/* * 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 * 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 ext4_get_block() by Al Viro, 2000 */ #include <linux/module.h> #include <linux/fs.h> #include <linux/time.h> #include <linux/ext4_jbd2.h> #include <linux/jbd2.h> #include <linux/smp_lock.h> #include <linux/highuid.h> #include <linux/pagemap.h> #include <linux/quotaops.h> #include <linux/string.h> #include <linux/buffer_head.h> #include <linux/writeback.h> #include <linux/mpage.h> #include <linux/uio.h> #include <linux/bio.h> #include "xattr.h" #include "acl.h" /* * Test whether an inode is a fast symlink. */ static int ext4_inode_is_fast_symlink(struct inode *inode) { int ea_blocks = EXT4_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 ext4 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 ext4_forget(handle_t *handle, int is_metadata, struct inode *inode, struct buffer_head *bh, ext4_fsblk_t blocknr) { int err; might_sleep(); BUFFER_TRACE(bh, "enter"); jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, " "data mode %lx\n", bh, is_metadata, inode->i_mode, test_opt(inode->i_sb, DATA_FLAGS)); /* Never use the revoke function if we are doing full data * journaling: there is no need to, and a V1 superblock won't * support it. Otherwise, only skip the revoke on un-journaled * data blocks. */ if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA || (!is_metadata && !ext4_should_journal_data(inode))) { if (bh) { BUFFER_TRACE(bh, "call jbd2_journal_forget"); return ext4_journal_forget(handle, bh); } return 0; } /* * data!=journal && (is_metadata || should_journal_data(inode)) */ BUFFER_TRACE(bh, "call ext4_journal_revoke"); err = ext4_journal_revoke(handle, blocknr, bh); if (err) ext4_abort(inode->i_sb, __FUNCTION__, "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 ext4 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 > EXT4_MAX_TRANS_DATA) needed = EXT4_MAX_TRANS_DATA; return EXT4_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 = ext4_journal_start(inode, 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 (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS) return 0; if (!ext4_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 ext4_journal_test_restart(handle_t *handle, struct inode *inode) { jbd_debug(2, "restarting handle %p\n", handle); return ext4_journal_restart(handle, blocks_for_truncate(inode)); } /* * Called at the last iput() if i_nlink is zero. */ void ext4_delete_inode (struct inode * inode) { handle_t *handle; truncate_inode_pages(&inode->i_data, 0); if (is_bad_inode(inode)) goto no_delete; handle = start_transaction(inode); if (IS_ERR(handle)) { /* * If we're going to skip the normal cleanup, we still need to * make sure that the in-core orphan linked list is properly * cleaned up. */ ext4_orphan_del(NULL, inode); goto no_delete; } if (IS_SYNC(inode)) handle->h_sync = 1; inode->i_size = 0; if (inode->i_blocks) ext4_truncate(inode); /* * Kill off the orphan record which ext4_truncate created. * AKPM: I think this can be inside the above `if'. * Note that ext4_orphan_del() has to be able to cope with the * deletion of a non-existent orphan - this is because we don't * know if ext4_truncate() actually created an orphan record. * (Well, we could do this if we need to, but heck - it works) */ ext4_orphan_del(handle, inode); EXT4_I(inode)->i_dtime = get_seconds(); /* * One subtle ordering requirement: if anything has gone wrong * (transaction abort, IO errors, whatever), then we can still * do these next steps (the fs will already have been marked as * having errors), but we can't free the inode if the mark_dirty * fails. */ if (ext4_mark_inode_dirty(handle, inode)) /* If that failed, just do the required in-core inode clear. */ clear_inode(inode); else ext4_free_inode(handle, inode); ext4_journal_stop(handle); return; no_delete: clear_inode(inode); /* We must guarantee clearing of inode... */ } typedef struct { __le32 *p; __le32 key; struct buffer_head *bh; } Indirect; static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v) { p->key = *(p->p = v); p->bh = bh; } static int verify_chain(Indirect *from, Indirect *to) { while (from <= to && from->key == *from->p) from++; return (from > to); } /** * 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, long i_block, int 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 < 0) { ext4_warning (inode->i_sb, "ext4_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++] = 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, "ext4_block_to_path", "block > big"); } 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 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 *ext4_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, EXT4_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; } /** * ext4_find_near - find a place for allocation with sufficient locality * @inode: owner * @ind: descriptor of indirect block. * * This function returns the prefered 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_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 = ext4_group_first_block_no(inode->i_sb, ei->i_block_group); colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); return bg_start + colour; } /** * ext4_find_goal - find a prefered place for allocation. * @inode: owner * @block: block we want * @chain: chain of indirect blocks * @partial: pointer to the last triple within a chain * @goal: place to store the result. * * Normally this function find the prefered place for block allocation, * stores it in *@goal and returns zero. */ static ext4_fsblk_t ext4_find_goal(struct inode *inode, long block, Indirect chain[4], Indirect *partial) { struct ext4_block_alloc_info *block_i; block_i = EXT4_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 ext4_find_near(inode, partial); } /** * 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 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; } /** * ext4_alloc_blocks: multiple allocate blocks needed for a branch * @indirect_blks: the number of blocks need to allocate for indirect * blocks * * @new_blocks: on return it will store the new block numbers for * the indirect blocks(if needed) and the first direct block, * @blks: on return it will store the total number of allocated * direct blocks */ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ext4_fsblk_t goal, int indirect_blks, int blks, ext4_fsblk_t new_blocks[4], int *err) { int target, i; unsigned long count = 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) */ target = blks + indirect_blks; while (1) { count = target; /* allocating blocks for indirect blocks and direct blocks */ current_block = ext4_new_blocks(handle,inode,goal,&count,err); if (*err) goto failed_out; target -= count; /* allocate blocks for indirect blocks */ while (index < indirect_blks && count) { new_blocks[index++] = current_block++; count--; } if (count > 0) break; } /* save the new block number for the first direct block */ new_blocks[index] = current_block; /* total number of blocks allocated for direct blocks */ ret = count; *err = 0; return ret; failed_out: for (i = 0; i <index; i++) ext4_free_blocks(handle, inode, new_blocks[i], 1); return ret; } /** * ext4_alloc_branch - allocate and set up a chain of blocks. * @inode: owner * @indirect_blks: number of allocated indirect blocks * @blks: number of allocated direct blocks * @offsets: offsets (in the blocks) to store the pointers to next. * @branch: place to store the chain in. * * This function allocates blocks, zeroes out all but the last one, * links them into chain and (if we are synchronous) writes them to disk. * In other words, it prepares a branch that can be spliced onto the * inode. It stores the information about that chain in the branch[], in * the same format as 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, int indirect_blks, int *blks, ext4_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; ext4_fsblk_t new_blocks[4]; ext4_fsblk_t current_block; num = ext4_alloc_blocks(handle, inode, goal, indirect_blks, *blks, new_blocks, &err); if (err) return err; branch[0].key = cpu_to_le32(new_blocks[0]); /* * metadata blocks and data blocks are allocated. */ for (n = 1; n <= indirect_blks; n++) { /* * Get buffer_head for parent block, zero it out * and set the pointer to new one, then send * parent to disk. */ bh = sb_getblk(inode->i_sb, new_blocks[n-1]); branch[n].bh = bh; lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); err = ext4_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 ext4_journal_dirty_metadata"); err = ext4_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 jbd2_journal_forget"); ext4_journal_forget(handle, branch[i].bh); } for (i = 0; i <indirect_blks; i++) ext4_free_blocks(handle, inode, new_blocks[i], 1); ext4_free_blocks(handle, inode, new_blocks[i], num); return err; } /** * ext4_splice_branch - splice the allocated branch onto inode. * @inode: owner * @block: (logical) number of block we are adding * @chain: chain of indirect blocks (with a missing link - see * 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, long block, Indirect *where, int num, int blks) { int i; int err = 0; struct ext4_block_alloc_info *block_i; ext4_fsblk_t current_block; block_i = EXT4_I(inode)->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 = 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++); } /* * update the most recently allocated logical & physical block * in i_block_alloc_info, to assist find the proper goal block for next * allocation */ if (block_i) { block_i->last_alloc_logical_block = block + blks - 1; block_i->last_alloc_physical_block = le32_to_cpu(where[num].key) + blks - 1; } /* We are done with atomic stuff, now do the rest of housekeeping */ inode->i_ctime = CURRENT_TIME_SEC; ext4_mark_inode_dirty(handle, inode); /* 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_journal_dirty_metadata"); err = ext4_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 jbd2_journal_forget"); ext4_journal_forget(handle, where[i].bh); ext4_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1); } ext4_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 ext4_get_blocks_handle(handle_t *handle, struct inode *inode, sector_t iblock, unsigned long maxblocks, struct buffer_head *bh_result, int create, int extend_disksize) { int err = -EIO; int offsets[4]; Indirect chain[4]; Indirect *partial; ext4_fsblk_t goal; int indirect_blks; int blocks_to_boundary = 0; int depth; struct ext4_inode_info *ei = EXT4_I(inode); int count = 0; ext4_fsblk_t first_block = 0; J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)); J_ASSERT(handle != NULL || create == 0); depth = ext4_block_to_path(inode,iblock,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); clear_buffer_new(bh_result); count++; /*map more blocks*/ while (count < maxblocks && count <= blocks_to_boundary) { ext4_fsblk_t blk; if (!verify_chain(chain, partial)) { /* * Indirect block might be removed by * truncate while we were reading it. * Handling of that case: forget what we've * got now. Flag the err as EAGAIN, so it * will reread. */ err = -EAGAIN; count = 0; break; } blk = le32_to_cpu(*(chain[depth-1].p + count)); if (blk == first_block + count) count++; else break; } if (err != -EAGAIN) goto got_it; } /* Next simple case - plain lookup or failed read of indirect block */ if (!create || err == -EIO) goto cleanup; mutex_lock(&ei->truncate_mutex); /* * If the indirect block is missing while we are reading * the chain(ext4_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 = ext4_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)) ext4_init_block_alloc_info(inode); goal = ext4_find_goal(inode, iblock, chain, 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, maxblocks, blocks_to_boundary); /* * Block out ext4_truncate while we alter the tree */ err = ext4_alloc_branch(handle, inode, 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, iblock, partial, indirect_blks, count); /* * i_disksize growing is protected by truncate_mutex. Don't forget to * protect it if you're about to implement concurrent * ext4_get_block() -bzzz */ if (!err && extend_disksize && inode->i_size > ei->i_disksize) ei->i_disksize = inode->i_size; mutex_unlock(&ei->truncate_mutex); if (err) goto cleanup; set_buffer_new(bh_result); got_it: map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); if (count > blocks_to_boundary) set_buffer_boundary(bh_result); err = count; /* Clean up and exit */ partial = chain + depth - 1; /* the whole chain */ cleanup: while (partial > chain) { BUFFER_TRACE(partial->bh, "call brelse"); brelse(partial->bh); partial--; } BUFFER_TRACE(bh_result, "returned"); out: return err; } #define DIO_CREDITS (EXT4_RESERVE_TRANS_BLOCKS + 32) static int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { handle_t *handle = ext4_journal_current_handle(); int ret = 0; unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; if (!create) goto get_block; /* A read */ if (max_blocks == 1) goto get_block; /* A single block get */ if (handle->h_transaction->t_state == T_LOCKED) { /* * Huge direct-io writes can hold off commits for long * periods of time. Let this commit run. */ ext4_journal_stop(handle); handle = ext4_journal_start(inode, DIO_CREDITS); if (IS_ERR(handle)) ret = PTR_ERR(handle); goto get_block; } if (handle->h_buffer_credits <= EXT4_RESERVE_TRANS_BLOCKS) { /* * Getting low on buffer credits... */ ret = ext4_journal_extend(handle, DIO_CREDITS); if (ret > 0) { /* * Couldn't extend the transaction. Start a new one. */ ret = ext4_journal_restart(handle, DIO_CREDITS); } } get_block: if (ret == 0) { ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks, bh_result, create, 0); if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; } } return ret; } /* * `handle' can be NULL if create is zero */ struct buffer_head *ext4_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 = ext4_get_blocks_wrap(handle, inode, block, 1, &dummy, create, 1); /* * ext4_get_blocks_handle() returns number of blocks * mapped. 0 in case of a HOLE. */ if (err > 0) { if (err > 1) WARN_ON(1); err = 0; } *errp = err; if (!err && buffer_mapped(&dummy)) { struct buffer_head *bh; bh = sb_getblk(inode->i_sb, dummy.b_blocknr); if (!bh) { *errp = -EIO; goto err; } if (buffer_new(&dummy)) { J_ASSERT(create != 0); J_ASSERT(handle != 0); /* * 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 ext4_get_block instead, so it's not a * problem. */ lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); fatal = ext4_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 ext4_journal_dirty_metadata"); err = ext4_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 *ext4_bread(handle_t *handle, struct inode *inode, int block, int create, int *err) { struct buffer_head * bh; bh = ext4_getblk(handle, inode, block, create, err); if (!bh) return bh; if (buffer_uptodate(bh)) return bh; ll_rw_block(READ_META, 1, &bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; put_bh(bh); *err = -EIO; return NULL; } static int walk_page_buffers( handle_t *handle, struct buffer_head *head, unsigned from, unsigned to, int *partial, int (*fn)( handle_t *handle, struct buffer_head *bh)) { struct buffer_head *bh; unsigned block_start, block_end; unsigned blocksize = head->b_size; int err, ret = 0; struct buffer_head *next; for ( bh = head, block_start = 0; ret == 0 && (bh != head || !block_start); block_start = block_end, bh = next) { next = bh->b_this_page; block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (partial && !buffer_uptodate(bh)) *partial = 1; continue; } err = (*fn)(handle, bh); if (!ret) ret = err; } return ret; } /* * To preserve ordering, it is essential that the hole instantiation and * the data write be encapsulated in a single transaction. We cannot * close off a transaction and start a new one between the ext4_get_block() * and the commit_write(). So doing the jbd2_journal_start at the start of * prepare_write() is the right place. * * Also, this function can nest inside ext4_writepage() -> * block_write_full_page(). In that case, we *know* that ext4_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, ext4 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 jbd2_journal_stop/journal_start * will _not_ run commit under these circumstances because handle->h_ref * is elevated. We'll still have enough credits for the tiny quotafile * write. */ static int do_journal_get_write_access(handle_t *handle, struct buffer_head *bh) { if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; return ext4_journal_get_write_access(handle, bh); } /* * The idea of this helper function is following: * if prepare_write has allocated some blocks, but not all of them, the * transaction must include the content of the newly allocated blocks. * This content is expected to be set to zeroes by block_prepare_write(). * 2006/10/14 SAW */ static int ext4_prepare_failure(struct file *file, struct page *page, unsigned from, unsigned to) { struct address_space *mapping; struct buffer_head *bh, *head, *next; unsigned block_start, block_end; unsigned blocksize; int ret; handle_t *handle = ext4_journal_current_handle(); mapping = page->mapping; if (ext4_should_writeback_data(mapping->host)) { /* optimization: no constraints about data */ skip: return ext4_journal_stop(handle); } head = page_buffers(page); blocksize = head->b_size; for ( bh = head, block_start = 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) continue; if (block_start >= to) { block_start = to; break; } if (!buffer_mapped(bh)) /* prepare_write failed on this bh */ break; if (ext4_should_journal_data(mapping->host)) { ret = do_journal_get_write_access(handle, bh); if (ret) { ext4_journal_stop(handle); return ret; } } /* * block_start here becomes the first block where the current iteration * of prepare_write failed. */ } if (block_start <= from) goto skip; /* commit allocated and zeroed buffers */ return mapping->a_ops->commit_write(file, page, from, block_start); } static int ext4_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) { struct inode *inode = page->mapping->host; int ret, ret2; int needed_blocks = ext4_writepage_trans_blocks(inode); handle_t *handle; int retries = 0; retry: handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) return PTR_ERR(handle); if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode)) ret = nobh_prepare_write(page, from, to, ext4_get_block); else ret = block_prepare_write(page, from, to, ext4_get_block); if (ret) goto failure; if (ext4_should_journal_data(inode)) { ret = walk_page_buffers(handle, page_buffers(page), from, to, NULL, do_journal_get_write_access); if (ret) /* fatal error, just put the handle and return */ ext4_journal_stop(handle); } return ret; failure: ret2 = ext4_prepare_failure(file, page, from, to); if (ret2 < 0) return ret2; if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; /* retry number exceeded, or other error like -EDQUOT */ return ret; } int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh) { int err = jbd2_journal_dirty_data(handle, bh); if (err) ext4_journal_abort_handle(__FUNCTION__, __FUNCTION__, bh, handle,err); return err; } /* For commit_write() in data=journal mode */ static int commit_write_fn(handle_t *handle, struct buffer_head *bh) { if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; set_buffer_uptodate(bh); return ext4_journal_dirty_metadata(handle, bh); } /* * 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(). * * ext4 never places buffers on inode->i_mapping->private_list. metadata * buffers are managed internally. */ static int ext4_ordered_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = page->mapping->host; int ret = 0, ret2; ret = walk_page_buffers(handle, page_buffers(page), from, to, NULL, ext4_journal_dirty_data); if (ret == 0) { /* * generic_commit_write() will run mark_inode_dirty() if i_size * changes. So let's piggyback the i_disksize mark_inode_dirty * into that. */ loff_t new_i_size; new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; if (new_i_size > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = new_i_size; ret = generic_commit_write(file, page, from, to); } ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret; } static int ext4_writeback_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = page->mapping->host; int ret = 0, ret2; loff_t new_i_size; new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; if (new_i_size > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = new_i_size; if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode)) ret = nobh_commit_write(file, page, from, to); else ret = generic_commit_write(file, page, from, to); ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret; } static int ext4_journalled_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = page->mapping->host; int ret = 0, ret2; int partial = 0; loff_t pos; /* * Here we duplicate the generic_commit_write() functionality */ pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; ret = walk_page_buffers(handle, page_buffers(page), from, to, &partial, commit_write_fn); if (!partial) SetPageUptodate(page); if (pos > inode->i_size) i_size_write(inode, pos); EXT4_I(inode)->i_state |= EXT4_STATE_JDATA; if (inode->i_size > EXT4_I(inode)->i_disksize) { EXT4_I(inode)->i_disksize = inode->i_size; ret2 = ext4_mark_inode_dirty(handle, inode); if (!ret) ret = ret2; } ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret; } /* * 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 ext4 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 ext4_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; journal_t *journal; int err; if (EXT4_I(inode)->i_state & EXT4_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. EXT4_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. */ EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA; journal = EXT4_JOURNAL(inode); jbd2_journal_lock_updates(journal); err = jbd2_journal_flush(journal); jbd2_journal_unlock_updates(journal); if (err) return 0; } return generic_block_bmap(mapping,block,ext4_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 jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh) { if (buffer_mapped(bh)) return ext4_journal_dirty_data(handle, bh); return 0; } /* * Note that we always start a transaction even if we're not journalling * data. This is to preserve ordering: any hole instantiation within * __block_write_full_page -> ext4_get_block() should be journalled * along with the data so we don't crash and then get metadata which * refers to old data. * * In all journalling modes block_write_full_page() will start the I/O. * * Problem: * * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> * ext4_writepage() * * Similar for: * * ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ... * * Same applies to ext4_get_block(). We will deadlock on various things like * lock_journal and i_truncate_mutex. * * Setting PF_MEMALLOC here doesn't work - too many internal memory * allocations fail. * * 16May01: If we're reentered then journal_current_handle() will be * non-zero. We simply *return*. * * 1 July 2001: @@@ FIXME: * In journalled data mode, a data buffer may be metadata against the * current transaction. But the same file is part of a shared mapping * and someone does a writepage() on it. * * We will move the buffer onto the async_data list, but *after* it has * been dirtied. So there's a small window where we have dirty data on * BJ_Metadata. * * Note that this only applies to the last partial page in the file. The * bit which block_write_full_page() uses prepare/commit for. (That's * broken code anyway: it's wrong for msync()). * * It's a rare case: affects the final partial page, for journalled data * where the file is subject to bith write() and writepage() in the same * transction. To fix it we'll need a custom block_write_full_page(). * We'll probably need that anyway for journalling writepage() output. * * We don't honour synchronous mounts for writepage(). That would be * disastrous. Any write() or metadata operation will sync the fs for * us. * * AKPM2: if all the page's buffers are mapped to disk and !data=journal, * we don't need to open a transaction here. */ static int ext4_ordered_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct buffer_head *page_bufs; handle_t *handle = NULL; int ret = 0; int err; J_ASSERT(PageLocked(page)); /* * We give up here if we're reentered, because it might be for a * different filesystem. */ if (ext4_journal_current_handle()) goto out_fail; handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out_fail; } if (!page_has_buffers(page)) { create_empty_buffers(page, inode->i_sb->s_blocksize, (1 << BH_Dirty)|(1 << BH_Uptodate)); } page_bufs = page_buffers(page); walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, bget_one); ret = block_write_full_page(page, ext4_get_block, wbc); /* * The page can become unlocked at any point now, and * truncate can then come in and change things. So we * can't touch *page from now on. But *page_bufs is * safe due to elevated refcount. */ /* * And attach them to the current transaction. But only if * block_write_full_page() succeeded. Otherwise they are unmapped, * and generally junk. */ if (ret == 0) { err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, jbd2_journal_dirty_data_fn); if (!ret) ret = err; } walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, bput_one); err = ext4_journal_stop(handle); if (!ret) ret = err; return ret; out_fail: redirty_page_for_writepage(wbc, page); unlock_page(page); return ret; } static int ext4_writeback_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; handle_t *handle = NULL; int ret = 0; int err; if (ext4_journal_current_handle()) goto out_fail; handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out_fail; } if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode)) ret = nobh_writepage(page, ext4_get_block, wbc); else ret = block_write_full_page(page, ext4_get_block, wbc); err = ext4_journal_stop(handle); if (!ret) ret = err; return ret; out_fail: redirty_page_for_writepage(wbc, page); unlock_page(page); return ret; } static int ext4_journalled_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; handle_t *handle = NULL; int ret = 0; int err; if (ext4_journal_current_handle()) goto no_write; handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto no_write; } if (!page_has_buffers(page) || PageChecked(page)) { /* * It's mmapped pagecache. Add buffers and journal it. There * doesn't seem much point in redirtying the page here. */ ClearPageChecked(page); ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE, ext4_get_block); if (ret != 0) { ext4_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, commit_write_fn); if (ret == 0) ret = err; EXT4_I(inode)->i_state |= EXT4_STATE_JDATA; unlock_page(page); } else { /* * It may be a page full of checkpoint-mode buffers. We don't * really know unless we go poke around in the buffer_heads. * But block_write_full_page will do the right thing. */ ret = block_write_full_page(page, ext4_get_block, wbc); } err = ext4_journal_stop(handle); if (!ret) ret = err; out: return ret; no_write: redirty_page_for_writepage(wbc, page); out_unlock: unlock_page(page); goto out; } static int ext4_readpage(struct file *file, struct page *page) { return mpage_readpage(page, ext4_get_block); } static int ext4_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { return mpage_readpages(mapping, pages, nr_pages, ext4_get_block); } static void ext4_invalidatepage(struct page *page, unsigned long offset) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); /* * If it's a full truncate we just forget about the pending dirtying */ if (offset == 0) ClearPageChecked(page); jbd2_journal_invalidatepage(journal, page, offset); } static int ext4_releasepage(struct page *page, gfp_t wait) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); WARN_ON(PageChecked(page)); if (!page_has_buffers(page)) return 0; return jbd2_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. */ static ssize_t ext4_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 = NULL; ssize_t ret; int orphan = 0; size_t count = iov_length(iov, nr_segs); if (rw == WRITE) { loff_t final_size = offset + count; handle = ext4_journal_start(inode, DIO_CREDITS); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } if (final_size > inode->i_size) { ret = ext4_orphan_add(handle, inode); if (ret) goto out_stop; orphan = 1; ei->i_disksize = inode->i_size; } } ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block, NULL); /* * Reacquire the handle: ext4_get_block() can restart the transaction */ handle = ext4_journal_current_handle(); out_stop: if (handle) { int err; if (orphan && inode->i_nlink) ext4_orphan_del(handle, inode); if (orphan && 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; } /* * Pages can be marked dirty completely asynchronously from ext4'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 ext4_journalled_set_page_dirty(struct page *page) { SetPageChecked(page); return __set_page_dirty_nobuffers(page); } static const struct address_space_operations ext4_ordered_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_ordered_writepage, .sync_page = block_sync_page, .prepare_write = ext4_prepare_write, .commit_write = ext4_ordered_commit_write, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, }; static const struct address_space_operations ext4_writeback_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_writeback_writepage, .sync_page = block_sync_page, .prepare_write = ext4_prepare_write, .commit_write = ext4_writeback_commit_write, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, }; static const struct address_space_operations ext4_journalled_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_journalled_writepage, .sync_page = block_sync_page, .prepare_write = ext4_prepare_write, .commit_write = ext4_journalled_commit_write, .set_page_dirty = ext4_journalled_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, }; void ext4_set_aops(struct inode *inode) { if (ext4_should_order_data(inode)) inode->i_mapping->a_ops = &ext4_ordered_aops; else if (ext4_should_writeback_data(inode)) inode->i_mapping->a_ops = &ext4_writeback_aops; else inode->i_mapping->a_ops = &ext4_journalled_aops; } /* * ext4_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. */ int ext4_block_truncate_page(handle_t *handle, struct page *page, struct address_space *mapping, loff_t from) { ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned blocksize, iblock, length, pos; struct inode *inode = mapping->host; struct buffer_head *bh; int err = 0; void *kaddr; blocksize = inode->i_sb->s_blocksize; length = blocksize - (offset & (blocksize - 1)); iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); /* * For "nobh" option, we can only work if we don't need to * read-in the page - otherwise we create buffers to do the IO. */ if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode) && PageUptodate(page)) { kaddr = kmap_atomic(page, KM_USER0); memset(kaddr + offset, 0, length); flush_dcache_page(page); kunmap_atomic(kaddr, KM_USER0); set_page_dirty(page); goto unlock; } if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); /* Find the buffer that contains "offset" */ bh = page_buffers(page); pos = blocksize; while (offset >= pos) { bh = bh->b_this_page; iblock++; pos += blocksize; } err = 0; if (buffer_freed(bh)) { BUFFER_TRACE(bh, "freed: skip"); goto unlock; } if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "unmapped"); ext4_get_block(inode, iblock, bh, 0); /* unmapped? It's a hole - nothing to do */ if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "still unmapped"); goto unlock; } } /* Ok, it's mapped. Make sure it's up-to-date */ if (PageUptodate(page)) set_buffer_uptodate(bh); if (!buffer_uptodate(bh)) { err = -EIO; ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); /* Uhhuh. Read error. Complain and punt. */ if (!buffer_uptodate(bh)) goto unlock; } if (ext4_should_journal_data(inode)) { BUFFER_TRACE(bh, "get write access"); err = ext4_journal_get_write_access(handle, bh); if (err) goto unlock; } kaddr = kmap_atomic(page, KM_USER0); memset(kaddr + offset, 0, length); flush_dcache_page(page); kunmap_atomic(kaddr, KM_USER0); BUFFER_TRACE(bh, "zeroed end of block"); err = 0; if (ext4_should_journal_data(inode)) { err = ext4_journal_dirty_metadata(handle, bh); } else { if (ext4_should_order_data(inode)) err = ext4_journal_dirty_data(handle, bh); mark_buffer_dirty(bh); } unlock: unlock_page(page); page_cache_release(page); return err; } /* * Probably it should be a library function... search for first non-zero word * or memcmp with zero_page, whatever is better for particular architecture. * Linus? */ static inline int all_zeroes(__le32 *p, __le32 *q) { while (p < q) if (*p++) return 0; return 1; } /** * 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 refered * from it (and it is on the path to the first completely truncated * data block, indeed). We have to free the top of that path along * with everything to the right of the path. Since no allocation * past the truncation point is possible until 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, int offsets[4], Indirect chain[4], __le32 *top) { Indirect *partial, *p; int k, err; *top = 0; /* Make k index the deepest non-null offest + 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. */ static void 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; if (try_to_extend_transaction(handle, inode)) { if (bh) { BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); ext4_journal_dirty_metadata(handle, bh); } ext4_mark_inode_dirty(handle, inode); ext4_journal_test_restart(handle, inode); if (bh) { BUFFER_TRACE(bh, "retaking write access"); ext4_journal_get_write_access(handle, bh); } } /* * Any buffers which are on the journal will be in memory. We find * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget() * on them. We've already detached each block from the file, so * bforget() in jbd2_journal_forget() should be safe. * * AKPM: turn on bforget in jbd2_journal_forget()!!! */ for (p = first; p < last; p++) { u32 nr = le32_to_cpu(*p); if (nr) { struct buffer_head *bh; *p = 0; bh = sb_find_get_block(inode->i_sb, nr); ext4_forget(handle, 0, inode, bh, nr); } } ext4_free_blocks(handle, inode, block_to_free, count); } /** * 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 refered from that array (numbers are stored as * little-endian 32-bit) and updating @inode->i_blocks appropriately. * * We accumulate contiguous runs of blocks to free. Conveniently, if these * blocks are contiguous then releasing them at one time will only affect one * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't * actually use a lot of journal space. * * @this_bh will be %NULL if @first and @last point into the inode's direct * block pointers. */ static void 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; 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 { ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); block_to_free = nr; block_to_free_p = p; count = 1; } } } if (count > 0) ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); if (this_bh) { BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata"); ext4_journal_dirty_metadata(handle, this_bh); } } /** * 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 refered 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 (is_handle_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 */ /* 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->i_sb, "ext4_free_branches", "Read failure, inode=%lu, block=%llu", inode->i_ino, nr); 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); /* * We've probably journalled the indirect block several * times during the truncate. But it's no longer * needed and we now drop it from the transaction via * jbd2_journal_revoke(). * * That's easy if it's exclusively part of this * transaction. But if it's part of the committing * transaction then jbd2_journal_forget() will simply * brelse() it. That means that if the underlying * block is reallocated in ext4_get_block(), * unmap_underlying_metadata() will find this block * and will try to get rid of it. damn, damn. * * If this block has already been committed to the * journal, a revoke record will be written. And * revoke records must be emitted *before* clearing * this block's bit in the bitmaps. */ ext4_forget(handle, 1, inode, bh, bh->b_blocknr); /* * Everything below this this pointer has been * released. Now let this top-of-subtree go. * * We want the freeing of this indirect block to be * atomic in the journal with the updating of the * bitmap block which owns it. So make some room in * the journal. * * We zero the parent pointer *after* freeing its * pointee in the bitmaps, so if extend_transaction() * for some reason fails to put the bitmap changes and * the release into the same transaction, recovery * will merely complain about releasing a free block, * rather than leaking blocks. */ if (is_handle_aborted(handle)) return; if (try_to_extend_transaction(handle, inode)) { ext4_mark_inode_dirty(handle, inode); ext4_journal_test_restart(handle, inode); } ext4_free_blocks(handle, inode, nr, 1); if (parent_bh) { /* * The block which we have just freed is * pointed to by an indirect block: journal it */ BUFFER_TRACE(parent_bh, "get_write_access"); if (!ext4_journal_get_write_access(handle, parent_bh)){ *p = 0; BUFFER_TRACE(parent_bh, "call ext4_journal_dirty_metadata"); ext4_journal_dirty_metadata(handle, 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); } } /* * ext4_truncate() * * We block out ext4_get_block() block instantiations across the entire * transaction, and VFS/VM ensures that ext4_truncate() cannot run * simultaneously on behalf of the same inode. * * As we work through the truncate and commmit bits of it to the journal there * is one core, guiding principle: the file's tree must always be consistent on * disk. We must be able to restart the truncate after a crash. * * The file's tree may be transiently inconsistent in memory (although it * probably isn't), but whenever we close off and commit a journal transaction, * the contents of (the filesystem + the journal) must be consistent and * restartable. It's pretty simple, really: bottom up, right to left (although * left-to-right works OK too). * * Note that at recovery time, journal replay occurs *before* the restart of * truncate against the orphan inode list. * * The committed inode has the new, desired i_size (which is the same as * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see * that this inode's truncate did not complete and it will again call * ext4_truncate() to have another go. So there will be instantiated blocks * to the right of the truncation point in a crashed ext4 filesystem. But * that's fine - as long as they are linked from the inode, the post-crash * ext4_truncate() run will find them and release them. */ void ext4_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; int offsets[4]; Indirect chain[4]; Indirect *partial; __le32 nr = 0; int n; long last_block; unsigned blocksize = inode->i_sb->s_blocksize; struct page *page; if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) return; if (ext4_inode_is_fast_symlink(inode)) return; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return; /* * We have to lock the EOF page here, because lock_page() nests * outside jbd2_journal_start(). */ if ((inode->i_size & (blocksize - 1)) == 0) { /* Block boundary? Nothing to do */ page = NULL; } else { page = grab_cache_page(mapping, inode->i_size >> PAGE_CACHE_SHIFT); if (!page) return; } if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) return ext4_ext_truncate(inode, page); handle = start_transaction(inode); if (IS_ERR(handle)) { if (page) { clear_highpage(page); flush_dcache_page(page); unlock_page(page); page_cache_release(page); } return; /* AKPM: return what? */ } last_block = (inode->i_size + blocksize-1) >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); if (page) ext4_block_truncate_page(handle, page, mapping, inode->i_size); 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; /* * 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; /* * From here we block out all ext4_get_block() callers who want to * modify the block allocation tree. */ mutex_lock(&ei->truncate_mutex); 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: ; } ext4_discard_reservation(inode); mutex_unlock(&ei->truncate_mutex); inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; ext4_mark_inode_dirty(handle, inode); /* * In a multi-transaction truncate, we only make the final transaction * synchronous */ if (IS_SYNC(inode)) handle->h_sync = 1; out_stop: /* * If this was a simple ftruncate(), and the file will remain alive * then we need to clear up the orphan record which we created above. * However, if this was a real unlink then we were called by * 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); } static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb, unsigned long ino, struct ext4_iloc *iloc) { unsigned long desc, group_desc, block_group; unsigned long offset; ext4_fsblk_t block; struct buffer_head *bh; struct ext4_group_desc * gdp; if (!ext4_valid_inum(sb, ino)) { /* * This error is already checked for in namei.c unless we are * looking at an NFS filehandle, in which case no error * report is needed */ return 0; } block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); if (block_group >= EXT4_SB(sb)->s_groups_count) { ext4_error(sb,"ext4_get_inode_block","group >= groups count"); return 0; } smp_rmb(); group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); desc = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); bh = EXT4_SB(sb)->s_group_desc[group_desc]; if (!bh) { ext4_error (sb, "ext4_get_inode_block", "Descriptor not loaded"); return 0; } gdp = (struct ext4_group_desc *)((__u8 *)bh->b_data + desc * EXT4_DESC_SIZE(sb)); /* * Figure out the offset within the block group inode table */ offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) * EXT4_INODE_SIZE(sb); block = ext4_inode_table(sb, gdp) + (offset >> EXT4_BLOCK_SIZE_BITS(sb)); iloc->block_group = block_group; iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1); return block; } /* * 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 * data in memory that is needed to recreate the on-disk version of this * inode. */ static int __ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc, int in_mem) { ext4_fsblk_t block; struct buffer_head *bh; block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc); if (!block) return -EIO; bh = sb_getblk(inode->i_sb, block); if (!bh) { ext4_error (inode->i_sb, "ext4_get_inode_loc", "unable to read inode block - " "inode=%lu, block=%llu", inode->i_ino, block); return -EIO; } if (!buffer_uptodate(bh)) { lock_buffer(bh); if (buffer_uptodate(bh)) { /* someone brought it uptodate while we waited */ unlock_buffer(bh); goto has_buffer; } /* * If we have all information of the inode in memory and this * is the only valid inode in the block, we need not read the * block. */ if (in_mem) { struct buffer_head *bitmap_bh; struct ext4_group_desc *desc; int inodes_per_buffer; int inode_offset, i; int block_group; int start; block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb); inodes_per_buffer = bh->b_size / EXT4_INODE_SIZE(inode->i_sb); inode_offset = ((inode->i_ino - 1) % EXT4_INODES_PER_GROUP(inode->i_sb)); start = inode_offset & ~(inodes_per_buffer - 1); /* Is the inode bitmap in cache? */ desc = ext4_get_group_desc(inode->i_sb, block_group, NULL); if (!desc) goto make_io; bitmap_bh = sb_getblk(inode->i_sb, ext4_inode_bitmap(inode->i_sb, desc)); if (!bitmap_bh) goto make_io; /* * If the inode bitmap isn't in cache then the * optimisation may end up performing two reads instead * of one, so skip it. */ if (!buffer_uptodate(bitmap_bh)) { brelse(bitmap_bh); goto make_io; } for (i = start; i < start + inodes_per_buffer; i++) { if (i == inode_offset) continue; if (ext4_test_bit(i, bitmap_bh->b_data)) break; } brelse(bitmap_bh); if (i == start + inodes_per_buffer) { /* all other inodes are free, so skip I/O */ memset(bh->b_data, 0, bh->b_size); set_buffer_uptodate(bh); unlock_buffer(bh); goto has_buffer; } } make_io: /* * There are other valid inodes in the buffer, this inode * has in-inode xattrs, or we don't have this inode in memory. * Read the block from disk. */ get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ_META, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { ext4_error(inode->i_sb, "ext4_get_inode_loc", "unable to read inode block - " "inode=%lu, block=%llu", inode->i_ino, block); brelse(bh); return -EIO; } } has_buffer: iloc->bh = bh; return 0; } int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) { /* We have all inode data except xattrs in memory here. */ return __ext4_get_inode_loc(inode, iloc, !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)); } void ext4_set_inode_flags(struct inode *inode) { unsigned int flags = EXT4_I(inode)->i_flags; inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); if (flags & EXT4_SYNC_FL) inode->i_flags |= S_SYNC; if (flags & EXT4_APPEND_FL) inode->i_flags |= S_APPEND; if (flags & EXT4_IMMUTABLE_FL) inode->i_flags |= S_IMMUTABLE; if (flags & EXT4_NOATIME_FL) inode->i_flags |= S_NOATIME; if (flags & EXT4_DIRSYNC_FL) inode->i_flags |= S_DIRSYNC; } void ext4_read_inode(struct inode * inode) { struct ext4_iloc iloc; struct ext4_inode *raw_inode; struct ext4_inode_info *ei = EXT4_I(inode); struct buffer_head *bh; int block; #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL ei->i_acl = EXT4_ACL_NOT_CACHED; ei->i_default_acl = EXT4_ACL_NOT_CACHED; #endif ei->i_block_alloc_info = NULL; if (__ext4_get_inode_loc(inode, &iloc, 0)) goto bad_inode; bh = iloc.bh; raw_inode = ext4_raw_inode(&iloc); inode->i_mode = le16_to_cpu(raw_inode->i_mode); inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); if(!(test_opt (inode->i_sb, NO_UID32))) { inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16; inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16; } inode->i_nlink = le16_to_cpu(raw_inode->i_links_count); inode->i_size = le32_to_cpu(raw_inode->i_size); inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime); inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime); inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime); inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0; ei->i_state = 0; ei->i_dir_start_lookup = 0; ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); /* We now have enough fields to check if the inode was active or not. * This is needed because nfsd might try to access dead inodes * the test is that same one that e2fsck uses * NeilBrown 1999oct15 */ if (inode->i_nlink == 0) { if (inode->i_mode == 0 || !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) { /* this inode is deleted */ brelse (bh); goto bad_inode; } /* The only unlinked inodes we let through here have * valid i_mode and are being read by the orphan * recovery code: that's fine, we're about to complete * the process of deleting those. */ } inode->i_blocks = le32_to_cpu(raw_inode->i_blocks); ei->i_flags = le32_to_cpu(raw_inode->i_flags); #ifdef EXT4_FRAGMENTS ei->i_faddr = le32_to_cpu(raw_inode->i_faddr); ei->i_frag_no = raw_inode->i_frag; ei->i_frag_size = raw_inode->i_fsize; #endif ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl); if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != cpu_to_le32(EXT4_OS_HURD)) ei->i_file_acl |= ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32; if (!S_ISREG(inode->i_mode)) { ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl); } else { inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32; } ei->i_disksize = inode->i_size; inode->i_generation = le32_to_cpu(raw_inode->i_generation); ei->i_block_group = iloc.block_group; /* * NOTE! The in-memory inode i_data array is in little-endian order * even on big-endian machines: we do NOT byteswap the block numbers! */ for (block = 0; block < EXT4_N_BLOCKS; block++) ei->i_data[block] = raw_inode->i_block[block]; INIT_LIST_HEAD(&ei->i_orphan); if (inode->i_ino >= EXT4_FIRST_INO(inode->i_sb) + 1 && EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { /* * When mke2fs creates big inodes it does not zero out * the unused bytes above EXT4_GOOD_OLD_INODE_SIZE, * so ignore those first few inodes. */ ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize); if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > EXT4_INODE_SIZE(inode->i_sb)) goto bad_inode; if (ei->i_extra_isize == 0) { /* The extra space is currently unused. Use it. */ ei->i_extra_isize = sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE; } else { __le32 *magic = (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize; if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) ei->i_state |= EXT4_STATE_XATTR; } } else ei->i_extra_isize = 0; if (S_ISREG(inode->i_mode)) { inode->i_op = &ext4_file_inode_operations; inode->i_fop = &ext4_file_operations; ext4_set_aops(inode); } else if (S_ISDIR(inode->i_mode)) { inode->i_op = &ext4_dir_inode_operations; inode->i_fop = &ext4_dir_operations; } else if (S_ISLNK(inode->i_mode)) { if (ext4_inode_is_fast_symlink(inode)) inode->i_op = &ext4_fast_symlink_inode_operations; else { inode->i_op = &ext4_symlink_inode_operations; ext4_set_aops(inode); } } else { inode->i_op = &ext4_special_inode_operations; if (raw_inode->i_block[0]) init_special_inode(inode, inode->i_mode, old_decode_dev(le32_to_cpu(raw_inode->i_block[0]))); else init_special_inode(inode, inode->i_mode, new_decode_dev(le32_to_cpu(raw_inode->i_block[1]))); } brelse (iloc.bh); ext4_set_inode_flags(inode); return; bad_inode: make_bad_inode(inode); return; } /* * Post the struct inode info into an on-disk inode location in the * buffer-cache. This gobbles the caller's reference to the * buffer_head in the inode location struct. * * The caller must have write access to iloc->bh. */ static int ext4_do_update_inode(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { struct ext4_inode *raw_inode = ext4_raw_inode(iloc); struct ext4_inode_info *ei = EXT4_I(inode); struct buffer_head *bh = iloc->bh; int err = 0, rc, block; /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ if (ei->i_state & EXT4_STATE_NEW) memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); raw_inode->i_mode = cpu_to_le16(inode->i_mode); if(!(test_opt(inode->i_sb, NO_UID32))) { raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid)); /* * Fix up interoperability with old kernels. Otherwise, old inodes get * re-used with the upper 16 bits of the uid/gid intact */ if(!ei->i_dtime) { raw_inode->i_uid_high = cpu_to_le16(high_16_bits(inode->i_uid)); raw_inode->i_gid_high = cpu_to_le16(high_16_bits(inode->i_gid)); } else { raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } } else { raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(inode->i_gid)); raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); raw_inode->i_size = cpu_to_le32(ei->i_disksize); raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec); raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec); raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec); raw_inode->i_blocks = cpu_to_le32(inode->i_blocks); raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); raw_inode->i_flags = cpu_to_le32(ei->i_flags); #ifdef EXT4_FRAGMENTS raw_inode->i_faddr = cpu_to_le32(ei->i_faddr); raw_inode->i_frag = ei->i_frag_no; raw_inode->i_fsize = ei->i_frag_size; #endif if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != cpu_to_le32(EXT4_OS_HURD)) raw_inode->i_file_acl_high = cpu_to_le16(ei->i_file_acl >> 32); raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl); if (!S_ISREG(inode->i_mode)) { raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl); } else { raw_inode->i_size_high = cpu_to_le32(ei->i_disksize >> 32); if (ei->i_disksize > 0x7fffffffULL) { struct super_block *sb = inode->i_sb; if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE) || EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV)) { /* If this is the first large file * created, add a flag to the superblock. */ err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh); if (err) goto out_brelse; ext4_update_dynamic_rev(sb); EXT4_SET_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE); sb->s_dirt = 1; handle->h_sync = 1; err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); } } } raw_inode->i_generation = cpu_to_le32(inode->i_generation); if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) { if (old_valid_dev(inode->i_rdev)) { raw_inode->i_block[0] = cpu_to_le32(old_encode_dev(inode->i_rdev)); raw_inode->i_block[1] = 0; } else { raw_inode->i_block[0] = 0; raw_inode->i_block[1] = cpu_to_le32(new_encode_dev(inode->i_rdev)); raw_inode->i_block[2] = 0; } } else for (block = 0; block < EXT4_N_BLOCKS; block++) raw_inode->i_block[block] = ei->i_data[block]; if (ei->i_extra_isize) raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); rc = ext4_journal_dirty_metadata(handle, bh); if (!err) err = rc; ei->i_state &= ~EXT4_STATE_NEW; out_brelse: brelse (bh); ext4_std_error(inode->i_sb, err); return err; } /* * ext4_write_inode() * * We are called from a few places: * * - Within generic_file_write() for O_SYNC files. * Here, there will be no transaction running. We wait for any running * trasnaction to commit. * * - Within sys_sync(), kupdate and such. * We wait on commit, if tol to. * * - Within prune_icache() (PF_MEMALLOC == true) * Here we simply return. We can't afford to block kswapd on the * journal commit. * * In all cases it is actually safe for us to return without doing anything, * because the inode has been copied into a raw inode buffer in * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for * knfsd. * * Note that we are absolutely dependent upon all inode dirtiers doing the * right thing: they *must* call mark_inode_dirty() after dirtying info in * which we are interested. * * It would be a bug for them to not do this. The code: * * mark_inode_dirty(inode) * stuff(); * inode->i_size = expr; * * is in error because a kswapd-driven write_inode() could occur while * `stuff()' is running, and the new i_size will be lost. Plus the inode * will no longer be on the superblock's dirty inode list. */ int ext4_write_inode(struct inode *inode, int wait) { if (current->flags & PF_MEMALLOC) return 0; if (ext4_journal_current_handle()) { jbd_debug(0, "called recursively, non-PF_MEMALLOC!\n"); dump_stack(); return -EIO; } if (!wait) return 0; return ext4_force_commit(inode->i_sb); } /* * ext4_setattr() * * Called from notify_change. * * We want to trap VFS attempts to truncate the file as soon as * possible. In particular, we want to make sure that when the VFS * shrinks i_size, we put the inode on the orphan list and modify * i_disksize immediately, so that during the subsequent flushing of * dirty pages and freeing of disk blocks, we can guarantee that any * commit will leave the blocks being flushed in an unused state on * disk. (On recovery, the inode will get truncated and the blocks will * be freed, so we have a strong guarantee that no future commit will * leave these blocks visible to the user.) * * Called with inode->sem down. */ int ext4_setattr(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; int error, rc = 0; const unsigned int ia_valid = attr->ia_valid; error = inode_change_ok(inode, attr); if (error) return error; if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) { handle_t *handle; /* (user+group)*(old+new) structure, inode write (sb, * inode block, ? - but truncate inode update has it) */ handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+ EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0; if (error) { ext4_journal_stop(handle); return error; } /* Update corresponding info in inode so that everything is in * one transaction */ if (attr->ia_valid & ATTR_UID) inode->i_uid = attr->ia_uid; if (attr->ia_valid & ATTR_GID) inode->i_gid = attr->ia_gid; error = ext4_mark_inode_dirty(handle, inode); ext4_journal_stop(handle); } if (S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) { handle_t *handle; handle = ext4_journal_start(inode, 3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } error = ext4_orphan_add(handle, inode); EXT4_I(inode)->i_disksize = attr->ia_size; rc = ext4_mark_inode_dirty(handle, inode); if (!error) error = rc; ext4_journal_stop(handle); } rc = inode_setattr(inode, attr); /* If inode_setattr's call to ext4_truncate failed to get a * transaction handle at all, we need to clean up the in-core * orphan list manually. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); if (!rc && (ia_valid & ATTR_MODE)) rc = ext4_acl_chmod(inode); err_out: ext4_std_error(inode->i_sb, error); if (!error) error = rc; return error; } /* * How many blocks doth make a writepage()? * * With N blocks per page, it may be: * N data blocks * 2 indirect block * 2 dindirect * 1 tindirect * N+5 bitmap blocks (from the above) * N+5 group descriptor summary blocks * 1 inode block * 1 superblock. * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files * * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS * * With ordered or writeback data it's the same, less the N data blocks. * * If the inode's direct blocks can hold an integral number of pages then a * page cannot straddle two indirect blocks, and we can only touch one indirect * and dindirect block, and the "5" above becomes "3". * * This still overestimates under most circumstances. If we were to pass the * start and end offsets in here as well we could do block_to_path() on each * block and work out the exact number of indirects which are touched. Pah. */ int ext4_writepage_trans_blocks(struct inode *inode) { int bpp = ext4_journal_blocks_per_page(inode); int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3; int ret; if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) return ext4_ext_writepage_trans_blocks(inode, bpp); if (ext4_should_journal_data(inode)) ret = 3 * (bpp + indirects) + 2; else ret = 2 * (bpp + indirects) + 2; #ifdef CONFIG_QUOTA /* We know that structure was already allocated during DQUOT_INIT so * we will be updating only the data blocks + inodes */ ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); #endif return ret; } /* * The caller must have previously called ext4_reserve_inode_write(). * Give this, we know that the caller already has write access to iloc->bh. */ int ext4_mark_iloc_dirty(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err = 0; /* the do_update_inode consumes one bh->b_count */ get_bh(iloc->bh); /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */ err = ext4_do_update_inode(handle, inode, iloc); put_bh(iloc->bh); return err; } /* * On success, We end up with an outstanding reference count against * iloc->bh. This _must_ be cleaned up later. */ int ext4_reserve_inode_write(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err = 0; if (handle) { err = ext4_get_inode_loc(inode, iloc); if (!err) { BUFFER_TRACE(iloc->bh, "get_write_access"); err = ext4_journal_get_write_access(handle, iloc->bh); if (err) { brelse(iloc->bh); iloc->bh = NULL; } } } ext4_std_error(inode->i_sb, err); return err; } /* * What we do here is to mark the in-core inode as clean with respect to inode * dirtiness (it may still be data-dirty). * This means that the in-core inode may be reaped by prune_icache * without having to perform any I/O. This is a very good thing, * because *any* task may call prune_icache - even ones which * have a transaction open against a different journal. * * Is this cheating? Not really. Sure, we haven't written the * inode out, but prune_icache isn't a user-visible syncing function. * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync) * we start and wait on commits. * * Is this efficient/effective? Well, we're being nice to the system * by cleaning up our inodes proactively so they can be reaped * without I/O. But we are potentially leaving up to five seconds' * worth of inodes floating about which prune_icache wants us to * write out. One way to fix that would be to get prune_icache() * to do a write_super() to free up some memory. It has the desired * effect. */ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; int err; might_sleep(); err = ext4_reserve_inode_write(handle, inode, &iloc); if (!err) err = ext4_mark_iloc_dirty(handle, inode, &iloc); return err; } /* * ext4_dirty_inode() is called from __mark_inode_dirty() * * We're really interested in the case where a file is being extended. * i_size has been changed by generic_commit_write() and we thus need * to include the updated inode in the current transaction. * * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks * are allocated to the file. * * If the inode is marked synchronous, we don't honour that here - doing * so would cause a commit on atime updates, which we don't bother doing. * We handle synchronous inodes at the highest possible level. */ void ext4_dirty_inode(struct inode *inode) { handle_t *current_handle = ext4_journal_current_handle(); handle_t *handle; handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) goto out; if (current_handle && current_handle->h_transaction != handle->h_transaction) { /* This task has a transaction open against a different fs */ printk(KERN_EMERG "%s: transactions do not match!\n", __FUNCTION__); } else { jbd_debug(5, "marking dirty. outer handle=%p\n", current_handle); ext4_mark_inode_dirty(handle, inode); } ext4_journal_stop(handle); out: return; } #if 0 /* * Bind an inode's backing buffer_head into this transaction, to prevent * it from being flushed to disk early. Unlike * ext4_reserve_inode_write, this leaves behind no bh reference and * returns no iloc structure, so the caller needs to repeat the iloc * lookup to mark the inode dirty later. */ static int ext4_pin_inode(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; int err = 0; if (handle) { err = ext4_get_inode_loc(inode, &iloc); if (!err) { BUFFER_TRACE(iloc.bh, "get_write_access"); err = jbd2_journal_get_write_access(handle, iloc.bh); if (!err) err = ext4_journal_dirty_metadata(handle, iloc.bh); brelse(iloc.bh); } } ext4_std_error(inode->i_sb, err); return err; } #endif int ext4_change_inode_journal_flag(struct inode *inode, int val) { journal_t *journal; handle_t *handle; int err; /* * We have to be very careful here: changing a data block's * journaling status dynamically is dangerous. If we write a * data block to the journal, change the status and then delete * that block, we risk forgetting to revoke the old log record * from the journal and so a subsequent replay can corrupt data. * So, first we make sure that the journal is empty and that * nobody is changing anything. */ journal = EXT4_JOURNAL(inode); if (is_journal_aborted(journal) || IS_RDONLY(inode)) return -EROFS; jbd2_journal_lock_updates(journal); jbd2_journal_flush(journal); /* * OK, there are no updates running now, and all cached data is * synced to disk. We are now in a completely consistent state * which doesn't have anything in the journal, and we know that * no filesystem updates are running, so it is safe to modify * the inode's in-core data-journaling state flag now. */ if (val) EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL; else EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL; ext4_set_aops(inode); jbd2_journal_unlock_updates(journal); /* Finally we can mark the inode as dirty. */ handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) return PTR_ERR(handle); err = ext4_mark_inode_dirty(handle, inode); handle->h_sync = 1; ext4_journal_stop(handle); ext4_std_error(inode->i_sb, err); return err; }