Linux-2.6.33.2/fs/ext2/inode.c
/*
* linux/fs/ext2/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@dcs.ed.ac.uk), 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 ext2_get_block() by Al Viro, 2000
*/
#include <linux/smp_lock.h>
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/module.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/fiemap.h>
#include <linux/namei.h>
#include "ext2.h"
#include "acl.h"
#include "xip.h"
MODULE_AUTHOR("Remy Card and others");
MODULE_DESCRIPTION("Second Extended Filesystem");
MODULE_LICENSE("GPL");
/*
* Test whether an inode is a fast symlink.
*/
static inline int ext2_inode_is_fast_symlink(struct inode *inode)
{
int ea_blocks = EXT2_I(inode)->i_file_acl ?
(inode->i_sb->s_blocksize >> 9) : 0;
return (S_ISLNK(inode->i_mode) &&
inode->i_blocks - ea_blocks == 0);
}
/*
* Called at the last iput() if i_nlink is zero.
*/
void ext2_delete_inode (struct inode * inode)
{
truncate_inode_pages(&inode->i_data, 0);
if (is_bad_inode(inode))
goto no_delete;
EXT2_I(inode)->i_dtime = get_seconds();
mark_inode_dirty(inode);
ext2_write_inode(inode, inode_needs_sync(inode));
inode->i_size = 0;
if (inode->i_blocks)
ext2_truncate (inode);
ext2_free_inode (inode);
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 inline int verify_chain(Indirect *from, Indirect *to)
{
while (from <= to && from->key == *from->p)
from++;
return (from > to);
}
/**
* ext2_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 ext2 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 ext2_block_to_path(struct inode *inode,
long i_block, int offsets[4], int *boundary)
{
int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
const long direct_blocks = EXT2_NDIR_BLOCKS,
indirect_blocks = ptrs,
double_blocks = (1 << (ptrs_bits * 2));
int n = 0;
int final = 0;
if (i_block < 0) {
ext2_msg(inode->i_sb, KERN_WARNING,
"warning: %s: block < 0", __func__);
} else if (i_block < direct_blocks) {
offsets[n++] = i_block;
final = direct_blocks;
} else if ( (i_block -= direct_blocks) < indirect_blocks) {
offsets[n++] = EXT2_IND_BLOCK;
offsets[n++] = i_block;
final = ptrs;
} else if ((i_block -= indirect_blocks) < double_blocks) {
offsets[n++] = EXT2_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++] = EXT2_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 {
ext2_msg(inode->i_sb, KERN_WARNING,
"warning: %s: block is too big", __func__);
}
if (boundary)
*boundary = final - 1 - (i_block & (ptrs - 1));
return n;
}
/**
* ext2_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 *ext2_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, EXT2_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;
read_lock(&EXT2_I(inode)->i_meta_lock);
if (!verify_chain(chain, p))
goto changed;
add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
read_unlock(&EXT2_I(inode)->i_meta_lock);
if (!p->key)
goto no_block;
}
return NULL;
changed:
read_unlock(&EXT2_I(inode)->i_meta_lock);
brelse(bh);
*err = -EAGAIN;
goto no_block;
failure:
*err = -EIO;
no_block:
return p;
}
/**
* ext2_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 ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
{
struct ext2_inode_info *ei = EXT2_I(inode);
__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
__le32 *p;
ext2_fsblk_t bg_start;
ext2_fsblk_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 refered from inode itself? OK, just put it into
* the same cylinder group then.
*/
bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
colour = (current->pid % 16) *
(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
return bg_start + colour;
}
/**
* ext2_find_goal - find a preferred place for allocation.
* @inode: owner
* @block: block we want
* @partial: pointer to the last triple within a chain
*
* Returns preferred place for a block (the goal).
*/
static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
Indirect *partial)
{
struct ext2_block_alloc_info *block_i;
block_i = EXT2_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 ext2_find_near(inode, partial);
}
/**
* ext2_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
ext2_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 don't hanel 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;
}
/**
* ext2_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 ext2_alloc_blocks(struct inode *inode,
ext2_fsblk_t goal, int indirect_blks, int blks,
ext2_fsblk_t new_blocks[4], int *err)
{
int target, i;
unsigned long count = 0;
int index = 0;
ext2_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 = ext2_new_blocks(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++)
ext2_free_blocks(inode, new_blocks[i], 1);
return ret;
}
/**
* ext2_alloc_branch - allocate and set up a chain of blocks.
* @inode: owner
* @num: depth of the chain (number of blocks to allocate)
* @offsets: offsets (in the blocks) to store the pointers to next.
* @branch: place to store the chain in.
*
* This function allocates @num 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 ext2_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 ext2_get_block(), excpet 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
* ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
* as described above and return 0.
*/
static int ext2_alloc_branch(struct inode *inode,
int indirect_blks, int *blks, ext2_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;
ext2_fsblk_t new_blocks[4];
ext2_fsblk_t current_block;
num = ext2_alloc_blocks(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);
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);
}
set_buffer_uptodate(bh);
unlock_buffer(bh);
mark_buffer_dirty_inode(bh, inode);
/* We used to sync bh here if IS_SYNC(inode).
* But we now rely upon generic_write_sync()
* and b_inode_buffers. But not for directories.
*/
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
sync_dirty_buffer(bh);
}
*blks = num;
return err;
}
/**
* ext2_splice_branch - splice the allocated branch onto inode.
* @inode: owner
* @block: (logical) number of block we are adding
* @where: location of missing link
* @num: number of indirect blocks we are adding
* @blks: number of direct blocks we are adding
*
* This function fills the missing link and does all housekeeping needed in
* inode (->i_blocks, etc.). In case of success we end up with the full
* chain to new block and return 0.
*/
static void ext2_splice_branch(struct inode *inode,
long block, Indirect *where, int num, int blks)
{
int i;
struct ext2_block_alloc_info *block_i;
ext2_fsblk_t current_block;
block_i = EXT2_I(inode)->i_block_alloc_info;
/* XXX LOCKING probably should have i_meta_lock ?*/
/* 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 */
/* had we spliced it onto indirect block? */
if (where->bh)
mark_buffer_dirty_inode(where->bh, inode);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
}
/*
* 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.
*
* return > 0, # of blocks mapped or allocated.
* return = 0, if plain lookup failed.
* return < 0, error case.
*/
static int ext2_get_blocks(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;
ext2_fsblk_t goal;
int indirect_blks;
int blocks_to_boundary = 0;
int depth;
struct ext2_inode_info *ei = EXT2_I(inode);
int count = 0;
ext2_fsblk_t first_block = 0;
depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
if (depth == 0)
return (err);
partial = ext2_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); /* What's this do? */
count++;
/*map more blocks*/
while (count < maxblocks && count <= blocks_to_boundary) {
ext2_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, go to 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 = ext2_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))
ext2_init_block_alloc_info(inode);
goal = ext2_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 = ext2_blks_to_allocate(partial, indirect_blks,
maxblocks, blocks_to_boundary);
/*
* XXX ???? Block out ext2_truncate while we alter the tree
*/
err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
offsets + (partial - chain), partial);
if (err) {
mutex_unlock(&ei->truncate_mutex);
goto cleanup;
}
if (ext2_use_xip(inode->i_sb)) {
/*
* we need to clear the block
*/
err = ext2_clear_xip_target (inode,
le32_to_cpu(chain[depth-1].key));
if (err) {
mutex_unlock(&ei->truncate_mutex);
goto cleanup;
}
}
ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
mutex_unlock(&ei->truncate_mutex);
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) {
brelse(partial->bh);
partial--;
}
return err;
}
int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
{
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
int ret = ext2_get_blocks(inode, iblock, max_blocks,
bh_result, create);
if (ret > 0) {
bh_result->b_size = (ret << inode->i_blkbits);
ret = 0;
}
return ret;
}
int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
return generic_block_fiemap(inode, fieinfo, start, len,
ext2_get_block);
}
static int ext2_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, ext2_get_block, wbc);
}
static int ext2_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, ext2_get_block);
}
static int
ext2_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
}
int __ext2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
ext2_get_block);
}
static int
ext2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
*pagep = NULL;
return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
}
static int
ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
/*
* Dir-in-pagecache still uses ext2_write_begin. Would have to rework
* directory handling code to pass around offsets rather than struct
* pages in order to make this work easily.
*/
return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
ext2_get_block);
}
static int ext2_nobh_writepage(struct page *page,
struct writeback_control *wbc)
{
return nobh_writepage(page, ext2_get_block, wbc);
}
static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping,block,ext2_get_block);
}
static ssize_t
ext2_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;
return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, ext2_get_block, NULL);
}
static int
ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
return mpage_writepages(mapping, wbc, ext2_get_block);
}
const struct address_space_operations ext2_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
.writepage = ext2_writepage,
.sync_page = block_sync_page,
.write_begin = ext2_write_begin,
.write_end = generic_write_end,
.bmap = ext2_bmap,
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
const struct address_space_operations ext2_aops_xip = {
.bmap = ext2_bmap,
.get_xip_mem = ext2_get_xip_mem,
};
const struct address_space_operations ext2_nobh_aops = {
.readpage = ext2_readpage,
.readpages = ext2_readpages,
.writepage = ext2_nobh_writepage,
.sync_page = block_sync_page,
.write_begin = ext2_nobh_write_begin,
.write_end = nobh_write_end,
.bmap = ext2_bmap,
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
.error_remove_page = generic_error_remove_page,
};
/*
* 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;
}
/**
* ext2_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 ext2_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 ext2_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 ext2_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].p
* (no partially truncated stuff there).
*/
static Indirect *ext2_find_shared(struct inode *inode,
int depth,
int offsets[4],
Indirect chain[4],
__le32 *top)
{
Indirect *partial, *p;
int k, err;
*top = 0;
for (k = depth; k > 1 && !offsets[k-1]; k--)
;
partial = ext2_get_branch(inode, k, offsets, chain, &err);
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.
*/
write_lock(&EXT2_I(inode)->i_meta_lock);
if (!partial->key && *partial->p) {
write_unlock(&EXT2_I(inode)->i_meta_lock);
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;
*p->p = 0;
}
write_unlock(&EXT2_I(inode)->i_meta_lock);
while(partial > p)
{
brelse(partial->bh);
partial--;
}
no_top:
return partial;
}
/**
* ext2_free_data - free a list of data blocks
* @inode: inode we are dealing with
* @p: array of block numbers
* @q: 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.
*/
static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
{
unsigned long block_to_free = 0, count = 0;
unsigned long nr;
for ( ; p < q ; p++) {
nr = le32_to_cpu(*p);
if (nr) {
*p = 0;
/* accumulate blocks to free if they're contiguous */
if (count == 0)
goto free_this;
else if (block_to_free == nr - count)
count++;
else {
mark_inode_dirty(inode);
ext2_free_blocks (inode, block_to_free, count);
free_this:
block_to_free = nr;
count = 1;
}
}
}
if (count > 0) {
mark_inode_dirty(inode);
ext2_free_blocks (inode, block_to_free, count);
}
}
/**
* ext2_free_branches - free an array of branches
* @inode: inode we are dealing with
* @p: array of block numbers
* @q: 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 ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
{
struct buffer_head * bh;
unsigned long nr;
if (depth--) {
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
for ( ; p < q ; p++) {
nr = le32_to_cpu(*p);
if (!nr)
continue;
*p = 0;
bh = sb_bread(inode->i_sb, nr);
/*
* A read failure? Report error and clear slot
* (should be rare).
*/
if (!bh) {
ext2_error(inode->i_sb, "ext2_free_branches",
"Read failure, inode=%ld, block=%ld",
inode->i_ino, nr);
continue;
}
ext2_free_branches(inode,
(__le32*)bh->b_data,
(__le32*)bh->b_data + addr_per_block,
depth);
bforget(bh);
ext2_free_blocks(inode, nr, 1);
mark_inode_dirty(inode);
}
} else
ext2_free_data(inode, p, q);
}
void ext2_truncate(struct inode *inode)
{
__le32 *i_data = EXT2_I(inode)->i_data;
struct ext2_inode_info *ei = EXT2_I(inode);
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
int offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n;
long iblock;
unsigned blocksize;
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)))
return;
if (ext2_inode_is_fast_symlink(inode))
return;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
blocksize = inode->i_sb->s_blocksize;
iblock = (inode->i_size + blocksize-1)
>> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
if (mapping_is_xip(inode->i_mapping))
xip_truncate_page(inode->i_mapping, inode->i_size);
else if (test_opt(inode->i_sb, NOBH))
nobh_truncate_page(inode->i_mapping,
inode->i_size, ext2_get_block);
else
block_truncate_page(inode->i_mapping,
inode->i_size, ext2_get_block);
n = ext2_block_to_path(inode, iblock, offsets, NULL);
if (n == 0)
return;
/*
* From here we block out all ext2_get_block() callers who want to
* modify the block allocation tree.
*/
mutex_lock(&ei->truncate_mutex);
if (n == 1) {
ext2_free_data(inode, i_data+offsets[0],
i_data + EXT2_NDIR_BLOCKS);
goto do_indirects;
}
partial = ext2_find_shared(inode, n, offsets, chain, &nr);
/* Kill the top of shared branch (already detached) */
if (nr) {
if (partial == chain)
mark_inode_dirty(inode);
else
mark_buffer_dirty_inode(partial->bh, inode);
ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
}
/* Clear the ends of indirect blocks on the shared branch */
while (partial > chain) {
ext2_free_branches(inode,
partial->p + 1,
(__le32*)partial->bh->b_data+addr_per_block,
(chain+n-1) - partial);
mark_buffer_dirty_inode(partial->bh, inode);
brelse (partial->bh);
partial--;
}
do_indirects:
/* Kill the remaining (whole) subtrees */
switch (offsets[0]) {
default:
nr = i_data[EXT2_IND_BLOCK];
if (nr) {
i_data[EXT2_IND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 1);
}
case EXT2_IND_BLOCK:
nr = i_data[EXT2_DIND_BLOCK];
if (nr) {
i_data[EXT2_DIND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 2);
}
case EXT2_DIND_BLOCK:
nr = i_data[EXT2_TIND_BLOCK];
if (nr) {
i_data[EXT2_TIND_BLOCK] = 0;
mark_inode_dirty(inode);
ext2_free_branches(inode, &nr, &nr+1, 3);
}
case EXT2_TIND_BLOCK:
;
}
ext2_discard_reservation(inode);
mutex_unlock(&ei->truncate_mutex);
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
if (inode_needs_sync(inode)) {
sync_mapping_buffers(inode->i_mapping);
ext2_sync_inode (inode);
} else {
mark_inode_dirty(inode);
}
}
static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
struct buffer_head **p)
{
struct buffer_head * bh;
unsigned long block_group;
unsigned long block;
unsigned long offset;
struct ext2_group_desc * gdp;
*p = NULL;
if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
goto Einval;
block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
gdp = ext2_get_group_desc(sb, block_group, NULL);
if (!gdp)
goto Egdp;
/*
* Figure out the offset within the block group inode table
*/
offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
block = le32_to_cpu(gdp->bg_inode_table) +
(offset >> EXT2_BLOCK_SIZE_BITS(sb));
if (!(bh = sb_bread(sb, block)))
goto Eio;
*p = bh;
offset &= (EXT2_BLOCK_SIZE(sb) - 1);
return (struct ext2_inode *) (bh->b_data + offset);
Einval:
ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
(unsigned long) ino);
return ERR_PTR(-EINVAL);
Eio:
ext2_error(sb, "ext2_get_inode",
"unable to read inode block - inode=%lu, block=%lu",
(unsigned long) ino, block);
Egdp:
return ERR_PTR(-EIO);
}
void ext2_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT2_I(inode)->i_flags;
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT2_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT2_APPEND_FL)
inode->i_flags |= S_APPEND;
if (flags & EXT2_IMMUTABLE_FL)
inode->i_flags |= S_IMMUTABLE;
if (flags & EXT2_NOATIME_FL)
inode->i_flags |= S_NOATIME;
if (flags & EXT2_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
}
/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
void ext2_get_inode_flags(struct ext2_inode_info *ei)
{
unsigned int flags = ei->vfs_inode.i_flags;
ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
if (flags & S_SYNC)
ei->i_flags |= EXT2_SYNC_FL;
if (flags & S_APPEND)
ei->i_flags |= EXT2_APPEND_FL;
if (flags & S_IMMUTABLE)
ei->i_flags |= EXT2_IMMUTABLE_FL;
if (flags & S_NOATIME)
ei->i_flags |= EXT2_NOATIME_FL;
if (flags & S_DIRSYNC)
ei->i_flags |= EXT2_DIRSYNC_FL;
}
struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
{
struct ext2_inode_info *ei;
struct buffer_head * bh;
struct ext2_inode *raw_inode;
struct inode *inode;
long ret = -EIO;
int n;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
ei = EXT2_I(inode);
ei->i_block_alloc_info = NULL;
raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
if (IS_ERR(raw_inode)) {
ret = PTR_ERR(raw_inode);
goto bad_inode;
}
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_mtime.tv_nsec = inode->i_ctime.tv_nsec = 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 && (inode->i_mode == 0 || ei->i_dtime)) {
/* this inode is deleted */
brelse (bh);
ret = -ESTALE;
goto bad_inode;
}
inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
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;
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
ei->i_dir_acl = 0;
if (S_ISREG(inode->i_mode))
inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
else
ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
ei->i_dtime = 0;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_state = 0;
ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
ei->i_dir_start_lookup = 0;
/*
* 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 (n = 0; n < EXT2_N_BLOCKS; n++)
ei->i_data[n] = raw_inode->i_block[n];
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext2_file_inode_operations;
if (ext2_use_xip(inode->i_sb)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_file_operations;
}
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
} else if (S_ISLNK(inode->i_mode)) {
if (ext2_inode_is_fast_symlink(inode)) {
inode->i_op = &ext2_fast_symlink_inode_operations;
nd_terminate_link(ei->i_data, inode->i_size,
sizeof(ei->i_data) - 1);
} else {
inode->i_op = &ext2_symlink_inode_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
}
} else {
inode->i_op = &ext2_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 (bh);
ext2_set_inode_flags(inode);
unlock_new_inode(inode);
return inode;
bad_inode:
iget_failed(inode);
return ERR_PTR(ret);
}
int ext2_write_inode(struct inode *inode, int do_sync)
{
struct ext2_inode_info *ei = EXT2_I(inode);
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
uid_t uid = inode->i_uid;
gid_t gid = inode->i_gid;
struct buffer_head * bh;
struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
int n;
int err = 0;
if (IS_ERR(raw_inode))
return -EIO;
/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT2_STATE_NEW)
memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
ext2_get_inode_flags(ei);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
if (!(test_opt(sb, NO_UID32))) {
raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
raw_inode->i_gid_low = cpu_to_le16(low_16_bits(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(uid));
raw_inode->i_gid_high = cpu_to_le16(high_16_bits(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(uid));
raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(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(inode->i_size);
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);
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;
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(inode->i_size >> 32);
if (inode->i_size > 0x7fffffffULL) {
if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
EXT2_SB(sb)->s_es->s_rev_level ==
cpu_to_le32(EXT2_GOOD_OLD_REV)) {
/* If this is the first large file
* created, add a flag to the superblock.
*/
lock_kernel();
ext2_update_dynamic_rev(sb);
EXT2_SET_RO_COMPAT_FEATURE(sb,
EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
unlock_kernel();
ext2_write_super(sb);
}
}
}
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 (n = 0; n < EXT2_N_BLOCKS; n++)
raw_inode->i_block[n] = ei->i_data[n];
mark_buffer_dirty(bh);
if (do_sync) {
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh)) {
printk ("IO error syncing ext2 inode [%s:%08lx]\n",
sb->s_id, (unsigned long) ino);
err = -EIO;
}
}
ei->i_state &= ~EXT2_STATE_NEW;
brelse (bh);
return err;
}
int ext2_sync_inode(struct inode *inode)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = 0, /* sys_fsync did this */
};
return sync_inode(inode, &wbc);
}
int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
int error;
error = inode_change_ok(inode, iattr);
if (error)
return error;
if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
(iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
error = vfs_dq_transfer(inode, iattr) ? -EDQUOT : 0;
if (error)
return error;
}
error = inode_setattr(inode, iattr);
if (!error && (iattr->ia_valid & ATTR_MODE))
error = ext2_acl_chmod(inode);
return error;
}