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aha/fs/ext3/inode.c
Dmitry Monakhov c459001fa4 ext3: quota macros cleanup [V2] 
Currently all quota block reservation macros contains hardcoded "2"
aka MAXQUOTAS value. This is no good because in some places it is not
obvious to understand what does this digit represent. Let's introduce
new macro with self descriptive name.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-12-23 13:33:54 +01:00

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/*
* 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/module.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/ext3_jbd.h>
#include <linux/jbd.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include <linux/fiemap.h>
#include <linux/namei.h>
#include "xattr.h"
#include "acl.h"
static int ext3_writepage_trans_blocks(struct inode *inode);
/*
* 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();
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 the last iput() if i_nlink is zero.
*/
void ext3_delete_inode (struct inode * inode)
{
handle_t *handle;
truncate_inode_pages(&inode->i_data, 0);
if (is_bad_inode(inode))
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 which ext3_truncate created.
* AKPM: I think this can be inside the above `if'.
* Note that ext3_orphan_del() has to be able to cope with the
* deletion of a non-existent orphan - this is because we don't
* know if ext3_truncate() actually created an orphan record.
* (Well, we could do this if we need to, but heck - it works)
*/
ext3_orphan_del(handle, inode);
EXT3_I(inode)->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 do the required in-core inode clear. */
clear_inode(inode);
else
ext3_free_inode(handle, inode);
ext3_journal_stop(handle);
return;
no_delete:
clear_inode(inode); /* We must guarantee clearing of 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
* @indirect_blks: the number of blocks need to allocate for indirect
* blocks
*
* @new_blocks: on return it will store the new block numbers for
* the indirect blocks(if needed) and the first direct block,
* @blks: on return it will store the total number of allocated
* direct blocks
*/
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.
* @inode: owner
* @indirect_blks: number of allocated indirect blocks
* @blks: number of allocated direct blocks
* @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]);
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.
* @inode: owner
* @block: (logical) number of block we are adding
* @chain: chain of indirect blocks (with a missing link - see
* ext3_alloc_branch)
* @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);
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 */
inode->i_ctime = CURRENT_TIME_SEC;
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;
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;
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);
/*
* Block out ext3_truncate while we alter the tree
*/
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:
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) {
if (err > 1)
WARN_ON(1);
err = 0;
}
*errp = err;
if (!err && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
if (!bh) {
*errp = -EIO;
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 (buffer_uptodate(bh))
return bh;
ll_rw_block(READ_META, 1, &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)
{
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
return ext3_journal_get_write_access(handle, bh);
}
/*
* 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);
}
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;
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(file, mapping, pos, len, flags, pagep, fsdata,
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;
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;
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;
int ret = 0, ret2;
int partial = 0;
unsigned from, to;
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_I(inode)->i_state |= EXT3_STATE_JDATA;
if (inode->i_size > EXT3_I(inode)->i_disksize) {
EXT3_I(inode)->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_I(inode)->i_state & 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_I(inode)->i_state &= ~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 give up here if we're reentered, because it might be for a
* different filesystem.
*/
if (ext3_journal_current_handle())
goto out_fail;
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;
if (ext3_journal_current_handle())
goto out_fail;
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;
}
if (test_opt(inode->i_sb, NOBH) && ext3_should_writeback_data(inode))
ret = nobh_writepage(page, ext3_get_block, wbc);
else
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;
if (ext3_journal_current_handle())
goto no_write;
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_prepare_write(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_I(inode)->i_state |= EXT3_STATE_JDATA;
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)
{
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 long offset)
{
journal_t *journal = EXT3_JOURNAL(page->mapping->host);
/*
* 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);
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;
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, inode->i_sb->s_bdev, iov,
offset, nr_segs,
ext3_get_block, NULL);
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. Bail out and pretend
* the write failed... */
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:
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,
.sync_page = block_sync_page,
.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,
.sync_page = block_sync_page,
.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,
.sync_page = block_sync_page,
.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(handle_t *handle, struct page *page,
struct address_space *mapping, loff_t from)
{
ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, iblock, length, pos;
struct inode *inode = mapping->host;
struct buffer_head *bh;
int err = 0;
blocksize = inode->i_sb->s_blocksize;
length = blocksize - (offset & (blocksize - 1));
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
/*
* For "nobh" option, we can only work if we don't need to
* read-in the page - otherwise we create buffers to do the IO.
*/
if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
ext3_should_writeback_data(inode) && PageUptodate(page)) {
zero_user(page, offset, length);
set_page_dirty(page);
goto unlock;
}
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 (!buffer_uptodate(bh)) {
err = -EIO;
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
/* Uhhuh. Read error. Complain and punt. */
if (!buffer_uptodate(bh))
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 unlock;
}
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);
}
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 refered
* 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");
ext3_journal_dirty_metadata(handle, bh);
}
ext3_mark_inode_dirty(handle, inode);
truncate_restart_transaction(handle, inode);
if (bh) {
BUFFER_TRACE(bh, "retaking write access");
ext3_journal_get_write_access(handle, bh);
}
}
/*
* 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 refered 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 refered 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);
/*
* 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.
*
* If this block has already been committed to the
* journal, a revoke record will be written. And
* revoke records must be emitted *before* clearing
* this block's bit in the bitmaps.
*/
ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
/*
* 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);
}
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 (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return 0;
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 commmit 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);
struct address_space *mapping = inode->i_mapping;
int offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n;
long last_block;
unsigned blocksize = inode->i_sb->s_blocksize;
struct page *page;
if (!ext3_can_truncate(inode))
goto out_notrans;
if (inode->i_size == 0 && ext3_should_writeback_data(inode))
ei->i_state |= EXT3_STATE_FLUSH_ON_CLOSE;
/*
* We have to lock the EOF page here, because lock_page() nests
* outside journal_start().
*/
if ((inode->i_size & (blocksize - 1)) == 0) {
/* Block boundary? Nothing to do */
page = NULL;
} else {
page = grab_cache_page(mapping,
inode->i_size >> PAGE_CACHE_SHIFT);
if (!page)
goto out_notrans;
}
handle = start_transaction(inode);
if (IS_ERR(handle)) {
if (page) {
clear_highpage(page);
flush_dcache_page(page);
unlock_page(page);
page_cache_release(page);
}
goto out_notrans;
}
last_block = (inode->i_size + blocksize-1)
>> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
if (page)
ext3_block_truncate_page(handle, page, mapping, inode->i_size);
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 */
BUFFER_TRACE(partial->bh, "get_write_access");
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_delete_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);
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);
}
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 (!bh) {
ext3_error (inode->i_sb, "ext3_get_inode_loc",
"unable to read inode block - "
"inode=%lu, block="E3FSBLK,
inode->i_ino, block);
return -EIO;
}
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 (!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.
*/
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ_META, 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_I(inode)->i_state & 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 */
void ext3_get_inode_flags(struct ext3_inode_info *ei)
{
unsigned int flags = ei->vfs_inode.i_flags;
ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
if (flags & S_SYNC)
ei->i_flags |= EXT3_SYNC_FL;
if (flags & S_APPEND)
ei->i_flags |= EXT3_APPEND_FL;
if (flags & S_IMMUTABLE)
ei->i_flags |= EXT3_IMMUTABLE_FL;
if (flags & S_NOATIME)
ei->i_flags |= EXT3_NOATIME_FL;
if (flags & S_DIRSYNC)
ei->i_flags |= EXT3_DIRSYNC_FL;
}
struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
{
struct ext3_iloc iloc;
struct ext3_inode *raw_inode;
struct ext3_inode_info *ei;
struct buffer_head *bh;
struct inode *inode;
journal_t *journal = EXT3_SB(sb)->s_journal;
transaction_t *transaction;
long ret;
int block;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
ei = EXT3_I(inode);
ei->i_block_alloc_info = NULL;
ret = __ext3_get_inode_loc(inode, &iloc, 0);
if (ret < 0)
goto bad_inode;
bh = iloc.bh;
raw_inode = ext3_raw_inode(&iloc);
inode->i_mode = le16_to_cpu(raw_inode->i_mode);
inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
if(!(test_opt (inode->i_sb, NO_UID32))) {
inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
}
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
inode->i_size = le32_to_cpu(raw_inode->i_size);
inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
ei->i_state = 0;
ei->i_dir_start_lookup = 0;
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
/* We now have enough fields to check if the inode was active or not.
* This is needed because nfsd might try to access dead inodes
* the test is that same one that e2fsck uses
* NeilBrown 1999oct15
*/
if (inode->i_nlink == 0) {
if (inode->i_mode == 0 ||
!(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
/* this inode is deleted */
brelse (bh);
ret = -ESTALE;
goto bad_inode;
}
/* The only unlinked inodes we let through here have
* valid i_mode and are being read by the orphan
* recovery code: that's fine, we're about to complete
* the process of deleting those. */
}
inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
#ifdef EXT3_FRAGMENTS
ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
ei->i_frag_no = raw_inode->i_frag;
ei->i_frag_size = raw_inode->i_fsize;
#endif
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
if (!S_ISREG(inode->i_mode)) {
ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
} else {
inode->i_size |=
((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
}
ei->i_disksize = inode->i_size;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_block_group = iloc.block_group;
/*
* NOTE! The in-memory inode i_data array is in little-endian order
* even on big-endian machines: we do NOT byteswap the block numbers!
*/
for (block = 0; block < EXT3_N_BLOCKS; block++)
ei->i_data[block] = raw_inode->i_block[block];
INIT_LIST_HEAD(&ei->i_orphan);
/*
* Set transaction id's of transactions that have to be committed
* to finish f[data]sync. We set them to currently running transaction
* as we cannot be sure that the inode or some of its metadata isn't
* part of the transaction - the inode could have been reclaimed and
* now it is reread from disk.
*/
if (journal) {
tid_t tid;
spin_lock(&journal->j_state_lock);
if (journal->j_running_transaction)
transaction = journal->j_running_transaction;
else
transaction = journal->j_committing_transaction;
if (transaction)
tid = transaction->t_tid;
else
tid = journal->j_commit_sequence;
spin_unlock(&journal->j_state_lock);
atomic_set(&ei->i_sync_tid, tid);
atomic_set(&ei->i_datasync_tid, tid);
}
if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
/*
* When mke2fs creates big inodes it does not zero out
* the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
* so ignore those first few inodes.
*/
ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
EXT3_INODE_SIZE(inode->i_sb)) {
brelse (bh);
ret = -EIO;
goto bad_inode;
}
if (ei->i_extra_isize == 0) {
/* The extra space is currently unused. Use it. */
ei->i_extra_isize = sizeof(struct ext3_inode) -
EXT3_GOOD_OLD_INODE_SIZE;
} else {
__le32 *magic = (void *)raw_inode +
EXT3_GOOD_OLD_INODE_SIZE +
ei->i_extra_isize;
if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
ei->i_state |= EXT3_STATE_XATTR;
}
} else
ei->i_extra_isize = 0;
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext3_file_inode_operations;
inode->i_fop = &ext3_file_operations;
ext3_set_aops(inode);
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext3_dir_inode_operations;
inode->i_fop = &ext3_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
if (ext3_inode_is_fast_symlink(inode)) {
inode->i_op = &ext3_fast_symlink_inode_operations;
nd_terminate_link(ei->i_data, inode->i_size,
sizeof(ei->i_data) - 1);
} else {
inode->i_op = &ext3_symlink_inode_operations;
ext3_set_aops(inode);
}
} else {
inode->i_op = &ext3_special_inode_operations;
if (raw_inode->i_block[0])
init_special_inode(inode, inode->i_mode,
old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
else
init_special_inode(inode, inode->i_mode,
new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
}
brelse (iloc.bh);
ext3_set_inode_flags(inode);
unlock_new_inode(inode);
return inode;
bad_inode:
iget_failed(inode);
return ERR_PTR(ret);
}
/*
* Post the struct inode info into an on-disk inode location in the
* buffer-cache. This gobbles the caller's reference to the
* buffer_head in the inode location struct.
*
* The caller must have write access to iloc->bh.
*/
static int ext3_do_update_inode(handle_t *handle,
struct inode *inode,
struct ext3_iloc *iloc)
{
struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
struct ext3_inode_info *ei = EXT3_I(inode);
struct buffer_head *bh = iloc->bh;
int err = 0, rc, block;
again:
/* we can't allow multiple procs in here at once, its a bit racey */
lock_buffer(bh);
/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT3_STATE_NEW)
memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
ext3_get_inode_flags(ei);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
if(!(test_opt(inode->i_sb, NO_UID32))) {
raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
/*
* Fix up interoperability with old kernels. Otherwise, old inodes get
* re-used with the upper 16 bits of the uid/gid intact
*/
if(!ei->i_dtime) {
raw_inode->i_uid_high =
cpu_to_le16(high_16_bits(inode->i_uid));
raw_inode->i_gid_high =
cpu_to_le16(high_16_bits(inode->i_gid));
} else {
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
} else {
raw_inode->i_uid_low =
cpu_to_le16(fs_high2lowuid(inode->i_uid));
raw_inode->i_gid_low =
cpu_to_le16(fs_high2lowgid(inode->i_gid));
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
raw_inode->i_size = cpu_to_le32(ei->i_disksize);
raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
raw_inode->i_flags = cpu_to_le32(ei->i_flags);
#ifdef EXT3_FRAGMENTS
raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
raw_inode->i_frag = ei->i_frag_no;
raw_inode->i_fsize = ei->i_frag_size;
#endif
raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
if (!S_ISREG(inode->i_mode)) {
raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
} else {
raw_inode->i_size_high =
cpu_to_le32(ei->i_disksize >> 32);
if (ei->i_disksize > 0x7fffffffULL) {
struct super_block *sb = inode->i_sb;
if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
EXT3_SB(sb)->s_es->s_rev_level ==
cpu_to_le32(EXT3_GOOD_OLD_REV)) {
/* If this is the first large file
* created, add a flag to the superblock.
*/
unlock_buffer(bh);
err = ext3_journal_get_write_access(handle,
EXT3_SB(sb)->s_sbh);
if (err)
goto out_brelse;
ext3_update_dynamic_rev(sb);
EXT3_SET_RO_COMPAT_FEATURE(sb,
EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
handle->h_sync = 1;
err = ext3_journal_dirty_metadata(handle,
EXT3_SB(sb)->s_sbh);
/* get our lock and start over */
goto again;
}
}
}
raw_inode->i_generation = cpu_to_le32(inode->i_generation);
if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
if (old_valid_dev(inode->i_rdev)) {
raw_inode->i_block[0] =
cpu_to_le32(old_encode_dev(inode->i_rdev));
raw_inode->i_block[1] = 0;
} else {
raw_inode->i_block[0] = 0;
raw_inode->i_block[1] =
cpu_to_le32(new_encode_dev(inode->i_rdev));
raw_inode->i_block[2] = 0;
}
} else for (block = 0; block < EXT3_N_BLOCKS; block++)
raw_inode->i_block[block] = ei->i_data[block];
if (ei->i_extra_isize)
raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
unlock_buffer(bh);
rc = ext3_journal_dirty_metadata(handle, bh);
if (!err)
err = rc;
ei->i_state &= ~EXT3_STATE_NEW;
atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
out_brelse:
brelse (bh);
ext3_std_error(inode->i_sb, err);
return err;
}
/*
* ext3_write_inode()
*
* We are called from a few places:
*
* - Within generic_file_write() for O_SYNC files.
* Here, there will be no transaction running. We wait for any running
* trasnaction to commit.
*
* - Within sys_sync(), kupdate and such.
* We wait on commit, if tol to.
*
* - Within prune_icache() (PF_MEMALLOC == true)
* Here we simply return. We can't afford to block kswapd on the
* journal commit.
*
* In all cases it is actually safe for us to return without doing anything,
* because the inode has been copied into a raw inode buffer in
* ext3_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
* knfsd.
*
* Note that we are absolutely dependent upon all inode dirtiers doing the
* right thing: they *must* call mark_inode_dirty() after dirtying info in
* which we are interested.
*
* It would be a bug for them to not do this. The code:
*
* mark_inode_dirty(inode)
* stuff();
* inode->i_size = expr;
*
* is in error because a kswapd-driven write_inode() could occur while
* `stuff()' is running, and the new i_size will be lost. Plus the inode
* will no longer be on the superblock's dirty inode list.
*/
int ext3_write_inode(struct inode *inode, int wait)
{
if (current->flags & PF_MEMALLOC)
return 0;
if (ext3_journal_current_handle()) {
jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
dump_stack();
return -EIO;
}
if (!wait)
return 0;
return ext3_force_commit(inode->i_sb);
}
/*
* ext3_setattr()
*
* Called from notify_change.
*
* We want to trap VFS attempts to truncate the file as soon as
* possible. In particular, we want to make sure that when the VFS
* shrinks i_size, we put the inode on the orphan list and modify
* i_disksize immediately, so that during the subsequent flushing of
* dirty pages and freeing of disk blocks, we can guarantee that any
* commit will leave the blocks being flushed in an unused state on
* disk. (On recovery, the inode will get truncated and the blocks will
* be freed, so we have a strong guarantee that no future commit will
* leave these blocks visible to the user.)
*
* Called with inode->sem down.
*/
int ext3_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
int error, rc = 0;
const unsigned int ia_valid = attr->ia_valid;
error = inode_change_ok(inode, attr);
if (error)
return error;
if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
handle_t *handle;
/* (user+group)*(old+new) structure, inode write (sb,
* inode block, ? - but truncate inode update has it) */
handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
goto err_out;
}
error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
if (error) {
ext3_journal_stop(handle);
return error;
}
/* Update corresponding info in inode so that everything is in
* one transaction */
if (attr->ia_valid & ATTR_UID)
inode->i_uid = attr->ia_uid;
if (attr->ia_valid & ATTR_GID)
inode->i_gid = attr->ia_gid;
error = ext3_mark_inode_dirty(handle, inode);
ext3_journal_stop(handle);
}
if (S_ISREG(inode->i_mode) &&
attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
handle_t *handle;
handle = ext3_journal_start(inode, 3);
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
goto err_out;
}
error = ext3_orphan_add(handle, inode);
EXT3_I(inode)->i_disksize = attr->ia_size;
rc = ext3_mark_inode_dirty(handle, inode);
if (!error)
error = rc;
ext3_journal_stop(handle);
}
rc = inode_setattr(inode, attr);
if (!rc && (ia_valid & ATTR_MODE))
rc = ext3_acl_chmod(inode);
err_out:
ext3_std_error(inode->i_sb, error);
if (!error)
error = rc;
return error;
}
/*
* How many blocks doth make a writepage()?
*
* With N blocks per page, it may be:
* N data blocks
* 2 indirect block
* 2 dindirect
* 1 tindirect
* N+5 bitmap blocks (from the above)
* N+5 group descriptor summary blocks
* 1 inode block
* 1 superblock.
* 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
*
* 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
*
* With ordered or writeback data it's the same, less the N data blocks.
*
* If the inode's direct blocks can hold an integral number of pages then a
* page cannot straddle two indirect blocks, and we can only touch one indirect
* and dindirect block, and the "5" above becomes "3".
*
* This still overestimates under most circumstances. If we were to pass the
* start and end offsets in here as well we could do block_to_path() on each
* block and work out the exact number of indirects which are touched. Pah.
*/
static int ext3_writepage_trans_blocks(struct inode *inode)
{
int bpp = ext3_journal_blocks_per_page(inode);
int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
int ret;
if (ext3_should_journal_data(inode))
ret = 3 * (bpp + indirects) + 2;
else
ret = 2 * (bpp + indirects) + 2;
#ifdef CONFIG_QUOTA
/* We know that structure was already allocated during vfs_dq_init so
* we will be updating only the data blocks + inodes */
ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
#endif
return ret;
}
/*
* The caller must have previously called ext3_reserve_inode_write().
* Give this, we know that the caller already has write access to iloc->bh.
*/
int ext3_mark_iloc_dirty(handle_t *handle,
struct inode *inode, struct ext3_iloc *iloc)
{
int err = 0;
/* the do_update_inode consumes one bh->b_count */
get_bh(iloc->bh);
/* ext3_do_update_inode() does journal_dirty_metadata */
err = ext3_do_update_inode(handle, inode, iloc);
put_bh(iloc->bh);
return err;
}
/*
* On success, We end up with an outstanding reference count against
* iloc->bh. This _must_ be cleaned up later.
*/
int
ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
struct ext3_iloc *iloc)
{
int err = 0;
if (handle) {
err = ext3_get_inode_loc(inode, iloc);
if (!err) {
BUFFER_TRACE(iloc->bh, "get_write_access");
err = ext3_journal_get_write_access(handle, iloc->bh);
if (err) {
brelse(iloc->bh);
iloc->bh = NULL;
}
}
}
ext3_std_error(inode->i_sb, err);
return err;
}
/*
* What we do here is to mark the in-core inode as clean with respect to inode
* dirtiness (it may still be data-dirty).
* This means that the in-core inode may be reaped by prune_icache
* without having to perform any I/O. This is a very good thing,
* because *any* task may call prune_icache - even ones which
* have a transaction open against a different journal.
*
* Is this cheating? Not really. Sure, we haven't written the
* inode out, but prune_icache isn't a user-visible syncing function.
* Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
* we start and wait on commits.
*
* Is this efficient/effective? Well, we're being nice to the system
* by cleaning up our inodes proactively so they can be reaped
* without I/O. But we are potentially leaving up to five seconds'
* worth of inodes floating about which prune_icache wants us to
* write out. One way to fix that would be to get prune_icache()
* to do a write_super() to free up some memory. It has the desired
* effect.
*/
int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
{
struct ext3_iloc iloc;
int err;
might_sleep();
err = ext3_reserve_inode_write(handle, inode, &iloc);
if (!err)
err = ext3_mark_iloc_dirty(handle, inode, &iloc);
return err;
}
/*
* ext3_dirty_inode() is called from __mark_inode_dirty()
*
* We're really interested in the case where a file is being extended.
* i_size has been changed by generic_commit_write() and we thus need
* to include the updated inode in the current transaction.
*
* Also, vfs_dq_alloc_space() will always dirty the inode when blocks
* are allocated to the file.
*
* If the inode is marked synchronous, we don't honour that here - doing
* so would cause a commit on atime updates, which we don't bother doing.
* We handle synchronous inodes at the highest possible level.
*/
void ext3_dirty_inode(struct inode *inode)
{
handle_t *current_handle = ext3_journal_current_handle();
handle_t *handle;
handle = ext3_journal_start(inode, 2);
if (IS_ERR(handle))
goto out;
if (current_handle &&
current_handle->h_transaction != handle->h_transaction) {
/* This task has a transaction open against a different fs */
printk(KERN_EMERG "%s: transactions do not match!\n",
__func__);
} else {
jbd_debug(5, "marking dirty. outer handle=%p\n",
current_handle);
ext3_mark_inode_dirty(handle, inode);
}
ext3_journal_stop(handle);
out:
return;
}
#if 0
/*
* Bind an inode's backing buffer_head into this transaction, to prevent
* it from being flushed to disk early. Unlike
* ext3_reserve_inode_write, this leaves behind no bh reference and
* returns no iloc structure, so the caller needs to repeat the iloc
* lookup to mark the inode dirty later.
*/
static int ext3_pin_inode(handle_t *handle, struct inode *inode)
{
struct ext3_iloc iloc;
int err = 0;
if (handle) {
err = ext3_get_inode_loc(inode, &iloc);
if (!err) {
BUFFER_TRACE(iloc.bh, "get_write_access");
err = journal_get_write_access(handle, iloc.bh);
if (!err)
err = ext3_journal_dirty_metadata(handle,
iloc.bh);
brelse(iloc.bh);
}
}
ext3_std_error(inode->i_sb, err);
return err;
}
#endif
int ext3_change_inode_journal_flag(struct inode *inode, int val)
{
journal_t *journal;
handle_t *handle;
int err;
/*
* We have to be very careful here: changing a data block's
* journaling status dynamically is dangerous. If we write a
* data block to the journal, change the status and then delete
* that block, we risk forgetting to revoke the old log record
* from the journal and so a subsequent replay can corrupt data.
* So, first we make sure that the journal is empty and that
* nobody is changing anything.
*/
journal = EXT3_JOURNAL(inode);
if (is_journal_aborted(journal))
return -EROFS;
journal_lock_updates(journal);
journal_flush(journal);
/*
* OK, there are no updates running now, and all cached data is
* synced to disk. We are now in a completely consistent state
* which doesn't have anything in the journal, and we know that
* no filesystem updates are running, so it is safe to modify
* the inode's in-core data-journaling state flag now.
*/
if (val)
EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
else
EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
ext3_set_aops(inode);
journal_unlock_updates(journal);
/* Finally we can mark the inode as dirty. */
handle = ext3_journal_start(inode, 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
err = ext3_mark_inode_dirty(handle, inode);
handle->h_sync = 1;
ext3_journal_stop(handle);
ext3_std_error(inode->i_sb, err);
return err;
}
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