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