flags1;
depth = ext_depth(inode);
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
uninitialized = ext4_ext_is_uninitialized(ex);
if (map->m_lblk + map->m_len < ee_block + ee_len) {
split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
EXT4_EXT_MAY_ZEROOUT : 0;
flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
if (uninitialized)
split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
EXT4_EXT_MARK_UNINIT2;
err = ext4_split_extent_at(handle, inode, path,
map->m_lblk + map->m_len, split_flag1, flags1);
}
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode, map->m_lblk, path);
if (IS_ERR(path))
return PTR_ERR(path);
if (map->m_lblk >= ee_block) {
split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT ?
EXT4_EXT_MAY_ZEROOUT : 0;
if (uninitialized)
split_flag1 |= EXT4_EXT_MARK_UNINIT1;
if (split_flag & EXT4_EXT_MARK_UNINIT2)
split_flag1 |= EXT4_EXT_MARK_UNINIT2;
err = ext4_split_extent_at(handle, inode, path,
map->m_lblk, split_flag1, flags);
if (err)
goto out;
}
ext4_ext_show_leaf(inode, path);
out:
return err ? err : map->m_len;
}
#define EXT4_EXT_ZERO_LEN 7
/*
* This function is called by ext4_ext_map_blocks() if someone tries to write
* to an uninitialized extent. It may result in splitting the uninitialized
* extent into multiple extents (up to three - one initialized and two
* uninitialized).
* There are three possibilities:
* a> There is no split required: Entire extent should be initialized
* b> Splits in two extents: Write is happening at either end of the extent
* c> Splits in three extents: Somone is writing in middle of the extent
*/
static int ext4_ext_convert_to_initialized(handle_t *handle,
struct inode *inode,
struct ext4_map_blocks *map,
struct ext4_ext_path *path)
{
struct ext4_map_blocks split_map;
struct ext4_extent zero_ex;
struct ext4_extent *ex;
ext4_lblk_t ee_block, eof_block;
unsigned int allocated, ee_len, depth;
int err = 0;
int split_flag = 0;
ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
"block %llu, max_blocks %u\n", inode->i_ino,
(unsigned long long)map->m_lblk, map->m_len);
eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
if (eof_block < map->m_lblk + map->m_len)
eof_block = map->m_lblk + map->m_len;
depth = ext_depth(inode);
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
allocated = ee_len - (map->m_lblk - ee_block);
WARN_ON(map->m_lblk < ee_block);
/*
* It is safe to convert extent to initialized via explicit
* zeroout only if extent is fully insde i_size or new_size.
*/
split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
/* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
(EXT4_EXT_MAY_ZEROOUT & split_flag)) {
err = ext4_ext_zeroout(inode, ex);
if (err)
goto out;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
ext4_ext_mark_initialized(ex);
ext4_ext_try_to_merge(inode, path, ex);
err = ext4_ext_dirty(handle, inode, path + depth);
goto out;
}
/*
* four cases:
* 1. split the extent into three extents.
* 2. split the extent into two extents, zeroout the first half.
* 3. split the extent into two extents, zeroout the second half.
* 4. split the extent into two extents with out zeroout.
*/
split_map.m_lblk = map->m_lblk;
split_map.m_len = map->m_len;
if (allocated > map->m_len) {
if (allocated <= EXT4_EXT_ZERO_LEN &&
(EXT4_EXT_MAY_ZEROOUT & split_flag)) {
/* case 3 */
zero_ex.ee_block =
cpu_to_le32(map->m_lblk + map->m_len);
zero_ex.ee_len = cpu_to_le16(allocated - map->m_len);
ext4_ext_store_pblock(&zero_ex,
ext4_ext_pblock(ex) + map->m_lblk - ee_block);
err = ext4_ext_zeroout(inode, &zero_ex);
if (err)
goto out;
split_map.m_lblk = map->m_lblk;
split_map.m_len = allocated;
} else if ((map->m_lblk - ee_block + map->m_len <
EXT4_EXT_ZERO_LEN) &&
(EXT4_EXT_MAY_ZEROOUT & split_flag)) {
/* case 2 */
if (map->m_lblk != ee_block) {
zero_ex.ee_block = ex->ee_block;
zero_ex.ee_len = cpu_to_le16(map->m_lblk -
ee_block);
ext4_ext_store_pblock(&zero_ex,
ext4_ext_pblock(ex));
err = ext4_ext_zeroout(inode, &zero_ex);
if (err)
goto out;
}
allocated = map->m_lblk - ee_block + map->m_len;
split_map.m_lblk = ee_block;
split_map.m_len = allocated;
}
}
allocated = ext4_split_extent(handle, inode, path,
&split_map, split_flag, 0);
if (allocated < 0)
err = allocated;
out:
return err ? err : allocated;
}
/*
* This function is called by ext4_ext_map_blocks() from
* ext4_get_blocks_dio_write() when DIO to write
* to an uninitialized extent.
*
* Writing to an uninitialized extent may result in splitting the uninitialized
* extent into multiple /initialized uninitialized extents (up to three)
* There are three possibilities:
* a> There is no split required: Entire extent should be uninitialized
* b> Splits in two extents: Write is happening at either end of the extent
* c> Splits in three extents: Somone is writing in middle of the extent
*
* One of more index blocks maybe needed if the extent tree grow after
* the uninitialized extent split. To prevent ENOSPC occur at the IO
* complete, we need to split the uninitialized extent before DIO submit
* the IO. The uninitialized extent called at this time will be split
* into three uninitialized extent(at most). After IO complete, the part
* being filled will be convert to initialized by the end_io callback function
* via ext4_convert_unwritten_extents().
*
* Returns the size of uninitialized extent to be written on success.
*/
static int ext4_split_unwritten_extents(handle_t *handle,
struct inode *inode,
struct ext4_map_blocks *map,
struct ext4_ext_path *path,
int flags)
{
ext4_lblk_t eof_block;
ext4_lblk_t ee_block;
struct ext4_extent *ex;
unsigned int ee_len;
int split_flag = 0, depth;
ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
"block %llu, max_blocks %u\n", inode->i_ino,
(unsigned long long)map->m_lblk, map->m_len);
eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
if (eof_block < map->m_lblk + map->m_len)
eof_block = map->m_lblk + map->m_len;
/*
* It is safe to convert extent to initialized via explicit
* zeroout only if extent is fully insde i_size or new_size.
*/
depth = ext_depth(inode);
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
split_flag |= EXT4_EXT_MARK_UNINIT2;
flags |= EXT4_GET_BLOCKS_PRE_IO;
return ext4_split_extent(handle, inode, path, map, split_flag, flags);
}
static int ext4_convert_unwritten_extents_endio(handle_t *handle,
struct inode *inode,
struct ext4_ext_path *path)
{
struct ext4_extent *ex;
struct ext4_extent_header *eh;
int depth;
int err = 0;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
"block %llu, max_blocks %u\n", inode->i_ino,
(unsigned long long)le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex));
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
/* first mark the extent as initialized */
ext4_ext_mark_initialized(ex);
/* note: ext4_ext_correct_indexes() isn't needed here because
* borders are not changed
*/
ext4_ext_try_to_merge(inode, path, ex);
/* Mark modified extent as dirty */
err = ext4_ext_dirty(handle, inode, path + depth);
out:
ext4_ext_show_leaf(inode, path);
return err;
}
static void unmap_underlying_metadata_blocks(struct block_device *bdev,
sector_t block, int count)
{
int i;
for (i = 0; i < count; i++)
unmap_underlying_metadata(bdev, block + i);
}
/*
* Handle EOFBLOCKS_FL flag, clearing it if necessary
*/
static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
ext4_lblk_t lblk,
struct ext4_ext_path *path,
unsigned int len)
{
int i, depth;
struct ext4_extent_header *eh;
struct ext4_extent *last_ex;
if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
return 0;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
if (unlikely(!eh->eh_entries)) {
EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
"EOFBLOCKS_FL set");
return -EIO;
}
last_ex = EXT_LAST_EXTENT(eh);
/*
* We should clear the EOFBLOCKS_FL flag if we are writing the
* last block in the last extent in the file. We test this by
* first checking to see if the caller to
* ext4_ext_get_blocks() was interested in the last block (or
* a block beyond the last block) in the current extent. If
* this turns out to be false, we can bail out from this
* function immediately.
*/
if (lblk + len < le32_to_cpu(last_ex->ee_block) +
ext4_ext_get_actual_len(last_ex))
return 0;
/*
* If the caller does appear to be planning to write at or
* beyond the end of the current extent, we then test to see
* if the current extent is the last extent in the file, by
* checking to make sure it was reached via the rightmost node
* at each level of the tree.
*/
for (i = depth-1; i >= 0; i--)
if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
return 0;
ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
return ext4_mark_inode_dirty(handle, inode);
}
static int
ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map,
struct ext4_ext_path *path, int flags,
unsigned int allocated, ext4_fsblk_t newblock)
{
int ret = 0;
int err = 0;
ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
"block %llu, max_blocks %u, flags %d, allocated %u",
inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
flags, allocated);
ext4_ext_show_leaf(inode, path);
/* get_block() before submit the IO, split the extent */
if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
ret = ext4_split_unwritten_extents(handle, inode, map,
path, flags);
/*
* Flag the inode(non aio case) or end_io struct (aio case)
* that this IO needs to conversion to written when IO is
* completed
*/
if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
io->flag = EXT4_IO_END_UNWRITTEN;
atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
} else
ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
if (ext4_should_dioread_nolock(inode))
map->m_flags |= EXT4_MAP_UNINIT;
goto out;
}
/* IO end_io complete, convert the filled extent to written */
if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
ret = ext4_convert_unwritten_extents_endio(handle, inode,
path);
if (ret >= 0) {
ext4_update_inode_fsync_trans(handle, inode, 1);
err = check_eofblocks_fl(handle, inode, map->m_lblk,
path, map->m_len);
} else
err = ret;
goto out2;
}
/* buffered IO case */
/*
* repeat fallocate creation request
* we already have an unwritten extent
*/
if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
goto map_out;
/* buffered READ or buffered write_begin() lookup */
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
/*
* We have blocks reserved already. We
* return allocated blocks so that delalloc
* won't do block reservation for us. But
* the buffer head will be unmapped so that
* a read from the block returns 0s.
*/
map->m_flags |= EXT4_MAP_UNWRITTEN;
goto out1;
}
/* buffered write, writepage time, convert*/
ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
if (ret >= 0) {
ext4_update_inode_fsync_trans(handle, inode, 1);
err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
map->m_len);
if (err < 0)
goto out2;
}
out:
if (ret <= 0) {
err = ret;
goto out2;
} else
allocated = ret;
map->m_flags |= EXT4_MAP_NEW;
/*
* if we allocated more blocks than requested
* we need to make sure we unmap the extra block
* allocated. The actual needed block will get
* unmapped later when we find the buffer_head marked
* new.
*/
if (allocated > map->m_len) {
unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
newblock + map->m_len,
allocated - map->m_len);
allocated = map->m_len;
}
/*
* If we have done fallocate with the offset that is already
* delayed allocated, we would have block reservation
* and quota reservation done in the delayed write path.
* But fallocate would have already updated quota and block
* count for this offset. So cancel these reservation
*/
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
ext4_da_update_reserve_space(inode, allocated, 0);
map_out:
map->m_flags |= EXT4_MAP_MAPPED;
out1:
if (allocated > map->m_len)
allocated = map->m_len;
ext4_ext_show_leaf(inode, path);
map->m_pblk = newblock;
map->m_len = allocated;
out2:
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
return err ? err : allocated;
}
/*
* Block allocation/map/preallocation routine for extents based files
*
*
* Need to be called with
* down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
* (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
*
* return > 0, number of of blocks already mapped/allocated
* if create == 0 and these are pre-allocated blocks
* buffer head is unmapped
* otherwise blocks are mapped
*
* return = 0, if plain look up failed (blocks have not been allocated)
* buffer head is unmapped
*
* return < 0, error case.
*/
int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map, int flags)
{
struct ext4_ext_path *path = NULL;
struct ext4_extent newex, *ex;
ext4_fsblk_t newblock = 0;
int err = 0, depth, ret;
unsigned int allocated = 0;
struct ext4_allocation_request ar;
ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
ext_debug("blocks %u/%u requested for inode %lu\n",
map->m_lblk, map->m_len, inode->i_ino);
trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
/* check in cache */
if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
if (!newex.ee_start_lo && !newex.ee_start_hi) {
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
/*
* block isn't allocated yet and
* user doesn't want to allocate it
*/
goto out2;
}
/* we should allocate requested block */
} else {
/* block is already allocated */
newblock = map->m_lblk
- le32_to_cpu(newex.ee_block)
+ ext4_ext_pblock(&newex);
/* number of remaining blocks in the extent */
allocated = ext4_ext_get_actual_len(&newex) -
(map->m_lblk - le32_to_cpu(newex.ee_block));
goto out;
}
}
/* find extent for this block */
path = ext4_ext_find_extent(inode, map->m_lblk, NULL);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
goto out2;
}
depth = ext_depth(inode);
/*
* consistent leaf must not be empty;
* this situation is possible, though, _during_ tree modification;
* this is why assert can't be put in ext4_ext_find_extent()
*/
if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
EXT4_ERROR_INODE(inode, "bad extent address "
"lblock: %lu, depth: %d pblock %lld",
(unsigned long) map->m_lblk, depth,
path[depth].p_block);
err = -EIO;
goto out2;
}
ex = path[depth].p_ext;
if (ex) {
ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
unsigned short ee_len;
/*
* Uninitialized extents are treated as holes, except that
* we split out initialized portions during a write.
*/
ee_len = ext4_ext_get_actual_len(ex);
/* if found extent covers block, simply return it */
if (in_range(map->m_lblk, ee_block, ee_len)) {
newblock = map->m_lblk - ee_block + ee_start;
/* number of remaining blocks in the extent */
allocated = ee_len - (map->m_lblk - ee_block);
ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
ee_block, ee_len, newblock);
/* Do not put uninitialized extent in the cache */
if (!ext4_ext_is_uninitialized(ex)) {
ext4_ext_put_in_cache(inode, ee_block,
ee_len, ee_start);
goto out;
}
ret = ext4_ext_handle_uninitialized_extents(handle,
inode, map, path, flags, allocated,
newblock);
return ret;
}
}
/*
* requested block isn't allocated yet;
* we couldn't try to create block if create flag is zero
*/
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
/*
* put just found gap into cache to speed up
* subsequent requests
*/
ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
goto out2;
}
/*
* Okay, we need to do block allocation.
*/
/* find neighbour allocated blocks */
ar.lleft = map->m_lblk;
err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
if (err)
goto out2;
ar.lright = map->m_lblk;
err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright);
if (err)
goto out2;
/*
* See if request is beyond maximum number of blocks we can have in
* a single extent. For an initialized extent this limit is
* EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
* EXT_UNINIT_MAX_LEN.
*/
if (map->m_len > EXT_INIT_MAX_LEN &&
!(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
map->m_len = EXT_INIT_MAX_LEN;
else if (map->m_len > EXT_UNINIT_MAX_LEN &&
(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
map->m_len = EXT_UNINIT_MAX_LEN;
/* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
newex.ee_block = cpu_to_le32(map->m_lblk);
newex.ee_len = cpu_to_le16(map->m_len);
err = ext4_ext_check_overlap(inode, &newex, path);
if (err)
allocated = ext4_ext_get_actual_len(&newex);
else
allocated = map->m_len;
/* allocate new block */
ar.inode = inode;
ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
ar.logical = map->m_lblk;
ar.len = allocated;
if (S_ISREG(inode->i_mode))
ar.flags = EXT4_MB_HINT_DATA;
else
/* disable in-core preallocation for non-regular files */
ar.flags = 0;
newblock = ext4_mb_new_blocks(handle, &ar, &err);
if (!newblock)
goto out2;
ext_debug("allocate new block: goal %llu, found %llu/%u\n",
ar.goal, newblock, allocated);
/* try to insert new extent into found leaf and return */
ext4_ext_store_pblock(&newex, newblock);
newex.ee_len = cpu_to_le16(ar.len);
/* Mark uninitialized */
if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
ext4_ext_mark_uninitialized(&newex);
/*
* io_end structure was created for every IO write to an
* uninitialized extent. To avoid unnecessary conversion,
* here we flag the IO that really needs the conversion.
* For non asycn direct IO case, flag the inode state
* that we need to perform conversion when IO is done.
*/
if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
if (io && !(io->flag & EXT4_IO_END_UNWRITTEN)) {
io->flag = EXT4_IO_END_UNWRITTEN;
atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
} else
ext4_set_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN);
}
if (ext4_should_dioread_nolock(inode))
map->m_flags |= EXT4_MAP_UNINIT;
}
err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
if (err)
goto out2;
err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
if (err) {
/* free data blocks we just allocated */
/* not a good idea to call discard here directly,
* but otherwise we'd need to call it every free() */
ext4_discard_preallocations(inode);
ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex),
ext4_ext_get_actual_len(&newex), 0);
goto out2;
}
/* previous routine could use block we allocated */
newblock = ext4_ext_pblock(&newex);
allocated = ext4_ext_get_actual_len(&newex);
if (allocated > map->m_len)
allocated = map->m_len;
map->m_flags |= EXT4_MAP_NEW;
/*
* Update reserved blocks/metadata blocks after successful
* block allocation which had been deferred till now.
*/
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
ext4_da_update_reserve_space(inode, allocated, 1);
/*
* Cache the extent and update transaction to commit on fdatasync only
* when it is _not_ an uninitialized extent.
*/
if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) {
ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock);
ext4_update_inode_fsync_trans(handle, inode, 1);
} else
ext4_update_inode_fsync_trans(handle, inode, 0);
out:
if (allocated > map->m_len)
allocated = map->m_len;
ext4_ext_show_leaf(inode, path);
map->m_flags |= EXT4_MAP_MAPPED;
map->m_pblk = newblock;
map->m_len = allocated;
out2:
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
newblock, map->m_len, err ? err : allocated);
return err ? err : allocated;
}
void ext4_ext_truncate(struct inode *inode)
{
struct address_space *mapping = inode->i_mapping;
struct super_block *sb = inode->i_sb;
ext4_lblk_t last_block;
handle_t *handle;
int err = 0;
/*
* finish any pending end_io work so we won't run the risk of
* converting any truncated blocks to initialized later
*/
ext4_flush_completed_IO(inode);
/*
* probably first extent we're gonna free will be last in block
*/
err = ext4_writepage_trans_blocks(inode);
handle = ext4_journal_start(inode, err);
if (IS_ERR(handle))
return;
if (inode->i_size & (sb->s_blocksize - 1))
ext4_block_truncate_page(handle, mapping, inode->i_size);
if (ext4_orphan_add(handle, inode))
goto out_stop;
down_write(&EXT4_I(inode)->i_data_sem);
ext4_ext_invalidate_cache(inode);
ext4_discard_preallocations(inode);
/*
* TODO: optimization is possible here.
* Probably we need not scan at all,
* because page truncation is enough.
*/
/* we have to know where to truncate from in crash case */
EXT4_I(inode)->i_disksize = inode->i_size;
ext4_mark_inode_dirty(handle, inode);
last_block = (inode->i_size + sb->s_blocksize - 1)
>> EXT4_BLOCK_SIZE_BITS(sb);
err = ext4_ext_remove_space(inode, last_block);
/* In a multi-transaction truncate, we only make the final
* transaction synchronous.
*/
if (IS_SYNC(inode))
ext4_handle_sync(handle);
out_stop:
up_write(&EXT4_I(inode)->i_data_sem);
/*
* If this was a simple ftruncate() and the file will remain alive,
* then we need to clear up the orphan record which we created above.
* However, if this was a real unlink then we were called by
* ext4_delete_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
}
static void ext4_falloc_update_inode(struct inode *inode,
int mode, loff_t new_size, int update_ctime)
{
struct timespec now;
if (update_ctime) {
now = current_fs_time(inode->i_sb);
if (!timespec_equal(&inode->i_ctime, &now))
inode->i_ctime = now;
}
/*
* Update only when preallocation was requested beyond
* the file size.
*/
if (!(mode & FALLOC_FL_KEEP_SIZE)) {
if (new_size > i_size_read(inode))
i_size_write(inode, new_size);
if (new_size > EXT4_I(inode)->i_disksize)
ext4_update_i_disksize(inode, new_size);
} else {
/*
* Mark that we allocate beyond EOF so the subsequent truncate
* can proceed even if the new size is the same as i_size.
*/
if (new_size > i_size_read(inode))
ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
}
}
/*
* preallocate space for a file. This implements ext4's fallocate file
* operation, which gets called from sys_fallocate system call.
* For block-mapped files, posix_fallocate should fall back to the method
* of writing zeroes to the required new blocks (the same behavior which is
* expected for file systems which do not support fallocate() system call).
*/
long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
{
struct inode *inode = file->f_path.dentry->d_inode;
handle_t *handle;
loff_t new_size;
unsigned int max_blocks;
int ret = 0;
int ret2 = 0;
int retries = 0;
struct ext4_map_blocks map;
unsigned int credits, blkbits = inode->i_blkbits;
/* We only support the FALLOC_FL_KEEP_SIZE mode */
if (mode & ~FALLOC_FL_KEEP_SIZE)
return -EOPNOTSUPP;
/*
* currently supporting (pre)allocate mode for extent-based
* files _only_
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return -EOPNOTSUPP;
trace_ext4_fallocate_enter(inode, offset, len, mode);
map.m_lblk = offset >> blkbits;
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
*/
max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
- map.m_lblk;
/*
* credits to insert 1 extent into extent tree
*/
credits = ext4_chunk_trans_blocks(inode, max_blocks);
mutex_lock(&inode->i_mutex);
ret = inode_newsize_ok(inode, (len + offset));
if (ret) {
mutex_unlock(&inode->i_mutex);
trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
return ret;
}
retry:
while (ret >= 0 && ret < max_blocks) {
map.m_lblk = map.m_lblk + ret;
map.m_len = max_blocks = max_blocks - ret;
handle = ext4_journal_start(inode, credits);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
break;
}
ret = ext4_map_blocks(handle, inode, &map,
EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
if (ret <= 0) {
#ifdef EXT4FS_DEBUG
WARN_ON(ret <= 0);
printk(KERN_ERR "%s: ext4_ext_map_blocks "
"returned error inode#%lu, block=%u, "
"max_blocks=%u", __func__,
inode->i_ino, map.m_lblk, max_blocks);
#endif
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
break;
}
if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
blkbits) >> blkbits))
new_size = offset + len;
else
new_size = (map.m_lblk + ret) << blkbits;
ext4_falloc_update_inode(inode, mode, new_size,
(map.m_flags & EXT4_MAP_NEW));
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
if (ret2)
break;
}
if (ret == -ENOSPC &&
ext4_should_retry_alloc(inode->i_sb, &retries)) {
ret = 0;
goto retry;
}
mutex_unlock(&inode->i_mutex);
trace_ext4_fallocate_exit(inode, offset, max_blocks,
ret > 0 ? ret2 : ret);
return ret > 0 ? ret2 : ret;
}
/*
* This function convert a range of blocks to written extents
* The caller of this function will pass the start offset and the size.
* all unwritten extents within this range will be converted to
* written extents.
*
* This function is called from the direct IO end io call back
* function, to convert the fallocated extents after IO is completed.
* Returns 0 on success.
*/
int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
ssize_t len)
{
handle_t *handle;
unsigned int max_blocks;
int ret = 0;
int ret2 = 0;
struct ext4_map_blocks map;
unsigned int credits, blkbits = inode->i_blkbits;
map.m_lblk = offset >> blkbits;
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
*/
max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
map.m_lblk);
/*
* credits to insert 1 extent into extent tree
*/
credits = ext4_chunk_trans_blocks(inode, max_blocks);
while (ret >= 0 && ret < max_blocks) {
map.m_lblk += ret;
map.m_len = (max_blocks -= ret);
handle = ext4_journal_start(inode, credits);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
break;
}
ret = ext4_map_blocks(handle, inode, &map,
EXT4_GET_BLOCKS_IO_CONVERT_EXT);
if (ret <= 0) {
WARN_ON(ret <= 0);
printk(KERN_ERR "%s: ext4_ext_map_blocks "
"returned error inode#%lu, block=%u, "
"max_blocks=%u", __func__,
inode->i_ino, map.m_lblk, map.m_len);
}
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
if (ret <= 0 || ret2 )
break;
}
return ret > 0 ? ret2 : ret;
}
/*
* Callback function called for each extent to gather FIEMAP information.
*/
static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
struct ext4_ext_cache *newex, struct ext4_extent *ex,
void *data)
{
__u64 logical;
__u64 physical;
__u64 length;
loff_t size;
__u32 flags = 0;
int ret = 0;
struct fiemap_extent_info *fieinfo = data;
unsigned char blksize_bits;
blksize_bits = inode->i_sb->s_blocksize_bits;
logical = (__u64)newex->ec_block << blksize_bits;
if (newex->ec_start == 0) {
/*
* No extent in extent-tree contains block @newex->ec_start,
* then the block may stay in 1)a hole or 2)delayed-extent.
*
* Holes or delayed-extents are processed as follows.
* 1. lookup dirty pages with specified range in pagecache.
* If no page is got, then there is no delayed-extent and
* return with EXT_CONTINUE.
* 2. find the 1st mapped buffer,
* 3. check if the mapped buffer is both in the request range
* and a delayed buffer. If not, there is no delayed-extent,
* then return.
* 4. a delayed-extent is found, the extent will be collected.
*/
ext4_lblk_t end = 0;
pgoff_t last_offset;
pgoff_t offset;
pgoff_t index;
struct page **pages = NULL;
struct buffer_head *bh = NULL;
struct buffer_head *head = NULL;
unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (pages == NULL)
return -ENOMEM;
offset = logical >> PAGE_SHIFT;
repeat:
last_offset = offset;
head = NULL;
ret = find_get_pages_tag(inode->i_mapping, &offset,
PAGECACHE_TAG_DIRTY, nr_pages, pages);
if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
/* First time, try to find a mapped buffer. */
if (ret == 0) {
out:
for (index = 0; index < ret; index++)
page_cache_release(pages[index]);
/* just a hole. */
kfree(pages);
return EXT_CONTINUE;
}
/* Try to find the 1st mapped buffer. */
end = ((__u64)pages[0]->index << PAGE_SHIFT) >>
blksize_bits;
if (!page_has_buffers(pages[0]))
goto out;
head = page_buffers(pages[0]);
if (!head)
goto out;
bh = head;
do {
if (buffer_mapped(bh)) {
/* get the 1st mapped buffer. */
if (end > newex->ec_block +
newex->ec_len)
/* The buffer is out of
* the request range.
*/
goto out;
goto found_mapped_buffer;
}
bh = bh->b_this_page;
end++;
} while (bh != head);
/* No mapped buffer found. */
goto out;
} else {
/*Find contiguous delayed buffers. */
if (ret > 0 && pages[0]->index == last_offset)
head = page_buffers(pages[0]);
bh = head;
}
found_mapped_buffer:
if (bh != NULL && buffer_delay(bh)) {
/* 1st or contiguous delayed buffer found. */
if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
/*
* 1st delayed buffer found, record
* the start of extent.
*/
flags |= FIEMAP_EXTENT_DELALLOC;
newex->ec_block = end;
logical = (__u64)end << blksize_bits;
}
/* Find contiguous delayed buffers. */
do {
if (!buffer_delay(bh))
goto found_delayed_extent;
bh = bh->b_this_page;
end++;
} while (bh != head);
for (index = 1; index < ret; index++) {
if (!page_has_buffers(pages[index])) {
bh = NULL;
break;
}
head = page_buffers(pages[index]);
if (!head) {
bh = NULL;
break;
}
if (pages[index]->index !=
pages[0]->index + index) {
/* Blocks are not contiguous. */
bh = NULL;
break;
}
bh = head;
do {
if (!buffer_delay(bh))
/* Delayed-extent ends. */
goto found_delayed_extent;
bh = bh->b_this_page;
end++;
} while (bh != head);
}
} else if (!(flags & FIEMAP_EXTENT_DELALLOC))
/* a hole found. */
goto out;
found_delayed_extent:
newex->ec_len = min(end - newex->ec_block,
(ext4_lblk_t)EXT_INIT_MAX_LEN);
if (ret == nr_pages && bh != NULL &&
newex->ec_len < EXT_INIT_MAX_LEN &&
buffer_delay(bh)) {
/* Have not collected an extent and continue. */
for (index = 0; index < ret; index++)
page_cache_release(pages[index]);
goto repeat;
}
for (index = 0; index < ret; index++)
page_cache_release(pages[index]);
kfree(pages);
}
physical = (__u64)newex->ec_start << blksize_bits;
length = (__u64)newex->ec_len << blksize_bits;
if (ex && ext4_ext_is_uninitialized(ex))
flags |= FIEMAP_EXTENT_UNWRITTEN;
size = i_size_read(inode);
if (logical + length >= size)
flags |= FIEMAP_EXTENT_LAST;
ret = fiemap_fill_next_extent(fieinfo, logical, physical,
length, flags);
if (ret < 0)
return ret;
if (ret == 1)
return EXT_BREAK;
return EXT_CONTINUE;
}
/* fiemap flags we can handle specified here */
#define EXT4_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
static int ext4_xattr_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo)
{
__u64 physical = 0;
__u64 length;
__u32 flags = FIEMAP_EXTENT_LAST;
int blockbits = inode->i_sb->s_blocksize_bits;
int error = 0;
/* in-inode? */
if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
struct ext4_iloc iloc;
int offset; /* offset of xattr in inode */
error = ext4_get_inode_loc(inode, &iloc);
if (error)
return error;
physical = iloc.bh->b_blocknr << blockbits;
offset = EXT4_GOOD_OLD_INODE_SIZE +
EXT4_I(inode)->i_extra_isize;
physical += offset;
length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
flags |= FIEMAP_EXTENT_DATA_INLINE;
brelse(iloc.bh);
} else { /* external block */
physical = EXT4_I(inode)->i_file_acl << blockbits;
length = inode->i_sb->s_blocksize;
}
if (physical)
error = fiemap_fill_next_extent(fieinfo, 0, physical,
length, flags);
return (error < 0 ? error : 0);
}
int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len)
{
ext4_lblk_t start_blk;
int error = 0;
/* fallback to generic here if not in extents fmt */
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return generic_block_fiemap(inode, fieinfo, start, len,
ext4_get_block);
if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
return -EBADR;
if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
error = ext4_xattr_fiemap(inode, fieinfo);
} else {
ext4_lblk_t len_blks;
__u64 last_blk;
start_blk = start >> inode->i_sb->s_blocksize_bits;
last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
if (last_blk >= EXT_MAX_BLOCK)
last_blk = EXT_MAX_BLOCK-1;
len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
/*
* Walk the extent tree gathering extent information.
* ext4_ext_fiemap_cb will push extents back to user.
*/
error = ext4_ext_walk_space(inode, start_blk, len_blks,
ext4_ext_fiemap_cb, fieinfo);
}
return error;
}
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