patch-2.4.15 linux/fs/ext3/inode.c
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- Lines: 2673
- Date:
Fri Nov 9 14:25:04 2001
- Orig file:
v2.4.14/linux/fs/ext3/inode.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.4.14/linux/fs/ext3/inode.c linux/fs/ext3/inode.c
@@ -0,0 +1,2672 @@
+/*
+ * linux/fs/ext3/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/inode.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Goal-directed block allocation by Stephen Tweedie
+ * (sct@redhat.com), 1993, 1998
+ * Big-endian to little-endian byte-swapping/bitmaps by
+ * David S. Miller (davem@caip.rutgers.edu), 1995
+ * 64-bit file support on 64-bit platforms by Jakub Jelinek
+ * (jj@sunsite.ms.mff.cuni.cz)
+ *
+ * Assorted race fixes, rewrite of ext3_get_block() by Al Viro, 2000
+ */
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/ext3_jbd.h>
+#include <linux/jbd.h>
+#include <linux/locks.h>
+#include <linux/smp_lock.h>
+#include <linux/highuid.h>
+#include <linux/quotaops.h>
+#include <linux/module.h>
+
+
+/*
+ * SEARCH_FROM_ZERO forces each block allocation to search from the start
+ * of the filesystem. This is to force rapid reallocation of recently-freed
+ * blocks. The file fragmentation is horrendous.
+ */
+#undef SEARCH_FROM_ZERO
+
+/* The ext3 forget function must perform a revoke if we are freeing data
+ * which has been journaled. Metadata (eg. indirect blocks) must be
+ * revoked in all cases.
+ *
+ * "bh" may be NULL: a metadata block may have been freed from memory
+ * but there may still be a record of it in the journal, and that record
+ * still needs to be revoked.
+ */
+
+static int ext3_forget(handle_t *handle, int is_metadata,
+ struct inode *inode, struct buffer_head *bh,
+ int blocknr)
+{
+ int err;
+
+ BUFFER_TRACE(bh, "enter");
+
+ jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
+ "data mode %lx\n",
+ bh, is_metadata, inode->i_mode,
+ test_opt(inode->i_sb, DATA_FLAGS));
+
+ /* Never use the revoke function if we are doing full data
+ * journaling: there is no need to, and a V1 superblock won't
+ * support it. Otherwise, only skip the revoke on un-journaled
+ * data blocks. */
+
+ if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
+ (!is_metadata && !ext3_should_journal_data(inode))) {
+ if (bh) {
+ BUFFER_TRACE(bh, "call journal_forget");
+ ext3_journal_forget(handle, bh);
+ }
+ return 0;
+ }
+
+ /*
+ * data!=journal && (is_metadata || should_journal_data(inode))
+ */
+ BUFFER_TRACE(bh, "call ext3_journal_revoke");
+ err = ext3_journal_revoke(handle, blocknr, bh);
+ if (err)
+ ext3_abort(inode->i_sb, __FUNCTION__,
+ "error %d when attempting revoke", err);
+ BUFFER_TRACE(bh, "exit");
+ return err;
+}
+
+/*
+ * 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)
+{
+ long needed;
+ handle_t *result;
+
+ needed = inode->i_blocks;
+ if (needed > EXT3_MAX_TRANS_DATA)
+ needed = EXT3_MAX_TRANS_DATA;
+
+ result = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS + needed);
+ if (!IS_ERR(result))
+ return result;
+
+ ext3_std_error(inode->i_sb, PTR_ERR(result));
+ return result;
+}
+
+/*
+ * Try to extend this transaction for the purposes of truncation.
+ *
+ * Returns 0 if we managed to create more room. If we can't create more
+ * room, and the transaction must be restarted we return 1.
+ */
+static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
+{
+ long needed;
+
+ if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
+ return 0;
+ needed = inode->i_blocks;
+ if (needed > EXT3_MAX_TRANS_DATA)
+ needed = EXT3_MAX_TRANS_DATA;
+ if (!ext3_journal_extend(handle, EXT3_RESERVE_TRANS_BLOCKS + needed))
+ 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 ext3_journal_test_restart(handle_t *handle, struct inode *inode)
+{
+ long needed = inode->i_blocks;
+ if (needed > EXT3_MAX_TRANS_DATA)
+ needed = EXT3_MAX_TRANS_DATA;
+ jbd_debug(2, "restarting handle %p\n", handle);
+ return ext3_journal_restart(handle, EXT3_DATA_TRANS_BLOCKS + needed);
+}
+
+/*
+ * Called at each iput()
+ */
+void ext3_put_inode (struct inode * inode)
+{
+ ext3_discard_prealloc (inode);
+}
+
+/*
+ * Called at the last iput() if i_nlink is zero.
+ */
+void ext3_delete_inode (struct inode * inode)
+{
+ handle_t *handle;
+
+ if (is_bad_inode(inode) ||
+ inode->i_ino == EXT3_ACL_IDX_INO ||
+ inode->i_ino == EXT3_ACL_DATA_INO)
+ goto no_delete;
+
+ lock_kernel();
+ handle = start_transaction(inode);
+ if (IS_ERR(handle)) {
+ /* If we're going to skip the normal cleanup, we still
+ * need to make sure that the in-core orphan linked list
+ * is properly cleaned up. */
+ ext3_orphan_del(NULL, inode);
+
+ ext3_std_error(inode->i_sb, PTR_ERR(handle));
+ unlock_kernel();
+ goto no_delete;
+ }
+
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+ inode->i_size = 0;
+ if (inode->i_blocks)
+ ext3_truncate(inode);
+ /*
+ * Kill off the orphan record which ext3_truncate created.
+ * AKPM: I think this can be inside the above `if'.
+ * Note that ext3_orphan_del() has to be able to cope with the
+ * deletion of a non-existent orphan - this is because we don't
+ * know if ext3_truncate() actually created an orphan record.
+ * (Well, we could do this if we need to, but heck - it works)
+ */
+ ext3_orphan_del(handle, inode);
+ inode->u.ext3_i.i_dtime = CURRENT_TIME;
+
+ /*
+ * One subtle ordering requirement: if anything has gone wrong
+ * (transaction abort, IO errors, whatever), then we can still
+ * do these next steps (the fs will already have been marked as
+ * having errors), but we can't free the inode if the mark_dirty
+ * fails.
+ */
+ if (ext3_mark_inode_dirty(handle, inode))
+ /* If that failed, just do the required in-core inode clear. */
+ clear_inode(inode);
+ else
+ ext3_free_inode(handle, inode);
+ ext3_journal_stop(handle, inode);
+ unlock_kernel();
+ return;
+no_delete:
+ clear_inode(inode); /* We must guarantee clearing of inode... */
+}
+
+void ext3_discard_prealloc (struct inode * inode)
+{
+#ifdef EXT3_PREALLOCATE
+ lock_kernel();
+ /* Writer: ->i_prealloc* */
+ if (inode->u.ext3_i.i_prealloc_count) {
+ unsigned short total = inode->u.ext3_i.i_prealloc_count;
+ unsigned long block = inode->u.ext3_i.i_prealloc_block;
+ inode->u.ext3_i.i_prealloc_count = 0;
+ inode->u.ext3_i.i_prealloc_block = 0;
+ /* Writer: end */
+ ext3_free_blocks (inode, block, total);
+ }
+ unlock_kernel();
+#endif
+}
+
+static int ext3_alloc_block (handle_t *handle,
+ struct inode * inode, unsigned long goal, int *err)
+{
+#ifdef EXT3FS_DEBUG
+ static unsigned long alloc_hits = 0, alloc_attempts = 0;
+#endif
+ unsigned long result;
+
+#ifdef EXT3_PREALLOCATE
+ /* Writer: ->i_prealloc* */
+ if (inode->u.ext3_i.i_prealloc_count &&
+ (goal == inode->u.ext3_i.i_prealloc_block ||
+ goal + 1 == inode->u.ext3_i.i_prealloc_block))
+ {
+ result = inode->u.ext3_i.i_prealloc_block++;
+ inode->u.ext3_i.i_prealloc_count--;
+ /* Writer: end */
+ ext3_debug ("preallocation hit (%lu/%lu).\n",
+ ++alloc_hits, ++alloc_attempts);
+ } else {
+ ext3_discard_prealloc (inode);
+ ext3_debug ("preallocation miss (%lu/%lu).\n",
+ alloc_hits, ++alloc_attempts);
+ if (S_ISREG(inode->i_mode))
+ result = ext3_new_block (inode, goal,
+ &inode->u.ext3_i.i_prealloc_count,
+ &inode->u.ext3_i.i_prealloc_block, err);
+ else
+ result = ext3_new_block (inode, goal, 0, 0, err);
+ /*
+ * AKPM: this is somewhat sticky. I'm not surprised it was
+ * disabled in 2.2's ext3. Need to integrate b_committed_data
+ * guarding with preallocation, if indeed preallocation is
+ * effective.
+ */
+ }
+#else
+ result = ext3_new_block (handle, inode, goal, 0, 0, err);
+#endif
+ return result;
+}
+
+
+typedef struct {
+ u32 *p;
+ u32 key;
+ struct buffer_head *bh;
+} Indirect;
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, u32 *v)
+{
+ p->key = *(p->p = v);
+ p->bh = bh;
+}
+
+static inline int verify_chain(Indirect *from, Indirect *to)
+{
+ while (from <= to && from->key == *from->p)
+ from++;
+ return (from > to);
+}
+
+/**
+ * ext3_block_to_path - parse the block number into array of offsets
+ * @inode: inode in question (we are only interested in its superblock)
+ * @i_block: block number to be parsed
+ * @offsets: array to store the offsets in
+ *
+ * To store the locations of file's data ext3 uses a data structure common
+ * for UNIX filesystems - tree of pointers anchored in the inode, with
+ * data blocks at leaves and indirect blocks in intermediate nodes.
+ * This function translates the block number into path in that tree -
+ * return value is the path length and @offsets[n] is the offset of
+ * pointer to (n+1)th node in the nth one. If @block is out of range
+ * (negative or too large) warning is printed and zero returned.
+ *
+ * Note: function doesn't find node addresses, so no IO is needed. All
+ * we need to know is the capacity of indirect blocks (taken from the
+ * inode->i_sb).
+ */
+
+/*
+ * Portability note: the last comparison (check that we fit into triple
+ * indirect block) is spelled differently, because otherwise on an
+ * architecture with 32-bit longs and 8Kb pages we might get into trouble
+ * if our filesystem had 8Kb blocks. We might use long long, but that would
+ * kill us on x86. Oh, well, at least the sign propagation does not matter -
+ * i_block would have to be negative in the very beginning, so we would not
+ * get there at all.
+ */
+
+static int ext3_block_to_path(struct inode *inode, long i_block, int offsets[4])
+{
+ int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+ int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
+ const long direct_blocks = EXT3_NDIR_BLOCKS,
+ indirect_blocks = ptrs,
+ double_blocks = (1 << (ptrs_bits * 2));
+ int n = 0;
+
+ if (i_block < 0) {
+ ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
+ } else if (i_block < direct_blocks) {
+ offsets[n++] = i_block;
+ } else if ( (i_block -= direct_blocks) < indirect_blocks) {
+ offsets[n++] = EXT3_IND_BLOCK;
+ offsets[n++] = i_block;
+ } else if ((i_block -= indirect_blocks) < double_blocks) {
+ offsets[n++] = EXT3_DIND_BLOCK;
+ offsets[n++] = i_block >> ptrs_bits;
+ offsets[n++] = i_block & (ptrs - 1);
+ } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
+ offsets[n++] = EXT3_TIND_BLOCK;
+ offsets[n++] = i_block >> (ptrs_bits * 2);
+ offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
+ offsets[n++] = i_block & (ptrs - 1);
+ } else {
+ ext3_warning (inode->i_sb, "ext3_block_to_path", "block > big");
+ }
+ return n;
+}
+
+/**
+ * ext3_get_branch - read the chain of indirect blocks leading to data
+ * @inode: inode in question
+ * @depth: depth of the chain (1 - direct pointer, etc.)
+ * @offsets: offsets of pointers in inode/indirect blocks
+ * @chain: place to store the result
+ * @err: here we store the error value
+ *
+ * Function fills the array of triples <key, p, bh> and returns %NULL
+ * if everything went OK or the pointer to the last filled triple
+ * (incomplete one) otherwise. Upon the return chain[i].key contains
+ * the number of (i+1)-th block in the chain (as it is stored in memory,
+ * i.e. little-endian 32-bit), chain[i].p contains the address of that
+ * number (it points into struct inode for i==0 and into the bh->b_data
+ * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
+ * block for i>0 and NULL for i==0. In other words, it holds the block
+ * numbers of the chain, addresses they were taken from (and where we can
+ * verify that chain did not change) and buffer_heads hosting these
+ * numbers.
+ *
+ * Function stops when it stumbles upon zero pointer (absent block)
+ * (pointer to last triple returned, *@err == 0)
+ * or when it gets an IO error reading an indirect block
+ * (ditto, *@err == -EIO)
+ * or when it notices that chain had been changed while it was reading
+ * (ditto, *@err == -EAGAIN)
+ * or when it reads all @depth-1 indirect blocks successfully and finds
+ * the whole chain, all way to the data (returns %NULL, *err == 0).
+ */
+static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
+ Indirect chain[4], int *err)
+{
+ kdev_t dev = inode->i_dev;
+ int blocksize = inode->i_sb->s_blocksize;
+ Indirect *p = chain;
+ struct buffer_head *bh;
+
+ *err = 0;
+ /* i_data is not going away, no lock needed */
+ add_chain (chain, NULL, inode->u.ext3_i.i_data + *offsets);
+ if (!p->key)
+ goto no_block;
+ while (--depth) {
+ bh = bread(dev, le32_to_cpu(p->key), blocksize);
+ if (!bh)
+ goto failure;
+ /* Reader: pointers */
+ if (!verify_chain(chain, p))
+ goto changed;
+ add_chain(++p, bh, (u32*)bh->b_data + *++offsets);
+ /* Reader: end */
+ if (!p->key)
+ goto no_block;
+ }
+ return NULL;
+
+changed:
+ *err = -EAGAIN;
+ goto no_block;
+failure:
+ *err = -EIO;
+no_block:
+ return p;
+}
+
+/**
+ * ext3_find_near - find a place for allocation with sufficient locality
+ * @inode: owner
+ * @ind: descriptor of indirect block.
+ *
+ * This function returns the 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.
+ * Caller must make sure that @ind is valid and will stay that way.
+ */
+
+static inline unsigned long ext3_find_near(struct inode *inode, Indirect *ind)
+{
+ u32 *start = ind->bh ? (u32*) ind->bh->b_data : inode->u.ext3_i.i_data;
+ u32 *p;
+
+ /* Try to find previous block */
+ for (p = ind->p - 1; p >= start; p--)
+ if (*p)
+ return le32_to_cpu(*p);
+
+ /* No such thing, so let's try location of indirect block */
+ if (ind->bh)
+ return ind->bh->b_blocknr;
+
+ /*
+ * It is going to be refered from inode itself? OK, just put it into
+ * the same cylinder group then.
+ */
+ return (inode->u.ext3_i.i_block_group *
+ EXT3_BLOCKS_PER_GROUP(inode->i_sb)) +
+ le32_to_cpu(inode->i_sb->u.ext3_sb.s_es->s_first_data_block);
+}
+
+/**
+ * ext3_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. If the branch had been changed
+ * under us we return -EAGAIN.
+ */
+
+static int ext3_find_goal(struct inode *inode, long block, Indirect chain[4],
+ Indirect *partial, unsigned long *goal)
+{
+ /* Writer: ->i_next_alloc* */
+ if (block == inode->u.ext3_i.i_next_alloc_block + 1) {
+ inode->u.ext3_i.i_next_alloc_block++;
+ inode->u.ext3_i.i_next_alloc_goal++;
+ }
+#ifdef SEARCH_FROM_ZERO
+ inode->u.ext3_i.i_next_alloc_block = 0;
+ inode->u.ext3_i.i_next_alloc_goal = 0;
+#endif
+ /* Writer: end */
+ /* Reader: pointers, ->i_next_alloc* */
+ if (verify_chain(chain, partial)) {
+ /*
+ * try the heuristic for sequential allocation,
+ * failing that at least try to get decent locality.
+ */
+ if (block == inode->u.ext3_i.i_next_alloc_block)
+ *goal = inode->u.ext3_i.i_next_alloc_goal;
+ if (!*goal)
+ *goal = ext3_find_near(inode, partial);
+#ifdef SEARCH_FROM_ZERO
+ *goal = 0;
+#endif
+ return 0;
+ }
+ /* Reader: end */
+ return -EAGAIN;
+}
+
+/**
+ * ext3_alloc_branch - allocate and set up a chain of blocks.
+ * @inode: owner
+ * @num: depth of the chain (number of blocks to allocate)
+ * @offsets: offsets (in the blocks) to store the pointers to next.
+ * @branch: place to store the chain in.
+ *
+ * This function allocates @num blocks, zeroes out all but the last one,
+ * links them into chain and (if we are synchronous) writes them to disk.
+ * In other words, it prepares a branch that can be spliced onto the
+ * inode. It stores the information about that chain in the branch[], in
+ * the same format as ext3_get_branch() would do. We are calling it after
+ * we had read the existing part of chain and partial points to the last
+ * triple of that (one with zero ->key). Upon the exit we have the same
+ * picture as after the successful ext3_get_block(), excpet that in one
+ * place chain is disconnected - *branch->p is still zero (we did not
+ * set the last link), but branch->key contains the number that should
+ * be placed into *branch->p to fill that gap.
+ *
+ * If allocation fails we free all blocks we've allocated (and forget
+ * their buffer_heads) and return the error value the from failed
+ * ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ * as described above and return 0.
+ */
+
+static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
+ int num,
+ unsigned long goal,
+ int *offsets,
+ Indirect *branch)
+{
+ int blocksize = inode->i_sb->s_blocksize;
+ int n = 0, keys = 0;
+ int err = 0;
+ int i;
+ int parent = ext3_alloc_block(handle, inode, goal, &err);
+
+ branch[0].key = cpu_to_le32(parent);
+ if (parent) {
+ for (n = 1; n < num; n++) {
+ struct buffer_head *bh;
+ /* Allocate the next block */
+ int nr = ext3_alloc_block(handle, inode, parent, &err);
+ if (!nr)
+ break;
+ branch[n].key = cpu_to_le32(nr);
+ keys = n+1;
+
+ /*
+ * Get buffer_head for parent block, zero it out
+ * and set the pointer to new one, then send
+ * parent to disk.
+ */
+ bh = getblk(inode->i_dev, parent, blocksize);
+ branch[n].bh = bh;
+ lock_buffer(bh);
+ BUFFER_TRACE(bh, "call get_create_access");
+ err = ext3_journal_get_create_access(handle, bh);
+ if (err) {
+ unlock_buffer(bh);
+ brelse(bh);
+ break;
+ }
+
+ memset(bh->b_data, 0, blocksize);
+ branch[n].p = (u32*) bh->b_data + offsets[n];
+ *branch[n].p = branch[n].key;
+ BUFFER_TRACE(bh, "marking uptodate");
+ mark_buffer_uptodate(bh, 1);
+ unlock_buffer(bh);
+
+ BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+ err = ext3_journal_dirty_metadata(handle, bh);
+ if (err)
+ break;
+
+ parent = nr;
+ }
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+ }
+ if (n == num)
+ return 0;
+
+ /* Allocation failed, free what we already allocated */
+ for (i = 1; i < keys; i++) {
+ BUFFER_TRACE(branch[i].bh, "call journal_forget");
+ ext3_journal_forget(handle, branch[i].bh);
+ }
+ for (i = 0; i < keys; i++)
+ ext3_free_blocks(handle, inode, le32_to_cpu(branch[i].key), 1);
+ return err;
+}
+
+/**
+ * ext3_splice_branch - splice the allocated branch onto inode.
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @chain: chain of indirect blocks (with a missing link - see
+ * ext3_alloc_branch)
+ * @where: location of missing link
+ * @num: number of blocks we are adding
+ *
+ * This function verifies that chain (up to the missing link) had not
+ * changed, 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. Otherwise (== chain had been changed)
+ * we free the new blocks (forgetting their buffer_heads, indeed) and
+ * return -EAGAIN.
+ */
+
+static int ext3_splice_branch(handle_t *handle, struct inode *inode, long block,
+ Indirect chain[4], Indirect *where, int num)
+{
+ int i;
+ int err = 0;
+
+ /*
+ * If we're splicing into a [td]indirect block (as opposed to the
+ * inode) then we need to get write access to the [td]indirect block
+ * before the splice.
+ */
+ if (where->bh) {
+ BUFFER_TRACE(where->bh, "get_write_access");
+ err = ext3_journal_get_write_access(handle, where->bh);
+ if (err)
+ goto err_out;
+ }
+ /* Verify that place we are splicing to is still there and vacant */
+
+ /* Writer: pointers, ->i_next_alloc* */
+ if (!verify_chain(chain, where-1) || *where->p)
+ /* Writer: end */
+ goto changed;
+
+ /* That's it */
+
+ *where->p = where->key;
+ inode->u.ext3_i.i_next_alloc_block = block;
+ inode->u.ext3_i.i_next_alloc_goal = le32_to_cpu(where[num-1].key);
+#ifdef SEARCH_FROM_ZERO
+ inode->u.ext3_i.i_next_alloc_block = 0;
+ inode->u.ext3_i.i_next_alloc_goal = 0;
+#endif
+ /* Writer: end */
+
+ /* We are done with atomic stuff, now do the rest of housekeeping */
+
+ inode->i_ctime = CURRENT_TIME;
+ ext3_mark_inode_dirty(handle, inode);
+
+ /* had we spliced it onto indirect block? */
+ if (where->bh) {
+ /*
+ * akpm: If we spliced it onto an indirect block, we haven't
+ * altered the inode. Note however that if it is being spliced
+ * onto an indirect block at the very end of the file (the
+ * file is growing) then we *will* alter the inode to reflect
+ * the new i_size. But that is not done here - it is done in
+ * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
+ */
+ jbd_debug(5, "splicing indirect only\n");
+ BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
+ err = ext3_journal_dirty_metadata(handle, where->bh);
+ if (err)
+ goto err_out;
+ } else {
+ /*
+ * OK, we spliced it into the inode itself on a direct block.
+ * Inode was dirtied above.
+ */
+ jbd_debug(5, "splicing direct\n");
+ }
+ return err;
+
+changed:
+ /*
+ * AKPM: if where[i].bh isn't part of the current updating
+ * transaction then we explode nastily. Test this code path.
+ */
+ jbd_debug(1, "the chain changed: try again\n");
+ err = -EAGAIN;
+
+err_out:
+ for (i = 1; i < num; i++) {
+ BUFFER_TRACE(where[i].bh, "call journal_forget");
+ ext3_journal_forget(handle, where[i].bh);
+ }
+ /* For the normal collision cleanup case, we free up the blocks.
+ * On genuine filesystem errors we don't even think about doing
+ * that. */
+ if (err == -EAGAIN)
+ for (i = 0; i < num; i++)
+ ext3_free_blocks(handle, inode,
+ le32_to_cpu(where[i].key), 1);
+ 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.
+ *
+ * akpm: `handle' can be NULL if create == 0.
+ */
+
+static int ext3_get_block_handle(handle_t *handle, struct inode *inode,
+ long iblock,
+ struct buffer_head *bh_result, int create)
+{
+ int err = -EIO;
+ int offsets[4];
+ Indirect chain[4];
+ Indirect *partial;
+ unsigned long goal;
+ int left;
+ int depth = ext3_block_to_path(inode, iblock, offsets);
+ loff_t new_size;
+
+ J_ASSERT(handle != NULL || create == 0);
+
+ if (depth == 0)
+ goto out;
+
+ lock_kernel();
+reread:
+ partial = ext3_get_branch(inode, depth, offsets, chain, &err);
+
+ /* Simplest case - block found, no allocation needed */
+ if (!partial) {
+ bh_result->b_state &= ~(1UL << BH_New);
+got_it:
+ bh_result->b_dev = inode->i_dev;
+ bh_result->b_blocknr = le32_to_cpu(chain[depth-1].key);
+ bh_result->b_state |= (1UL << BH_Mapped);
+ /* Clean up and exit */
+ partial = chain+depth-1; /* the whole chain */
+ goto cleanup;
+ }
+
+ /* Next simple case - plain lookup or failed read of indirect block */
+ if (!create || err == -EIO) {
+cleanup:
+ while (partial > chain) {
+ BUFFER_TRACE(partial->bh, "call brelse");
+ brelse(partial->bh);
+ partial--;
+ }
+ BUFFER_TRACE(bh_result, "returned");
+ unlock_kernel();
+out:
+ return err;
+ }
+
+ /*
+ * Indirect block might be removed by truncate while we were
+ * reading it. Handling of that case (forget what we've got and
+ * reread) is taken out of the main path.
+ */
+ if (err == -EAGAIN)
+ goto changed;
+
+ if (ext3_find_goal(inode, iblock, chain, partial, &goal) < 0)
+ goto changed;
+
+ left = (chain + depth) - partial;
+
+ /*
+ * Block out ext3_truncate while we alter the tree
+ */
+ down_read(&inode->u.ext3_i.truncate_sem);
+ err = ext3_alloc_branch(handle, inode, left, goal,
+ offsets+(partial-chain), partial);
+
+ /* The ext3_splice_branch call will free and forget any buffers
+ * on the new chain if there is a failure, but that risks using
+ * up transaction credits, especially for bitmaps where the
+ * credits cannot be returned. Can we handle this somehow? We
+ * may need to return -EAGAIN upwards in the worst case. --sct */
+ if (!err)
+ err = ext3_splice_branch(handle, inode, iblock, chain,
+ partial, left);
+ up_read(&inode->u.ext3_i.truncate_sem);
+ if (err == -EAGAIN)
+ goto changed;
+ if (err)
+ goto cleanup;
+
+ new_size = inode->i_size;
+ /*
+ * This is not racy against ext3_truncate's modification of i_disksize
+ * because VM/VFS ensures that the file cannot be extended while
+ * truncate is in progress. It is racy between multiple parallel
+ * instances of get_block, but we have the BKL.
+ */
+ if (new_size > inode->u.ext3_i.i_disksize)
+ inode->u.ext3_i.i_disksize = new_size;
+
+ bh_result->b_state |= (1UL << BH_New);
+ goto got_it;
+
+changed:
+ while (partial > chain) {
+ jbd_debug(1, "buffer chain changed, retrying\n");
+ BUFFER_TRACE(partial->bh, "brelsing");
+ brelse(partial->bh);
+ partial--;
+ }
+ goto reread;
+}
+
+static int ext3_get_block(struct inode *inode, long iblock,
+ struct buffer_head *bh_result, int create)
+{
+ handle_t *handle = 0;
+ int ret;
+
+ if (create) {
+ handle = ext3_journal_current_handle();
+ J_ASSERT(handle != 0);
+ }
+ ret = ext3_get_block_handle(handle, inode, iblock, bh_result, create);
+ return ret;
+}
+
+/*
+ * `handle' can be NULL if create is zero
+ */
+struct buffer_head *ext3_getblk(handle_t *handle, struct inode * inode,
+ long block, int create, int * errp)
+{
+ struct buffer_head dummy;
+ int fatal = 0, err;
+
+ J_ASSERT(handle != NULL || create == 0);
+
+ dummy.b_state = 0;
+ dummy.b_blocknr = -1000;
+ buffer_trace_init(&dummy.b_history);
+ *errp = ext3_get_block_handle(handle, inode, block, &dummy, create);
+ if (!*errp && buffer_mapped(&dummy)) {
+ struct buffer_head *bh;
+ bh = getblk(dummy.b_dev, dummy.b_blocknr,
+ inode->i_sb->s_blocksize);
+ 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
+ ext3_get_block instead, so it's not a
+ problem. */
+ lock_kernel();
+ lock_buffer(bh);
+ BUFFER_TRACE(bh, "call get_create_access");
+ fatal = ext3_journal_get_create_access(handle, bh);
+ if (!fatal) {
+ memset(bh->b_data, 0,
+ inode->i_sb->s_blocksize);
+ mark_buffer_uptodate(bh, 1);
+ }
+ unlock_buffer(bh);
+ BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+ err = ext3_journal_dirty_metadata(handle, bh);
+ if (!fatal) fatal = err;
+ unlock_kernel();
+ } else {
+ BUFFER_TRACE(bh, "not a new buffer");
+ }
+ if (fatal) {
+ *errp = fatal;
+ brelse(bh);
+ bh = NULL;
+ }
+ return bh;
+ }
+ return NULL;
+}
+
+struct buffer_head *ext3_bread(handle_t *handle, struct inode * inode,
+ int block, int create, int *err)
+{
+ struct buffer_head * bh;
+ int prev_blocks;
+
+ prev_blocks = inode->i_blocks;
+
+ bh = ext3_getblk (handle, inode, block, create, err);
+ if (!bh)
+ return bh;
+#ifdef EXT3_PREALLOCATE
+ /*
+ * If the inode has grown, and this is a directory, then use a few
+ * more of the preallocated blocks to keep directory fragmentation
+ * down. The preallocated blocks are guaranteed to be contiguous.
+ */
+ if (create &&
+ S_ISDIR(inode->i_mode) &&
+ inode->i_blocks > prev_blocks &&
+ EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
+ EXT3_FEATURE_COMPAT_DIR_PREALLOC)) {
+ int i;
+ struct buffer_head *tmp_bh;
+
+ for (i = 1;
+ inode->u.ext3_i.i_prealloc_count &&
+ i < EXT3_SB(inode->i_sb)->s_es->s_prealloc_dir_blocks;
+ i++) {
+ /*
+ * ext3_getblk will zero out the contents of the
+ * directory for us
+ */
+ tmp_bh = ext3_getblk(handle, inode,
+ block+i, create, err);
+ if (!tmp_bh) {
+ brelse (bh);
+ return 0;
+ }
+ brelse (tmp_bh);
+ }
+ }
+#endif
+ if (buffer_uptodate(bh))
+ return bh;
+ ll_rw_block (READ, 1, &bh);
+ wait_on_buffer (bh);
+ if (buffer_uptodate(bh))
+ return bh;
+ brelse (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;
+
+ for ( bh = head, block_start = 0;
+ ret == 0 && (bh != head || !block_start);
+ block_start = block_end, bh = bh->b_this_page)
+ {
+ block_end = block_start + blocksize;
+ if (block_end <= from || block_start >= to) {
+ if (partial && !buffer_uptodate(bh))
+ *partial = 1;
+ continue;
+ }
+ err = (*fn)(handle, bh);
+ if (!ret)
+ ret = err;
+ }
+ return ret;
+}
+
+/*
+ * To preserve ordering, it is essential that the hole instantiation and
+ * the data write be encapsulated in a single transaction. We cannot
+ * close off a transaction and start a new one between the ext3_get_block()
+ * and the commit_write(). So doing the journal_start at the start of
+ * prepare_write() is the right place.
+ *
+ * Also, this function can nest inside ext3_writepage() ->
+ * block_write_full_page(). In that case, we *know* that ext3_writepage()
+ * has generated enough buffer credits to do the whole page. So we won't
+ * block on the journal in that case, which is good, because the caller may
+ * be PF_MEMALLOC.
+ *
+ * By accident, ext3 can be reentered when a transaction is open via
+ * quota file writes. If we were to commit the transaction while thus
+ * reentered, there can be a deadlock - we would be holding a quota
+ * lock, and the commit would never complete if another thread had a
+ * transaction open and was blocking on the quota lock - a ranking
+ * violation.
+ *
+ * So what we do is to rely on the fact that journal_stop/journal_start
+ * will _not_ run commit under these circumstances because handle->h_ref
+ * is elevated. We'll still have enough credits for the tiny quotafile
+ * write.
+ */
+
+static int do_journal_get_write_access(handle_t *handle,
+ struct buffer_head *bh)
+{
+ return ext3_journal_get_write_access(handle, bh);
+}
+
+static int ext3_prepare_write(struct file *file, struct page *page,
+ unsigned from, unsigned to)
+{
+ struct inode *inode = page->mapping->host;
+ handle_t *handle = ext3_journal_current_handle();
+ int ret, needed_blocks = ext3_writepage_trans_blocks(inode);
+
+ lock_kernel();
+ handle = ext3_journal_start(inode, needed_blocks);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+ ret = block_prepare_write(page, from, to, ext3_get_block);
+ if (ret != 0)
+ goto prepare_write_failed;
+
+ if (ext3_should_journal_data(inode))
+ ret = walk_page_buffers(handle, page->buffers,
+ from, to, NULL, do_journal_get_write_access);
+prepare_write_failed:
+ if (ret)
+ ext3_journal_stop(handle, inode);
+out:
+ unlock_kernel();
+ return ret;
+}
+
+static int journal_dirty_sync_data(handle_t *handle, struct buffer_head *bh)
+{
+ return ext3_journal_dirty_data(handle, bh, 0);
+}
+
+/*
+ * For ext3_writepage(). We also brelse() the buffer to account for
+ * the bget() which ext3_writepage() performs.
+ */
+static int journal_dirty_async_data(handle_t *handle, struct buffer_head *bh)
+{
+ int ret = ext3_journal_dirty_data(handle, bh, 1);
+ __brelse(bh);
+ return ret;
+}
+
+/* For commit_write() in data=journal mode */
+static int commit_write_fn(handle_t *handle, struct buffer_head *bh)
+{
+ set_bit(BH_Uptodate, &bh->b_state);
+ return ext3_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 block_symlink().
+ *
+ * ext3 inode->i_dirty_buffers policy: If we're journalling data we
+ * definitely don't want them to appear on the inode at all - instead
+ * we need to manage them at the JBD layer and we need to intercept
+ * the relevant sync operations and translate them into journal operations.
+ *
+ * If we're not journalling data then we can just leave the buffers
+ * on ->i_dirty_buffers. If someone writes them out for us then thanks.
+ * Otherwise we'll do it in commit, if we're using ordered data.
+ */
+
+static int ext3_commit_write(struct file *file, struct page *page,
+ unsigned from, unsigned to)
+{
+ handle_t *handle = ext3_journal_current_handle();
+ struct inode *inode = page->mapping->host;
+ int ret = 0, ret2;
+
+ lock_kernel();
+ if (ext3_should_journal_data(inode)) {
+ /*
+ * Here we duplicate the generic_commit_write() functionality
+ */
+ int partial = 0;
+ loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+ ret = walk_page_buffers(handle, page->buffers,
+ from, to, &partial, commit_write_fn);
+ if (!partial)
+ SetPageUptodate(page);
+ kunmap(page);
+ if (pos > inode->i_size)
+ inode->i_size = pos;
+ set_bit(EXT3_STATE_JDATA, &inode->u.ext3_i.i_state);
+ } else {
+ if (ext3_should_order_data(inode)) {
+ ret = walk_page_buffers(handle, page->buffers,
+ from, to, NULL, journal_dirty_sync_data);
+ }
+ /* Be careful here if generic_commit_write becomes a
+ * required invocation after block_prepare_write. */
+ if (ret == 0)
+ ret = generic_commit_write(file, page, from, to);
+ }
+ if (inode->i_size > inode->u.ext3_i.i_disksize) {
+ inode->u.ext3_i.i_disksize = inode->i_size;
+ ret2 = ext3_mark_inode_dirty(handle, inode);
+ if (!ret)
+ ret = ret2;
+ }
+ ret2 = ext3_journal_stop(handle, inode);
+ unlock_kernel();
+ 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 ext3 data-journaling
+ * filesystem and enables swap, then they may get a nasty shock when the
+ * data getting swapped to that swapfile suddenly gets overwritten by
+ * the original zero's written out previously to the journal and
+ * awaiting writeback in the kernel's buffer cache.
+ *
+ * So, if we see any bmap calls here on a modified, data-journaled file,
+ * take extra steps to flush any blocks which might be in the cache.
+ */
+static int ext3_bmap(struct address_space *mapping, long block)
+{
+ struct inode *inode = mapping->host;
+ journal_t *journal;
+ int err;
+
+ if (test_and_clear_bit(EXT3_STATE_JDATA, &inode->u.ext3_i.i_state)) {
+ /*
+ * This is a REALLY heavyweight approach, but the use of
+ * bmap on dirty files is expected to be extremely rare:
+ * only if we run lilo or swapon on a freshly made file
+ * do we expect this to happen.
+ *
+ * (bmap requires CAP_SYS_RAWIO so this does not
+ * represent an unprivileged user DOS attack --- we'd be
+ * in trouble if mortal users could trigger this path at
+ * will.)
+ *
+ * NB. EXT3_STATE_JDATA is not set on files other than
+ * regular files. If somebody wants to bmap a directory
+ * or symlink and gets confused because the buffer
+ * hasn't yet been flushed to disk, they deserve
+ * everything they get.
+ */
+
+ journal = EXT3_JOURNAL(inode);
+ journal_lock_updates(journal);
+ err = journal_flush(journal);
+ journal_unlock_updates(journal);
+
+ if (err)
+ return 0;
+ }
+
+ return generic_block_bmap(mapping,block,ext3_get_block);
+}
+
+static int bget_one(handle_t *handle, struct buffer_head *bh)
+{
+ atomic_inc(&bh->b_count);
+ 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 -> ext3_get_block() should be journalled
+ * along with the data so we don't crash and then get metadata which
+ * refers to old data.
+ *
+ * In all journalling modes block_write_full_page() will start the I/O.
+ *
+ * Problem:
+ *
+ * ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
+ * ext3_writepage()
+ *
+ * Similar for:
+ *
+ * ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
+ *
+ * Same applies to ext3_get_block(). We will deadlock on various things like
+ * lock_journal and i_truncate_sem.
+ *
+ * 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.
+ */
+static int ext3_writepage(struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct buffer_head *page_buffers;
+ handle_t *handle = NULL;
+ int ret = 0, err;
+ int needed;
+ int order_data;
+
+ J_ASSERT(PageLocked(page));
+
+ /*
+ * We give up here if we're reentered, because it might be
+ * for a different filesystem. One *could* look for a
+ * nested transaction opportunity.
+ */
+ lock_kernel();
+ if (ext3_journal_current_handle())
+ goto out_fail;
+
+ needed = ext3_writepage_trans_blocks(inode);
+ if (current->flags & PF_MEMALLOC)
+ handle = ext3_journal_try_start(inode, needed);
+ else
+ handle = ext3_journal_start(inode, needed);
+
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out_fail;
+ }
+
+ order_data = ext3_should_order_data(inode) ||
+ ext3_should_journal_data(inode);
+
+ unlock_kernel();
+
+ page_buffers = NULL; /* Purely to prevent compiler warning */
+
+ /* bget() all the buffers */
+ if (order_data) {
+ if (!page->buffers)
+ create_empty_buffers(page,
+ inode->i_dev, inode->i_sb->s_blocksize);
+ page_buffers = page->buffers;
+ walk_page_buffers(handle, page_buffers, 0,
+ PAGE_CACHE_SIZE, NULL, bget_one);
+ }
+
+ ret = block_write_full_page(page, ext3_get_block);
+
+ /*
+ * 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_buffers is
+ * safe due to elevated refcount.
+ */
+
+ handle = ext3_journal_current_handle();
+ lock_kernel();
+
+ /* And attach them to the current transaction */
+ if (order_data) {
+ err = walk_page_buffers(handle, page_buffers,
+ 0, PAGE_CACHE_SIZE, NULL, journal_dirty_async_data);
+ if (!ret)
+ ret = err;
+ }
+
+ err = ext3_journal_stop(handle, inode);
+ if (!ret)
+ ret = err;
+ unlock_kernel();
+ return ret;
+
+out_fail:
+
+ unlock_kernel();
+ SetPageDirty(page);
+ UnlockPage(page);
+ return ret;
+}
+
+static int ext3_readpage(struct file *file, struct page *page)
+{
+ return block_read_full_page(page,ext3_get_block);
+}
+
+
+static int ext3_flushpage(struct page *page, unsigned long offset)
+{
+ journal_t *journal = EXT3_JOURNAL(page->mapping->host);
+ return journal_flushpage(journal, page, offset);
+}
+
+static int ext3_releasepage(struct page *page, int wait)
+{
+ journal_t *journal = EXT3_JOURNAL(page->mapping->host);
+ return journal_try_to_free_buffers(journal, page, wait);
+}
+
+
+struct address_space_operations ext3_aops = {
+ readpage: ext3_readpage, /* BKL not held. Don't need */
+ writepage: ext3_writepage, /* BKL not held. We take it */
+ sync_page: block_sync_page,
+ prepare_write: ext3_prepare_write, /* BKL not held. We take it */
+ commit_write: ext3_commit_write, /* BKL not held. We take it */
+ bmap: ext3_bmap, /* BKL held */
+ flushpage: ext3_flushpage, /* BKL not held. Don't need */
+ releasepage: ext3_releasepage, /* BKL not held. Don't need */
+};
+
+/*
+ * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This required during truncate. We need to physically zero the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
+ */
+static int ext3_block_truncate_page(handle_t *handle,
+ struct address_space *mapping, loff_t from)
+{
+ unsigned long index = from >> PAGE_CACHE_SHIFT;
+ unsigned offset = from & (PAGE_CACHE_SIZE-1);
+ unsigned blocksize, iblock, length, pos;
+ struct inode *inode = mapping->host;
+ struct page *page;
+ struct buffer_head *bh;
+ int err;
+
+ blocksize = inode->i_sb->s_blocksize;
+ length = offset & (blocksize - 1);
+
+ /* Block boundary? Nothing to do */
+ if (!length)
+ return 0;
+
+ length = blocksize - length;
+ iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+ page = grab_cache_page(mapping, index);
+ err = -ENOMEM;
+ if (!page)
+ goto out;
+
+ if (!page->buffers)
+ create_empty_buffers(page, inode->i_dev, blocksize);
+
+ /* Find the buffer that contains "offset" */
+ bh = page->buffers;
+ pos = blocksize;
+ while (offset >= pos) {
+ bh = bh->b_this_page;
+ iblock++;
+ pos += blocksize;
+ }
+
+ err = 0;
+ if (!buffer_mapped(bh)) {
+ /* Hole? Nothing to do */
+ if (buffer_uptodate(bh))
+ goto unlock;
+ ext3_get_block(inode, iblock, bh, 0);
+ /* Still unmapped? Nothing to do */
+ if (!buffer_mapped(bh))
+ goto unlock;
+ }
+
+ /* Ok, it's mapped. Make sure it's up-to-date */
+ if (Page_Uptodate(page))
+ set_bit(BH_Uptodate, &bh->b_state);
+
+ if (!buffer_uptodate(bh)) {
+ err = -EIO;
+ ll_rw_block(READ, 1, &bh);
+ wait_on_buffer(bh);
+ /* Uhhuh. Read error. Complain and punt. */
+ if (!buffer_uptodate(bh))
+ goto unlock;
+ }
+
+ if (ext3_should_journal_data(inode)) {
+ BUFFER_TRACE(bh, "get write access");
+ err = ext3_journal_get_write_access(handle, bh);
+ if (err)
+ goto unlock;
+ }
+
+ memset(kmap(page) + offset, 0, length);
+ flush_dcache_page(page);
+ kunmap(page);
+
+ BUFFER_TRACE(bh, "zeroed end of block");
+
+ err = 0;
+ if (ext3_should_journal_data(inode)) {
+ err = ext3_journal_dirty_metadata(handle, bh);
+ } else {
+ if (ext3_should_order_data(inode))
+ err = ext3_journal_dirty_data(handle, bh, 0);
+ __mark_buffer_dirty(bh);
+ }
+
+unlock:
+ UnlockPage(page);
+ page_cache_release(page);
+out:
+ 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(u32 *p, u32 *q)
+{
+ while (p < q)
+ if (*p++)
+ return 0;
+ return 1;
+}
+
+/**
+ * ext3_find_shared - find the indirect blocks for partial truncation.
+ * @inode: inode in question
+ * @depth: depth of the affected branch
+ * @offsets: offsets of pointers in that branch (see ext3_block_to_path)
+ * @chain: place to store the pointers to partial indirect blocks
+ * @top: place to the (detached) top of branch
+ *
+ * This is a helper function used by ext3_truncate().
+ *
+ * When we do truncate() we may have to clean the ends of several
+ * indirect blocks but leave the blocks themselves alive. Block is
+ * partially truncated if some data below the new i_size is refered
+ * from it (and it is on the path to the first completely truncated
+ * data block, indeed). We have to free the top of that path along
+ * with everything to the right of the path. Since no allocation
+ * past the truncation point is possible until ext3_truncate()
+ * finishes, we may safely do the latter, but top of branch may
+ * require special attention - pageout below the truncation point
+ * might try to populate it.
+ *
+ * We atomically detach the top of branch from the tree, store the
+ * block number of its root in *@top, pointers to buffer_heads of
+ * partially truncated blocks - in @chain[].bh and pointers to
+ * their last elements that should not be removed - in
+ * @chain[].p. Return value is the pointer to last filled element
+ * of @chain.
+ *
+ * The work left to caller to do the actual freeing of subtrees:
+ * a) free the subtree starting from *@top
+ * b) free the subtrees whose roots are stored in
+ * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
+ * c) free the subtrees growing from the inode past the @chain[0].
+ * (no partially truncated stuff there). */
+
+static Indirect *ext3_find_shared(struct inode *inode,
+ int depth,
+ int offsets[4],
+ Indirect chain[4],
+ u32 *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 = ext3_get_branch(inode, k, offsets, chain, &err);
+ /* Writer: pointers */
+ if (!partial)
+ partial = chain + k-1;
+ /*
+ * If the branch acquired continuation since we've looked at it -
+ * fine, it should all survive and (new) top doesn't belong to us.
+ */
+ if (!partial->key && *partial->p)
+ /* Writer: end */
+ goto no_top;
+ for (p=partial; p>chain && all_zeroes((u32*)p->bh->b_data,p->p); p--)
+ ;
+ /*
+ * OK, we've found the last block that must survive. The rest of our
+ * branch should be detached before unlocking. However, if that rest
+ * of branch is all ours and does not grow immediately from the inode
+ * it's easier to cheat and just decrement partial->p.
+ */
+ if (p == chain + k - 1 && p > chain) {
+ p->p--;
+ } else {
+ *top = *p->p;
+ /* Nope, don't do this in ext3. Must leave the tree intact */
+#if 0
+ *p->p = 0;
+#endif
+ }
+ /* Writer: end */
+
+ while(partial > p)
+ {
+ brelse(partial->bh);
+ partial--;
+ }
+no_top:
+ return partial;
+}
+
+/*
+ * Zero a number of block pointers in either an inode or an indirect block.
+ * If we restart the transaction we must again get write access to the
+ * indirect block for further modification.
+ *
+ * We release `count' blocks on disk, but (last - first) may be greater
+ * than `count' because there can be holes in there.
+ */
+static void
+ext3_clear_blocks(handle_t *handle, struct inode *inode, struct buffer_head *bh,
+ unsigned long block_to_free, unsigned long count,
+ u32 *first, u32 *last)
+{
+ u32 *p;
+ kdev_t dev = inode->i_sb->s_dev;
+ unsigned long blocksize = inode->i_sb->s_blocksize;
+
+ if (try_to_extend_transaction(handle, inode)) {
+ if (bh) {
+ BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+ ext3_journal_dirty_metadata(handle, bh);
+ }
+ ext3_mark_inode_dirty(handle, inode);
+ ext3_journal_test_restart(handle, inode);
+ BUFFER_TRACE(bh, "get_write_access");
+ ext3_journal_get_write_access(handle, bh);
+ }
+
+ /*
+ * Any buffers which are on the journal will be in memory. We find
+ * them on the hash table so journal_revoke() will run journal_forget()
+ * on them. We've already detached each block from the file, so
+ * bforget() in journal_forget() should be safe.
+ *
+ * AKPM: turn on bforget in journal_forget()!!!
+ */
+ for (p = first; p < last; p++) {
+ u32 nr = le32_to_cpu(*p);
+ if (nr) {
+ struct buffer_head *bh;
+
+ *p = 0;
+ bh = get_hash_table(dev, nr, blocksize);
+ ext3_forget(handle, 0, inode, bh, nr);
+ }
+ }
+
+ ext3_free_blocks(handle, inode, block_to_free, count);
+}
+
+/**
+ * ext3_free_data - free a list of data blocks
+ * @handle: handle for this transaction
+ * @inode: inode we are dealing with
+ * @this_bh: indirect buffer_head which contains *@first and *@last
+ * @first: array of block numbers
+ * @last: points immediately past the end of array
+ *
+ * We are freeing all blocks refered from that array (numbers are stored as
+ * little-endian 32-bit) and updating @inode->i_blocks appropriately.
+ *
+ * We accumulate contiguous runs of blocks to free. Conveniently, if these
+ * blocks are contiguous then releasing them at one time will only affect one
+ * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
+ * actually use a lot of journal space.
+ *
+ * @this_bh will be %NULL if @first and @last point into the inode's direct
+ * block pointers.
+ */
+static void ext3_free_data(handle_t *handle, struct inode *inode,
+ struct buffer_head *this_bh, u32 *first, u32 *last)
+{
+ unsigned long block_to_free = 0; /* Starting block # of a run */
+ unsigned long count = 0; /* Number of blocks in the run */
+ u32 *block_to_free_p = NULL; /* Pointer into inode/ind
+ corresponding to
+ block_to_free */
+ unsigned long nr; /* Current block # */
+ u32 *p; /* Pointer into inode/ind
+ for current block */
+ int err;
+
+ if (this_bh) { /* For indirect block */
+ BUFFER_TRACE(this_bh, "get_write_access");
+ err = ext3_journal_get_write_access(handle, this_bh);
+ /* Important: if we can't update the indirect pointers
+ * to the blocks, we can't free them. */
+ if (err)
+ return;
+ }
+
+ for (p = first; p < last; p++) {
+ nr = le32_to_cpu(*p);
+ if (nr) {
+ /* accumulate blocks to free if they're contiguous */
+ if (count == 0) {
+ block_to_free = nr;
+ block_to_free_p = p;
+ count = 1;
+ } else if (nr == block_to_free + count) {
+ count++;
+ } else {
+ ext3_clear_blocks(handle, inode, this_bh,
+ block_to_free,
+ count, block_to_free_p, p);
+ block_to_free = nr;
+ block_to_free_p = p;
+ count = 1;
+ }
+ }
+ }
+
+ if (count > 0)
+ ext3_clear_blocks(handle, inode, this_bh, block_to_free,
+ count, block_to_free_p, p);
+
+ if (this_bh) {
+ BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
+ ext3_journal_dirty_metadata(handle, this_bh);
+ }
+}
+
+/**
+ * ext3_free_branches - free an array of branches
+ * @handle: JBD handle for this transaction
+ * @inode: inode we are dealing with
+ * @parent_bh: the buffer_head which contains *@first and *@last
+ * @first: array of block numbers
+ * @last: pointer immediately past the end of array
+ * @depth: depth of the branches to free
+ *
+ * We are freeing all blocks refered from these branches (numbers are
+ * stored as little-endian 32-bit) and updating @inode->i_blocks
+ * appropriately.
+ */
+static void ext3_free_branches(handle_t *handle, struct inode *inode,
+ struct buffer_head *parent_bh,
+ u32 *first, u32 *last, int depth)
+{
+ unsigned long nr;
+ u32 *p;
+
+ if (is_handle_aborted(handle))
+ return;
+
+ if (depth--) {
+ struct buffer_head *bh;
+ int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+ p = last;
+ while (--p >= first) {
+ nr = le32_to_cpu(*p);
+ if (!nr)
+ continue; /* A hole */
+
+ /* Go read the buffer for the next level down */
+ bh = bread(inode->i_dev, nr, inode->i_sb->s_blocksize);
+
+ /*
+ * A read failure? Report error and clear slot
+ * (should be rare).
+ */
+ if (!bh) {
+ ext3_error(inode->i_sb, "ext3_free_branches",
+ "Read failure, inode=%ld, block=%ld",
+ inode->i_ino, nr);
+ continue;
+ }
+
+ /* This zaps the entire block. Bottom up. */
+ BUFFER_TRACE(bh, "free child branches");
+ ext3_free_branches(handle, inode, bh, (u32*)bh->b_data,
+ (u32*)bh->b_data + addr_per_block,
+ depth);
+
+ /*
+ * We've probably journalled the indirect block several
+ * times during the truncate. But it's no longer
+ * needed and we now drop it from the transaction via
+ * journal_revoke().
+ *
+ * That's easy if it's exclusively part of this
+ * transaction. But if it's part of the committing
+ * transaction then journal_forget() will simply
+ * brelse() it. That means that if the underlying
+ * block is reallocated in ext3_get_block(),
+ * unmap_underlying_metadata() will find this block
+ * and will try to get rid of it. damn, damn.
+ *
+ * If this block has already been committed to the
+ * journal, a revoke record will be written. And
+ * revoke records must be emitted *before* clearing
+ * this block's bit in the bitmaps.
+ */
+ ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
+
+ /*
+ * Everything below this this pointer has been
+ * released. Now let this top-of-subtree go.
+ *
+ * We want the freeing of this indirect block to be
+ * atomic in the journal with the updating of the
+ * bitmap block which owns it. So make some room in
+ * the journal.
+ *
+ * We zero the parent pointer *after* freeing its
+ * pointee in the bitmaps, so if extend_transaction()
+ * for some reason fails to put the bitmap changes and
+ * the release into the same transaction, recovery
+ * will merely complain about releasing a free block,
+ * rather than leaking blocks.
+ */
+ if (is_handle_aborted(handle))
+ return;
+ if (try_to_extend_transaction(handle, inode)) {
+ ext3_mark_inode_dirty(handle, inode);
+ ext3_journal_test_restart(handle, inode);
+ }
+
+ ext3_free_blocks(handle, inode, nr, 1);
+
+ if (parent_bh) {
+ /*
+ * The block which we have just freed is
+ * pointed to by an indirect block: journal it
+ */
+ BUFFER_TRACE(parent_bh, "get_write_access");
+ if (!ext3_journal_get_write_access(handle,
+ parent_bh)){
+ *p = 0;
+ BUFFER_TRACE(parent_bh,
+ "call ext3_journal_dirty_metadata");
+ ext3_journal_dirty_metadata(handle,
+ parent_bh);
+ }
+ }
+ }
+ } else {
+ /* We have reached the bottom of the tree. */
+ BUFFER_TRACE(parent_bh, "free data blocks");
+ ext3_free_data(handle, inode, parent_bh, first, last);
+ }
+}
+
+/*
+ * ext3_truncate()
+ *
+ * We block out ext3_get_block() block instantiations across the entire
+ * transaction, and VFS/VM ensures that ext3_truncate() cannot run
+ * simultaneously on behalf of the same inode.
+ *
+ * As we work through the truncate and commmit bits of it to the journal there
+ * is one core, guiding principle: the file's tree must always be consistent on
+ * disk. We must be able to restart the truncate after a crash.
+ *
+ * The file's tree may be transiently inconsistent in memory (although it
+ * probably isn't), but whenever we close off and commit a journal transaction,
+ * the contents of (the filesystem + the journal) must be consistent and
+ * restartable. It's pretty simple, really: bottom up, right to left (although
+ * left-to-right works OK too).
+ *
+ * Note that at recovery time, journal replay occurs *before* the restart of
+ * truncate against the orphan inode list.
+ *
+ * The committed inode has the new, desired i_size (which is the same as
+ * i_disksize in this case). After a crash, ext3_orphan_cleanup() will see
+ * that this inode's truncate did not complete and it will again call
+ * ext3_truncate() to have another go. So there will be instantiated blocks
+ * to the right of the truncation point in a crashed ext3 filesystem. But
+ * that's fine - as long as they are linked from the inode, the post-crash
+ * ext3_truncate() run will find them and release them.
+ */
+
+void ext3_truncate(struct inode * inode)
+{
+ handle_t *handle;
+ u32 *i_data = inode->u.ext3_i.i_data;
+ int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+ int offsets[4];
+ Indirect chain[4];
+ Indirect *partial;
+ int nr = 0;
+ int n;
+ long last_block;
+ unsigned blocksize;
+
+ if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+ S_ISLNK(inode->i_mode)))
+ return;
+ if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+ return;
+
+ ext3_discard_prealloc(inode);
+
+ handle = start_transaction(inode);
+ if (IS_ERR(handle))
+ return; /* AKPM: return what? */
+
+ blocksize = inode->i_sb->s_blocksize;
+ last_block = (inode->i_size + blocksize-1)
+ >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
+
+ ext3_block_truncate_page(handle, inode->i_mapping, inode->i_size);
+
+
+ n = ext3_block_to_path(inode, last_block, offsets);
+ if (n == 0)
+ goto out_stop; /* error */
+
+ /*
+ * OK. This truncate is going to happen. We add the inode to the
+ * orphan list, so that if this truncate spans multiple transactions,
+ * and we crash, we will resume the truncate when the filesystem
+ * recovers. It also marks the inode dirty, to catch the new size.
+ *
+ * Implication: the file must always be in a sane, consistent
+ * truncatable state while each transaction commits.
+ */
+ if (ext3_orphan_add(handle, inode))
+ goto out_stop;
+
+ /*
+ * The orphan list entry will now protect us from any crash which
+ * occurs before the truncate completes, so it is now safe to propagate
+ * the new, shorter inode size (held for now in i_size) into the
+ * on-disk inode. We do this via i_disksize, which is the value which
+ * ext3 *really* writes onto the disk inode.
+ */
+ inode->u.ext3_i.i_disksize = inode->i_size;
+
+ /*
+ * From here we block out all ext3_get_block() callers who want to
+ * modify the block allocation tree.
+ */
+ down_write(&inode->u.ext3_i.truncate_sem);
+
+ if (n == 1) { /* direct blocks */
+ ext3_free_data(handle, inode, NULL, i_data+offsets[0],
+ i_data + EXT3_NDIR_BLOCKS);
+ goto do_indirects;
+ }
+
+ partial = ext3_find_shared(inode, n, offsets, chain, &nr);
+ /* Kill the top of shared branch (not detached) */
+ if (nr) {
+ if (partial == chain) {
+ /* Shared branch grows from the inode */
+ ext3_free_branches(handle, inode, NULL,
+ &nr, &nr+1, (chain+n-1) - partial);
+ *partial->p = 0;
+ /*
+ * We mark the inode dirty prior to restart,
+ * and prior to stop. No need for it here.
+ */
+ } else {
+ /* Shared branch grows from an indirect block */
+ BUFFER_TRACE(partial->bh, "get_write_access");
+ ext3_free_branches(handle, inode, partial->bh,
+ partial->p,
+ partial->p+1, (chain+n-1) - partial);
+ }
+ }
+ /* Clear the ends of indirect blocks on the shared branch */
+ while (partial > chain) {
+ ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
+ (u32*)partial->bh->b_data + addr_per_block,
+ (chain+n-1) - partial);
+ BUFFER_TRACE(partial->bh, "call brelse");
+ brelse (partial->bh);
+ partial--;
+ }
+do_indirects:
+ /* Kill the remaining (whole) subtrees */
+ switch (offsets[0]) {
+ default:
+ nr = i_data[EXT3_IND_BLOCK];
+ if (nr) {
+ ext3_free_branches(handle, inode, NULL,
+ &nr, &nr+1, 1);
+ i_data[EXT3_IND_BLOCK] = 0;
+ }
+ case EXT3_IND_BLOCK:
+ nr = i_data[EXT3_DIND_BLOCK];
+ if (nr) {
+ ext3_free_branches(handle, inode, NULL,
+ &nr, &nr+1, 2);
+ i_data[EXT3_DIND_BLOCK] = 0;
+ }
+ case EXT3_DIND_BLOCK:
+ nr = i_data[EXT3_TIND_BLOCK];
+ if (nr) {
+ ext3_free_branches(handle, inode, NULL,
+ &nr, &nr+1, 3);
+ i_data[EXT3_TIND_BLOCK] = 0;
+ }
+ case EXT3_TIND_BLOCK:
+ ;
+ }
+ up_write(&inode->u.ext3_i.truncate_sem);
+ inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ ext3_mark_inode_dirty(handle, inode);
+
+ /* In a multi-transaction truncate, we only make the final
+ * transaction synchronous */
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+out_stop:
+ /*
+ * If this was a simple ftruncate(), and the file will remain alive
+ * then we need to clear up the orphan record which we created above.
+ * However, if this was a real unlink then we were called by
+ * ext3_delete_inode(), and we allow that function to clean up the
+ * orphan info for us.
+ */
+ if (inode->i_nlink)
+ ext3_orphan_del(handle, inode);
+
+ ext3_journal_stop(handle, inode);
+}
+
+/*
+ * ext3_get_inode_loc returns with an extra refcount against the
+ * inode's underlying buffer_head on success.
+ */
+
+int ext3_get_inode_loc (struct inode *inode, struct ext3_iloc *iloc)
+{
+ struct buffer_head *bh = 0;
+ unsigned long block;
+ unsigned long block_group;
+ unsigned long group_desc;
+ unsigned long desc;
+ unsigned long offset;
+ struct ext3_group_desc * gdp;
+
+ if ((inode->i_ino != EXT3_ROOT_INO &&
+ inode->i_ino != EXT3_ACL_IDX_INO &&
+ inode->i_ino != EXT3_ACL_DATA_INO &&
+ inode->i_ino != EXT3_JOURNAL_INO &&
+ inode->i_ino < EXT3_FIRST_INO(inode->i_sb)) ||
+ inode->i_ino > le32_to_cpu(
+ inode->i_sb->u.ext3_sb.s_es->s_inodes_count)) {
+ ext3_error (inode->i_sb, "ext3_get_inode_loc",
+ "bad inode number: %lu", inode->i_ino);
+ goto bad_inode;
+ }
+ block_group = (inode->i_ino - 1) / EXT3_INODES_PER_GROUP(inode->i_sb);
+ if (block_group >= inode->i_sb->u.ext3_sb.s_groups_count) {
+ ext3_error (inode->i_sb, "ext3_get_inode_loc",
+ "group >= groups count");
+ goto bad_inode;
+ }
+ group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(inode->i_sb);
+ desc = block_group & (EXT3_DESC_PER_BLOCK(inode->i_sb) - 1);
+ bh = inode->i_sb->u.ext3_sb.s_group_desc[group_desc];
+ if (!bh) {
+ ext3_error (inode->i_sb, "ext3_get_inode_loc",
+ "Descriptor not loaded");
+ goto bad_inode;
+ }
+
+ gdp = (struct ext3_group_desc *) bh->b_data;
+ /*
+ * Figure out the offset within the block group inode table
+ */
+ offset = ((inode->i_ino - 1) % EXT3_INODES_PER_GROUP(inode->i_sb)) *
+ EXT3_INODE_SIZE(inode->i_sb);
+ block = le32_to_cpu(gdp[desc].bg_inode_table) +
+ (offset >> EXT3_BLOCK_SIZE_BITS(inode->i_sb));
+ if (!(bh = bread (inode->i_dev, block, inode->i_sb->s_blocksize))) {
+ ext3_error (inode->i_sb, "ext3_get_inode_loc",
+ "unable to read inode block - "
+ "inode=%lu, block=%lu", inode->i_ino, block);
+ goto bad_inode;
+ }
+ offset &= (EXT3_BLOCK_SIZE(inode->i_sb) - 1);
+
+ iloc->bh = bh;
+ iloc->raw_inode = (struct ext3_inode *) (bh->b_data + offset);
+ iloc->block_group = block_group;
+
+ return 0;
+
+ bad_inode:
+ return -EIO;
+}
+
+void ext3_read_inode(struct inode * inode)
+{
+ struct ext3_iloc iloc;
+ struct ext3_inode *raw_inode;
+ struct buffer_head *bh;
+ int block;
+
+ if(ext3_get_inode_loc(inode, &iloc))
+ goto bad_inode;
+ bh = iloc.bh;
+ raw_inode = iloc.raw_inode;
+ init_rwsem(&inode->u.ext3_i.truncate_sem);
+ 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 = le32_to_cpu(raw_inode->i_atime);
+ inode->i_ctime = le32_to_cpu(raw_inode->i_ctime);
+ inode->i_mtime = le32_to_cpu(raw_inode->i_mtime);
+ inode->u.ext3_i.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 ||
+ !(inode->i_sb->u.ext3_sb.s_mount_state & EXT3_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_blksize = PAGE_SIZE; /* This is the optimal IO size
+ * (for stat), not the fs block
+ * size */
+ inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
+ inode->i_version = ++event;
+ inode->u.ext3_i.i_flags = le32_to_cpu(raw_inode->i_flags);
+#ifdef EXT3_FRAGMENTS
+ inode->u.ext3_i.i_faddr = le32_to_cpu(raw_inode->i_faddr);
+ inode->u.ext3_i.i_frag_no = raw_inode->i_frag;
+ inode->u.ext3_i.i_frag_size = raw_inode->i_fsize;
+#endif
+ inode->u.ext3_i.i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
+ if (!S_ISREG(inode->i_mode)) {
+ inode->u.ext3_i.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;
+ }
+ inode->u.ext3_i.i_disksize = inode->i_size;
+ inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+#ifdef EXT3_PREALLOCATE
+ inode->u.ext3_i.i_prealloc_count = 0;
+#endif
+ inode->u.ext3_i.i_block_group = iloc.block_group;
+
+ /*
+ * NOTE! The in-memory inode i_data array is in little-endian order
+ * even on big-endian machines: we do NOT byteswap the block numbers!
+ */
+ for (block = 0; block < EXT3_N_BLOCKS; block++)
+ inode->u.ext3_i.i_data[block] = iloc.raw_inode->i_block[block];
+ INIT_LIST_HEAD(&inode->u.ext3_i.i_orphan);
+
+ brelse (iloc.bh);
+
+ if (inode->i_ino == EXT3_ACL_IDX_INO ||
+ inode->i_ino == EXT3_ACL_DATA_INO)
+ /* Nothing to do */ ;
+ else if (S_ISREG(inode->i_mode)) {
+ inode->i_op = &ext3_file_inode_operations;
+ inode->i_fop = &ext3_file_operations;
+ inode->i_mapping->a_ops = &ext3_aops;
+ } else if (S_ISDIR(inode->i_mode)) {
+ inode->i_op = &ext3_dir_inode_operations;
+ inode->i_fop = &ext3_dir_operations;
+ } else if (S_ISLNK(inode->i_mode)) {
+ if (!inode->i_blocks)
+ inode->i_op = &ext3_fast_symlink_inode_operations;
+ else {
+ inode->i_op = &page_symlink_inode_operations;
+ inode->i_mapping->a_ops = &ext3_aops;
+ }
+ } else
+ init_special_inode(inode, inode->i_mode,
+ le32_to_cpu(iloc.raw_inode->i_block[0]));
+ /* inode->i_attr_flags = 0; unused */
+ if (inode->u.ext3_i.i_flags & EXT3_SYNC_FL) {
+ /* inode->i_attr_flags |= ATTR_FLAG_SYNCRONOUS; unused */
+ inode->i_flags |= S_SYNC;
+ }
+ if (inode->u.ext3_i.i_flags & EXT3_APPEND_FL) {
+ /* inode->i_attr_flags |= ATTR_FLAG_APPEND; unused */
+ inode->i_flags |= S_APPEND;
+ }
+ if (inode->u.ext3_i.i_flags & EXT3_IMMUTABLE_FL) {
+ /* inode->i_attr_flags |= ATTR_FLAG_IMMUTABLE; unused */
+ inode->i_flags |= S_IMMUTABLE;
+ }
+ if (inode->u.ext3_i.i_flags & EXT3_NOATIME_FL) {
+ /* inode->i_attr_flags |= ATTR_FLAG_NOATIME; unused */
+ inode->i_flags |= S_NOATIME;
+ }
+ 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.
+ */
+
+static int ext3_do_update_inode(handle_t *handle,
+ struct inode *inode,
+ struct ext3_iloc *iloc)
+{
+ struct ext3_inode *raw_inode = iloc->raw_inode;
+ struct buffer_head *bh = iloc->bh;
+ int err = 0, rc, block;
+
+ if (handle) {
+ BUFFER_TRACE(bh, "get_write_access");
+ err = ext3_journal_get_write_access(handle, bh);
+ if (err)
+ goto out_brelse;
+ }
+ 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(!inode->u.ext3_i.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(inode->u.ext3_i.i_disksize);
+ raw_inode->i_atime = cpu_to_le32(inode->i_atime);
+ raw_inode->i_ctime = cpu_to_le32(inode->i_ctime);
+ raw_inode->i_mtime = cpu_to_le32(inode->i_mtime);
+ raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
+ raw_inode->i_dtime = cpu_to_le32(inode->u.ext3_i.i_dtime);
+ raw_inode->i_flags = cpu_to_le32(inode->u.ext3_i.i_flags);
+#ifdef EXT3_FRAGMENTS
+ raw_inode->i_faddr = cpu_to_le32(inode->u.ext3_i.i_faddr);
+ raw_inode->i_frag = inode->u.ext3_i.i_frag_no;
+ raw_inode->i_fsize = inode->u.ext3_i.i_frag_size;
+#else
+ /* If we are not tracking these fields in the in-memory inode,
+ * then preserve them on disk, but still initialise them to zero
+ * for new inodes. */
+ if (inode->u.ext3_i.i_state & EXT3_STATE_NEW) {
+ raw_inode->i_faddr = 0;
+ raw_inode->i_frag = 0;
+ raw_inode->i_fsize = 0;
+ }
+#endif
+ raw_inode->i_file_acl = cpu_to_le32(inode->u.ext3_i.i_file_acl);
+ if (!S_ISREG(inode->i_mode)) {
+ raw_inode->i_dir_acl = cpu_to_le32(inode->u.ext3_i.i_dir_acl);
+ } else {
+ raw_inode->i_size_high =
+ cpu_to_le32(inode->u.ext3_i.i_disksize >> 32);
+ if (inode->u.ext3_i.i_disksize > 0x7fffffffULL) {
+ struct super_block *sb = inode->i_sb;
+ if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
+ EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
+ EXT3_SB(sb)->s_es->s_rev_level ==
+ cpu_to_le32(EXT3_GOOD_OLD_REV)) {
+ /* If this is the first large file
+ * created, add a flag to the superblock.
+ */
+ err = ext3_journal_get_write_access(handle,
+ sb->u.ext3_sb.s_sbh);
+ if (err)
+ goto out_brelse;
+ ext3_update_dynamic_rev(sb);
+ EXT3_SET_RO_COMPAT_FEATURE(sb,
+ EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
+ sb->s_dirt = 1;
+ handle->h_sync = 1;
+ err = ext3_journal_dirty_metadata(handle,
+ sb->u.ext3_sb.s_sbh);
+ }
+ }
+ }
+ raw_inode->i_generation = le32_to_cpu(inode->i_generation);
+ if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+ raw_inode->i_block[0] =
+ cpu_to_le32(kdev_t_to_nr(inode->i_rdev));
+ else for (block = 0; block < EXT3_N_BLOCKS; block++)
+ raw_inode->i_block[block] = inode->u.ext3_i.i_data[block];
+
+ BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+ rc = ext3_journal_dirty_metadata(handle, bh);
+ if (!err)
+ err = rc;
+ inode->u.ext3_i.i_state &= ~EXT3_STATE_NEW;
+
+out_brelse:
+ brelse (bh);
+ ext3_std_error(inode->i_sb, err);
+ return err;
+}
+
+/*
+ * ext3_write_inode()
+ *
+ * We are called from a few places:
+ *
+ * - Within generic_file_write() for O_SYNC files.
+ * Here, there will be no transaction running. We wait for any running
+ * trasnaction to commit.
+ *
+ * - Within sys_sync(), kupdate and such.
+ * We wait on commit, if tol to.
+ *
+ * - Within prune_icache() (PF_MEMALLOC == true)
+ * Here we simply return. We can't afford to block kswapd on the
+ * journal commit.
+ *
+ * In all cases it is actually safe for us to return without doing anything,
+ * because the inode has been copied into a raw inode buffer in
+ * ext3_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
+ * knfsd.
+ *
+ * Note that we are absolutely dependent upon all inode dirtiers doing the
+ * right thing: they *must* call mark_inode_dirty() after dirtying info in
+ * which we are interested.
+ *
+ * It would be a bug for them to not do this. The code:
+ *
+ * mark_inode_dirty(inode)
+ * stuff();
+ * inode->i_size = expr;
+ *
+ * is in error because a kswapd-driven write_inode() could occur while
+ * `stuff()' is running, and the new i_size will be lost. Plus the inode
+ * will no longer be on the superblock's dirty inode list.
+ */
+void ext3_write_inode(struct inode *inode, int wait)
+{
+ if (current->flags & PF_MEMALLOC)
+ return;
+
+ if (ext3_journal_current_handle()) {
+ jbd_debug(0, "called recursively, non-PF_MEMALLOC!\n");
+ return;
+ }
+
+ if (!wait)
+ return;
+
+ ext3_force_commit(inode->i_sb);
+}
+
+/*
+ * ext3_setattr()
+ *
+ * Called from notify_change.
+ *
+ * We want to trap VFS attempts to truncate the file as soon as
+ * possible. In particular, we want to make sure that when the VFS
+ * shrinks i_size, we put the inode on the orphan list and modify
+ * i_disksize immediately, so that during the subsequent flushing of
+ * dirty pages and freeing of disk blocks, we can guarantee that any
+ * commit will leave the blocks being flushed in an unused state on
+ * disk. (On recovery, the inode will get truncated and the blocks will
+ * be freed, so we have a strong guarantee that no future commit will
+ * leave these blocks visible to the user.)
+ *
+ * This is only needed for regular files. rmdir() has its own path, and
+ * we can never truncate a direcory except on final unlink (at which
+ * point i_nlink is zero so recovery is easy.)
+ *
+ * Called with the BKL.
+ */
+
+int ext3_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ struct inode *inode = dentry->d_inode;
+ int error, rc;
+
+ error = inode_change_ok(inode, attr);
+ if (error)
+ return error;
+
+ if (attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
+ handle_t *handle;
+
+ handle = ext3_journal_start(inode, 3);
+ if (IS_ERR(handle)) {
+ error = PTR_ERR(handle);
+ goto err_out;
+ }
+
+ error = ext3_orphan_add(handle, inode);
+ inode->u.ext3_i.i_disksize = attr->ia_size;
+ rc = ext3_mark_inode_dirty(handle, inode);
+ if (!error)
+ error = rc;
+ ext3_journal_stop(handle, inode);
+ }
+
+ inode_setattr(inode, attr);
+
+ /* If inode_setattr's call to ext3_truncate failed to get a
+ * transaction handle at all, we need to clean up the in-core
+ * orphan list manually. */
+ if (inode->i_nlink)
+ ext3_orphan_del(NULL, inode);
+
+err_out:
+ ext3_std_error(inode->i_sb, error);
+ return 0;
+}
+
+
+/*
+ * akpm: how many blocks doth make a writepage()?
+ *
+ * With N blocks per page, it may be:
+ * N data blocks
+ * 2 indirect block
+ * 2 dindirect
+ * 1 tindirect
+ * N+5 bitmap blocks (from the above)
+ * N+5 group descriptor summary blocks
+ * 1 inode block
+ * 1 superblock.
+ * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
+ *
+ * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
+ *
+ * With ordered or writeback data it's the same, less the N data blocks.
+ *
+ * If the inode's direct blocks can hold an integral number of pages then a
+ * page cannot straddle two indirect blocks, and we can only touch one indirect
+ * and dindirect block, and the "5" above becomes "3".
+ *
+ * This still overestimates under most circumstances. If we were to pass the
+ * start and end offsets in here as well we could do block_to_path() on each
+ * block and work out the exact number of indirects which are touched. Pah.
+ */
+
+int ext3_writepage_trans_blocks(struct inode *inode)
+{
+ int bpp = ext3_journal_blocks_per_page(inode);
+ int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
+ int ret;
+
+ if (ext3_should_journal_data(inode))
+ ret = 3 * (bpp + indirects) + 2;
+ else
+ ret = 2 * (bpp + indirects) + 2;
+
+#ifdef CONFIG_QUOTA
+ ret += 2 * EXT3_SINGLEDATA_TRANS_BLOCKS;
+#endif
+
+ return ret;
+}
+
+int
+ext3_mark_iloc_dirty(handle_t *handle,
+ struct inode *inode,
+ struct ext3_iloc *iloc)
+{
+ int err = 0;
+
+ if (handle) {
+ /* the do_update_inode consumes one bh->b_count */
+ atomic_inc(&iloc->bh->b_count);
+ err = ext3_do_update_inode(handle, inode, iloc);
+ /* ext3_do_update_inode() does journal_dirty_metadata */
+ brelse(iloc->bh);
+ } else {
+ printk(KERN_EMERG __FUNCTION__ ": called with no handle!\n");
+ }
+ return err;
+}
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh. This _must_ be cleaned up later.
+ */
+
+int
+ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
+ struct ext3_iloc *iloc)
+{
+ int err = 0;
+ if (handle) {
+ err = ext3_get_inode_loc(inode, iloc);
+ if (!err) {
+ BUFFER_TRACE(iloc->bh, "get_write_access");
+ err = ext3_journal_get_write_access(handle, iloc->bh);
+ if (err) {
+ brelse(iloc->bh);
+ iloc->bh = NULL;
+ }
+ }
+ }
+ ext3_std_error(inode->i_sb, err);
+ return err;
+}
+
+/*
+ * akpm: What we do here is to mark the in-core inode as clean
+ * with respect to inode dirtiness (it may still be data-dirty).
+ * This means that the in-core inode may be reaped by prune_icache
+ * without having to perform any I/O. This is a very good thing,
+ * because *any* task may call prune_icache - even ones which
+ * have a transaction open against a different journal.
+ *
+ * Is this cheating? Not really. Sure, we haven't written the
+ * inode out, but prune_icache isn't a user-visible syncing function.
+ * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
+ * we start and wait on commits.
+ *
+ * Is this efficient/effective? Well, we're being nice to the system
+ * by cleaning up our inodes proactively so they can be reaped
+ * without I/O. But we are potentially leaving up to five seconds'
+ * worth of inodes floating about which prune_icache wants us to
+ * write out. One way to fix that would be to get prune_icache()
+ * to do a write_super() to free up some memory. It has the desired
+ * effect.
+ */
+int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
+{
+ struct ext3_iloc iloc;
+ int err;
+
+ err = ext3_reserve_inode_write(handle, inode, &iloc);
+ if (!err)
+ err = ext3_mark_iloc_dirty(handle, inode, &iloc);
+ return err;
+}
+
+/*
+ * akpm: ext3_dirty_inode() is called from __mark_inode_dirty()
+ *
+ * We're really interested in the case where a file is being extended.
+ * i_size has been changed by generic_commit_write() and we thus need
+ * to include the updated inode in the current transaction.
+ *
+ * Also, 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 ext3_dirty_inode(struct inode *inode)
+{
+ handle_t *current_handle = ext3_journal_current_handle();
+ handle_t *handle;
+
+ lock_kernel();
+ handle = ext3_journal_start(inode, 1);
+ 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 __FUNCTION__": transactions do not match!\n");
+ } else {
+ jbd_debug(5, "marking dirty. outer handle=%p\n",
+ current_handle);
+ ext3_mark_inode_dirty(handle, inode);
+ }
+ ext3_journal_stop(handle, inode);
+out:
+ unlock_kernel();
+}
+
+#ifdef AKPM
+/*
+ * Bind an inode's backing buffer_head into this transaction, to prevent
+ * it from being flushed to disk early. Unlike
+ * ext3_reserve_inode_write, this leaves behind no bh reference and
+ * returns no iloc structure, so the caller needs to repeat the iloc
+ * lookup to mark the inode dirty later.
+ */
+static inline int
+ext3_pin_inode(handle_t *handle, struct inode *inode)
+{
+ struct ext3_iloc iloc;
+
+ int err = 0;
+ if (handle) {
+ err = ext3_get_inode_loc(inode, &iloc);
+ if (!err) {
+ BUFFER_TRACE(iloc.bh, "get_write_access");
+ err = journal_get_write_access(handle, iloc.bh);
+ if (!err)
+ err = ext3_journal_dirty_metadata(handle,
+ iloc.bh);
+ brelse(iloc.bh);
+ }
+ }
+ ext3_std_error(inode->i_sb, err);
+ return err;
+}
+#endif
+
+int ext3_change_inode_journal_flag(struct inode *inode, int val)
+{
+ journal_t *journal;
+ handle_t *handle;
+ int err;
+
+ /*
+ * We have to be very careful here: changing a data block's
+ * journaling status dynamically is dangerous. If we write a
+ * data block to the journal, change the status and then delete
+ * that block, we risk forgetting to revoke the old log record
+ * from the journal and so a subsequent replay can corrupt data.
+ * So, first we make sure that the journal is empty and that
+ * nobody is changing anything.
+ */
+
+ journal = EXT3_JOURNAL(inode);
+ if (is_journal_aborted(journal) || IS_RDONLY(inode))
+ return -EROFS;
+
+ journal_lock_updates(journal);
+ journal_flush(journal);
+
+ /*
+ * OK, there are no updates running now, and all cached data is
+ * synced to disk. We are now in a completely consistent state
+ * which doesn't have anything in the journal, and we know that
+ * no filesystem updates are running, so it is safe to modify
+ * the inode's in-core data-journaling state flag now.
+ */
+
+ if (val)
+ inode->u.ext3_i.i_flags |= EXT3_JOURNAL_DATA_FL;
+ else
+ inode->u.ext3_i.i_flags &= ~EXT3_JOURNAL_DATA_FL;
+
+ journal_unlock_updates(journal);
+
+ /* Finally we can mark the inode as dirty. */
+
+ handle = ext3_journal_start(inode, 1);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ err = ext3_mark_inode_dirty(handle, inode);
+ handle->h_sync = 1;
+ ext3_journal_stop(handle, inode);
+ ext3_std_error(inode->i_sb, err);
+
+ return err;
+}
+
+
+/*
+ * ext3_aops_journal_start().
+ *
+ * <This function died, but the comment lives on>
+ *
+ * We need to take the inode semaphore *outside* the
+ * journal_start/journal_stop. Otherwise, a different task could do a
+ * wait_for_commit() while holding ->i_sem, which deadlocks. The rule
+ * is: transaction open/closes are considered to be a locking operation
+ * and they nest *inside* ->i_sem.
+ * ----------------------------------------------------------------------------
+ * Possible problem:
+ * ext3_file_write()
+ * -> generic_file_write()
+ * -> __alloc_pages()
+ * -> page_launder()
+ * -> ext3_writepage()
+ *
+ * And the writepage can be on a different fs while we have a
+ * transaction open against this one! Bad.
+ *
+ * I tried making the task PF_MEMALLOC here, but that simply results in
+ * 0-order allocation failures passed back to generic_file_write().
+ * Instead, we rely on the reentrancy protection in ext3_writepage().
+ * ----------------------------------------------------------------------------
+ * When we do the journal_start() here we don't really need to reserve
+ * any blocks - we won't need any until we hit ext3_prepare_write(),
+ * which does all the needed journal extending. However! There is a
+ * problem with quotas:
+ *
+ * Thread 1:
+ * sys_sync
+ * ->sync_dquots
+ * ->commit_dquot
+ * ->lock_dquot
+ * ->write_dquot
+ * ->ext3_file_write
+ * ->journal_start
+ * ->ext3_prepare_write
+ * ->journal_extend
+ * ->journal_start
+ * Thread 2:
+ * ext3_create (for example)
+ * ->ext3_new_inode
+ * ->dquot_initialize
+ * ->lock_dquot
+ *
+ * Deadlock. Thread 1's journal_start blocks because thread 2 has a
+ * transaction open. Thread 2's transaction will never close because
+ * thread 2 is stuck waiting for the dquot lock.
+ *
+ * So. We must ensure that thread 1 *never* needs to extend the journal
+ * for quota writes. We do that by reserving enough journal blocks
+ * here, in ext3_aops_journal_start() to ensure that the forthcoming "see if we
+ * need to extend" test in ext3_prepare_write() succeeds.
+ */
+
+
+MODULE_LICENSE("GPL");
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)