blob: b6e5934f5dd68f6fea324f182c76086486c8edb3 [file] [log] [blame]
/*
* linux/fs/ext3/inode.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Goal-directed block allocation by Stephen Tweedie
* (sct@redhat.com), 1993, 1998
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*
* Assorted race fixes, rewrite of ext3_get_block() by Al Viro, 2000
*/
#include <linux/highuid.h>
#include <linux/quotaops.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/namei.h>
#include <linux/aio.h>
#include "ext3.h"
#include "xattr.h"
#include "acl.h"
static int ext3_writepage_trans_blocks(struct inode *inode);
static int ext3_block_truncate_page(struct inode *inode, loff_t from);
/*
* Test whether an inode is a fast symlink.
*/
static int ext3_inode_is_fast_symlink(struct inode *inode)
{
int ea_blocks = EXT3_I(inode)->i_file_acl ?
(inode->i_sb->s_blocksize >> 9) : 0;
return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}
/*
* The ext3 forget function must perform a revoke if we are freeing data
* which has been journaled. Metadata (eg. indirect blocks) must be
* revoked in all cases.
*
* "bh" may be NULL: a metadata block may have been freed from memory
* but there may still be a record of it in the journal, and that record
* still needs to be revoked.
*/
int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
struct buffer_head *bh, ext3_fsblk_t blocknr)
{
int err;
might_sleep();
trace_ext3_forget(inode, is_metadata, blocknr);
BUFFER_TRACE(bh, "enter");
jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
"data mode %lx\n",
bh, is_metadata, inode->i_mode,
test_opt(inode->i_sb, DATA_FLAGS));
/* Never use the revoke function if we are doing full data
* journaling: there is no need to, and a V1 superblock won't
* support it. Otherwise, only skip the revoke on un-journaled
* data blocks. */
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
(!is_metadata && !ext3_should_journal_data(inode))) {
if (bh) {
BUFFER_TRACE(bh, "call journal_forget");
return ext3_journal_forget(handle, bh);
}
return 0;
}
/*
* data!=journal && (is_metadata || should_journal_data(inode))
*/
BUFFER_TRACE(bh, "call ext3_journal_revoke");
err = ext3_journal_revoke(handle, blocknr, bh);
if (err)
ext3_abort(inode->i_sb, __func__,
"error %d when attempting revoke", err);
BUFFER_TRACE(bh, "exit");
return err;
}
/*
* Work out how many blocks we need to proceed with the next chunk of a
* truncate transaction.
*/
static unsigned long blocks_for_truncate(struct inode *inode)
{
unsigned long needed;
needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
/* Give ourselves just enough room to cope with inodes in which
* i_blocks is corrupt: we've seen disk corruptions in the past
* which resulted in random data in an inode which looked enough
* like a regular file for ext3 to try to delete it. Things
* will go a bit crazy if that happens, but at least we should
* try not to panic the whole kernel. */
if (needed < 2)
needed = 2;
/* But we need to bound the transaction so we don't overflow the
* journal. */
if (needed > EXT3_MAX_TRANS_DATA)
needed = EXT3_MAX_TRANS_DATA;
return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
}
/*
* Truncate transactions can be complex and absolutely huge. So we need to
* be able to restart the transaction at a conventient checkpoint to make
* sure we don't overflow the journal.
*
* start_transaction gets us a new handle for a truncate transaction,
* and extend_transaction tries to extend the existing one a bit. If
* extend fails, we need to propagate the failure up and restart the
* transaction in the top-level truncate loop. --sct
*/
static handle_t *start_transaction(struct inode *inode)
{
handle_t *result;
result = ext3_journal_start(inode, blocks_for_truncate(inode));
if (!IS_ERR(result))
return result;
ext3_std_error(inode->i_sb, PTR_ERR(result));
return result;
}
/*
* Try to extend this transaction for the purposes of truncation.
*
* Returns 0 if we managed to create more room. If we can't create more
* room, and the transaction must be restarted we return 1.
*/
static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
{
if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
return 0;
if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
return 0;
return 1;
}
/*
* Restart the transaction associated with *handle. This does a commit,
* so before we call here everything must be consistently dirtied against
* this transaction.
*/
static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
{
int ret;
jbd_debug(2, "restarting handle %p\n", handle);
/*
* Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
* At this moment, get_block can be called only for blocks inside
* i_size since page cache has been already dropped and writes are
* blocked by i_mutex. So we can safely drop the truncate_mutex.
*/
mutex_unlock(&EXT3_I(inode)->truncate_mutex);
ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
mutex_lock(&EXT3_I(inode)->truncate_mutex);
return ret;
}
/*
* Called at inode eviction from icache
*/
void ext3_evict_inode (struct inode *inode)
{
struct ext3_inode_info *ei = EXT3_I(inode);
struct ext3_block_alloc_info *rsv;
handle_t *handle;
int want_delete = 0;
trace_ext3_evict_inode(inode);
if (!inode->i_nlink && !is_bad_inode(inode)) {
dquot_initialize(inode);
want_delete = 1;
}
/*
* When journalling data dirty buffers are tracked only in the journal.
* So although mm thinks everything is clean and ready for reaping the
* inode might still have some pages to write in the running
* transaction or waiting to be checkpointed. Thus calling
* journal_invalidatepage() (via truncate_inode_pages()) to discard
* these buffers can cause data loss. Also even if we did not discard
* these buffers, we would have no way to find them after the inode
* is reaped and thus user could see stale data if he tries to read
* them before the transaction is checkpointed. So be careful and
* force everything to disk here... We use ei->i_datasync_tid to
* store the newest transaction containing inode's data.
*
* Note that directories do not have this problem because they don't
* use page cache.
*
* The s_journal check handles the case when ext3_get_journal() fails
* and puts the journal inode.
*/
if (inode->i_nlink && ext3_should_journal_data(inode) &&
EXT3_SB(inode->i_sb)->s_journal &&
(S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
inode->i_ino != EXT3_JOURNAL_INO) {
tid_t commit_tid = atomic_read(&ei->i_datasync_tid);
journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
log_start_commit(journal, commit_tid);
log_wait_commit(journal, commit_tid);
filemap_write_and_wait(&inode->i_data);
}
truncate_inode_pages(&inode->i_data, 0);
ext3_discard_reservation(inode);
rsv = ei->i_block_alloc_info;
ei->i_block_alloc_info = NULL;
if (unlikely(rsv))
kfree(rsv);
if (!want_delete)
goto no_delete;
handle = start_transaction(inode);
if (IS_ERR(handle)) {
/*
* If we're going to skip the normal cleanup, we still need to
* make sure that the in-core orphan linked list is properly
* cleaned up.
*/
ext3_orphan_del(NULL, inode);
goto no_delete;
}
if (IS_SYNC(inode))
handle->h_sync = 1;
inode->i_size = 0;
if (inode->i_blocks)
ext3_truncate(inode);
/*
* Kill off the orphan record created when the inode lost the last
* link. Note that ext3_orphan_del() has to be able to cope with the
* deletion of a non-existent orphan - ext3_truncate() could
* have removed the record.
*/
ext3_orphan_del(handle, inode);
ei->i_dtime = get_seconds();
/*
* One subtle ordering requirement: if anything has gone wrong
* (transaction abort, IO errors, whatever), then we can still
* do these next steps (the fs will already have been marked as
* having errors), but we can't free the inode if the mark_dirty
* fails.
*/
if (ext3_mark_inode_dirty(handle, inode)) {
/* If that failed, just dquot_drop() and be done with that */
dquot_drop(inode);
clear_inode(inode);
} else {
ext3_xattr_delete_inode(handle, inode);
dquot_free_inode(inode);
dquot_drop(inode);
clear_inode(inode);
ext3_free_inode(handle, inode);
}
ext3_journal_stop(handle);
return;
no_delete:
clear_inode(inode);
dquot_drop(inode);
}
typedef struct {
__le32 *p;
__le32 key;
struct buffer_head *bh;
} Indirect;
static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
p->key = *(p->p = v);
p->bh = bh;
}
static int verify_chain(Indirect *from, Indirect *to)
{
while (from <= to && from->key == *from->p)
from++;
return (from > to);
}
/**
* ext3_block_to_path - parse the block number into array of offsets
* @inode: inode in question (we are only interested in its superblock)
* @i_block: block number to be parsed
* @offsets: array to store the offsets in
* @boundary: set this non-zero if the referred-to block is likely to be
* followed (on disk) by an indirect block.
*
* To store the locations of file's data ext3 uses a data structure common
* for UNIX filesystems - tree of pointers anchored in the inode, with
* data blocks at leaves and indirect blocks in intermediate nodes.
* This function translates the block number into path in that tree -
* return value is the path length and @offsets[n] is the offset of
* pointer to (n+1)th node in the nth one. If @block is out of range
* (negative or too large) warning is printed and zero returned.
*
* Note: function doesn't find node addresses, so no IO is needed. All
* we need to know is the capacity of indirect blocks (taken from the
* inode->i_sb).
*/
/*
* Portability note: the last comparison (check that we fit into triple
* indirect block) is spelled differently, because otherwise on an
* architecture with 32-bit longs and 8Kb pages we might get into trouble
* if our filesystem had 8Kb blocks. We might use long long, but that would
* kill us on x86. Oh, well, at least the sign propagation does not matter -
* i_block would have to be negative in the very beginning, so we would not
* get there at all.
*/
static int ext3_block_to_path(struct inode *inode,
long i_block, int offsets[4], int *boundary)
{
int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
const long direct_blocks = EXT3_NDIR_BLOCKS,
indirect_blocks = ptrs,
double_blocks = (1 << (ptrs_bits * 2));
int n = 0;
int final = 0;
if (i_block < 0) {
ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
} else if (i_block < direct_blocks) {
offsets[n++] = i_block;
final = direct_blocks;
} else if ( (i_block -= direct_blocks) < indirect_blocks) {
offsets[n++] = EXT3_IND_BLOCK;
offsets[n++] = i_block;
final = ptrs;
} else if ((i_block -= indirect_blocks) < double_blocks) {
offsets[n++] = EXT3_DIND_BLOCK;
offsets[n++] = i_block >> ptrs_bits;
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
offsets[n++] = EXT3_TIND_BLOCK;
offsets[n++] = i_block >> (ptrs_bits * 2);
offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else {
ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
}
if (boundary)
*boundary = final - 1 - (i_block & (ptrs - 1));
return n;
}
/**
* ext3_get_branch - read the chain of indirect blocks leading to data
* @inode: inode in question
* @depth: depth of the chain (1 - direct pointer, etc.)
* @offsets: offsets of pointers in inode/indirect blocks
* @chain: place to store the result
* @err: here we store the error value
*
* Function fills the array of triples <key, p, bh> and returns %NULL
* if everything went OK or the pointer to the last filled triple
* (incomplete one) otherwise. Upon the return chain[i].key contains
* the number of (i+1)-th block in the chain (as it is stored in memory,
* i.e. little-endian 32-bit), chain[i].p contains the address of that
* number (it points into struct inode for i==0 and into the bh->b_data
* for i>0) and chain[i].bh points to the buffer_head of i-th indirect
* block for i>0 and NULL for i==0. In other words, it holds the block
* numbers of the chain, addresses they were taken from (and where we can
* verify that chain did not change) and buffer_heads hosting these
* numbers.
*
* Function stops when it stumbles upon zero pointer (absent block)
* (pointer to last triple returned, *@err == 0)
* or when it gets an IO error reading an indirect block
* (ditto, *@err == -EIO)
* or when it notices that chain had been changed while it was reading
* (ditto, *@err == -EAGAIN)
* or when it reads all @depth-1 indirect blocks successfully and finds
* the whole chain, all way to the data (returns %NULL, *err == 0).
*/
static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
Indirect chain[4], int *err)
{
struct super_block *sb = inode->i_sb;
Indirect *p = chain;
struct buffer_head *bh;
*err = 0;
/* i_data is not going away, no lock needed */
add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
if (!p->key)
goto no_block;
while (--depth) {
bh = sb_bread(sb, le32_to_cpu(p->key));
if (!bh)
goto failure;
/* Reader: pointers */
if (!verify_chain(chain, p))
goto changed;
add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
/* Reader: end */
if (!p->key)
goto no_block;
}
return NULL;
changed:
brelse(bh);
*err = -EAGAIN;
goto no_block;
failure:
*err = -EIO;
no_block:
return p;
}
/**
* ext3_find_near - find a place for allocation with sufficient locality
* @inode: owner
* @ind: descriptor of indirect block.
*
* This function returns the preferred place for block allocation.
* It is used when heuristic for sequential allocation fails.
* Rules are:
* + if there is a block to the left of our position - allocate near it.
* + if pointer will live in indirect block - allocate near that block.
* + if pointer will live in inode - allocate in the same
* cylinder group.
*
* In the latter case we colour the starting block by the callers PID to
* prevent it from clashing with concurrent allocations for a different inode
* in the same block group. The PID is used here so that functionally related
* files will be close-by on-disk.
*
* Caller must make sure that @ind is valid and will stay that way.
*/
static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
{
struct ext3_inode_info *ei = EXT3_I(inode);
__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
__le32 *p;
ext3_fsblk_t bg_start;
ext3_grpblk_t colour;
/* Try to find previous block */
for (p = ind->p - 1; p >= start; p--) {
if (*p)
return le32_to_cpu(*p);
}
/* No such thing, so let's try location of indirect block */
if (ind->bh)
return ind->bh->b_blocknr;
/*
* It is going to be referred to from the inode itself? OK, just put it
* into the same cylinder group then.
*/
bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
colour = (current->pid % 16) *
(EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
return bg_start + colour;
}
/**
* ext3_find_goal - find a preferred place for allocation.
* @inode: owner
* @block: block we want
* @partial: pointer to the last triple within a chain
*
* Normally this function find the preferred place for block allocation,
* returns it.
*/
static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
Indirect *partial)
{
struct ext3_block_alloc_info *block_i;
block_i = EXT3_I(inode)->i_block_alloc_info;
/*
* try the heuristic for sequential allocation,
* failing that at least try to get decent locality.
*/
if (block_i && (block == block_i->last_alloc_logical_block + 1)
&& (block_i->last_alloc_physical_block != 0)) {
return block_i->last_alloc_physical_block + 1;
}
return ext3_find_near(inode, partial);
}
/**
* ext3_blks_to_allocate - Look up the block map and count the number
* of direct blocks need to be allocated for the given branch.
*
* @branch: chain of indirect blocks
* @k: number of blocks need for indirect blocks
* @blks: number of data blocks to be mapped.
* @blocks_to_boundary: the offset in the indirect block
*
* return the total number of blocks to be allocate, including the
* direct and indirect blocks.
*/
static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
int blocks_to_boundary)
{
unsigned long count = 0;
/*
* Simple case, [t,d]Indirect block(s) has not allocated yet
* then it's clear blocks on that path have not allocated
*/
if (k > 0) {
/* right now we don't handle cross boundary allocation */
if (blks < blocks_to_boundary + 1)
count += blks;
else
count += blocks_to_boundary + 1;
return count;
}
count++;
while (count < blks && count <= blocks_to_boundary &&
le32_to_cpu(*(branch[0].p + count)) == 0) {
count++;
}
return count;
}
/**
* ext3_alloc_blocks - multiple allocate blocks needed for a branch
* @handle: handle for this transaction
* @inode: owner
* @goal: preferred place for allocation
* @indirect_blks: the number of blocks need to allocate for indirect
* blocks
* @blks: number of blocks need to allocated for direct blocks
* @new_blocks: on return it will store the new block numbers for
* the indirect blocks(if needed) and the first direct block,
* @err: here we store the error value
*
* return the number of direct blocks allocated
*/
static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
ext3_fsblk_t goal, int indirect_blks, int blks,
ext3_fsblk_t new_blocks[4], int *err)
{
int target, i;
unsigned long count = 0;
int index = 0;
ext3_fsblk_t current_block = 0;
int ret = 0;
/*
* Here we try to allocate the requested multiple blocks at once,
* on a best-effort basis.
* To build a branch, we should allocate blocks for
* the indirect blocks(if not allocated yet), and at least
* the first direct block of this branch. That's the
* minimum number of blocks need to allocate(required)
*/
target = blks + indirect_blks;
while (1) {
count = target;
/* allocating blocks for indirect blocks and direct blocks */
current_block = ext3_new_blocks(handle,inode,goal,&count,err);
if (*err)
goto failed_out;
target -= count;
/* allocate blocks for indirect blocks */
while (index < indirect_blks && count) {
new_blocks[index++] = current_block++;
count--;
}
if (count > 0)
break;
}
/* save the new block number for the first direct block */
new_blocks[index] = current_block;
/* total number of blocks allocated for direct blocks */
ret = count;
*err = 0;
return ret;
failed_out:
for (i = 0; i <index; i++)
ext3_free_blocks(handle, inode, new_blocks[i], 1);
return ret;
}
/**
* ext3_alloc_branch - allocate and set up a chain of blocks.
* @handle: handle for this transaction
* @inode: owner
* @indirect_blks: number of allocated indirect blocks
* @blks: number of allocated direct blocks
* @goal: preferred place for allocation
* @offsets: offsets (in the blocks) to store the pointers to next.
* @branch: place to store the chain in.
*
* This function allocates blocks, zeroes out all but the last one,
* links them into chain and (if we are synchronous) writes them to disk.
* In other words, it prepares a branch that can be spliced onto the
* inode. It stores the information about that chain in the branch[], in
* the same format as ext3_get_branch() would do. We are calling it after
* we had read the existing part of chain and partial points to the last
* triple of that (one with zero ->key). Upon the exit we have the same
* picture as after the successful ext3_get_block(), except that in one
* place chain is disconnected - *branch->p is still zero (we did not
* set the last link), but branch->key contains the number that should
* be placed into *branch->p to fill that gap.
*
* If allocation fails we free all blocks we've allocated (and forget
* their buffer_heads) and return the error value the from failed
* ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
* as described above and return 0.
*/
static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
int indirect_blks, int *blks, ext3_fsblk_t goal,
int *offsets, Indirect *branch)
{
int blocksize = inode->i_sb->s_blocksize;
int i, n = 0;
int err = 0;
struct buffer_head *bh;
int num;
ext3_fsblk_t new_blocks[4];
ext3_fsblk_t current_block;
num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
*blks, new_blocks, &err);
if (err)
return err;
branch[0].key = cpu_to_le32(new_blocks[0]);
/*
* metadata blocks and data blocks are allocated.
*/
for (n = 1; n <= indirect_blks; n++) {
/*
* Get buffer_head for parent block, zero it out
* and set the pointer to new one, then send
* parent to disk.
*/
bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
if (unlikely(!bh)) {
err = -ENOMEM;
goto failed;
}
branch[n].bh = bh;
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
err = ext3_journal_get_create_access(handle, bh);
if (err) {
unlock_buffer(bh);
brelse(bh);
goto failed;
}
memset(bh->b_data, 0, blocksize);
branch[n].p = (__le32 *) bh->b_data + offsets[n];
branch[n].key = cpu_to_le32(new_blocks[n]);
*branch[n].p = branch[n].key;
if ( n == indirect_blks) {
current_block = new_blocks[n];
/*
* End of chain, update the last new metablock of
* the chain to point to the new allocated
* data blocks numbers
*/
for (i=1; i < num; i++)
*(branch[n].p + i) = cpu_to_le32(++current_block);
}
BUFFER_TRACE(bh, "marking uptodate");
set_buffer_uptodate(bh);
unlock_buffer(bh);
BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
err = ext3_journal_dirty_metadata(handle, bh);
if (err)
goto failed;
}
*blks = num;
return err;
failed:
/* Allocation failed, free what we already allocated */
for (i = 1; i <= n ; i++) {
BUFFER_TRACE(branch[i].bh, "call journal_forget");
ext3_journal_forget(handle, branch[i].bh);
}
for (i = 0; i < indirect_blks; i++)
ext3_free_blocks(handle, inode, new_blocks[i], 1);
ext3_free_blocks(handle, inode, new_blocks[i], num);
return err;
}
/**
* ext3_splice_branch - splice the allocated branch onto inode.
* @handle: handle for this transaction
* @inode: owner
* @block: (logical) number of block we are adding
* @where: location of missing link
* @num: number of indirect blocks we are adding
* @blks: number of direct blocks we are adding
*
* This function fills the missing link and does all housekeeping needed in
* inode (->i_blocks, etc.). In case of success we end up with the full
* chain to new block and return 0.
*/
static int ext3_splice_branch(handle_t *handle, struct inode *inode,
long block, Indirect *where, int num, int blks)
{
int i;
int err = 0;
struct ext3_block_alloc_info *block_i;
ext3_fsblk_t current_block;
struct ext3_inode_info *ei = EXT3_I(inode);
struct timespec now;
block_i = ei->i_block_alloc_info;
/*
* If we're splicing into a [td]indirect block (as opposed to the
* inode) then we need to get write access to the [td]indirect block
* before the splice.
*/
if (where->bh) {
BUFFER_TRACE(where->bh, "get_write_access");
err = ext3_journal_get_write_access(handle, where->bh);
if (err)
goto err_out;
}
/* That's it */
*where->p = where->key;
/*
* Update the host buffer_head or inode to point to more just allocated
* direct blocks blocks
*/
if (num == 0 && blks > 1) {
current_block = le32_to_cpu(where->key) + 1;
for (i = 1; i < blks; i++)
*(where->p + i ) = cpu_to_le32(current_block++);
}
/*
* update the most recently allocated logical & physical block
* in i_block_alloc_info, to assist find the proper goal block for next
* allocation
*/
if (block_i) {
block_i->last_alloc_logical_block = block + blks - 1;
block_i->last_alloc_physical_block =
le32_to_cpu(where[num].key) + blks - 1;
}
/* We are done with atomic stuff, now do the rest of housekeeping */
now = CURRENT_TIME_SEC;
if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) {
inode->i_ctime = now;
ext3_mark_inode_dirty(handle, inode);
}
/* ext3_mark_inode_dirty already updated i_sync_tid */
atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
/* had we spliced it onto indirect block? */
if (where->bh) {
/*
* If we spliced it onto an indirect block, we haven't
* altered the inode. Note however that if it is being spliced
* onto an indirect block at the very end of the file (the
* file is growing) then we *will* alter the inode to reflect
* the new i_size. But that is not done here - it is done in
* generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
*/
jbd_debug(5, "splicing indirect only\n");
BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
err = ext3_journal_dirty_metadata(handle, where->bh);
if (err)
goto err_out;
} else {
/*
* OK, we spliced it into the inode itself on a direct block.
* Inode was dirtied above.
*/
jbd_debug(5, "splicing direct\n");
}
return err;
err_out:
for (i = 1; i <= num; i++) {
BUFFER_TRACE(where[i].bh, "call journal_forget");
ext3_journal_forget(handle, where[i].bh);
ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
}
ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
return err;
}
/*
* Allocation strategy is simple: if we have to allocate something, we will
* have to go the whole way to leaf. So let's do it before attaching anything
* to tree, set linkage between the newborn blocks, write them if sync is
* required, recheck the path, free and repeat if check fails, otherwise
* set the last missing link (that will protect us from any truncate-generated
* removals - all blocks on the path are immune now) and possibly force the
* write on the parent block.
* That has a nice additional property: no special recovery from the failed
* allocations is needed - we simply release blocks and do not touch anything
* reachable from inode.
*
* `handle' can be NULL if create == 0.
*
* The BKL may not be held on entry here. Be sure to take it early.
* return > 0, # of blocks mapped or allocated.
* return = 0, if plain lookup failed.
* return < 0, error case.
*/
int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
sector_t iblock, unsigned long maxblocks,
struct buffer_head *bh_result,
int create)
{
int err = -EIO;
int offsets[4];
Indirect chain[4];
Indirect *partial;
ext3_fsblk_t goal;
int indirect_blks;
int blocks_to_boundary = 0;
int depth;
struct ext3_inode_info *ei = EXT3_I(inode);
int count = 0;
ext3_fsblk_t first_block = 0;
trace_ext3_get_blocks_enter(inode, iblock, maxblocks, create);
J_ASSERT(handle != NULL || create == 0);
depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
if (depth == 0)
goto out;
partial = ext3_get_branch(inode, depth, offsets, chain, &err);
/* Simplest case - block found, no allocation needed */
if (!partial) {
first_block = le32_to_cpu(chain[depth - 1].key);
clear_buffer_new(bh_result);
count++;
/*map more blocks*/
while (count < maxblocks && count <= blocks_to_boundary) {
ext3_fsblk_t blk;
if (!verify_chain(chain, chain + depth - 1)) {
/*
* Indirect block might be removed by
* truncate while we were reading it.
* Handling of that case: forget what we've
* got now. Flag the err as EAGAIN, so it
* will reread.
*/
err = -EAGAIN;
count = 0;
break;
}
blk = le32_to_cpu(*(chain[depth-1].p + count));
if (blk == first_block + count)
count++;
else
break;
}
if (err != -EAGAIN)
goto got_it;
}
/* Next simple case - plain lookup or failed read of indirect block */
if (!create || err == -EIO)
goto cleanup;
/*
* Block out ext3_truncate while we alter the tree
*/
mutex_lock(&ei->truncate_mutex);
/*
* If the indirect block is missing while we are reading
* the chain(ext3_get_branch() returns -EAGAIN err), or
* if the chain has been changed after we grab the semaphore,
* (either because another process truncated this branch, or
* another get_block allocated this branch) re-grab the chain to see if
* the request block has been allocated or not.
*
* Since we already block the truncate/other get_block
* at this point, we will have the current copy of the chain when we
* splice the branch into the tree.
*/
if (err == -EAGAIN || !verify_chain(chain, partial)) {
while (partial > chain) {
brelse(partial->bh);
partial--;
}
partial = ext3_get_branch(inode, depth, offsets, chain, &err);
if (!partial) {
count++;
mutex_unlock(&ei->truncate_mutex);
if (err)
goto cleanup;
clear_buffer_new(bh_result);
goto got_it;
}
}
/*
* Okay, we need to do block allocation. Lazily initialize the block
* allocation info here if necessary
*/
if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
ext3_init_block_alloc_info(inode);
goal = ext3_find_goal(inode, iblock, partial);
/* the number of blocks need to allocate for [d,t]indirect blocks */
indirect_blks = (chain + depth) - partial - 1;
/*
* Next look up the indirect map to count the totoal number of
* direct blocks to allocate for this branch.
*/
count = ext3_blks_to_allocate(partial, indirect_blks,
maxblocks, blocks_to_boundary);
err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
offsets + (partial - chain), partial);
/*
* The ext3_splice_branch call will free and forget any buffers
* on the new chain if there is a failure, but that risks using
* up transaction credits, especially for bitmaps where the
* credits cannot be returned. Can we handle this somehow? We
* may need to return -EAGAIN upwards in the worst case. --sct
*/
if (!err)
err = ext3_splice_branch(handle, inode, iblock,
partial, indirect_blks, count);
mutex_unlock(&ei->truncate_mutex);
if (err)
goto cleanup;
set_buffer_new(bh_result);
got_it:
map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
if (count > blocks_to_boundary)
set_buffer_boundary(bh_result);
err = count;
/* Clean up and exit */
partial = chain + depth - 1; /* the whole chain */
cleanup:
while (partial > chain) {
BUFFER_TRACE(partial->bh, "call brelse");
brelse(partial->bh);
partial--;
}
BUFFER_TRACE(bh_result, "returned");
out:
trace_ext3_get_blocks_exit(inode, iblock,
depth ? le32_to_cpu(chain[depth-1].key) : 0,
count, err);
return err;
}
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
/*
* Number of credits we need for writing DIO_MAX_BLOCKS:
* We need sb + group descriptor + bitmap + inode -> 4
* For B blocks with A block pointers per block we need:
* 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
* If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
*/
#define DIO_CREDITS 25
static int ext3_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
handle_t *handle = ext3_journal_current_handle();
int ret = 0, started = 0;
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
if (create && !handle) { /* Direct IO write... */
if (max_blocks > DIO_MAX_BLOCKS)
max_blocks = DIO_MAX_BLOCKS;
handle = ext3_journal_start(inode, DIO_CREDITS +
EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
started = 1;
}
ret = ext3_get_blocks_handle(handle, inode, iblock,
max_blocks, bh_result, create);
if (ret > 0) {
bh_result->b_size = (ret << inode->i_blkbits);
ret = 0;
}
if (started)
ext3_journal_stop(handle);
out:
return ret;
}
int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
return generic_block_fiemap(inode, fieinfo, start, len,
ext3_get_block);
}
/*
* `handle' can be NULL if create is zero
*/
struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
long block, int create, int *errp)
{
struct buffer_head dummy;
int fatal = 0, err;
J_ASSERT(handle != NULL || create == 0);
dummy.b_state = 0;
dummy.b_blocknr = -1000;
buffer_trace_init(&dummy.b_history);
err = ext3_get_blocks_handle(handle, inode, block, 1,
&dummy, create);
/*
* ext3_get_blocks_handle() returns number of blocks
* mapped. 0 in case of a HOLE.
*/
if (err > 0) {
WARN_ON(err > 1);
err = 0;
}
*errp = err;
if (!err && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
if (unlikely(!bh)) {
*errp = -ENOMEM;
goto err;
}
if (buffer_new(&dummy)) {
J_ASSERT(create != 0);
J_ASSERT(handle != NULL);
/*
* Now that we do not always journal data, we should
* keep in mind whether this should always journal the
* new buffer as metadata. For now, regular file
* writes use ext3_get_block instead, so it's not a
* problem.
*/
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
fatal = ext3_journal_get_create_access(handle, bh);
if (!fatal && !buffer_uptodate(bh)) {
memset(bh->b_data,0,inode->i_sb->s_blocksize);
set_buffer_uptodate(bh);
}
unlock_buffer(bh);
BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
err = ext3_journal_dirty_metadata(handle, bh);
if (!fatal)
fatal = err;
} else {
BUFFER_TRACE(bh, "not a new buffer");
}
if (fatal) {
*errp = fatal;
brelse(bh);
bh = NULL;
}
return bh;
}
err:
return NULL;
}
struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
int block, int create, int *err)
{
struct buffer_head * bh;
bh = ext3_getblk(handle, inode, block, create, err);
if (!bh)
return bh;
if (bh_uptodate_or_lock(bh))
return bh;
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
put_bh(bh);
*err = -EIO;
return NULL;
}
static int walk_page_buffers( handle_t *handle,
struct buffer_head *head,
unsigned from,
unsigned to,
int *partial,
int (*fn)( handle_t *handle,
struct buffer_head *bh))
{
struct buffer_head *bh;
unsigned block_start, block_end;
unsigned blocksize = head->b_size;
int err, ret = 0;
struct buffer_head *next;
for ( bh = head, block_start = 0;
ret == 0 && (bh != head || !block_start);
block_start = block_end, bh = next)
{
next = bh->b_this_page;
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (partial && !buffer_uptodate(bh))
*partial = 1;
continue;
}
err = (*fn)(handle, bh);
if (!ret)
ret = err;
}
return ret;
}
/*
* To preserve ordering, it is essential that the hole instantiation and
* the data write be encapsulated in a single transaction. We cannot
* close off a transaction and start a new one between the ext3_get_block()
* and the commit_write(). So doing the journal_start at the start of
* prepare_write() is the right place.
*
* Also, this function can nest inside ext3_writepage() ->
* block_write_full_page(). In that case, we *know* that ext3_writepage()
* has generated enough buffer credits to do the whole page. So we won't
* block on the journal in that case, which is good, because the caller may
* be PF_MEMALLOC.
*
* By accident, ext3 can be reentered when a transaction is open via
* quota file writes. If we were to commit the transaction while thus
* reentered, there can be a deadlock - we would be holding a quota
* lock, and the commit would never complete if another thread had a
* transaction open and was blocking on the quota lock - a ranking
* violation.
*
* So what we do is to rely on the fact that journal_stop/journal_start
* will _not_ run commit under these circumstances because handle->h_ref
* is elevated. We'll still have enough credits for the tiny quotafile
* write.
*/
static int do_journal_get_write_access(handle_t *handle,
struct buffer_head *bh)
{
int dirty = buffer_dirty(bh);
int ret;
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
/*
* __block_prepare_write() could have dirtied some buffers. Clean
* the dirty bit as jbd2_journal_get_write_access() could complain
* otherwise about fs integrity issues. Setting of the dirty bit
* by __block_prepare_write() isn't a real problem here as we clear
* the bit before releasing a page lock and thus writeback cannot
* ever write the buffer.
*/
if (dirty)
clear_buffer_dirty(bh);
ret = ext3_journal_get_write_access(handle, bh);
if (!ret && dirty)
ret = ext3_journal_dirty_metadata(handle, bh);
return ret;
}
/*
* Truncate blocks that were not used by write. We have to truncate the
* pagecache as well so that corresponding buffers get properly unmapped.
*/
static void ext3_truncate_failed_write(struct inode *inode)
{
truncate_inode_pages(inode->i_mapping, inode->i_size);
ext3_truncate(inode);
}
/*
* Truncate blocks that were not used by direct IO write. We have to zero out
* the last file block as well because direct IO might have written to it.
*/
static void ext3_truncate_failed_direct_write(struct inode *inode)
{
ext3_block_truncate_page(inode, inode->i_size);
ext3_truncate(inode);
}
static int ext3_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = mapping->host;
int ret;
handle_t *handle;
int retries = 0;
struct page *page;
pgoff_t index;
unsigned from, to;
/* Reserve one block more for addition to orphan list in case
* we allocate blocks but write fails for some reason */
int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;
trace_ext3_write_begin(inode, pos, len, flags);
index = pos >> PAGE_CACHE_SHIFT;
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
retry:
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
*pagep = page;
handle = ext3_journal_start(inode, needed_blocks);
if (IS_ERR(handle)) {
unlock_page(page);
page_cache_release(page);
ret = PTR_ERR(handle);
goto out;
}
ret = __block_write_begin(page, pos, len, ext3_get_block);
if (ret)
goto write_begin_failed;
if (ext3_should_journal_data(inode)) {
ret = walk_page_buffers(handle, page_buffers(page),
from, to, NULL, do_journal_get_write_access);
}
write_begin_failed:
if (ret) {
/*
* block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold i_mutex.
*
* Add inode to orphan list in case we crash before truncate
* finishes. Do this only if ext3_can_truncate() agrees so
* that orphan processing code is happy.
*/
if (pos + len > inode->i_size && ext3_can_truncate(inode))
ext3_orphan_add(handle, inode);
ext3_journal_stop(handle);
unlock_page(page);
page_cache_release(page);
if (pos + len > inode->i_size)
ext3_truncate_failed_write(inode);
}
if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
goto retry;
out:
return ret;
}
int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
{
int err = journal_dirty_data(handle, bh);
if (err)
ext3_journal_abort_handle(__func__, __func__,
bh, handle, err);
return err;
}
/* For ordered writepage and write_end functions */
static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
{
/*
* Write could have mapped the buffer but it didn't copy the data in
* yet. So avoid filing such buffer into a transaction.
*/
if (buffer_mapped(bh) && buffer_uptodate(bh))
return ext3_journal_dirty_data(handle, bh);
return 0;
}
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
{
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
set_buffer_uptodate(bh);
return ext3_journal_dirty_metadata(handle, bh);
}
/*
* This is nasty and subtle: ext3_write_begin() could have allocated blocks
* for the whole page but later we failed to copy the data in. Update inode
* size according to what we managed to copy. The rest is going to be
* truncated in write_end function.
*/
static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
{
/* What matters to us is i_disksize. We don't write i_size anywhere */
if (pos + copied > inode->i_size)
i_size_write(inode, pos + copied);
if (pos + copied > EXT3_I(inode)->i_disksize) {
EXT3_I(inode)->i_disksize = pos + copied;
mark_inode_dirty(inode);
}
}
/*
* We need to pick up the new inode size which generic_commit_write gave us
* `file' can be NULL - eg, when called from page_symlink().
*
* ext3 never places buffers on inode->i_mapping->private_list. metadata
* buffers are managed internally.
*/
static int ext3_ordered_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext3_journal_current_handle();
struct inode *inode = file->f_mapping->host;
unsigned from, to;
int ret = 0, ret2;
trace_ext3_ordered_write_end(inode, pos, len, copied);
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + copied;
ret = walk_page_buffers(handle, page_buffers(page),
from, to, NULL, journal_dirty_data_fn);
if (ret == 0)
update_file_sizes(inode, pos, copied);
/*
* There may be allocated blocks outside of i_size because
* we failed to copy some data. Prepare for truncate.
*/
if (pos + len > inode->i_size && ext3_can_truncate(inode))
ext3_orphan_add(handle, inode);
ret2 = ext3_journal_stop(handle);
if (!ret)
ret = ret2;
unlock_page(page);
page_cache_release(page);
if (pos + len > inode->i_size)
ext3_truncate_failed_write(inode);
return ret ? ret : copied;
}
static int ext3_writeback_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext3_journal_current_handle();
struct inode *inode = file->f_mapping->host;
int ret;
trace_ext3_writeback_write_end(inode, pos, len, copied);
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
update_file_sizes(inode, pos, copied);
/*
* There may be allocated blocks outside of i_size because
* we failed to copy some data. Prepare for truncate.
*/
if (pos + len > inode->i_size && ext3_can_truncate(inode))
ext3_orphan_add(handle, inode);
ret = ext3_journal_stop(handle);
unlock_page(page);
page_cache_release(page);
if (pos + len > inode->i_size)
ext3_truncate_failed_write(inode);
return ret ? ret : copied;
}
static int ext3_journalled_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext3_journal_current_handle();
struct inode *inode = mapping->host;
struct ext3_inode_info *ei = EXT3_I(inode);
int ret = 0, ret2;
int partial = 0;
unsigned from, to;
trace_ext3_journalled_write_end(inode, pos, len, copied);
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
if (copied < len) {
if (!PageUptodate(page))
copied = 0;
page_zero_new_buffers(page, from + copied, to);
to = from + copied;
}
ret = walk_page_buffers(handle, page_buffers(page), from,
to, &partial, write_end_fn);
if (!partial)
SetPageUptodate(page);
if (pos + copied > inode->i_size)
i_size_write(inode, pos + copied);
/*
* There may be allocated blocks outside of i_size because
* we failed to copy some data. Prepare for truncate.
*/
if (pos + len > inode->i_size && ext3_can_truncate(inode))
ext3_orphan_add(handle, inode);
ext3_set_inode_state(inode, EXT3_STATE_JDATA);
atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
if (inode->i_size > ei->i_disksize) {
ei->i_disksize = inode->i_size;
ret2 = ext3_mark_inode_dirty(handle, inode);
if (!ret)
ret = ret2;
}
ret2 = ext3_journal_stop(handle);
if (!ret)
ret = ret2;
unlock_page(page);
page_cache_release(page);
if (pos + len > inode->i_size)
ext3_truncate_failed_write(inode);
return ret ? ret : copied;
}
/*
* bmap() is special. It gets used by applications such as lilo and by
* the swapper to find the on-disk block of a specific piece of data.
*
* Naturally, this is dangerous if the block concerned is still in the
* journal. If somebody makes a swapfile on an ext3 data-journaling
* filesystem and enables swap, then they may get a nasty shock when the
* data getting swapped to that swapfile suddenly gets overwritten by
* the original zero's written out previously to the journal and
* awaiting writeback in the kernel's buffer cache.
*
* So, if we see any bmap calls here on a modified, data-journaled file,
* take extra steps to flush any blocks which might be in the cache.
*/
static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
{
struct inode *inode = mapping->host;
journal_t *journal;
int err;
if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
/*
* This is a REALLY heavyweight approach, but the use of
* bmap on dirty files is expected to be extremely rare:
* only if we run lilo or swapon on a freshly made file
* do we expect this to happen.
*
* (bmap requires CAP_SYS_RAWIO so this does not
* represent an unprivileged user DOS attack --- we'd be
* in trouble if mortal users could trigger this path at
* will.)
*
* NB. EXT3_STATE_JDATA is not set on files other than
* regular files. If somebody wants to bmap a directory
* or symlink and gets confused because the buffer
* hasn't yet been flushed to disk, they deserve
* everything they get.
*/
ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
journal = EXT3_JOURNAL(inode);
journal_lock_updates(journal);
err = journal_flush(journal);
journal_unlock_updates(journal);
if (err)
return 0;
}
return generic_block_bmap(mapping,block,ext3_get_block);
}
static int bget_one(handle_t *handle, struct buffer_head *bh)
{
get_bh(bh);
return 0;
}
static int bput_one(handle_t *handle, struct buffer_head *bh)
{
put_bh(bh);
return 0;
}
static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
{
return !buffer_mapped(bh);
}
/*
* Note that we always start a transaction even if we're not journalling
* data. This is to preserve ordering: any hole instantiation within
* __block_write_full_page -> ext3_get_block() should be journalled
* along with the data so we don't crash and then get metadata which
* refers to old data.
*
* In all journalling modes block_write_full_page() will start the I/O.
*
* Problem:
*
* ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
* ext3_writepage()
*
* Similar for:
*
* ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
*
* Same applies to ext3_get_block(). We will deadlock on various things like
* lock_journal and i_truncate_mutex.
*
* Setting PF_MEMALLOC here doesn't work - too many internal memory
* allocations fail.
*
* 16May01: If we're reentered then journal_current_handle() will be
* non-zero. We simply *return*.
*
* 1 July 2001: @@@ FIXME:
* In journalled data mode, a data buffer may be metadata against the
* current transaction. But the same file is part of a shared mapping
* and someone does a writepage() on it.
*
* We will move the buffer onto the async_data list, but *after* it has
* been dirtied. So there's a small window where we have dirty data on
* BJ_Metadata.
*
* Note that this only applies to the last partial page in the file. The
* bit which block_write_full_page() uses prepare/commit for. (That's
* broken code anyway: it's wrong for msync()).
*
* It's a rare case: affects the final partial page, for journalled data
* where the file is subject to bith write() and writepage() in the same
* transction. To fix it we'll need a custom block_write_full_page().
* We'll probably need that anyway for journalling writepage() output.
*
* We don't honour synchronous mounts for writepage(). That would be
* disastrous. Any write() or metadata operation will sync the fs for
* us.
*
* AKPM2: if all the page's buffers are mapped to disk and !data=journal,
* we don't need to open a transaction here.
*/
static int ext3_ordered_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct buffer_head *page_bufs;
handle_t *handle = NULL;
int ret = 0;
int err;
J_ASSERT(PageLocked(page));
/*
* We don't want to warn for emergency remount. The condition is
* ordered to avoid dereferencing inode->i_sb in non-error case to
* avoid slow-downs.
*/
WARN_ON_ONCE(IS_RDONLY(inode) &&
!(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
/*
* We give up here if we're reentered, because it might be for a
* different filesystem.
*/
if (ext3_journal_current_handle())
goto out_fail;
trace_ext3_ordered_writepage(page);
if (!page_has_buffers(page)) {
create_empty_buffers(page, inode->i_sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
page_bufs = page_buffers(page);
} else {
page_bufs = page_buffers(page);
if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
NULL, buffer_unmapped)) {
/* Provide NULL get_block() to catch bugs if buffers
* weren't really mapped */
return block_write_full_page(page, NULL, wbc);
}
}
handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out_fail;
}
walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, bget_one);
ret = block_write_full_page(page, ext3_get_block, wbc);
/*
* The page can become unlocked at any point now, and
* truncate can then come in and change things. So we
* can't touch *page from now on. But *page_bufs is
* safe due to elevated refcount.
*/
/*
* And attach them to the current transaction. But only if
* block_write_full_page() succeeded. Otherwise they are unmapped,
* and generally junk.
*/
if (ret == 0) {
err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
NULL, journal_dirty_data_fn);
if (!ret)
ret = err;
}
walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, bput_one);
err = ext3_journal_stop(handle);
if (!ret)
ret = err;
return ret;
out_fail:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return ret;
}
static int ext3_writeback_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
handle_t *handle = NULL;
int ret = 0;
int err;
J_ASSERT(PageLocked(page));
/*
* We don't want to warn for emergency remount. The condition is
* ordered to avoid dereferencing inode->i_sb in non-error case to
* avoid slow-downs.
*/
WARN_ON_ONCE(IS_RDONLY(inode) &&
!(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
if (ext3_journal_current_handle())
goto out_fail;
trace_ext3_writeback_writepage(page);
if (page_has_buffers(page)) {
if (!walk_page_buffers(NULL, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
/* Provide NULL get_block() to catch bugs if buffers
* weren't really mapped */
return block_write_full_page(page, NULL, wbc);
}
}
handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out_fail;
}
ret = block_write_full_page(page, ext3_get_block, wbc);
err = ext3_journal_stop(handle);
if (!ret)
ret = err;
return ret;
out_fail:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return ret;
}
static int ext3_journalled_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
handle_t *handle = NULL;
int ret = 0;
int err;
J_ASSERT(PageLocked(page));
/*
* We don't want to warn for emergency remount. The condition is
* ordered to avoid dereferencing inode->i_sb in non-error case to
* avoid slow-downs.
*/
WARN_ON_ONCE(IS_RDONLY(inode) &&
!(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
if (ext3_journal_current_handle())
goto no_write;
trace_ext3_journalled_writepage(page);
handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto no_write;
}
if (!page_has_buffers(page) || PageChecked(page)) {
/*
* It's mmapped pagecache. Add buffers and journal it. There
* doesn't seem much point in redirtying the page here.
*/
ClearPageChecked(page);
ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
ext3_get_block);
if (ret != 0) {
ext3_journal_stop(handle);
goto out_unlock;
}
ret = walk_page_buffers(handle, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
err = walk_page_buffers(handle, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, write_end_fn);
if (ret == 0)
ret = err;
ext3_set_inode_state(inode, EXT3_STATE_JDATA);
atomic_set(&EXT3_I(inode)->i_datasync_tid,
handle->h_transaction->t_tid);
unlock_page(page);
} else {
/*
* It may be a page full of checkpoint-mode buffers. We don't
* really know unless we go poke around in the buffer_heads.
* But block_write_full_page will do the right thing.
*/
ret = block_write_full_page(page, ext3_get_block, wbc);
}
err = ext3_journal_stop(handle);
if (!ret)
ret = err;
out:
return ret;
no_write:
redirty_page_for_writepage(wbc, page);
out_unlock:
unlock_page(page);
goto out;
}
static int ext3_readpage(struct file *file, struct page *page)
{
trace_ext3_readpage(page);
return mpage_readpage(page, ext3_get_block);
}
static int
ext3_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
}
static void ext3_invalidatepage(struct page *page, unsigned int offset,
unsigned int length)
{
journal_t *journal = EXT3_JOURNAL(page->mapping->host);
trace_ext3_invalidatepage(page, offset);
/*
* If it's a full truncate we just forget about the pending dirtying
*/
if (offset == 0)
ClearPageChecked(page);
journal_invalidatepage(journal, page, offset);
}
static int ext3_releasepage(struct page *page, gfp_t wait)
{
journal_t *journal = EXT3_JOURNAL(page->mapping->host);
trace_ext3_releasepage(page);
WARN_ON(PageChecked(page));
if (!page_has_buffers(page))
return 0;
return journal_try_to_free_buffers(journal, page, wait);
}
/*
* If the O_DIRECT write will extend the file then add this inode to the
* orphan list. So recovery will truncate it back to the original size
* if the machine crashes during the write.
*
* If the O_DIRECT write is intantiating holes inside i_size and the machine
* crashes then stale disk data _may_ be exposed inside the file. But current
* VFS code falls back into buffered path in that case so we are safe.
*/
static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset,
unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct ext3_inode_info *ei = EXT3_I(inode);
handle_t *handle;
ssize_t ret;
int orphan = 0;
size_t count = iov_length(iov, nr_segs);
int retries = 0;
trace_ext3_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
if (rw == WRITE) {
loff_t final_size = offset + count;
if (final_size > inode->i_size) {
/* Credits for sb + inode write */
handle = ext3_journal_start(inode, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext3_orphan_add(handle, inode);
if (ret) {
ext3_journal_stop(handle);
goto out;
}
orphan = 1;
ei->i_disksize = inode->i_size;
ext3_journal_stop(handle);
}
}
retry:
ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
ext3_get_block);
/*
* In case of error extending write may have instantiated a few
* blocks outside i_size. Trim these off again.
*/
if (unlikely((rw & WRITE) && ret < 0)) {
loff_t isize = i_size_read(inode);
loff_t end = offset + iov_length(iov, nr_segs);
if (end > isize)
ext3_truncate_failed_direct_write(inode);
}
if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
goto retry;
if (orphan) {
int err;
/* Credits for sb + inode write */
handle = ext3_journal_start(inode, 2);
if (IS_ERR(handle)) {
/* This is really bad luck. We've written the data
* but cannot extend i_size. Truncate allocated blocks
* and pretend the write failed... */
ext3_truncate_failed_direct_write(inode);
ret = PTR_ERR(handle);
goto out;
}
if (inode->i_nlink)
ext3_orphan_del(handle, inode);
if (ret > 0) {
loff_t end = offset + ret;
if (end > inode->i_size) {
ei->i_disksize = end;
i_size_write(inode, end);
/*
* We're going to return a positive `ret'
* here due to non-zero-length I/O, so there's
* no way of reporting error returns from
* ext3_mark_inode_dirty() to userspace. So
* ignore it.
*/
ext3_mark_inode_dirty(handle, inode);
}
}
err = ext3_journal_stop(handle);
if (ret == 0)
ret = err;
}
out:
trace_ext3_direct_IO_exit(inode, offset,
iov_length(iov, nr_segs), rw, ret);
return ret;
}
/*
* Pages can be marked dirty completely asynchronously from ext3's journalling
* activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
* much here because ->set_page_dirty is called under VFS locks. The page is
* not necessarily locked.
*
* We cannot just dirty the page and leave attached buffers clean, because the
* buffers' dirty state is "definitive". We cannot just set the buffers dirty
* or jbddirty because all the journalling code will explode.
*
* So what we do is to mark the page "pending dirty" and next time writepage
* is called, propagate that into the buffers appropriately.
*/
static int ext3_journalled_set_page_dirty(struct page *page)
{
SetPageChecked(page);
return __set_page_dirty_nobuffers(page);
}
static const struct address_space_operations ext3_ordered_aops = {
.readpage = ext3_readpage,
.readpages = ext3_readpages,
.writepage = ext3_ordered_writepage,
.write_begin = ext3_write_begin,
.write_end = ext3_ordered_write_end,
.bmap = ext3_bmap,
.invalidatepage = ext3_invalidatepage,
.releasepage = ext3_releasepage,
.direct_IO = ext3_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext3_writeback_aops = {
.readpage = ext3_readpage,
.readpages = ext3_readpages,
.writepage = ext3_writeback_writepage,
.write_begin = ext3_write_begin,
.write_end = ext3_writeback_write_end,
.bmap = ext3_bmap,
.invalidatepage = ext3_invalidatepage,
.releasepage = ext3_releasepage,
.direct_IO = ext3_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext3_journalled_aops = {
.readpage = ext3_readpage,
.readpages = ext3_readpages,
.writepage = ext3_journalled_writepage,
.write_begin = ext3_write_begin,
.write_end = ext3_journalled_write_end,
.set_page_dirty = ext3_journalled_set_page_dirty,
.bmap = ext3_bmap,
.invalidatepage = ext3_invalidatepage,
.releasepage = ext3_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
void ext3_set_aops(struct inode *inode)
{
if (ext3_should_order_data(inode))
inode->i_mapping->a_ops = &ext3_ordered_aops;
else if (ext3_should_writeback_data(inode))
inode->i_mapping->a_ops = &ext3_writeback_aops;
else
inode->i_mapping->a_ops = &ext3_journalled_aops;
}
/*
* ext3_block_truncate_page() zeroes out a mapping from file offset `from'
* up to the end of the block which corresponds to `from'.
* This required during truncate. We need to physically zero the tail end
* of that block so it doesn't yield old data if the file is later grown.
*/
static int ext3_block_truncate_page(struct inode *inode, loff_t from)
{
ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE - 1);
unsigned blocksize, iblock, length, pos;
struct page *page;
handle_t *handle = NULL;
struct buffer_head *bh;
int err = 0;
/* Truncated on block boundary - nothing to do */
blocksize = inode->i_sb->s_blocksize;
if ((from & (blocksize - 1)) == 0)
return 0;
page = grab_cache_page(inode->i_mapping, index);
if (!page)
return -ENOMEM;
length = blocksize - (offset & (blocksize - 1));
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
/* Find the buffer that contains "offset" */
bh = page_buffers(page);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
iblock++;
pos += blocksize;
}
err = 0;
if (buffer_freed(bh)) {
BUFFER_TRACE(bh, "freed: skip");
goto unlock;
}
if (!buffer_mapped(bh)) {
BUFFER_TRACE(bh, "unmapped");
ext3_get_block(inode, iblock, bh, 0);
/* unmapped? It's a hole - nothing to do */
if (!buffer_mapped(bh)) {
BUFFER_TRACE(bh, "still unmapped");
goto unlock;
}
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (PageUptodate(page))
set_buffer_uptodate(bh);
if (!bh_uptodate_or_lock(bh)) {
err = bh_submit_read(bh);
/* Uhhuh. Read error. Complain and punt. */
if (err)
goto unlock;
}
/* data=writeback mode doesn't need transaction to zero-out data */
if (!ext3_should_writeback_data(inode)) {
/* We journal at most one block */
handle = ext3_journal_start(inode, 1);
if (IS_ERR(handle)) {
clear_highpage(page);
flush_dcache_page(page);
err = PTR_ERR(handle);
goto unlock;
}
}
if (ext3_should_journal_data(inode)) {
BUFFER_TRACE(bh, "get write access");
err = ext3_journal_get_write_access(handle, bh);
if (err)
goto stop;
}
zero_user(page, offset, length);
BUFFER_TRACE(bh, "zeroed end of block");
err = 0;
if (ext3_should_journal_data(inode)) {
err = ext3_journal_dirty_metadata(handle, bh);
} else {
if (ext3_should_order_data(inode))
err = ext3_journal_dirty_data(handle, bh);
mark_buffer_dirty(bh);
}
stop:
if (handle)
ext3_journal_stop(handle);
unlock:
unlock_page(page);
page_cache_release(page);
return err;
}
/*
* Probably it should be a library function... search for first non-zero word
* or memcmp with zero_page, whatever is better for particular architecture.
* Linus?
*/
static inline int all_zeroes(__le32 *p, __le32 *q)
{
while (p < q)
if (*p++)
return 0;
return 1;
}
/**
* ext3_find_shared - find the indirect blocks for partial truncation.
* @inode: inode in question
* @depth: depth of the affected branch
* @offsets: offsets of pointers in that branch (see ext3_block_to_path)
* @chain: place to store the pointers to partial indirect blocks
* @top: place to the (detached) top of branch
*
* This is a helper function used by ext3_truncate().
*
* When we do truncate() we may have to clean the ends of several
* indirect blocks but leave the blocks themselves alive. Block is
* partially truncated if some data below the new i_size is referred
* from it (and it is on the path to the first completely truncated
* data block, indeed). We have to free the top of that path along
* with everything to the right of the path. Since no allocation
* past the truncation point is possible until ext3_truncate()
* finishes, we may safely do the latter, but top of branch may
* require special attention - pageout below the truncation point
* might try to populate it.
*
* We atomically detach the top of branch from the tree, store the
* block number of its root in *@top, pointers to buffer_heads of
* partially truncated blocks - in @chain[].bh and pointers to
* their last elements that should not be removed - in
* @chain[].p. Return value is the pointer to last filled element
* of @chain.
*
* The work left to caller to do the actual freeing of subtrees:
* a) free the subtree starting from *@top
* b) free the subtrees whose roots are stored in
* (@chain[i].p+1 .. end of @chain[i].bh->b_data)
* c) free the subtrees growing from the inode past the @chain[0].
* (no partially truncated stuff there). */
static Indirect *ext3_find_shared(struct inode *inode, int depth,
int offsets[4], Indirect chain[4], __le32 *top)
{
Indirect *partial, *p;
int k, err;
*top = 0;
/* Make k index the deepest non-null offset + 1 */
for (k = depth; k > 1 && !offsets[k-1]; k--)
;
partial = ext3_get_branch(inode, k, offsets, chain, &err);
/* Writer: pointers */
if (!partial)
partial = chain + k-1;
/*
* If the branch acquired continuation since we've looked at it -
* fine, it should all survive and (new) top doesn't belong to us.
*/
if (!partial->key && *partial->p)
/* Writer: end */
goto no_top;
for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
;
/*
* OK, we've found the last block that must survive. The rest of our
* branch should be detached before unlocking. However, if that rest
* of branch is all ours and does not grow immediately from the inode
* it's easier to cheat and just decrement partial->p.
*/
if (p == chain + k - 1 && p > chain) {
p->p--;
} else {
*top = *p->p;
/* Nope, don't do this in ext3. Must leave the tree intact */
#if 0
*p->p = 0;
#endif
}
/* Writer: end */
while(partial > p) {
brelse(partial->bh);
partial--;
}
no_top:
return partial;
}
/*
* Zero a number of block pointers in either an inode or an indirect block.
* If we restart the transaction we must again get write access to the
* indirect block for further modification.
*
* We release `count' blocks on disk, but (last - first) may be greater
* than `count' because there can be holes in there.
*/
static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext3_fsblk_t block_to_free,
unsigned long count, __le32 *first, __le32 *last)
{
__le32 *p;
if (try_to_extend_transaction(handle, inode)) {
if (bh) {
BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
if (ext3_journal_dirty_metadata(handle, bh))
return;
}
ext3_mark_inode_dirty(handle, inode);
truncate_restart_transaction(handle, inode);
if (bh) {
BUFFER_TRACE(bh, "retaking write access");
if (ext3_journal_get_write_access(handle, bh))
return;
}
}
/*
* Any buffers which are on the journal will be in memory. We find
* them on the hash table so journal_revoke() will run journal_forget()
* on them. We've already detached each block from the file, so
* bforget() in journal_forget() should be safe.
*
* AKPM: turn on bforget in journal_forget()!!!
*/
for (p = first; p < last; p++) {
u32 nr = le32_to_cpu(*p);
if (nr) {
struct buffer_head *bh;
*p = 0;
bh = sb_find_get_block(inode->i_sb, nr);
ext3_forget(handle, 0, inode, bh, nr);
}
}
ext3_free_blocks(handle, inode, block_to_free, count);
}
/**
* ext3_free_data - free a list of data blocks
* @handle: handle for this transaction
* @inode: inode we are dealing with
* @this_bh: indirect buffer_head which contains *@first and *@last
* @first: array of block numbers
* @last: points immediately past the end of array
*
* We are freeing all blocks referred from that array (numbers are stored as
* little-endian 32-bit) and updating @inode->i_blocks appropriately.
*
* We accumulate contiguous runs of blocks to free. Conveniently, if these
* blocks are contiguous then releasing them at one time will only affect one
* or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
* actually use a lot of journal space.
*
* @this_bh will be %NULL if @first and @last point into the inode's direct
* block pointers.
*/
static void ext3_free_data(handle_t *handle, struct inode *inode,
struct buffer_head *this_bh,
__le32 *first, __le32 *last)
{
ext3_fsblk_t block_to_free = 0; /* Starting block # of a run */
unsigned long count = 0; /* Number of blocks in the run */
__le32 *block_to_free_p = NULL; /* Pointer into inode/ind
corresponding to
block_to_free */
ext3_fsblk_t nr; /* Current block # */
__le32 *p; /* Pointer into inode/ind
for current block */
int err;
if (this_bh) { /* For indirect block */
BUFFER_TRACE(this_bh, "get_write_access");
err = ext3_journal_get_write_access(handle, this_bh);
/* Important: if we can't update the indirect pointers
* to the blocks, we can't free them. */
if (err)
return;
}
for (p = first; p < last; p++) {
nr = le32_to_cpu(*p);
if (nr) {
/* accumulate blocks to free if they're contiguous */
if (count == 0) {
block_to_free = nr;
block_to_free_p = p;
count = 1;
} else if (nr == block_to_free + count) {
count++;
} else {
ext3_clear_blocks(handle, inode, this_bh,
block_to_free,
count, block_to_free_p, p);
block_to_free = nr;
block_to_free_p = p;
count = 1;
}
}
}
if (count > 0)
ext3_clear_blocks(handle, inode, this_bh, block_to_free,
count, block_to_free_p, p);
if (this_bh) {
BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
/*
* The buffer head should have an attached journal head at this
* point. However, if the data is corrupted and an indirect
* block pointed to itself, it would have been detached when
* the block was cleared. Check for this instead of OOPSing.
*/
if (bh2jh(this_bh))
ext3_journal_dirty_metadata(handle, this_bh);
else
ext3_error(inode->i_sb, "ext3_free_data",
"circular indirect block detected, "
"inode=%lu, block=%llu",
inode->i_ino,
(unsigned long long)this_bh->b_blocknr);
}
}
/**
* ext3_free_branches - free an array of branches
* @handle: JBD handle for this transaction
* @inode: inode we are dealing with
* @parent_bh: the buffer_head which contains *@first and *@last
* @first: array of block numbers
* @last: pointer immediately past the end of array
* @depth: depth of the branches to free
*
* We are freeing all blocks referred from these branches (numbers are
* stored as little-endian 32-bit) and updating @inode->i_blocks
* appropriately.
*/
static void ext3_free_branches(handle_t *handle, struct inode *inode,
struct buffer_head *parent_bh,
__le32 *first, __le32 *last, int depth)
{
ext3_fsblk_t nr;
__le32 *p;
if (is_handle_aborted(handle))
return;
if (depth--) {
struct buffer_head *bh;
int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
p = last;
while (--p >= first) {
nr = le32_to_cpu(*p);
if (!nr)
continue; /* A hole */
/* Go read the buffer for the next level down */
bh = sb_bread(inode->i_sb, nr);
/*
* A read failure? Report error and clear slot
* (should be rare).
*/
if (!bh) {
ext3_error(inode->i_sb, "ext3_free_branches",
"Read failure, inode=%lu, block="E3FSBLK,
inode->i_ino, nr);
continue;
}
/* This zaps the entire block. Bottom up. */
BUFFER_TRACE(bh, "free child branches");
ext3_free_branches(handle, inode, bh,
(__le32*)bh->b_data,
(__le32*)bh->b_data + addr_per_block,
depth);
/*
* Everything below this this pointer has been
* released. Now let this top-of-subtree go.
*
* We want the freeing of this indirect block to be
* atomic in the journal with the updating of the
* bitmap block which owns it. So make some room in
* the journal.
*
* We zero the parent pointer *after* freeing its
* pointee in the bitmaps, so if extend_transaction()
* for some reason fails to put the bitmap changes and
* the release into the same transaction, recovery
* will merely complain about releasing a free block,
* rather than leaking blocks.
*/
if (is_handle_aborted(handle))
return;
if (try_to_extend_transaction(handle, inode)) {
ext3_mark_inode_dirty(handle, inode);
truncate_restart_transaction(handle, inode);
}
/*
* We've probably journalled the indirect block several
* times during the truncate. But it's no longer
* needed and we now drop it from the transaction via
* journal_revoke().
*
* That's easy if it's exclusively part of this
* transaction. But if it's part of the committing
* transaction then journal_forget() will simply
* brelse() it. That means that if the underlying
* block is reallocated in ext3_get_block(),
* unmap_underlying_metadata() will find this block
* and will try to get rid of it. damn, damn. Thus
* we don't allow a block to be reallocated until
* a transaction freeing it has fully committed.
*
* We also have to make sure journal replay after a
* crash does not overwrite non-journaled data blocks
* with old metadata when the block got reallocated for
* data. Thus we have to store a revoke record for a
* block in the same transaction in which we free the
* block.
*/
ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
ext3_free_blocks(handle, inode, nr, 1);
if (parent_bh) {
/*
* The block which we have just freed is
* pointed to by an indirect block: journal it
*/
BUFFER_TRACE(parent_bh, "get_write_access");
if (!ext3_journal_get_write_access(handle,
parent_bh)){
*p = 0;
BUFFER_TRACE(parent_bh,
"call ext3_journal_dirty_metadata");
ext3_journal_dirty_metadata(handle,
parent_bh);
}
}
}
} else {
/* We have reached the bottom of the tree. */
BUFFER_TRACE(parent_bh, "free data blocks");
ext3_free_data(handle, inode, parent_bh, first, last);
}
}
int ext3_can_truncate(struct inode *inode)
{
if (S_ISREG(inode->i_mode))
return 1;
if (S_ISDIR(inode->i_mode))
return 1;
if (S_ISLNK(inode->i_mode))
return !ext3_inode_is_fast_symlink(inode);
return 0;
}
/*
* ext3_truncate()
*
* We block out ext3_get_block() block instantiations across the entire
* transaction, and VFS/VM ensures that ext3_truncate() cannot run
* simultaneously on behalf of the same inode.
*
* As we work through the truncate and commit bits of it to the journal there
* is one core, guiding principle: the file's tree must always be consistent on
* disk. We must be able to restart the truncate after a crash.
*
* The file's tree may be transiently inconsistent in memory (although it
* probably isn't), but whenever we close off and commit a journal transaction,
* the contents of (the filesystem + the journal) must be consistent and
* restartable. It's pretty simple, really: bottom up, right to left (although
* left-to-right works OK too).
*
* Note that at recovery time, journal replay occurs *before* the restart of
* truncate against the orphan inode list.
*
* The committed inode has the new, desired i_size (which is the same as
* i_disksize in this case). After a crash, ext3_orphan_cleanup() will see
* that this inode's truncate did not complete and it will again call
* ext3_truncate() to have another go. So there will be instantiated blocks
* to the right of the truncation point in a crashed ext3 filesystem. But
* that's fine - as long as they are linked from the inode, the post-crash
* ext3_truncate() run will find them and release them.
*/
void ext3_truncate(struct inode *inode)
{
handle_t *handle;
struct ext3_inode_info *ei = EXT3_I(inode);
__le32 *i_data = ei->i_data;
int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
int offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n;
long last_block;
unsigned blocksize = inode->i_sb->s_blocksize;
trace_ext3_truncate_enter(inode);
if (!ext3_can_truncate(inode))
goto out_notrans;
if (inode->i_size == 0 && ext3_should_writeback_data(inode))
ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
handle = start_transaction(inode);
if (IS_ERR(handle))
goto out_notrans;
last_block = (inode->i_size + blocksize-1)
>> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
n = ext3_block_to_path(inode, last_block, offsets, NULL);
if (n == 0)
goto out_stop; /* error */
/*
* OK. This truncate is going to happen. We add the inode to the
* orphan list, so that if this truncate spans multiple transactions,
* and we crash, we will resume the truncate when the filesystem
* recovers. It also marks the inode dirty, to catch the new size.
*
* Implication: the file must always be in a sane, consistent
* truncatable state while each transaction commits.
*/
if (ext3_orphan_add(handle, inode))
goto out_stop;
/*
* The orphan list entry will now protect us from any crash which
* occurs before the truncate completes, so it is now safe to propagate
* the new, shorter inode size (held for now in i_size) into the
* on-disk inode. We do this via i_disksize, which is the value which
* ext3 *really* writes onto the disk inode.
*/
ei->i_disksize = inode->i_size;
/*
* From here we block out all ext3_get_block() callers who want to
* modify the block allocation tree.
*/
mutex_lock(&ei->truncate_mutex);
if (n == 1) { /* direct blocks */
ext3_free_data(handle, inode, NULL, i_data+offsets[0],
i_data + EXT3_NDIR_BLOCKS);
goto do_indirects;
}
partial = ext3_find_shared(inode, n, offsets, chain, &nr);
/* Kill the top of shared branch (not detached) */
if (nr) {
if (partial == chain) {
/* Shared branch grows from the inode */
ext3_free_branches(handle, inode, NULL,
&nr, &nr+1, (chain+n-1) - partial);
*partial->p = 0;
/*
* We mark the inode dirty prior to restart,
* and prior to stop. No need for it here.
*/
} else {
/* Shared branch grows from an indirect block */
ext3_free_branches(handle, inode, partial->bh,
partial->p,
partial->p+1, (chain+n-1) - partial);
}
}
/* Clear the ends of indirect blocks on the shared branch */
while (partial > chain) {
ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
(__le32*)partial->bh->b_data+addr_per_block,
(chain+n-1) - partial);
BUFFER_TRACE(partial->bh, "call brelse");
brelse (partial->bh);
partial--;
}
do_indirects:
/* Kill the remaining (whole) subtrees */
switch (offsets[0]) {
default:
nr = i_data[EXT3_IND_BLOCK];
if (nr) {
ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
i_data[EXT3_IND_BLOCK] = 0;
}
case EXT3_IND_BLOCK:
nr = i_data[EXT3_DIND_BLOCK];
if (nr) {
ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
i_data[EXT3_DIND_BLOCK] = 0;
}
case EXT3_DIND_BLOCK:
nr = i_data[EXT3_TIND_BLOCK];
if (nr) {
ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
i_data[EXT3_TIND_BLOCK] = 0;
}
case EXT3_TIND_BLOCK:
;
}
ext3_discard_reservation(inode);
mutex_unlock(&ei->truncate_mutex);
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
ext3_mark_inode_dirty(handle, inode);
/*
* In a multi-transaction truncate, we only make the final transaction
* synchronous
*/
if (IS_SYNC(inode))
handle->h_sync = 1;
out_stop:
/*
* 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
* ext3_evict_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext3_orphan_del(handle, inode);
ext3_journal_stop(handle);
trace_ext3_truncate_exit(inode);
return;
out_notrans:
/*
* Delete the inode from orphan list so that it doesn't stay there
* forever and trigger assertion on umount.
*/
if (inode->i_nlink)
ext3_orphan_del(NULL, inode);
trace_ext3_truncate_exit(inode);
}
static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
unsigned long ino, struct ext3_iloc *iloc)
{
unsigned long block_group;
unsigned long offset;
ext3_fsblk_t block;
struct ext3_group_desc *gdp;
if (!ext3_valid_inum(sb, ino)) {
/*
* This error is already checked for in namei.c unless we are
* looking at an NFS filehandle, in which case no error
* report is needed
*/
return 0;
}
block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
gdp = ext3_get_group_desc(sb, block_group, NULL);
if (!gdp)
return 0;
/*
* Figure out the offset within the block group inode table
*/
offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
EXT3_INODE_SIZE(sb);
block = le32_to_cpu(gdp->bg_inode_table) +
(offset >> EXT3_BLOCK_SIZE_BITS(sb));
iloc->block_group = block_group;
iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
return block;
}
/*
* ext3_get_inode_loc returns with an extra refcount against the inode's
* underlying buffer_head on success. If 'in_mem' is true, we have all
* data in memory that is needed to recreate the on-disk version of this
* inode.
*/
static int __ext3_get_inode_loc(struct inode *inode,
struct ext3_iloc *iloc, int in_mem)
{
ext3_fsblk_t block;
struct buffer_head *bh;
block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
if (!block)
return -EIO;
bh = sb_getblk(inode->i_sb, block);
if (unlikely(!bh)) {
ext3_error (inode->i_sb, "ext3_get_inode_loc",
"unable to read inode block - "
"inode=%lu, block="E3FSBLK,
inode->i_ino, block);
return -ENOMEM;
}
if (!buffer_uptodate(bh)) {
lock_buffer(bh);
/*
* If the buffer has the write error flag, we have failed
* to write out another inode in the same block. In this
* case, we don't have to read the block because we may
* read the old inode data successfully.
*/
if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
set_buffer_uptodate(bh);
if (buffer_uptodate(bh)) {
/* someone brought it uptodate while we waited */
unlock_buffer(bh);
goto has_buffer;
}
/*
* If we have all information of the inode in memory and this
* is the only valid inode in the block, we need not read the
* block.
*/
if (in_mem) {
struct buffer_head *bitmap_bh;
struct ext3_group_desc *desc;
int inodes_per_buffer;
int inode_offset, i;
int block_group;
int start;
block_group = (inode->i_ino - 1) /
EXT3_INODES_PER_GROUP(inode->i_sb);
inodes_per_buffer = bh->b_size /
EXT3_INODE_SIZE(inode->i_sb);
inode_offset = ((inode->i_ino - 1) %
EXT3_INODES_PER_GROUP(inode->i_sb));
start = inode_offset & ~(inodes_per_buffer - 1);
/* Is the inode bitmap in cache? */
desc = ext3_get_group_desc(inode->i_sb,
block_group, NULL);
if (!desc)
goto make_io;
bitmap_bh = sb_getblk(inode->i_sb,
le32_to_cpu(desc->bg_inode_bitmap));
if (unlikely(!bitmap_bh))
goto make_io;
/*
* If the inode bitmap isn't in cache then the
* optimisation may end up performing two reads instead
* of one, so skip it.
*/
if (!buffer_uptodate(bitmap_bh)) {
brelse(bitmap_bh);
goto make_io;
}
for (i = start; i < start + inodes_per_buffer; i++) {
if (i == inode_offset)
continue;
if (ext3_test_bit(i, bitmap_bh->b_data))
break;
}
brelse(bitmap_bh);
if (i == start + inodes_per_buffer) {
/* all other inodes are free, so skip I/O */
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
unlock_buffer(bh);
goto has_buffer;
}
}
make_io:
/*
* There are other valid inodes in the buffer, this inode
* has in-inode xattrs, or we don't have this inode in memory.
* Read the block from disk.
*/
trace_ext3_load_inode(inode);
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
ext3_error(inode->i_sb, "ext3_get_inode_loc",
"unable to read inode block - "
"inode=%lu, block="E3FSBLK,
inode->i_ino, block);
brelse(bh);
return -EIO;
}
}
has_buffer:
iloc->bh = bh;
return 0;
}
int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
{
/* We have all inode data except xattrs in memory here. */
return __ext3_get_inode_loc(inode, iloc,
!ext3_test_inode_state(inode, EXT3_STATE_XATTR));
}
void ext3_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT3_I(inode)->i_flags;
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT3_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT3_APPEND_FL)
inode->i_flags |= S_APPEND;
if (flags & EXT3_IMMUTABLE_FL)
inode->i_flags |= S_IMMUTABLE;
if (flags & EXT3_NOATIME_FL)
inode->i_flags |= S_NOATIME;
if (flags & EXT3_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
}
/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */