This patch moves functions from inode.c to indirect.c.
The moved functions are ext4_ind_* functions and their helpers.
Functions called from inode.c are declared extern.
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
- mmp.o
+ mmp.o indirect.o
ext4-$(CONFIG_EXT4_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
extern qsize_t *ext4_get_reserved_space(struct inode *inode);
extern void ext4_da_update_reserve_space(struct inode *inode,
int used, int quota_claim);
+
+/* indirect.c */
+extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
+ struct ext4_map_blocks *map, int flags);
+extern ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
+ const struct iovec *iov, loff_t offset,
+ unsigned long nr_segs);
+extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
+extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk);
extern void ext4_ind_truncate(struct inode *inode);
/* ioctl.c */
--- /dev/null
+/*
+ * linux/fs/ext4/indirect.c
+ *
+ * from
+ *
+ * linux/fs/ext4/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
+ */
+
+#include <linux/module.h>
+#include "ext4_jbd2.h"
+#include "truncate.h"
+
+#include <trace/events/ext4.h>
+
+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;
+}
+
+/**
+ * ext4_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 ext4 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 ext4_block_to_path(struct inode *inode,
+ ext4_lblk_t i_block,
+ ext4_lblk_t offsets[4], int *boundary)
+{
+ int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+ int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
+ const long direct_blocks = EXT4_NDIR_BLOCKS,
+ indirect_blocks = ptrs,
+ double_blocks = (1 << (ptrs_bits * 2));
+ int n = 0;
+ int final = 0;
+
+ if (i_block < direct_blocks) {
+ offsets[n++] = i_block;
+ final = direct_blocks;
+ } else if ((i_block -= direct_blocks) < indirect_blocks) {
+ offsets[n++] = EXT4_IND_BLOCK;
+ offsets[n++] = i_block;
+ final = ptrs;
+ } else if ((i_block -= indirect_blocks) < double_blocks) {
+ offsets[n++] = EXT4_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++] = EXT4_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 {
+ ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
+ i_block + direct_blocks +
+ indirect_blocks + double_blocks, inode->i_ino);
+ }
+ if (boundary)
+ *boundary = final - 1 - (i_block & (ptrs - 1));
+ return n;
+}
+
+/**
+ * ext4_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 reads all @depth-1 indirect blocks successfully and finds
+ * the whole chain, all way to the data (returns %NULL, *err == 0).
+ *
+ * Need to be called with
+ * down_read(&EXT4_I(inode)->i_data_sem)
+ */
+static Indirect *ext4_get_branch(struct inode *inode, int depth,
+ ext4_lblk_t *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, EXT4_I(inode)->i_data + *offsets);
+ if (!p->key)
+ goto no_block;
+ while (--depth) {
+ bh = sb_getblk(sb, le32_to_cpu(p->key));
+ if (unlikely(!bh))
+ goto failure;
+
+ if (!bh_uptodate_or_lock(bh)) {
+ if (bh_submit_read(bh) < 0) {
+ put_bh(bh);
+ goto failure;
+ }
+ /* validate block references */
+ if (ext4_check_indirect_blockref(inode, bh)) {
+ put_bh(bh);
+ goto failure;
+ }
+ }
+
+ add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
+ /* Reader: end */
+ if (!p->key)
+ goto no_block;
+ }
+ return NULL;
+
+failure:
+ *err = -EIO;
+no_block:
+ return p;
+}
+
+/**
+ * ext4_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 ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
+ __le32 *p;
+ ext4_fsblk_t bg_start;
+ ext4_fsblk_t last_block;
+ ext4_grpblk_t colour;
+ ext4_group_t block_group;
+ int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
+
+ /* 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.
+ */
+ block_group = ei->i_block_group;
+ if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+ block_group &= ~(flex_size-1);
+ if (S_ISREG(inode->i_mode))
+ block_group++;
+ }
+ bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
+ last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
+
+ /*
+ * If we are doing delayed allocation, we don't need take
+ * colour into account.
+ */
+ if (test_opt(inode->i_sb, DELALLOC))
+ return bg_start;
+
+ if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
+ colour = (current->pid % 16) *
+ (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+ else
+ colour = (current->pid % 16) * ((last_block - bg_start) / 16);
+ return bg_start + colour;
+}
+
+/**
+ * ext4_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.
+ * Because this is only used for non-extent files, we limit the block nr
+ * to 32 bits.
+ */
+static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
+ Indirect *partial)
+{
+ ext4_fsblk_t goal;
+
+ /*
+ * XXX need to get goal block from mballoc's data structures
+ */
+
+ goal = ext4_find_near(inode, partial);
+ goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
+ return goal;
+}
+
+/**
+ * ext4_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 ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
+ int blocks_to_boundary)
+{
+ unsigned int 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;
+}
+
+/**
+ * ext4_alloc_blocks: multiple allocate blocks needed for a branch
+ * @handle: handle for this transaction
+ * @inode: inode which needs allocated blocks
+ * @iblock: the logical block to start allocated at
+ * @goal: preferred physical block of allocation
+ * @indirect_blks: the number of blocks need to allocate for indirect
+ * blocks
+ * @blks: number of desired blocks
+ * @new_blocks: on return it will store the new block numbers for
+ * the indirect blocks(if needed) and the first direct block,
+ * @err: on return it will store the error code
+ *
+ * This function will return the number of blocks allocated as
+ * requested by the passed-in parameters.
+ */
+static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
+ ext4_lblk_t iblock, ext4_fsblk_t goal,
+ int indirect_blks, int blks,
+ ext4_fsblk_t new_blocks[4], int *err)
+{
+ struct ext4_allocation_request ar;
+ int target, i;
+ unsigned long count = 0, blk_allocated = 0;
+ int index = 0;
+ ext4_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)
+ */
+ /* first we try to allocate the indirect blocks */
+ target = indirect_blks;
+ while (target > 0) {
+ count = target;
+ /* allocating blocks for indirect blocks and direct blocks */
+ current_block = ext4_new_meta_blocks(handle, inode, goal,
+ 0, &count, err);
+ if (*err)
+ goto failed_out;
+
+ if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) {
+ EXT4_ERROR_INODE(inode,
+ "current_block %llu + count %lu > %d!",
+ current_block, count,
+ EXT4_MAX_BLOCK_FILE_PHYS);
+ *err = -EIO;
+ goto failed_out;
+ }
+
+ target -= count;
+ /* allocate blocks for indirect blocks */
+ while (index < indirect_blks && count) {
+ new_blocks[index++] = current_block++;
+ count--;
+ }
+ if (count > 0) {
+ /*
+ * save the new block number
+ * for the first direct block
+ */
+ new_blocks[index] = current_block;
+ printk(KERN_INFO "%s returned more blocks than "
+ "requested\n", __func__);
+ WARN_ON(1);
+ break;
+ }
+ }
+
+ target = blks - count ;
+ blk_allocated = count;
+ if (!target)
+ goto allocated;
+ /* Now allocate data blocks */
+ memset(&ar, 0, sizeof(ar));
+ ar.inode = inode;
+ ar.goal = goal;
+ ar.len = target;
+ ar.logical = iblock;
+ if (S_ISREG(inode->i_mode))
+ /* enable in-core preallocation only for regular files */
+ ar.flags = EXT4_MB_HINT_DATA;
+
+ current_block = ext4_mb_new_blocks(handle, &ar, err);
+ if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) {
+ EXT4_ERROR_INODE(inode,
+ "current_block %llu + ar.len %d > %d!",
+ current_block, ar.len,
+ EXT4_MAX_BLOCK_FILE_PHYS);
+ *err = -EIO;
+ goto failed_out;
+ }
+
+ if (*err && (target == blks)) {
+ /*
+ * if the allocation failed and we didn't allocate
+ * any blocks before
+ */
+ goto failed_out;
+ }
+ if (!*err) {
+ if (target == blks) {
+ /*
+ * save the new block number
+ * for the first direct block
+ */
+ new_blocks[index] = current_block;
+ }
+ blk_allocated += ar.len;
+ }
+allocated:
+ /* total number of blocks allocated for direct blocks */
+ ret = blk_allocated;
+ *err = 0;
+ return ret;
+failed_out:
+ for (i = 0; i < index; i++)
+ ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0);
+ return ret;
+}
+
+/**
+ * ext4_alloc_branch - allocate and set up a chain of blocks.
+ * @handle: handle for this transaction
+ * @inode: owner
+ * @indirect_blks: number of allocated indirect blocks
+ * @blks: number of allocated direct blocks
+ * @goal: preferred place for allocation
+ * @offsets: offsets (in the blocks) to store the pointers to next.
+ * @branch: place to store the chain in.
+ *
+ * This function allocates blocks, zeroes out all but the last one,
+ * links them into chain and (if we are synchronous) writes them to disk.
+ * In other words, it prepares a branch that can be spliced onto the
+ * inode. It stores the information about that chain in the branch[], in
+ * the same format as ext4_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 ext4_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
+ * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ * as described above and return 0.
+ */
+static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
+ ext4_lblk_t iblock, int indirect_blks,
+ int *blks, ext4_fsblk_t goal,
+ ext4_lblk_t *offsets, Indirect *branch)
+{
+ int blocksize = inode->i_sb->s_blocksize;
+ int i, n = 0;
+ int err = 0;
+ struct buffer_head *bh;
+ int num;
+ ext4_fsblk_t new_blocks[4];
+ ext4_fsblk_t current_block;
+
+ num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
+ *blks, new_blocks, &err);
+ if (err)
+ return err;
+
+ branch[0].key = cpu_to_le32(new_blocks[0]);
+ /*
+ * metadata blocks and data blocks are allocated.
+ */
+ for (n = 1; n <= indirect_blks; n++) {
+ /*
+ * Get buffer_head for parent block, zero it out
+ * and set the pointer to new one, then send
+ * parent to disk.
+ */
+ bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+ if (unlikely(!bh)) {
+ err = -EIO;
+ goto failed;
+ }
+
+ branch[n].bh = bh;
+ lock_buffer(bh);
+ BUFFER_TRACE(bh, "call get_create_access");
+ err = ext4_journal_get_create_access(handle, bh);
+ if (err) {
+ /* Don't brelse(bh) here; it's done in
+ * ext4_journal_forget() below */
+ unlock_buffer(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 ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, inode, bh);
+ if (err)
+ goto failed;
+ }
+ *blks = num;
+ return err;
+failed:
+ /* Allocation failed, free what we already allocated */
+ ext4_free_blocks(handle, inode, NULL, new_blocks[0], 1, 0);
+ for (i = 1; i <= n ; i++) {
+ /*
+ * branch[i].bh is newly allocated, so there is no
+ * need to revoke the block, which is why we don't
+ * need to set EXT4_FREE_BLOCKS_METADATA.
+ */
+ ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1,
+ EXT4_FREE_BLOCKS_FORGET);
+ }
+ for (i = n+1; i < indirect_blks; i++)
+ ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0);
+
+ ext4_free_blocks(handle, inode, NULL, new_blocks[i], num, 0);
+
+ return err;
+}
+
+/**
+ * ext4_splice_branch - splice the allocated branch onto inode.
+ * @handle: handle for this transaction
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @chain: chain of indirect blocks (with a missing link - see
+ * ext4_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 ext4_splice_branch(handle_t *handle, struct inode *inode,
+ ext4_lblk_t block, Indirect *where, int num,
+ int blks)
+{
+ int i;
+ int err = 0;
+ ext4_fsblk_t current_block;
+
+ /*
+ * 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 = ext4_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++);
+ }
+
+ /* We are done with atomic stuff, now do the rest of housekeeping */
+ /* 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->ext4_dirty_inode.
+ */
+ jbd_debug(5, "splicing indirect only\n");
+ BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, inode, where->bh);
+ if (err)
+ goto err_out;
+ } else {
+ /*
+ * OK, we spliced it into the inode itself on a direct block.
+ */
+ ext4_mark_inode_dirty(handle, inode);
+ jbd_debug(5, "splicing direct\n");
+ }
+ return err;
+
+err_out:
+ for (i = 1; i <= num; i++) {
+ /*
+ * branch[i].bh is newly allocated, so there is no
+ * need to revoke the block, which is why we don't
+ * need to set EXT4_FREE_BLOCKS_METADATA.
+ */
+ ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
+ EXT4_FREE_BLOCKS_FORGET);
+ }
+ ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key),
+ blks, 0);
+
+ return err;
+}
+
+/*
+ * The ext4_ind_map_blocks() function handles non-extents inodes
+ * (i.e., using the traditional indirect/double-indirect i_blocks
+ * scheme) for ext4_map_blocks().
+ *
+ * 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.
+ *
+ * The ext4_ind_get_blocks() function should be called with
+ * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
+ * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
+ * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
+ * blocks.
+ */
+int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
+ struct ext4_map_blocks *map,
+ int flags)
+{
+ int err = -EIO;
+ ext4_lblk_t offsets[4];
+ Indirect chain[4];
+ Indirect *partial;
+ ext4_fsblk_t goal;
+ int indirect_blks;
+ int blocks_to_boundary = 0;
+ int depth;
+ int count = 0;
+ ext4_fsblk_t first_block = 0;
+
+ trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
+ J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
+ J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
+ depth = ext4_block_to_path(inode, map->m_lblk, offsets,
+ &blocks_to_boundary);
+
+ if (depth == 0)
+ goto out;
+
+ partial = ext4_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);
+ count++;
+ /*map more blocks*/
+ while (count < map->m_len && count <= blocks_to_boundary) {
+ ext4_fsblk_t blk;
+
+ blk = le32_to_cpu(*(chain[depth-1].p + count));
+
+ if (blk == first_block + count)
+ count++;
+ else
+ break;
+ }
+ goto got_it;
+ }
+
+ /* Next simple case - plain lookup or failed read of indirect block */
+ if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
+ goto cleanup;
+
+ /*
+ * Okay, we need to do block allocation.
+ */
+ goal = ext4_find_goal(inode, map->m_lblk, 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 = ext4_blks_to_allocate(partial, indirect_blks,
+ map->m_len, blocks_to_boundary);
+ /*
+ * Block out ext4_truncate while we alter the tree
+ */
+ err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks,
+ &count, goal,
+ offsets + (partial - chain), partial);
+
+ /*
+ * The ext4_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 = ext4_splice_branch(handle, inode, map->m_lblk,
+ partial, indirect_blks, count);
+ if (err)
+ goto cleanup;
+
+ map->m_flags |= EXT4_MAP_NEW;
+
+ ext4_update_inode_fsync_trans(handle, inode, 1);
+got_it:
+ map->m_flags |= EXT4_MAP_MAPPED;
+ map->m_pblk = le32_to_cpu(chain[depth-1].key);
+ map->m_len = count;
+ if (count > blocks_to_boundary)
+ map->m_flags |= EXT4_MAP_BOUNDARY;
+ 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--;
+ }
+out:
+ trace_ext4_ind_map_blocks_exit(inode, map->m_lblk,
+ map->m_pblk, map->m_len, err);
+ return err;
+}
+
+/*
+ * O_DIRECT for ext3 (or indirect map) based files
+ *
+ * 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.
+ */
+ssize_t ext4_ind_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 ext4_inode_info *ei = EXT4_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 = ext4_journal_start(inode, 2);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+ ret = ext4_orphan_add(handle, inode);
+ if (ret) {
+ ext4_journal_stop(handle);
+ goto out;
+ }
+ orphan = 1;
+ ei->i_disksize = inode->i_size;
+ ext4_journal_stop(handle);
+ }
+ }
+
+retry:
+ if (rw == READ && ext4_should_dioread_nolock(inode))
+ ret = __blockdev_direct_IO(rw, iocb, inode,
+ inode->i_sb->s_bdev, iov,
+ offset, nr_segs,
+ ext4_get_block, NULL, NULL, 0);
+ else {
+ ret = blockdev_direct_IO(rw, iocb, inode,
+ inode->i_sb->s_bdev, iov,
+ offset, nr_segs,
+ ext4_get_block, NULL);
+
+ if (unlikely((rw & WRITE) && ret < 0)) {
+ loff_t isize = i_size_read(inode);
+ loff_t end = offset + iov_length(iov, nr_segs);
+
+ if (end > isize)
+ ext4_truncate_failed_write(inode);
+ }
+ }
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+
+ if (orphan) {
+ int err;
+
+ /* Credits for sb + inode write */
+ handle = ext4_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);
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+
+ goto out;
+ }
+ if (inode->i_nlink)
+ ext4_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
+ * ext4_mark_inode_dirty() to userspace. So
+ * ignore it.
+ */
+ ext4_mark_inode_dirty(handle, inode);
+ }
+ }
+ err = ext4_journal_stop(handle);
+ if (ret == 0)
+ ret = err;
+ }
+out:
+ return ret;
+}
+
+/*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate a new block at @lblocks for non extent file based file
+ */
+int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
+ int blk_bits;
+
+ if (lblock < EXT4_NDIR_BLOCKS)
+ return 0;
+
+ lblock -= EXT4_NDIR_BLOCKS;
+
+ if (ei->i_da_metadata_calc_len &&
+ (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
+ ei->i_da_metadata_calc_len++;
+ return 0;
+ }
+ ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
+ ei->i_da_metadata_calc_len = 1;
+ blk_bits = order_base_2(lblock);
+ return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
+}
+
+int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+ int indirects;
+
+ /* if nrblocks are contiguous */
+ if (chunk) {
+ /*
+ * With N contiguous data blocks, we need at most
+ * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
+ * 2 dindirect blocks, and 1 tindirect block
+ */
+ return DIV_ROUND_UP(nrblocks,
+ EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
+ }
+ /*
+ * if nrblocks are not contiguous, worse case, each block touch
+ * a indirect block, and each indirect block touch a double indirect
+ * block, plus a triple indirect block
+ */
+ indirects = nrblocks * 2 + 1;
+ return indirects;
+}
+
+/*
+ * 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 = ext4_journal_start(inode, ext4_blocks_for_truncate(inode));
+ if (!IS_ERR(result))
+ return result;
+
+ ext4_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 (!ext4_handle_valid(handle))
+ return 0;
+ if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
+ return 0;
+ if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode)))
+ return 0;
+ return 1;
+}
+
+/*
+ * 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;
+}
+
+/**
+ * ext4_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 ext4_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 ext4_truncate().
+ *
+ * When we do truncate() we may have to clean the ends of several
+ * indirect blocks but leave the blocks themselves alive. Block is
+ * partially truncated if some data below the new i_size is referred
+ * from it (and it is on the path to the first completely truncated
+ * data block, indeed). We have to free the top of that path along
+ * with everything to the right of the path. Since no allocation
+ * past the truncation point is possible until ext4_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 *ext4_find_shared(struct inode *inode, int depth,
+ ext4_lblk_t 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 = ext4_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 ext4. 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.
+ *
+ * Return 0 on success, 1 on invalid block range
+ * and < 0 on fatal error.
+ */
+static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
+ struct buffer_head *bh,
+ ext4_fsblk_t block_to_free,
+ unsigned long count, __le32 *first,
+ __le32 *last)
+{
+ __le32 *p;
+ int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED;
+ int err;
+
+ if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+ flags |= EXT4_FREE_BLOCKS_METADATA;
+
+ if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
+ count)) {
+ EXT4_ERROR_INODE(inode, "attempt to clear invalid "
+ "blocks %llu len %lu",
+ (unsigned long long) block_to_free, count);
+ return 1;
+ }
+
+ if (try_to_extend_transaction(handle, inode)) {
+ if (bh) {
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, inode, bh);
+ if (unlikely(err))
+ goto out_err;
+ }
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (unlikely(err))
+ goto out_err;
+ err = ext4_truncate_restart_trans(handle, inode,
+ ext4_blocks_for_truncate(inode));
+ if (unlikely(err))
+ goto out_err;
+ if (bh) {
+ BUFFER_TRACE(bh, "retaking write access");
+ err = ext4_journal_get_write_access(handle, bh);
+ if (unlikely(err))
+ goto out_err;
+ }
+ }
+
+ for (p = first; p < last; p++)
+ *p = 0;
+
+ ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
+ return 0;
+out_err:
+ ext4_std_error(inode->i_sb, err);
+ return err;
+}
+
+/**
+ * ext4_free_data - free a list of data blocks
+ * @handle: handle for this transaction
+ * @inode: inode we are dealing with
+ * @this_bh: indirect buffer_head which contains *@first and *@last
+ * @first: array of block numbers
+ * @last: points immediately past the end of array
+ *
+ * We are freeing all blocks referred from that array (numbers are stored as
+ * little-endian 32-bit) and updating @inode->i_blocks appropriately.
+ *
+ * We accumulate contiguous runs of blocks to free. Conveniently, if these
+ * blocks are contiguous then releasing them at one time will only affect one
+ * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
+ * actually use a lot of journal space.
+ *
+ * @this_bh will be %NULL if @first and @last point into the inode's direct
+ * block pointers.
+ */
+static void ext4_free_data(handle_t *handle, struct inode *inode,
+ struct buffer_head *this_bh,
+ __le32 *first, __le32 *last)
+{
+ ext4_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 */
+ ext4_fsblk_t nr; /* Current block # */
+ __le32 *p; /* Pointer into inode/ind
+ for current block */
+ int err = 0;
+
+ if (this_bh) { /* For indirect block */
+ BUFFER_TRACE(this_bh, "get_write_access");
+ err = ext4_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 {
+ err = ext4_clear_blocks(handle, inode, this_bh,
+ block_to_free, count,
+ block_to_free_p, p);
+ if (err)
+ break;
+ block_to_free = nr;
+ block_to_free_p = p;
+ count = 1;
+ }
+ }
+ }
+
+ if (!err && count > 0)
+ err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
+ count, block_to_free_p, p);
+ if (err < 0)
+ /* fatal error */
+ return;
+
+ if (this_bh) {
+ BUFFER_TRACE(this_bh, "call ext4_handle_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 ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
+ ext4_handle_dirty_metadata(handle, inode, this_bh);
+ else
+ EXT4_ERROR_INODE(inode,
+ "circular indirect block detected at "
+ "block %llu",
+ (unsigned long long) this_bh->b_blocknr);
+ }
+}
+
+/**
+ * ext4_free_branches - free an array of branches
+ * @handle: JBD handle for this transaction
+ * @inode: inode we are dealing with
+ * @parent_bh: the buffer_head which contains *@first and *@last
+ * @first: array of block numbers
+ * @last: pointer immediately past the end of array
+ * @depth: depth of the branches to free
+ *
+ * We are freeing all blocks referred from these branches (numbers are
+ * stored as little-endian 32-bit) and updating @inode->i_blocks
+ * appropriately.
+ */
+static void ext4_free_branches(handle_t *handle, struct inode *inode,
+ struct buffer_head *parent_bh,
+ __le32 *first, __le32 *last, int depth)
+{
+ ext4_fsblk_t nr;
+ __le32 *p;
+
+ if (ext4_handle_is_aborted(handle))
+ return;
+
+ if (depth--) {
+ struct buffer_head *bh;
+ int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+ p = last;
+ while (--p >= first) {
+ nr = le32_to_cpu(*p);
+ if (!nr)
+ continue; /* A hole */
+
+ if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
+ nr, 1)) {
+ EXT4_ERROR_INODE(inode,
+ "invalid indirect mapped "
+ "block %lu (level %d)",
+ (unsigned long) nr, depth);
+ break;
+ }
+
+ /* 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) {
+ EXT4_ERROR_INODE_BLOCK(inode, nr,
+ "Read failure");
+ continue;
+ }
+
+ /* This zaps the entire block. Bottom up. */
+ BUFFER_TRACE(bh, "free child branches");
+ ext4_free_branches(handle, inode, bh,
+ (__le32 *) bh->b_data,
+ (__le32 *) bh->b_data + addr_per_block,
+ depth);
+ brelse(bh);
+
+ /*
+ * 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 (ext4_handle_is_aborted(handle))
+ return;
+ if (try_to_extend_transaction(handle, inode)) {
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_truncate_restart_trans(handle, inode,
+ ext4_blocks_for_truncate(inode));
+ }
+
+ /*
+ * The forget flag here is critical because if
+ * we are journaling (and not doing data
+ * journaling), we have to make sure a revoke
+ * record is written to prevent the journal
+ * replay from overwriting the (former)
+ * indirect block if it gets reallocated as a
+ * data block. This must happen in the same
+ * transaction where the data blocks are
+ * actually freed.
+ */
+ ext4_free_blocks(handle, inode, NULL, nr, 1,
+ EXT4_FREE_BLOCKS_METADATA|
+ EXT4_FREE_BLOCKS_FORGET);
+
+ 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 (!ext4_journal_get_write_access(handle,
+ parent_bh)){
+ *p = 0;
+ BUFFER_TRACE(parent_bh,
+ "call ext4_handle_dirty_metadata");
+ ext4_handle_dirty_metadata(handle,
+ inode,
+ parent_bh);
+ }
+ }
+ }
+ } else {
+ /* We have reached the bottom of the tree. */
+ BUFFER_TRACE(parent_bh, "free data blocks");
+ ext4_free_data(handle, inode, parent_bh, first, last);
+ }
+}
+
+void ext4_ind_truncate(struct inode *inode)
+{
+ handle_t *handle;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ __le32 *i_data = ei->i_data;
+ int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+ struct address_space *mapping = inode->i_mapping;
+ ext4_lblk_t offsets[4];
+ Indirect chain[4];
+ Indirect *partial;
+ __le32 nr = 0;
+ int n = 0;
+ ext4_lblk_t last_block, max_block;
+ unsigned blocksize = inode->i_sb->s_blocksize;
+
+ handle = start_transaction(inode);
+ if (IS_ERR(handle))
+ return; /* AKPM: return what? */
+
+ last_block = (inode->i_size + blocksize-1)
+ >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
+ max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
+ >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
+
+ if (inode->i_size & (blocksize - 1))
+ if (ext4_block_truncate_page(handle, mapping, inode->i_size))
+ goto out_stop;
+
+ if (last_block != max_block) {
+ n = ext4_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 (ext4_orphan_add(handle, inode))
+ goto out_stop;
+
+ /*
+ * From here we block out all ext4_get_block() callers who want to
+ * modify the block allocation tree.
+ */
+ down_write(&ei->i_data_sem);
+
+ ext4_discard_preallocations(inode);
+
+ /*
+ * 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
+ * ext4 *really* writes onto the disk inode.
+ */
+ ei->i_disksize = inode->i_size;
+
+ if (last_block == max_block) {
+ /*
+ * It is unnecessary to free any data blocks if last_block is
+ * equal to the indirect block limit.
+ */
+ goto out_unlock;
+ } else if (n == 1) { /* direct blocks */
+ ext4_free_data(handle, inode, NULL, i_data+offsets[0],
+ i_data + EXT4_NDIR_BLOCKS);
+ goto do_indirects;
+ }
+
+ partial = ext4_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 */
+ ext4_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");
+ ext4_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) {
+ ext4_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[EXT4_IND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
+ i_data[EXT4_IND_BLOCK] = 0;
+ }
+ case EXT4_IND_BLOCK:
+ nr = i_data[EXT4_DIND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
+ i_data[EXT4_DIND_BLOCK] = 0;
+ }
+ case EXT4_DIND_BLOCK:
+ nr = i_data[EXT4_TIND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
+ i_data[EXT4_TIND_BLOCK] = 0;
+ }
+ case EXT4_TIND_BLOCK:
+ ;
+ }
+
+out_unlock:
+ up_write(&ei->i_data_sem);
+ inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
+ ext4_mark_inode_dirty(handle, inode);
+
+ /*
+ * In a multi-transaction truncate, we only make the final transaction
+ * synchronous
+ */
+ if (IS_SYNC(inode))
+ ext4_handle_sync(handle);
+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
+ * ext4_delete_inode(), and we allow that function to clean up the
+ * orphan info for us.
+ */
+ if (inode->i_nlink)
+ ext4_orphan_del(handle, inode);
+
+ ext4_journal_stop(handle);
+ trace_ext4_truncate_exit(inode);
+}
+
*
* 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)
*
return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}
-/*
- * 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 = ext4_journal_start(inode, ext4_blocks_for_truncate(inode));
- if (!IS_ERR(result))
- return result;
-
- ext4_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 (!ext4_handle_valid(handle))
- return 0;
- if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
- return 0;
- if (!ext4_journal_extend(handle, ext4_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
ext4_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;
-}
-
-/**
- * ext4_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 ext4 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 ext4_block_to_path(struct inode *inode,
- ext4_lblk_t i_block,
- ext4_lblk_t offsets[4], int *boundary)
-{
- int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
- int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
- const long direct_blocks = EXT4_NDIR_BLOCKS,
- indirect_blocks = ptrs,
- double_blocks = (1 << (ptrs_bits * 2));
- int n = 0;
- int final = 0;
-
- if (i_block < direct_blocks) {
- offsets[n++] = i_block;
- final = direct_blocks;
- } else if ((i_block -= direct_blocks) < indirect_blocks) {
- offsets[n++] = EXT4_IND_BLOCK;
- offsets[n++] = i_block;
- final = ptrs;
- } else if ((i_block -= indirect_blocks) < double_blocks) {
- offsets[n++] = EXT4_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++] = EXT4_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 {
- ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
- i_block + direct_blocks +
- indirect_blocks + double_blocks, inode->i_ino);
- }
- if (boundary)
- *boundary = final - 1 - (i_block & (ptrs - 1));
- return n;
-}
-
-/**
- * ext4_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 reads all @depth-1 indirect blocks successfully and finds
- * the whole chain, all way to the data (returns %NULL, *err == 0).
- *
- * Need to be called with
- * down_read(&EXT4_I(inode)->i_data_sem)
- */
-static Indirect *ext4_get_branch(struct inode *inode, int depth,
- ext4_lblk_t *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, EXT4_I(inode)->i_data + *offsets);
- if (!p->key)
- goto no_block;
- while (--depth) {
- bh = sb_getblk(sb, le32_to_cpu(p->key));
- if (unlikely(!bh))
- goto failure;
-
- if (!bh_uptodate_or_lock(bh)) {
- if (bh_submit_read(bh) < 0) {
- put_bh(bh);
- goto failure;
- }
- /* validate block references */
- if (ext4_check_indirect_blockref(inode, bh)) {
- put_bh(bh);
- goto failure;
- }
- }
-
- add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
- /* Reader: end */
- if (!p->key)
- goto no_block;
- }
- return NULL;
-
-failure:
- *err = -EIO;
-no_block:
- return p;
-}
-
-/**
- * ext4_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 ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
-{
- struct ext4_inode_info *ei = EXT4_I(inode);
- __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
- __le32 *p;
- ext4_fsblk_t bg_start;
- ext4_fsblk_t last_block;
- ext4_grpblk_t colour;
- ext4_group_t block_group;
- int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
-
- /* 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.
- */
- block_group = ei->i_block_group;
- if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
- block_group &= ~(flex_size-1);
- if (S_ISREG(inode->i_mode))
- block_group++;
- }
- bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
- last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
-
- /*
- * If we are doing delayed allocation, we don't need take
- * colour into account.
- */
- if (test_opt(inode->i_sb, DELALLOC))
- return bg_start;
-
- if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
- colour = (current->pid % 16) *
- (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
- else
- colour = (current->pid % 16) * ((last_block - bg_start) / 16);
- return bg_start + colour;
-}
-
-/**
- * ext4_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.
- * Because this is only used for non-extent files, we limit the block nr
- * to 32 bits.
- */
-static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
- Indirect *partial)
-{
- ext4_fsblk_t goal;
-
- /*
- * XXX need to get goal block from mballoc's data structures
- */
-
- goal = ext4_find_near(inode, partial);
- goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
- return goal;
-}
-
-/**
- * ext4_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 ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
- int blocks_to_boundary)
-{
- unsigned int 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;
-}
-
-/**
- * ext4_alloc_blocks: multiple allocate blocks needed for a branch
- * @handle: handle for this transaction
- * @inode: inode which needs allocated blocks
- * @iblock: the logical block to start allocated at
- * @goal: preferred physical block of allocation
- * @indirect_blks: the number of blocks need to allocate for indirect
- * blocks
- * @blks: number of desired blocks
- * @new_blocks: on return it will store the new block numbers for
- * the indirect blocks(if needed) and the first direct block,
- * @err: on return it will store the error code
- *
- * This function will return the number of blocks allocated as
- * requested by the passed-in parameters.
- */
-static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
- ext4_lblk_t iblock, ext4_fsblk_t goal,
- int indirect_blks, int blks,
- ext4_fsblk_t new_blocks[4], int *err)
-{
- struct ext4_allocation_request ar;
- int target, i;
- unsigned long count = 0, blk_allocated = 0;
- int index = 0;
- ext4_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)
- */
- /* first we try to allocate the indirect blocks */
- target = indirect_blks;
- while (target > 0) {
- count = target;
- /* allocating blocks for indirect blocks and direct blocks */
- current_block = ext4_new_meta_blocks(handle, inode, goal,
- 0, &count, err);
- if (*err)
- goto failed_out;
-
- if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) {
- EXT4_ERROR_INODE(inode,
- "current_block %llu + count %lu > %d!",
- current_block, count,
- EXT4_MAX_BLOCK_FILE_PHYS);
- *err = -EIO;
- goto failed_out;
- }
-
- target -= count;
- /* allocate blocks for indirect blocks */
- while (index < indirect_blks && count) {
- new_blocks[index++] = current_block++;
- count--;
- }
- if (count > 0) {
- /*
- * save the new block number
- * for the first direct block
- */
- new_blocks[index] = current_block;
- printk(KERN_INFO "%s returned more blocks than "
- "requested\n", __func__);
- WARN_ON(1);
- break;
- }
- }
-
- target = blks - count ;
- blk_allocated = count;
- if (!target)
- goto allocated;
- /* Now allocate data blocks */
- memset(&ar, 0, sizeof(ar));
- ar.inode = inode;
- ar.goal = goal;
- ar.len = target;
- ar.logical = iblock;
- if (S_ISREG(inode->i_mode))
- /* enable in-core preallocation only for regular files */
- ar.flags = EXT4_MB_HINT_DATA;
-
- current_block = ext4_mb_new_blocks(handle, &ar, err);
- if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) {
- EXT4_ERROR_INODE(inode,
- "current_block %llu + ar.len %d > %d!",
- current_block, ar.len,
- EXT4_MAX_BLOCK_FILE_PHYS);
- *err = -EIO;
- goto failed_out;
- }
-
- if (*err && (target == blks)) {
- /*
- * if the allocation failed and we didn't allocate
- * any blocks before
- */
- goto failed_out;
- }
- if (!*err) {
- if (target == blks) {
- /*
- * save the new block number
- * for the first direct block
- */
- new_blocks[index] = current_block;
- }
- blk_allocated += ar.len;
- }
-allocated:
- /* total number of blocks allocated for direct blocks */
- ret = blk_allocated;
- *err = 0;
- return ret;
-failed_out:
- for (i = 0; i < index; i++)
- ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0);
- return ret;
-}
-
-/**
- * ext4_alloc_branch - allocate and set up a chain of blocks.
- * @handle: handle for this transaction
- * @inode: owner
- * @indirect_blks: number of allocated indirect blocks
- * @blks: number of allocated direct blocks
- * @goal: preferred place for allocation
- * @offsets: offsets (in the blocks) to store the pointers to next.
- * @branch: place to store the chain in.
- *
- * This function allocates blocks, zeroes out all but the last one,
- * links them into chain and (if we are synchronous) writes them to disk.
- * In other words, it prepares a branch that can be spliced onto the
- * inode. It stores the information about that chain in the branch[], in
- * the same format as ext4_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 ext4_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
- * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
- * as described above and return 0.
- */
-static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
- ext4_lblk_t iblock, int indirect_blks,
- int *blks, ext4_fsblk_t goal,
- ext4_lblk_t *offsets, Indirect *branch)
-{
- int blocksize = inode->i_sb->s_blocksize;
- int i, n = 0;
- int err = 0;
- struct buffer_head *bh;
- int num;
- ext4_fsblk_t new_blocks[4];
- ext4_fsblk_t current_block;
-
- num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
- *blks, new_blocks, &err);
- if (err)
- return err;
-
- branch[0].key = cpu_to_le32(new_blocks[0]);
- /*
- * metadata blocks and data blocks are allocated.
- */
- for (n = 1; n <= indirect_blks; n++) {
- /*
- * Get buffer_head for parent block, zero it out
- * and set the pointer to new one, then send
- * parent to disk.
- */
- bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
- if (unlikely(!bh)) {
- err = -EIO;
- goto failed;
- }
-
- branch[n].bh = bh;
- lock_buffer(bh);
- BUFFER_TRACE(bh, "call get_create_access");
- err = ext4_journal_get_create_access(handle, bh);
- if (err) {
- /* Don't brelse(bh) here; it's done in
- * ext4_journal_forget() below */
- unlock_buffer(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 ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, inode, bh);
- if (err)
- goto failed;
- }
- *blks = num;
- return err;
-failed:
- /* Allocation failed, free what we already allocated */
- ext4_free_blocks(handle, inode, NULL, new_blocks[0], 1, 0);
- for (i = 1; i <= n ; i++) {
- /*
- * branch[i].bh is newly allocated, so there is no
- * need to revoke the block, which is why we don't
- * need to set EXT4_FREE_BLOCKS_METADATA.
- */
- ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1,
- EXT4_FREE_BLOCKS_FORGET);
- }
- for (i = n+1; i < indirect_blks; i++)
- ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0);
-
- ext4_free_blocks(handle, inode, NULL, new_blocks[i], num, 0);
-
- return err;
-}
-
-/**
- * ext4_splice_branch - splice the allocated branch onto inode.
- * @handle: handle for this transaction
- * @inode: owner
- * @block: (logical) number of block we are adding
- * @chain: chain of indirect blocks (with a missing link - see
- * ext4_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 ext4_splice_branch(handle_t *handle, struct inode *inode,
- ext4_lblk_t block, Indirect *where, int num,
- int blks)
-{
- int i;
- int err = 0;
- ext4_fsblk_t current_block;
-
- /*
- * 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 = ext4_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++);
- }
-
- /* We are done with atomic stuff, now do the rest of housekeeping */
- /* 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->ext4_dirty_inode.
- */
- jbd_debug(5, "splicing indirect only\n");
- BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, inode, where->bh);
- if (err)
- goto err_out;
- } else {
- /*
- * OK, we spliced it into the inode itself on a direct block.
- */
- ext4_mark_inode_dirty(handle, inode);
- jbd_debug(5, "splicing direct\n");
- }
- return err;
-
-err_out:
- for (i = 1; i <= num; i++) {
- /*
- * branch[i].bh is newly allocated, so there is no
- * need to revoke the block, which is why we don't
- * need to set EXT4_FREE_BLOCKS_METADATA.
- */
- ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
- EXT4_FREE_BLOCKS_FORGET);
- }
- ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key),
- blks, 0);
-
- return err;
-}
-
-/*
- * The ext4_ind_map_blocks() function handles non-extents inodes
- * (i.e., using the traditional indirect/double-indirect i_blocks
- * scheme) for ext4_map_blocks().
- *
- * 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.
- *
- * The ext4_ind_get_blocks() function should be called with
- * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
- * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
- * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
- * blocks.
- */
-static int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
- struct ext4_map_blocks *map,
- int flags)
-{
- int err = -EIO;
- ext4_lblk_t offsets[4];
- Indirect chain[4];
- Indirect *partial;
- ext4_fsblk_t goal;
- int indirect_blks;
- int blocks_to_boundary = 0;
- int depth;
- int count = 0;
- ext4_fsblk_t first_block = 0;
-
- trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
- J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
- J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
- depth = ext4_block_to_path(inode, map->m_lblk, offsets,
- &blocks_to_boundary);
-
- if (depth == 0)
- goto out;
-
- partial = ext4_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);
- count++;
- /*map more blocks*/
- while (count < map->m_len && count <= blocks_to_boundary) {
- ext4_fsblk_t blk;
-
- blk = le32_to_cpu(*(chain[depth-1].p + count));
-
- if (blk == first_block + count)
- count++;
- else
- break;
- }
- goto got_it;
- }
-
- /* Next simple case - plain lookup or failed read of indirect block */
- if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
- goto cleanup;
-
- /*
- * Okay, we need to do block allocation.
- */
- goal = ext4_find_goal(inode, map->m_lblk, 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 = ext4_blks_to_allocate(partial, indirect_blks,
- map->m_len, blocks_to_boundary);
- /*
- * Block out ext4_truncate while we alter the tree
- */
- err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks,
- &count, goal,
- offsets + (partial - chain), partial);
-
- /*
- * The ext4_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 = ext4_splice_branch(handle, inode, map->m_lblk,
- partial, indirect_blks, count);
- if (err)
- goto cleanup;
-
- map->m_flags |= EXT4_MAP_NEW;
-
- ext4_update_inode_fsync_trans(handle, inode, 1);
-got_it:
- map->m_flags |= EXT4_MAP_MAPPED;
- map->m_pblk = le32_to_cpu(chain[depth-1].key);
- map->m_len = count;
- if (count > blocks_to_boundary)
- map->m_flags |= EXT4_MAP_BOUNDARY;
- 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--;
- }
-out:
- trace_ext4_ind_map_blocks_exit(inode, map->m_lblk,
- map->m_pblk, map->m_len, err);
- return err;
-}
-
#ifdef CONFIG_QUOTA
qsize_t *ext4_get_reserved_space(struct inode *inode)
{
}
#endif
-/*
- * Calculate the number of metadata blocks need to reserve
- * to allocate a new block at @lblocks for non extent file based file
- */
-static int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
-{
- struct ext4_inode_info *ei = EXT4_I(inode);
- sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
- int blk_bits;
-
- if (lblock < EXT4_NDIR_BLOCKS)
- return 0;
-
- lblock -= EXT4_NDIR_BLOCKS;
-
- if (ei->i_da_metadata_calc_len &&
- (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
- ei->i_da_metadata_calc_len++;
- return 0;
- }
- ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
- ei->i_da_metadata_calc_len = 1;
- blk_bits = order_base_2(lblock);
- return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
-}
-
/*
* Calculate the number of metadata blocks need to reserve
* to allocate a block located at @lblock
return try_to_free_buffers(page);
}
-/*
- * O_DIRECT for ext3 (or indirect map) based files
- *
- * 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 ext4_ind_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 ext4_inode_info *ei = EXT4_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 = ext4_journal_start(inode, 2);
- if (IS_ERR(handle)) {
- ret = PTR_ERR(handle);
- goto out;
- }
- ret = ext4_orphan_add(handle, inode);
- if (ret) {
- ext4_journal_stop(handle);
- goto out;
- }
- orphan = 1;
- ei->i_disksize = inode->i_size;
- ext4_journal_stop(handle);
- }
- }
-
-retry:
- if (rw == READ && ext4_should_dioread_nolock(inode))
- ret = __blockdev_direct_IO(rw, iocb, inode,
- inode->i_sb->s_bdev, iov,
- offset, nr_segs,
- ext4_get_block, NULL, NULL, 0);
- else {
- ret = blockdev_direct_IO(rw, iocb, inode,
- inode->i_sb->s_bdev, iov,
- offset, nr_segs,
- ext4_get_block, NULL);
-
- if (unlikely((rw & WRITE) && ret < 0)) {
- loff_t isize = i_size_read(inode);
- loff_t end = offset + iov_length(iov, nr_segs);
-
- if (end > isize)
- ext4_truncate_failed_write(inode);
- }
- }
- if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
- goto retry;
-
- if (orphan) {
- int err;
-
- /* Credits for sb + inode write */
- handle = ext4_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);
- if (inode->i_nlink)
- ext4_orphan_del(NULL, inode);
-
- goto out;
- }
- if (inode->i_nlink)
- ext4_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
- * ext4_mark_inode_dirty() to userspace. So
- * ignore it.
- */
- ext4_mark_inode_dirty(handle, inode);
- }
- }
- err = ext4_journal_stop(handle);
- if (ret == 0)
- ret = err;
- }
-out:
- return ret;
-}
-
/*
* ext4_get_block used when preparing for a DIO write or buffer write.
* We allocate an uinitialized extent if blocks haven't been allocated.
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;
-}
-
-/**
- * ext4_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 ext4_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 ext4_truncate().
- *
- * When we do truncate() we may have to clean the ends of several
- * indirect blocks but leave the blocks themselves alive. Block is
- * partially truncated if some data below the new i_size is referred
- * from it (and it is on the path to the first completely truncated
- * data block, indeed). We have to free the top of that path along
- * with everything to the right of the path. Since no allocation
- * past the truncation point is possible until ext4_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 *ext4_find_shared(struct inode *inode, int depth,
- ext4_lblk_t 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 = ext4_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 ext4. 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.
- *
- * Return 0 on success, 1 on invalid block range
- * and < 0 on fatal error.
- */
-static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
- struct buffer_head *bh,
- ext4_fsblk_t block_to_free,
- unsigned long count, __le32 *first,
- __le32 *last)
-{
- __le32 *p;
- int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED;
- int err;
-
- if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
- flags |= EXT4_FREE_BLOCKS_METADATA;
-
- if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
- count)) {
- EXT4_ERROR_INODE(inode, "attempt to clear invalid "
- "blocks %llu len %lu",
- (unsigned long long) block_to_free, count);
- return 1;
- }
-
- if (try_to_extend_transaction(handle, inode)) {
- if (bh) {
- BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, inode, bh);
- if (unlikely(err))
- goto out_err;
- }
- err = ext4_mark_inode_dirty(handle, inode);
- if (unlikely(err))
- goto out_err;
- err = ext4_truncate_restart_trans(handle, inode,
- ext4_blocks_for_truncate(inode));
- if (unlikely(err))
- goto out_err;
- if (bh) {
- BUFFER_TRACE(bh, "retaking write access");
- err = ext4_journal_get_write_access(handle, bh);
- if (unlikely(err))
- goto out_err;
- }
- }
-
- for (p = first; p < last; p++)
- *p = 0;
-
- ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
- return 0;
-out_err:
- ext4_std_error(inode->i_sb, err);
- return err;
-}
-
-/**
- * ext4_free_data - free a list of data blocks
- * @handle: handle for this transaction
- * @inode: inode we are dealing with
- * @this_bh: indirect buffer_head which contains *@first and *@last
- * @first: array of block numbers
- * @last: points immediately past the end of array
- *
- * We are freeing all blocks referred from that array (numbers are stored as
- * little-endian 32-bit) and updating @inode->i_blocks appropriately.
- *
- * We accumulate contiguous runs of blocks to free. Conveniently, if these
- * blocks are contiguous then releasing them at one time will only affect one
- * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
- * actually use a lot of journal space.
- *
- * @this_bh will be %NULL if @first and @last point into the inode's direct
- * block pointers.
- */
-static void ext4_free_data(handle_t *handle, struct inode *inode,
- struct buffer_head *this_bh,
- __le32 *first, __le32 *last)
-{
- ext4_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 */
- ext4_fsblk_t nr; /* Current block # */
- __le32 *p; /* Pointer into inode/ind
- for current block */
- int err = 0;
-
- if (this_bh) { /* For indirect block */
- BUFFER_TRACE(this_bh, "get_write_access");
- err = ext4_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 {
- err = ext4_clear_blocks(handle, inode, this_bh,
- block_to_free, count,
- block_to_free_p, p);
- if (err)
- break;
- block_to_free = nr;
- block_to_free_p = p;
- count = 1;
- }
- }
- }
-
- if (!err && count > 0)
- err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
- count, block_to_free_p, p);
- if (err < 0)
- /* fatal error */
- return;
-
- if (this_bh) {
- BUFFER_TRACE(this_bh, "call ext4_handle_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 ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
- ext4_handle_dirty_metadata(handle, inode, this_bh);
- else
- EXT4_ERROR_INODE(inode,
- "circular indirect block detected at "
- "block %llu",
- (unsigned long long) this_bh->b_blocknr);
- }
-}
-
-/**
- * ext4_free_branches - free an array of branches
- * @handle: JBD handle for this transaction
- * @inode: inode we are dealing with
- * @parent_bh: the buffer_head which contains *@first and *@last
- * @first: array of block numbers
- * @last: pointer immediately past the end of array
- * @depth: depth of the branches to free
- *
- * We are freeing all blocks referred from these branches (numbers are
- * stored as little-endian 32-bit) and updating @inode->i_blocks
- * appropriately.
- */
-static void ext4_free_branches(handle_t *handle, struct inode *inode,
- struct buffer_head *parent_bh,
- __le32 *first, __le32 *last, int depth)
-{
- ext4_fsblk_t nr;
- __le32 *p;
-
- if (ext4_handle_is_aborted(handle))
- return;
-
- if (depth--) {
- struct buffer_head *bh;
- int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
- p = last;
- while (--p >= first) {
- nr = le32_to_cpu(*p);
- if (!nr)
- continue; /* A hole */
-
- if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
- nr, 1)) {
- EXT4_ERROR_INODE(inode,
- "invalid indirect mapped "
- "block %lu (level %d)",
- (unsigned long) nr, depth);
- break;
- }
-
- /* 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) {
- EXT4_ERROR_INODE_BLOCK(inode, nr,
- "Read failure");
- continue;
- }
-
- /* This zaps the entire block. Bottom up. */
- BUFFER_TRACE(bh, "free child branches");
- ext4_free_branches(handle, inode, bh,
- (__le32 *) bh->b_data,
- (__le32 *) bh->b_data + addr_per_block,
- depth);
- brelse(bh);
-
- /*
- * 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 (ext4_handle_is_aborted(handle))
- return;
- if (try_to_extend_transaction(handle, inode)) {
- ext4_mark_inode_dirty(handle, inode);
- ext4_truncate_restart_trans(handle, inode,
- ext4_blocks_for_truncate(inode));
- }
-
- /*
- * The forget flag here is critical because if
- * we are journaling (and not doing data
- * journaling), we have to make sure a revoke
- * record is written to prevent the journal
- * replay from overwriting the (former)
- * indirect block if it gets reallocated as a
- * data block. This must happen in the same
- * transaction where the data blocks are
- * actually freed.
- */
- ext4_free_blocks(handle, inode, NULL, nr, 1,
- EXT4_FREE_BLOCKS_METADATA|
- EXT4_FREE_BLOCKS_FORGET);
-
- 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 (!ext4_journal_get_write_access(handle,
- parent_bh)){
- *p = 0;
- BUFFER_TRACE(parent_bh,
- "call ext4_handle_dirty_metadata");
- ext4_handle_dirty_metadata(handle,
- inode,
- parent_bh);
- }
- }
- }
- } else {
- /* We have reached the bottom of the tree. */
- BUFFER_TRACE(parent_bh, "free data blocks");
- ext4_free_data(handle, inode, parent_bh, first, last);
- }
-}
-
int ext4_can_truncate(struct inode *inode)
{
if (S_ISREG(inode->i_mode))
trace_ext4_truncate_exit(inode);
}
-void ext4_ind_truncate(struct inode *inode)
-{
- handle_t *handle;
- struct ext4_inode_info *ei = EXT4_I(inode);
- __le32 *i_data = ei->i_data;
- int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
- struct address_space *mapping = inode->i_mapping;
- ext4_lblk_t offsets[4];
- Indirect chain[4];
- Indirect *partial;
- __le32 nr = 0;
- int n = 0;
- ext4_lblk_t last_block, max_block;
- unsigned blocksize = inode->i_sb->s_blocksize;
-
- handle = start_transaction(inode);
- if (IS_ERR(handle))
- return; /* AKPM: return what? */
-
- last_block = (inode->i_size + blocksize-1)
- >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
- max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
- >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
-
- if (inode->i_size & (blocksize - 1))
- if (ext4_block_truncate_page(handle, mapping, inode->i_size))
- goto out_stop;
-
- if (last_block != max_block) {
- n = ext4_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 (ext4_orphan_add(handle, inode))
- goto out_stop;
-
- /*
- * From here we block out all ext4_get_block() callers who want to
- * modify the block allocation tree.
- */
- down_write(&ei->i_data_sem);
-
- ext4_discard_preallocations(inode);
-
- /*
- * 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
- * ext4 *really* writes onto the disk inode.
- */
- ei->i_disksize = inode->i_size;
-
- if (last_block == max_block) {
- /*
- * It is unnecessary to free any data blocks if last_block is
- * equal to the indirect block limit.
- */
- goto out_unlock;
- } else if (n == 1) { /* direct blocks */
- ext4_free_data(handle, inode, NULL, i_data+offsets[0],
- i_data + EXT4_NDIR_BLOCKS);
- goto do_indirects;
- }
-
- partial = ext4_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 */
- ext4_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");
- ext4_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) {
- ext4_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[EXT4_IND_BLOCK];
- if (nr) {
- ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
- i_data[EXT4_IND_BLOCK] = 0;
- }
- case EXT4_IND_BLOCK:
- nr = i_data[EXT4_DIND_BLOCK];
- if (nr) {
- ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
- i_data[EXT4_DIND_BLOCK] = 0;
- }
- case EXT4_DIND_BLOCK:
- nr = i_data[EXT4_TIND_BLOCK];
- if (nr) {
- ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
- i_data[EXT4_TIND_BLOCK] = 0;
- }
- case EXT4_TIND_BLOCK:
- ;
- }
-
-out_unlock:
- up_write(&ei->i_data_sem);
- inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
- ext4_mark_inode_dirty(handle, inode);
-
- /*
- * In a multi-transaction truncate, we only make the final transaction
- * synchronous
- */
- if (IS_SYNC(inode))
- ext4_handle_sync(handle);
-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
- * ext4_delete_inode(), and we allow that function to clean up the
- * orphan info for us.
- */
- if (inode->i_nlink)
- ext4_orphan_del(handle, inode);
-
- ext4_journal_stop(handle);
- trace_ext4_truncate_exit(inode);
-}
-
/*
* ext4_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
return 0;
}
-static int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk)
-{
- int indirects;
-
- /* if nrblocks are contiguous */
- if (chunk) {
- /*
- * With N contiguous data blocks, we need at most
- * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
- * 2 dindirect blocks, and 1 tindirect block
- */
- return DIV_ROUND_UP(nrblocks,
- EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
- }
- /*
- * if nrblocks are not contiguous, worse case, each block touch
- * a indirect block, and each indirect block touch a double indirect
- * block, plus a triple indirect block
- */
- indirects = nrblocks * 2 + 1;
- return indirects;
-}
-
static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
projects / mirror_ubuntu-zesty-kernel.git / commitdiff