| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * linux/fs/jbd2/transaction.c |
| * |
| * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 |
| * |
| * Copyright 1998 Red Hat corp --- All Rights Reserved |
| * |
| * Generic filesystem transaction handling code; part of the ext2fs |
| * journaling system. |
| * |
| * This file manages transactions (compound commits managed by the |
| * journaling code) and handles (individual atomic operations by the |
| * filesystem). |
| */ |
| |
| #include <linux/time.h> |
| #include <linux/fs.h> |
| #include <linux/jbd2.h> |
| #include <linux/errno.h> |
| #include <linux/slab.h> |
| #include <linux/timer.h> |
| #include <linux/mm.h> |
| #include <linux/highmem.h> |
| #include <linux/hrtimer.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bug.h> |
| #include <linux/module.h> |
| #include <linux/sched/mm.h> |
| |
| #include <trace/events/jbd2.h> |
| |
| static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
| static void __jbd2_journal_unfile_buffer(struct journal_head *jh); |
| |
| static struct kmem_cache *transaction_cache; |
| int __init jbd2_journal_init_transaction_cache(void) |
| { |
| J_ASSERT(!transaction_cache); |
| transaction_cache = kmem_cache_create("jbd2_transaction_s", |
| sizeof(transaction_t), |
| 0, |
| SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY, |
| NULL); |
| if (!transaction_cache) { |
| pr_emerg("JBD2: failed to create transaction cache\n"); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| void jbd2_journal_destroy_transaction_cache(void) |
| { |
| kmem_cache_destroy(transaction_cache); |
| transaction_cache = NULL; |
| } |
| |
| void jbd2_journal_free_transaction(transaction_t *transaction) |
| { |
| if (unlikely(ZERO_OR_NULL_PTR(transaction))) |
| return; |
| kmem_cache_free(transaction_cache, transaction); |
| } |
| |
| /* |
| * Base amount of descriptor blocks we reserve for each transaction. |
| */ |
| static int jbd2_descriptor_blocks_per_trans(journal_t *journal) |
| { |
| int tag_space = journal->j_blocksize - sizeof(journal_header_t); |
| int tags_per_block; |
| |
| /* Subtract UUID */ |
| tag_space -= 16; |
| if (jbd2_journal_has_csum_v2or3(journal)) |
| tag_space -= sizeof(struct jbd2_journal_block_tail); |
| /* Commit code leaves a slack space of 16 bytes at the end of block */ |
| tags_per_block = (tag_space - 16) / journal_tag_bytes(journal); |
| /* |
| * Revoke descriptors are accounted separately so we need to reserve |
| * space for commit block and normal transaction descriptor blocks. |
| */ |
| return 1 + DIV_ROUND_UP(journal->j_max_transaction_buffers, |
| tags_per_block); |
| } |
| |
| /* |
| * jbd2_get_transaction: obtain a new transaction_t object. |
| * |
| * Simply initialise a new transaction. Initialize it in |
| * RUNNING state and add it to the current journal (which should not |
| * have an existing running transaction: we only make a new transaction |
| * once we have started to commit the old one). |
| * |
| * Preconditions: |
| * The journal MUST be locked. We don't perform atomic mallocs on the |
| * new transaction and we can't block without protecting against other |
| * processes trying to touch the journal while it is in transition. |
| * |
| */ |
| |
| static void jbd2_get_transaction(journal_t *journal, |
| transaction_t *transaction) |
| { |
| transaction->t_journal = journal; |
| transaction->t_state = T_RUNNING; |
| transaction->t_start_time = ktime_get(); |
| transaction->t_tid = journal->j_transaction_sequence++; |
| transaction->t_expires = jiffies + journal->j_commit_interval; |
| atomic_set(&transaction->t_updates, 0); |
| atomic_set(&transaction->t_outstanding_credits, |
| jbd2_descriptor_blocks_per_trans(journal) + |
| atomic_read(&journal->j_reserved_credits)); |
| atomic_set(&transaction->t_outstanding_revokes, 0); |
| atomic_set(&transaction->t_handle_count, 0); |
| INIT_LIST_HEAD(&transaction->t_inode_list); |
| INIT_LIST_HEAD(&transaction->t_private_list); |
| |
| /* Set up the commit timer for the new transaction. */ |
| journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
| add_timer(&journal->j_commit_timer); |
| |
| J_ASSERT(journal->j_running_transaction == NULL); |
| journal->j_running_transaction = transaction; |
| transaction->t_max_wait = 0; |
| transaction->t_start = jiffies; |
| transaction->t_requested = 0; |
| } |
| |
| /* |
| * Handle management. |
| * |
| * A handle_t is an object which represents a single atomic update to a |
| * filesystem, and which tracks all of the modifications which form part |
| * of that one update. |
| */ |
| |
| /* |
| * Update transaction's maximum wait time, if debugging is enabled. |
| * |
| * t_max_wait is carefully updated here with use of atomic compare exchange. |
| * Note that there could be multiplre threads trying to do this simultaneously |
| * hence using cmpxchg to avoid any use of locks in this case. |
| * With this t_max_wait can be updated w/o enabling jbd2_journal_enable_debug. |
| */ |
| static inline void update_t_max_wait(transaction_t *transaction, |
| unsigned long ts) |
| { |
| unsigned long oldts, newts; |
| |
| if (time_after(transaction->t_start, ts)) { |
| newts = jbd2_time_diff(ts, transaction->t_start); |
| oldts = READ_ONCE(transaction->t_max_wait); |
| while (oldts < newts) |
| oldts = cmpxchg(&transaction->t_max_wait, oldts, newts); |
| } |
| } |
| |
| /* |
| * Wait until running transaction passes to T_FLUSH state and new transaction |
| * can thus be started. Also starts the commit if needed. The function expects |
| * running transaction to exist and releases j_state_lock. |
| */ |
| static void wait_transaction_locked(journal_t *journal) |
| __releases(journal->j_state_lock) |
| { |
| DEFINE_WAIT(wait); |
| int need_to_start; |
| tid_t tid = journal->j_running_transaction->t_tid; |
| |
| prepare_to_wait_exclusive(&journal->j_wait_transaction_locked, &wait, |
| TASK_UNINTERRUPTIBLE); |
| need_to_start = !tid_geq(journal->j_commit_request, tid); |
| read_unlock(&journal->j_state_lock); |
| if (need_to_start) |
| jbd2_log_start_commit(journal, tid); |
| jbd2_might_wait_for_commit(journal); |
| schedule(); |
| finish_wait(&journal->j_wait_transaction_locked, &wait); |
| } |
| |
| /* |
| * Wait until running transaction transitions from T_SWITCH to T_FLUSH |
| * state and new transaction can thus be started. The function releases |
| * j_state_lock. |
| */ |
| static void wait_transaction_switching(journal_t *journal) |
| __releases(journal->j_state_lock) |
| { |
| DEFINE_WAIT(wait); |
| |
| if (WARN_ON(!journal->j_running_transaction || |
| journal->j_running_transaction->t_state != T_SWITCH)) { |
| read_unlock(&journal->j_state_lock); |
| return; |
| } |
| prepare_to_wait_exclusive(&journal->j_wait_transaction_locked, &wait, |
| TASK_UNINTERRUPTIBLE); |
| read_unlock(&journal->j_state_lock); |
| /* |
| * We don't call jbd2_might_wait_for_commit() here as there's no |
| * waiting for outstanding handles happening anymore in T_SWITCH state |
| * and handling of reserved handles actually relies on that for |
| * correctness. |
| */ |
| schedule(); |
| finish_wait(&journal->j_wait_transaction_locked, &wait); |
| } |
| |
| static void sub_reserved_credits(journal_t *journal, int blocks) |
| { |
| atomic_sub(blocks, &journal->j_reserved_credits); |
| wake_up(&journal->j_wait_reserved); |
| } |
| |
| /* |
| * Wait until we can add credits for handle to the running transaction. Called |
| * with j_state_lock held for reading. Returns 0 if handle joined the running |
| * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and |
| * caller must retry. |
| * |
| * Note: because j_state_lock may be dropped depending on the return |
| * value, we need to fake out sparse so ti doesn't complain about a |
| * locking imbalance. Callers of add_transaction_credits will need to |
| * make a similar accomodation. |
| */ |
| static int add_transaction_credits(journal_t *journal, int blocks, |
| int rsv_blocks) |
| __must_hold(&journal->j_state_lock) |
| { |
| transaction_t *t = journal->j_running_transaction; |
| int needed; |
| int total = blocks + rsv_blocks; |
| |
| /* |
| * If the current transaction is locked down for commit, wait |
| * for the lock to be released. |
| */ |
| if (t->t_state != T_RUNNING) { |
| WARN_ON_ONCE(t->t_state >= T_FLUSH); |
| wait_transaction_locked(journal); |
| __acquire(&journal->j_state_lock); /* fake out sparse */ |
| return 1; |
| } |
| |
| /* |
| * If there is not enough space left in the log to write all |
| * potential buffers requested by this operation, we need to |
| * stall pending a log checkpoint to free some more log space. |
| */ |
| needed = atomic_add_return(total, &t->t_outstanding_credits); |
| if (needed > journal->j_max_transaction_buffers) { |
| /* |
| * If the current transaction is already too large, |
| * then start to commit it: we can then go back and |
| * attach this handle to a new transaction. |
| */ |
| atomic_sub(total, &t->t_outstanding_credits); |
| |
| /* |
| * Is the number of reserved credits in the current transaction too |
| * big to fit this handle? Wait until reserved credits are freed. |
| */ |
| if (atomic_read(&journal->j_reserved_credits) + total > |
| journal->j_max_transaction_buffers) { |
| read_unlock(&journal->j_state_lock); |
| jbd2_might_wait_for_commit(journal); |
| wait_event(journal->j_wait_reserved, |
| atomic_read(&journal->j_reserved_credits) + total <= |
| journal->j_max_transaction_buffers); |
| __acquire(&journal->j_state_lock); /* fake out sparse */ |
| return 1; |
| } |
| |
| wait_transaction_locked(journal); |
| __acquire(&journal->j_state_lock); /* fake out sparse */ |
| return 1; |
| } |
| |
| /* |
| * The commit code assumes that it can get enough log space |
| * without forcing a checkpoint. This is *critical* for |
| * correctness: a checkpoint of a buffer which is also |
| * associated with a committing transaction creates a deadlock, |
| * so commit simply cannot force through checkpoints. |
| * |
| * We must therefore ensure the necessary space in the journal |
| * *before* starting to dirty potentially checkpointed buffers |
| * in the new transaction. |
| */ |
| if (jbd2_log_space_left(journal) < journal->j_max_transaction_buffers) { |
| atomic_sub(total, &t->t_outstanding_credits); |
| read_unlock(&journal->j_state_lock); |
| jbd2_might_wait_for_commit(journal); |
| write_lock(&journal->j_state_lock); |
| if (jbd2_log_space_left(journal) < |
| journal->j_max_transaction_buffers) |
| __jbd2_log_wait_for_space(journal); |
| write_unlock(&journal->j_state_lock); |
| __acquire(&journal->j_state_lock); /* fake out sparse */ |
| return 1; |
| } |
| |
| /* No reservation? We are done... */ |
| if (!rsv_blocks) |
| return 0; |
| |
| needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits); |
| /* We allow at most half of a transaction to be reserved */ |
| if (needed > journal->j_max_transaction_buffers / 2) { |
| sub_reserved_credits(journal, rsv_blocks); |
| atomic_sub(total, &t->t_outstanding_credits); |
| read_unlock(&journal->j_state_lock); |
| jbd2_might_wait_for_commit(journal); |
| wait_event(journal->j_wait_reserved, |
| atomic_read(&journal->j_reserved_credits) + rsv_blocks |
| <= journal->j_max_transaction_buffers / 2); |
| __acquire(&journal->j_state_lock); /* fake out sparse */ |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * start_this_handle: Given a handle, deal with any locking or stalling |
| * needed to make sure that there is enough journal space for the handle |
| * to begin. Attach the handle to a transaction and set up the |
| * transaction's buffer credits. |
| */ |
| |
| static int start_this_handle(journal_t *journal, handle_t *handle, |
| gfp_t gfp_mask) |
| { |
| transaction_t *transaction, *new_transaction = NULL; |
| int blocks = handle->h_total_credits; |
| int rsv_blocks = 0; |
| unsigned long ts = jiffies; |
| |
| if (handle->h_rsv_handle) |
| rsv_blocks = handle->h_rsv_handle->h_total_credits; |
| |
| /* |
| * Limit the number of reserved credits to 1/2 of maximum transaction |
| * size and limit the number of total credits to not exceed maximum |
| * transaction size per operation. |
| */ |
| if ((rsv_blocks > journal->j_max_transaction_buffers / 2) || |
| (rsv_blocks + blocks > journal->j_max_transaction_buffers)) { |
| printk(KERN_ERR "JBD2: %s wants too many credits " |
| "credits:%d rsv_credits:%d max:%d\n", |
| current->comm, blocks, rsv_blocks, |
| journal->j_max_transaction_buffers); |
| WARN_ON(1); |
| return -ENOSPC; |
| } |
| |
| alloc_transaction: |
| /* |
| * This check is racy but it is just an optimization of allocating new |
| * transaction early if there are high chances we'll need it. If we |
| * guess wrong, we'll retry or free unused transaction. |
| */ |
| if (!data_race(journal->j_running_transaction)) { |
| /* |
| * If __GFP_FS is not present, then we may be being called from |
| * inside the fs writeback layer, so we MUST NOT fail. |
| */ |
| if ((gfp_mask & __GFP_FS) == 0) |
| gfp_mask |= __GFP_NOFAIL; |
| new_transaction = kmem_cache_zalloc(transaction_cache, |
| gfp_mask); |
| if (!new_transaction) |
| return -ENOMEM; |
| } |
| |
| jbd2_debug(3, "New handle %p going live.\n", handle); |
| |
| /* |
| * We need to hold j_state_lock until t_updates has been incremented, |
| * for proper journal barrier handling |
| */ |
| repeat: |
| read_lock(&journal->j_state_lock); |
| BUG_ON(journal->j_flags & JBD2_UNMOUNT); |
| if (is_journal_aborted(journal) || |
| (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
| read_unlock(&journal->j_state_lock); |
| jbd2_journal_free_transaction(new_transaction); |
| return -EROFS; |
| } |
| |
| /* |
| * Wait on the journal's transaction barrier if necessary. Specifically |
| * we allow reserved handles to proceed because otherwise commit could |
| * deadlock on page writeback not being able to complete. |
| */ |
| if (!handle->h_reserved && journal->j_barrier_count) { |
| read_unlock(&journal->j_state_lock); |
| wait_event(journal->j_wait_transaction_locked, |
| journal->j_barrier_count == 0); |
| goto repeat; |
| } |
| |
| if (!journal->j_running_transaction) { |
| read_unlock(&journal->j_state_lock); |
| if (!new_transaction) |
| goto alloc_transaction; |
| write_lock(&journal->j_state_lock); |
| if (!journal->j_running_transaction && |
| (handle->h_reserved || !journal->j_barrier_count)) { |
| jbd2_get_transaction(journal, new_transaction); |
| new_transaction = NULL; |
| } |
| write_unlock(&journal->j_state_lock); |
| goto repeat; |
| } |
| |
| transaction = journal->j_running_transaction; |
| |
| if (!handle->h_reserved) { |
| /* We may have dropped j_state_lock - restart in that case */ |
| if (add_transaction_credits(journal, blocks, rsv_blocks)) { |
| /* |
| * add_transaction_credits releases |
| * j_state_lock on a non-zero return |
| */ |
| __release(&journal->j_state_lock); |
| goto repeat; |
| } |
| } else { |
| /* |
| * We have handle reserved so we are allowed to join T_LOCKED |
| * transaction and we don't have to check for transaction size |
| * and journal space. But we still have to wait while running |
| * transaction is being switched to a committing one as it |
| * won't wait for any handles anymore. |
| */ |
| if (transaction->t_state == T_SWITCH) { |
| wait_transaction_switching(journal); |
| goto repeat; |
| } |
| sub_reserved_credits(journal, blocks); |
| handle->h_reserved = 0; |
| } |
| |
| /* OK, account for the buffers that this operation expects to |
| * use and add the handle to the running transaction. |
| */ |
| update_t_max_wait(transaction, ts); |
| handle->h_transaction = transaction; |
| handle->h_requested_credits = blocks; |
| handle->h_revoke_credits_requested = handle->h_revoke_credits; |
| handle->h_start_jiffies = jiffies; |
| atomic_inc(&transaction->t_updates); |
| atomic_inc(&transaction->t_handle_count); |
| jbd2_debug(4, "Handle %p given %d credits (total %d, free %lu)\n", |
| handle, blocks, |
| atomic_read(&transaction->t_outstanding_credits), |
| jbd2_log_space_left(journal)); |
| read_unlock(&journal->j_state_lock); |
| current->journal_info = handle; |
| |
| rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_); |
| jbd2_journal_free_transaction(new_transaction); |
| /* |
| * Ensure that no allocations done while the transaction is open are |
| * going to recurse back to the fs layer. |
| */ |
| handle->saved_alloc_context = memalloc_nofs_save(); |
| return 0; |
| } |
| |
| /* Allocate a new handle. This should probably be in a slab... */ |
| static handle_t *new_handle(int nblocks) |
| { |
| handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
| if (!handle) |
| return NULL; |
| handle->h_total_credits = nblocks; |
| handle->h_ref = 1; |
| |
| return handle; |
| } |
| |
| handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks, |
| int revoke_records, gfp_t gfp_mask, |
| unsigned int type, unsigned int line_no) |
| { |
| handle_t *handle = journal_current_handle(); |
| int err; |
| |
| if (!journal) |
| return ERR_PTR(-EROFS); |
| |
| if (handle) { |
| J_ASSERT(handle->h_transaction->t_journal == journal); |
| handle->h_ref++; |
| return handle; |
| } |
| |
| nblocks += DIV_ROUND_UP(revoke_records, |
| journal->j_revoke_records_per_block); |
| handle = new_handle(nblocks); |
| if (!handle) |
| return ERR_PTR(-ENOMEM); |
| if (rsv_blocks) { |
| handle_t *rsv_handle; |
| |
| rsv_handle = new_handle(rsv_blocks); |
| if (!rsv_handle) { |
| jbd2_free_handle(handle); |
| return ERR_PTR(-ENOMEM); |
| } |
| rsv_handle->h_reserved = 1; |
| rsv_handle->h_journal = journal; |
| handle->h_rsv_handle = rsv_handle; |
| } |
| handle->h_revoke_credits = revoke_records; |
| |
| err = start_this_handle(journal, handle, gfp_mask); |
| if (err < 0) { |
| if (handle->h_rsv_handle) |
| jbd2_free_handle(handle->h_rsv_handle); |
| jbd2_free_handle(handle); |
| return ERR_PTR(err); |
| } |
| handle->h_type = type; |
| handle->h_line_no = line_no; |
| trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, |
| handle->h_transaction->t_tid, type, |
| line_no, nblocks); |
| |
| return handle; |
| } |
| EXPORT_SYMBOL(jbd2__journal_start); |
| |
| |
| /** |
| * jbd2_journal_start() - Obtain a new handle. |
| * @journal: Journal to start transaction on. |
| * @nblocks: number of block buffer we might modify |
| * |
| * We make sure that the transaction can guarantee at least nblocks of |
| * modified buffers in the log. We block until the log can guarantee |
| * that much space. Additionally, if rsv_blocks > 0, we also create another |
| * handle with rsv_blocks reserved blocks in the journal. This handle is |
| * stored in h_rsv_handle. It is not attached to any particular transaction |
| * and thus doesn't block transaction commit. If the caller uses this reserved |
| * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop() |
| * on the parent handle will dispose the reserved one. Reserved handle has to |
| * be converted to a normal handle using jbd2_journal_start_reserved() before |
| * it can be used. |
| * |
| * Return a pointer to a newly allocated handle, or an ERR_PTR() value |
| * on failure. |
| */ |
| handle_t *jbd2_journal_start(journal_t *journal, int nblocks) |
| { |
| return jbd2__journal_start(journal, nblocks, 0, 0, GFP_NOFS, 0, 0); |
| } |
| EXPORT_SYMBOL(jbd2_journal_start); |
| |
| static void __jbd2_journal_unreserve_handle(handle_t *handle, transaction_t *t) |
| { |
| journal_t *journal = handle->h_journal; |
| |
| WARN_ON(!handle->h_reserved); |
| sub_reserved_credits(journal, handle->h_total_credits); |
| if (t) |
| atomic_sub(handle->h_total_credits, &t->t_outstanding_credits); |
| } |
| |
| void jbd2_journal_free_reserved(handle_t *handle) |
| { |
| journal_t *journal = handle->h_journal; |
| |
| /* Get j_state_lock to pin running transaction if it exists */ |
| read_lock(&journal->j_state_lock); |
| __jbd2_journal_unreserve_handle(handle, journal->j_running_transaction); |
| read_unlock(&journal->j_state_lock); |
| jbd2_free_handle(handle); |
| } |
| EXPORT_SYMBOL(jbd2_journal_free_reserved); |
| |
| /** |
| * jbd2_journal_start_reserved() - start reserved handle |
| * @handle: handle to start |
| * @type: for handle statistics |
| * @line_no: for handle statistics |
| * |
| * Start handle that has been previously reserved with jbd2_journal_reserve(). |
| * This attaches @handle to the running transaction (or creates one if there's |
| * not transaction running). Unlike jbd2_journal_start() this function cannot |
| * block on journal commit, checkpointing, or similar stuff. It can block on |
| * memory allocation or frozen journal though. |
| * |
| * Return 0 on success, non-zero on error - handle is freed in that case. |
| */ |
| int jbd2_journal_start_reserved(handle_t *handle, unsigned int type, |
| unsigned int line_no) |
| { |
| journal_t *journal = handle->h_journal; |
| int ret = -EIO; |
| |
| if (WARN_ON(!handle->h_reserved)) { |
| /* Someone passed in normal handle? Just stop it. */ |
| jbd2_journal_stop(handle); |
| return ret; |
| } |
| /* |
| * Usefulness of mixing of reserved and unreserved handles is |
| * questionable. So far nobody seems to need it so just error out. |
| */ |
| if (WARN_ON(current->journal_info)) { |
| jbd2_journal_free_reserved(handle); |
| return ret; |
| } |
| |
| handle->h_journal = NULL; |
| /* |
| * GFP_NOFS is here because callers are likely from writeback or |
| * similarly constrained call sites |
| */ |
| ret = start_this_handle(journal, handle, GFP_NOFS); |
| if (ret < 0) { |
| handle->h_journal = journal; |
| jbd2_journal_free_reserved(handle); |
| return ret; |
| } |
| handle->h_type = type; |
| handle->h_line_no = line_no; |
| trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, |
| handle->h_transaction->t_tid, type, |
| line_no, handle->h_total_credits); |
| return 0; |
| } |
| EXPORT_SYMBOL(jbd2_journal_start_reserved); |
| |
| /** |
| * jbd2_journal_extend() - extend buffer credits. |
| * @handle: handle to 'extend' |
| * @nblocks: nr blocks to try to extend by. |
| * @revoke_records: number of revoke records to try to extend by. |
| * |
| * Some transactions, such as large extends and truncates, can be done |
| * atomically all at once or in several stages. The operation requests |
| * a credit for a number of buffer modifications in advance, but can |
| * extend its credit if it needs more. |
| * |
| * jbd2_journal_extend tries to give the running handle more buffer credits. |
| * It does not guarantee that allocation - this is a best-effort only. |
| * The calling process MUST be able to deal cleanly with a failure to |
| * extend here. |
| * |
| * Return 0 on success, non-zero on failure. |
| * |
| * return code < 0 implies an error |
| * return code > 0 implies normal transaction-full status. |
| */ |
| int jbd2_journal_extend(handle_t *handle, int nblocks, int revoke_records) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| int result; |
| int wanted; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| journal = transaction->t_journal; |
| |
| result = 1; |
| |
| read_lock(&journal->j_state_lock); |
| |
| /* Don't extend a locked-down transaction! */ |
| if (transaction->t_state != T_RUNNING) { |
| jbd2_debug(3, "denied handle %p %d blocks: " |
| "transaction not running\n", handle, nblocks); |
| goto error_out; |
| } |
| |
| nblocks += DIV_ROUND_UP( |
| handle->h_revoke_credits_requested + revoke_records, |
| journal->j_revoke_records_per_block) - |
| DIV_ROUND_UP( |
| handle->h_revoke_credits_requested, |
| journal->j_revoke_records_per_block); |
| wanted = atomic_add_return(nblocks, |
| &transaction->t_outstanding_credits); |
| |
| if (wanted > journal->j_max_transaction_buffers) { |
| jbd2_debug(3, "denied handle %p %d blocks: " |
| "transaction too large\n", handle, nblocks); |
| atomic_sub(nblocks, &transaction->t_outstanding_credits); |
| goto error_out; |
| } |
| |
| trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev, |
| transaction->t_tid, |
| handle->h_type, handle->h_line_no, |
| handle->h_total_credits, |
| nblocks); |
| |
| handle->h_total_credits += nblocks; |
| handle->h_requested_credits += nblocks; |
| handle->h_revoke_credits += revoke_records; |
| handle->h_revoke_credits_requested += revoke_records; |
| result = 0; |
| |
| jbd2_debug(3, "extended handle %p by %d\n", handle, nblocks); |
| error_out: |
| read_unlock(&journal->j_state_lock); |
| return result; |
| } |
| |
| static void stop_this_handle(handle_t *handle) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| int revokes; |
| |
| J_ASSERT(journal_current_handle() == handle); |
| J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
| current->journal_info = NULL; |
| /* |
| * Subtract necessary revoke descriptor blocks from handle credits. We |
| * take care to account only for revoke descriptor blocks the |
| * transaction will really need as large sequences of transactions with |
| * small numbers of revokes are relatively common. |
| */ |
| revokes = handle->h_revoke_credits_requested - handle->h_revoke_credits; |
| if (revokes) { |
| int t_revokes, revoke_descriptors; |
| int rr_per_blk = journal->j_revoke_records_per_block; |
| |
| WARN_ON_ONCE(DIV_ROUND_UP(revokes, rr_per_blk) |
| > handle->h_total_credits); |
| t_revokes = atomic_add_return(revokes, |
| &transaction->t_outstanding_revokes); |
| revoke_descriptors = |
| DIV_ROUND_UP(t_revokes, rr_per_blk) - |
| DIV_ROUND_UP(t_revokes - revokes, rr_per_blk); |
| handle->h_total_credits -= revoke_descriptors; |
| } |
| atomic_sub(handle->h_total_credits, |
| &transaction->t_outstanding_credits); |
| if (handle->h_rsv_handle) |
| __jbd2_journal_unreserve_handle(handle->h_rsv_handle, |
| transaction); |
| if (atomic_dec_and_test(&transaction->t_updates)) |
| wake_up(&journal->j_wait_updates); |
| |
| rwsem_release(&journal->j_trans_commit_map, _THIS_IP_); |
| /* |
| * Scope of the GFP_NOFS context is over here and so we can restore the |
| * original alloc context. |
| */ |
| memalloc_nofs_restore(handle->saved_alloc_context); |
| } |
| |
| /** |
| * jbd2__journal_restart() - restart a handle . |
| * @handle: handle to restart |
| * @nblocks: nr credits requested |
| * @revoke_records: number of revoke record credits requested |
| * @gfp_mask: memory allocation flags (for start_this_handle) |
| * |
| * Restart a handle for a multi-transaction filesystem |
| * operation. |
| * |
| * If the jbd2_journal_extend() call above fails to grant new buffer credits |
| * to a running handle, a call to jbd2_journal_restart will commit the |
| * handle's transaction so far and reattach the handle to a new |
| * transaction capable of guaranteeing the requested number of |
| * credits. We preserve reserved handle if there's any attached to the |
| * passed in handle. |
| */ |
| int jbd2__journal_restart(handle_t *handle, int nblocks, int revoke_records, |
| gfp_t gfp_mask) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| tid_t tid; |
| int need_to_start; |
| int ret; |
| |
| /* If we've had an abort of any type, don't even think about |
| * actually doing the restart! */ |
| if (is_handle_aborted(handle)) |
| return 0; |
| journal = transaction->t_journal; |
| tid = transaction->t_tid; |
| |
| /* |
| * First unlink the handle from its current transaction, and start the |
| * commit on that. |
| */ |
| jbd2_debug(2, "restarting handle %p\n", handle); |
| stop_this_handle(handle); |
| handle->h_transaction = NULL; |
| |
| /* |
| * TODO: If we use READ_ONCE / WRITE_ONCE for j_commit_request we can |
| * get rid of pointless j_state_lock traffic like this. |
| */ |
| read_lock(&journal->j_state_lock); |
| need_to_start = !tid_geq(journal->j_commit_request, tid); |
| read_unlock(&journal->j_state_lock); |
| if (need_to_start) |
| jbd2_log_start_commit(journal, tid); |
| handle->h_total_credits = nblocks + |
| DIV_ROUND_UP(revoke_records, |
| journal->j_revoke_records_per_block); |
| handle->h_revoke_credits = revoke_records; |
| ret = start_this_handle(journal, handle, gfp_mask); |
| trace_jbd2_handle_restart(journal->j_fs_dev->bd_dev, |
| ret ? 0 : handle->h_transaction->t_tid, |
| handle->h_type, handle->h_line_no, |
| handle->h_total_credits); |
| return ret; |
| } |
| EXPORT_SYMBOL(jbd2__journal_restart); |
| |
| |
| int jbd2_journal_restart(handle_t *handle, int nblocks) |
| { |
| return jbd2__journal_restart(handle, nblocks, 0, GFP_NOFS); |
| } |
| EXPORT_SYMBOL(jbd2_journal_restart); |
| |
| /* |
| * Waits for any outstanding t_updates to finish. |
| * This is called with write j_state_lock held. |
| */ |
| void jbd2_journal_wait_updates(journal_t *journal) |
| { |
| DEFINE_WAIT(wait); |
| |
| while (1) { |
| /* |
| * Note that the running transaction can get freed under us if |
| * this transaction is getting committed in |
| * jbd2_journal_commit_transaction() -> |
| * jbd2_journal_free_transaction(). This can only happen when we |
| * release j_state_lock -> schedule() -> acquire j_state_lock. |
| * Hence we should everytime retrieve new j_running_transaction |
| * value (after j_state_lock release acquire cycle), else it may |
| * lead to use-after-free of old freed transaction. |
| */ |
| transaction_t *transaction = journal->j_running_transaction; |
| |
| if (!transaction) |
| break; |
| |
| prepare_to_wait(&journal->j_wait_updates, &wait, |
| TASK_UNINTERRUPTIBLE); |
| if (!atomic_read(&transaction->t_updates)) { |
| finish_wait(&journal->j_wait_updates, &wait); |
| break; |
| } |
| write_unlock(&journal->j_state_lock); |
| schedule(); |
| finish_wait(&journal->j_wait_updates, &wait); |
| write_lock(&journal->j_state_lock); |
| } |
| } |
| |
| /** |
| * jbd2_journal_lock_updates () - establish a transaction barrier. |
| * @journal: Journal to establish a barrier on. |
| * |
| * This locks out any further updates from being started, and blocks |
| * until all existing updates have completed, returning only once the |
| * journal is in a quiescent state with no updates running. |
| * |
| * The journal lock should not be held on entry. |
| */ |
| void jbd2_journal_lock_updates(journal_t *journal) |
| { |
| jbd2_might_wait_for_commit(journal); |
| |
| write_lock(&journal->j_state_lock); |
| ++journal->j_barrier_count; |
| |
| /* Wait until there are no reserved handles */ |
| if (atomic_read(&journal->j_reserved_credits)) { |
| write_unlock(&journal->j_state_lock); |
| wait_event(journal->j_wait_reserved, |
| atomic_read(&journal->j_reserved_credits) == 0); |
| write_lock(&journal->j_state_lock); |
| } |
| |
| /* Wait until there are no running t_updates */ |
| jbd2_journal_wait_updates(journal); |
| |
| write_unlock(&journal->j_state_lock); |
| |
| /* |
| * We have now established a barrier against other normal updates, but |
| * we also need to barrier against other jbd2_journal_lock_updates() calls |
| * to make sure that we serialise special journal-locked operations |
| * too. |
| */ |
| mutex_lock(&journal->j_barrier); |
| } |
| |
| /** |
| * jbd2_journal_unlock_updates () - release barrier |
| * @journal: Journal to release the barrier on. |
| * |
| * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
| * |
| * Should be called without the journal lock held. |
| */ |
| void jbd2_journal_unlock_updates (journal_t *journal) |
| { |
| J_ASSERT(journal->j_barrier_count != 0); |
| |
| mutex_unlock(&journal->j_barrier); |
| write_lock(&journal->j_state_lock); |
| --journal->j_barrier_count; |
| write_unlock(&journal->j_state_lock); |
| wake_up_all(&journal->j_wait_transaction_locked); |
| } |
| |
| static void warn_dirty_buffer(struct buffer_head *bh) |
| { |
| printk(KERN_WARNING |
| "JBD2: Spotted dirty metadata buffer (dev = %pg, blocknr = %llu). " |
| "There's a risk of filesystem corruption in case of system " |
| "crash.\n", |
| bh->b_bdev, (unsigned long long)bh->b_blocknr); |
| } |
| |
| /* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */ |
| static void jbd2_freeze_jh_data(struct journal_head *jh) |
| { |
| struct page *page; |
| int offset; |
| char *source; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| J_EXPECT_JH(jh, buffer_uptodate(bh), "Possible IO failure.\n"); |
| page = bh->b_page; |
| offset = offset_in_page(bh->b_data); |
| source = kmap_atomic(page); |
| /* Fire data frozen trigger just before we copy the data */ |
| jbd2_buffer_frozen_trigger(jh, source + offset, jh->b_triggers); |
| memcpy(jh->b_frozen_data, source + offset, bh->b_size); |
| kunmap_atomic(source); |
| |
| /* |
| * Now that the frozen data is saved off, we need to store any matching |
| * triggers. |
| */ |
| jh->b_frozen_triggers = jh->b_triggers; |
| } |
| |
| /* |
| * If the buffer is already part of the current transaction, then there |
| * is nothing we need to do. If it is already part of a prior |
| * transaction which we are still committing to disk, then we need to |
| * make sure that we do not overwrite the old copy: we do copy-out to |
| * preserve the copy going to disk. We also account the buffer against |
| * the handle's metadata buffer credits (unless the buffer is already |
| * part of the transaction, that is). |
| * |
| */ |
| static int |
| do_get_write_access(handle_t *handle, struct journal_head *jh, |
| int force_copy) |
| { |
| struct buffer_head *bh; |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| int error; |
| char *frozen_buffer = NULL; |
| unsigned long start_lock, time_lock; |
| |
| journal = transaction->t_journal; |
| |
| jbd2_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy); |
| |
| JBUFFER_TRACE(jh, "entry"); |
| repeat: |
| bh = jh2bh(jh); |
| |
| /* @@@ Need to check for errors here at some point. */ |
| |
| start_lock = jiffies; |
| lock_buffer(bh); |
| spin_lock(&jh->b_state_lock); |
| |
| /* If it takes too long to lock the buffer, trace it */ |
| time_lock = jbd2_time_diff(start_lock, jiffies); |
| if (time_lock > HZ/10) |
| trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev, |
| jiffies_to_msecs(time_lock)); |
| |
| /* We now hold the buffer lock so it is safe to query the buffer |
| * state. Is the buffer dirty? |
| * |
| * If so, there are two possibilities. The buffer may be |
| * non-journaled, and undergoing a quite legitimate writeback. |
| * Otherwise, it is journaled, and we don't expect dirty buffers |
| * in that state (the buffers should be marked JBD_Dirty |
| * instead.) So either the IO is being done under our own |
| * control and this is a bug, or it's a third party IO such as |
| * dump(8) (which may leave the buffer scheduled for read --- |
| * ie. locked but not dirty) or tune2fs (which may actually have |
| * the buffer dirtied, ugh.) */ |
| |
| if (buffer_dirty(bh)) { |
| /* |
| * First question: is this buffer already part of the current |
| * transaction or the existing committing transaction? |
| */ |
| if (jh->b_transaction) { |
| J_ASSERT_JH(jh, |
| jh->b_transaction == transaction || |
| jh->b_transaction == |
| journal->j_committing_transaction); |
| if (jh->b_next_transaction) |
| J_ASSERT_JH(jh, jh->b_next_transaction == |
| transaction); |
| warn_dirty_buffer(bh); |
| } |
| /* |
| * In any case we need to clean the dirty flag and we must |
| * do it under the buffer lock to be sure we don't race |
| * with running write-out. |
| */ |
| JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
| clear_buffer_dirty(bh); |
| set_buffer_jbddirty(bh); |
| } |
| |
| unlock_buffer(bh); |
| |
| error = -EROFS; |
| if (is_handle_aborted(handle)) { |
| spin_unlock(&jh->b_state_lock); |
| goto out; |
| } |
| error = 0; |
| |
| /* |
| * The buffer is already part of this transaction if b_transaction or |
| * b_next_transaction points to it |
| */ |
| if (jh->b_transaction == transaction || |
| jh->b_next_transaction == transaction) |
| goto done; |
| |
| /* |
| * this is the first time this transaction is touching this buffer, |
| * reset the modified flag |
| */ |
| jh->b_modified = 0; |
| |
| /* |
| * If the buffer is not journaled right now, we need to make sure it |
| * doesn't get written to disk before the caller actually commits the |
| * new data |
| */ |
| if (!jh->b_transaction) { |
| JBUFFER_TRACE(jh, "no transaction"); |
| J_ASSERT_JH(jh, !jh->b_next_transaction); |
| JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
| /* |
| * Make sure all stores to jh (b_modified, b_frozen_data) are |
| * visible before attaching it to the running transaction. |
| * Paired with barrier in jbd2_write_access_granted() |
| */ |
| smp_wmb(); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
| spin_unlock(&journal->j_list_lock); |
| goto done; |
| } |
| /* |
| * If there is already a copy-out version of this buffer, then we don't |
| * need to make another one |
| */ |
| if (jh->b_frozen_data) { |
| JBUFFER_TRACE(jh, "has frozen data"); |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| goto attach_next; |
| } |
| |
| JBUFFER_TRACE(jh, "owned by older transaction"); |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| J_ASSERT_JH(jh, jh->b_transaction == journal->j_committing_transaction); |
| |
| /* |
| * There is one case we have to be very careful about. If the |
| * committing transaction is currently writing this buffer out to disk |
| * and has NOT made a copy-out, then we cannot modify the buffer |
| * contents at all right now. The essence of copy-out is that it is |
| * the extra copy, not the primary copy, which gets journaled. If the |
| * primary copy is already going to disk then we cannot do copy-out |
| * here. |
| */ |
| if (buffer_shadow(bh)) { |
| JBUFFER_TRACE(jh, "on shadow: sleep"); |
| spin_unlock(&jh->b_state_lock); |
| wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE); |
| goto repeat; |
| } |
| |
| /* |
| * Only do the copy if the currently-owning transaction still needs it. |
| * If buffer isn't on BJ_Metadata list, the committing transaction is |
| * past that stage (here we use the fact that BH_Shadow is set under |
| * bh_state lock together with refiling to BJ_Shadow list and at this |
| * point we know the buffer doesn't have BH_Shadow set). |
| * |
| * Subtle point, though: if this is a get_undo_access, then we will be |
| * relying on the frozen_data to contain the new value of the |
| * committed_data record after the transaction, so we HAVE to force the |
| * frozen_data copy in that case. |
| */ |
| if (jh->b_jlist == BJ_Metadata || force_copy) { |
| JBUFFER_TRACE(jh, "generate frozen data"); |
| if (!frozen_buffer) { |
| JBUFFER_TRACE(jh, "allocate memory for buffer"); |
| spin_unlock(&jh->b_state_lock); |
| frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size, |
| GFP_NOFS | __GFP_NOFAIL); |
| goto repeat; |
| } |
| jh->b_frozen_data = frozen_buffer; |
| frozen_buffer = NULL; |
| jbd2_freeze_jh_data(jh); |
| } |
| attach_next: |
| /* |
| * Make sure all stores to jh (b_modified, b_frozen_data) are visible |
| * before attaching it to the running transaction. Paired with barrier |
| * in jbd2_write_access_granted() |
| */ |
| smp_wmb(); |
| jh->b_next_transaction = transaction; |
| |
| done: |
| spin_unlock(&jh->b_state_lock); |
| |
| /* |
| * If we are about to journal a buffer, then any revoke pending on it is |
| * no longer valid |
| */ |
| jbd2_journal_cancel_revoke(handle, jh); |
| |
| out: |
| if (unlikely(frozen_buffer)) /* It's usually NULL */ |
| jbd2_free(frozen_buffer, bh->b_size); |
| |
| JBUFFER_TRACE(jh, "exit"); |
| return error; |
| } |
| |
| /* Fast check whether buffer is already attached to the required transaction */ |
| static bool jbd2_write_access_granted(handle_t *handle, struct buffer_head *bh, |
| bool undo) |
| { |
| struct journal_head *jh; |
| bool ret = false; |
| |
| /* Dirty buffers require special handling... */ |
| if (buffer_dirty(bh)) |
| return false; |
| |
| /* |
| * RCU protects us from dereferencing freed pages. So the checks we do |
| * are guaranteed not to oops. However the jh slab object can get freed |
| * & reallocated while we work with it. So we have to be careful. When |
| * we see jh attached to the running transaction, we know it must stay |
| * so until the transaction is committed. Thus jh won't be freed and |
| * will be attached to the same bh while we run. However it can |
| * happen jh gets freed, reallocated, and attached to the transaction |
| * just after we get pointer to it from bh. So we have to be careful |
| * and recheck jh still belongs to our bh before we return success. |
| */ |
| rcu_read_lock(); |
| if (!buffer_jbd(bh)) |
| goto out; |
| /* This should be bh2jh() but that doesn't work with inline functions */ |
| jh = READ_ONCE(bh->b_private); |
| if (!jh) |
| goto out; |
| /* For undo access buffer must have data copied */ |
| if (undo && !jh->b_committed_data) |
| goto out; |
| if (READ_ONCE(jh->b_transaction) != handle->h_transaction && |
| READ_ONCE(jh->b_next_transaction) != handle->h_transaction) |
| goto out; |
| /* |
| * There are two reasons for the barrier here: |
| * 1) Make sure to fetch b_bh after we did previous checks so that we |
| * detect when jh went through free, realloc, attach to transaction |
| * while we were checking. Paired with implicit barrier in that path. |
| * 2) So that access to bh done after jbd2_write_access_granted() |
| * doesn't get reordered and see inconsistent state of concurrent |
| * do_get_write_access(). |
| */ |
| smp_mb(); |
| if (unlikely(jh->b_bh != bh)) |
| goto out; |
| ret = true; |
| out: |
| rcu_read_unlock(); |
| return ret; |
| } |
| |
| /** |
| * jbd2_journal_get_write_access() - notify intent to modify a buffer |
| * for metadata (not data) update. |
| * @handle: transaction to add buffer modifications to |
| * @bh: bh to be used for metadata writes |
| * |
| * Returns: error code or 0 on success. |
| * |
| * In full data journalling mode the buffer may be of type BJ_AsyncData, |
| * because we're ``write()ing`` a buffer which is also part of a shared mapping. |
| */ |
| |
| int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
| { |
| struct journal_head *jh; |
| int rc; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| |
| if (jbd2_write_access_granted(handle, bh, false)) |
| return 0; |
| |
| jh = jbd2_journal_add_journal_head(bh); |
| /* We do not want to get caught playing with fields which the |
| * log thread also manipulates. Make sure that the buffer |
| * completes any outstanding IO before proceeding. */ |
| rc = do_get_write_access(handle, jh, 0); |
| jbd2_journal_put_journal_head(jh); |
| return rc; |
| } |
| |
| |
| /* |
| * When the user wants to journal a newly created buffer_head |
| * (ie. getblk() returned a new buffer and we are going to populate it |
| * manually rather than reading off disk), then we need to keep the |
| * buffer_head locked until it has been completely filled with new |
| * data. In this case, we should be able to make the assertion that |
| * the bh is not already part of an existing transaction. |
| * |
| * The buffer should already be locked by the caller by this point. |
| * There is no lock ranking violation: it was a newly created, |
| * unlocked buffer beforehand. */ |
| |
| /** |
| * jbd2_journal_get_create_access () - notify intent to use newly created bh |
| * @handle: transaction to new buffer to |
| * @bh: new buffer. |
| * |
| * Call this if you create a new bh. |
| */ |
| int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
| int err; |
| |
| jbd2_debug(5, "journal_head %p\n", jh); |
| err = -EROFS; |
| if (is_handle_aborted(handle)) |
| goto out; |
| journal = transaction->t_journal; |
| err = 0; |
| |
| JBUFFER_TRACE(jh, "entry"); |
| /* |
| * The buffer may already belong to this transaction due to pre-zeroing |
| * in the filesystem's new_block code. It may also be on the previous, |
| * committing transaction's lists, but it HAS to be in Forget state in |
| * that case: the transaction must have deleted the buffer for it to be |
| * reused here. |
| */ |
| spin_lock(&jh->b_state_lock); |
| J_ASSERT_JH(jh, (jh->b_transaction == transaction || |
| jh->b_transaction == NULL || |
| (jh->b_transaction == journal->j_committing_transaction && |
| jh->b_jlist == BJ_Forget))); |
| |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); |
| |
| if (jh->b_transaction == NULL) { |
| /* |
| * Previous jbd2_journal_forget() could have left the buffer |
| * with jbddirty bit set because it was being committed. When |
| * the commit finished, we've filed the buffer for |
| * checkpointing and marked it dirty. Now we are reallocating |
| * the buffer so the transaction freeing it must have |
| * committed and so it's safe to clear the dirty bit. |
| */ |
| clear_buffer_dirty(jh2bh(jh)); |
| /* first access by this transaction */ |
| jh->b_modified = 0; |
| |
| JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
| spin_unlock(&journal->j_list_lock); |
| } else if (jh->b_transaction == journal->j_committing_transaction) { |
| /* first access by this transaction */ |
| jh->b_modified = 0; |
| |
| JBUFFER_TRACE(jh, "set next transaction"); |
| spin_lock(&journal->j_list_lock); |
| jh->b_next_transaction = transaction; |
| spin_unlock(&journal->j_list_lock); |
| } |
| spin_unlock(&jh->b_state_lock); |
| |
| /* |
| * akpm: I added this. ext3_alloc_branch can pick up new indirect |
| * blocks which contain freed but then revoked metadata. We need |
| * to cancel the revoke in case we end up freeing it yet again |
| * and the reallocating as data - this would cause a second revoke, |
| * which hits an assertion error. |
| */ |
| JBUFFER_TRACE(jh, "cancelling revoke"); |
| jbd2_journal_cancel_revoke(handle, jh); |
| out: |
| jbd2_journal_put_journal_head(jh); |
| return err; |
| } |
| |
| /** |
| * jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
| * non-rewindable consequences |
| * @handle: transaction |
| * @bh: buffer to undo |
| * |
| * Sometimes there is a need to distinguish between metadata which has |
| * been committed to disk and that which has not. The ext3fs code uses |
| * this for freeing and allocating space, we have to make sure that we |
| * do not reuse freed space until the deallocation has been committed, |
| * since if we overwrote that space we would make the delete |
| * un-rewindable in case of a crash. |
| * |
| * To deal with that, jbd2_journal_get_undo_access requests write access to a |
| * buffer for parts of non-rewindable operations such as delete |
| * operations on the bitmaps. The journaling code must keep a copy of |
| * the buffer's contents prior to the undo_access call until such time |
| * as we know that the buffer has definitely been committed to disk. |
| * |
| * We never need to know which transaction the committed data is part |
| * of, buffers touched here are guaranteed to be dirtied later and so |
| * will be committed to a new transaction in due course, at which point |
| * we can discard the old committed data pointer. |
| * |
| * Returns error number or 0 on success. |
| */ |
| int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
| { |
| int err; |
| struct journal_head *jh; |
| char *committed_data = NULL; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| |
| if (jbd2_write_access_granted(handle, bh, true)) |
| return 0; |
| |
| jh = jbd2_journal_add_journal_head(bh); |
| JBUFFER_TRACE(jh, "entry"); |
| |
| /* |
| * Do this first --- it can drop the journal lock, so we want to |
| * make sure that obtaining the committed_data is done |
| * atomically wrt. completion of any outstanding commits. |
| */ |
| err = do_get_write_access(handle, jh, 1); |
| if (err) |
| goto out; |
| |
| repeat: |
| if (!jh->b_committed_data) |
| committed_data = jbd2_alloc(jh2bh(jh)->b_size, |
| GFP_NOFS|__GFP_NOFAIL); |
| |
| spin_lock(&jh->b_state_lock); |
| if (!jh->b_committed_data) { |
| /* Copy out the current buffer contents into the |
| * preserved, committed copy. */ |
| JBUFFER_TRACE(jh, "generate b_committed data"); |
| if (!committed_data) { |
| spin_unlock(&jh->b_state_lock); |
| goto repeat; |
| } |
| |
| jh->b_committed_data = committed_data; |
| committed_data = NULL; |
| memcpy(jh->b_committed_data, bh->b_data, bh->b_size); |
| } |
| spin_unlock(&jh->b_state_lock); |
| out: |
| jbd2_journal_put_journal_head(jh); |
| if (unlikely(committed_data)) |
| jbd2_free(committed_data, bh->b_size); |
| return err; |
| } |
| |
| /** |
| * jbd2_journal_set_triggers() - Add triggers for commit writeout |
| * @bh: buffer to trigger on |
| * @type: struct jbd2_buffer_trigger_type containing the trigger(s). |
| * |
| * Set any triggers on this journal_head. This is always safe, because |
| * triggers for a committing buffer will be saved off, and triggers for |
| * a running transaction will match the buffer in that transaction. |
| * |
| * Call with NULL to clear the triggers. |
| */ |
| void jbd2_journal_set_triggers(struct buffer_head *bh, |
| struct jbd2_buffer_trigger_type *type) |
| { |
| struct journal_head *jh = jbd2_journal_grab_journal_head(bh); |
| |
| if (WARN_ON_ONCE(!jh)) |
| return; |
| jh->b_triggers = type; |
| jbd2_journal_put_journal_head(jh); |
| } |
| |
| void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data, |
| struct jbd2_buffer_trigger_type *triggers) |
| { |
| struct buffer_head *bh = jh2bh(jh); |
| |
| if (!triggers || !triggers->t_frozen) |
| return; |
| |
| triggers->t_frozen(triggers, bh, mapped_data, bh->b_size); |
| } |
| |
| void jbd2_buffer_abort_trigger(struct journal_head *jh, |
| struct jbd2_buffer_trigger_type *triggers) |
| { |
| if (!triggers || !triggers->t_abort) |
| return; |
| |
| triggers->t_abort(triggers, jh2bh(jh)); |
| } |
| |
| /** |
| * jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
| * @handle: transaction to add buffer to. |
| * @bh: buffer to mark |
| * |
| * mark dirty metadata which needs to be journaled as part of the current |
| * transaction. |
| * |
| * The buffer must have previously had jbd2_journal_get_write_access() |
| * called so that it has a valid journal_head attached to the buffer |
| * head. |
| * |
| * The buffer is placed on the transaction's metadata list and is marked |
| * as belonging to the transaction. |
| * |
| * Returns error number or 0 on success. |
| * |
| * Special care needs to be taken if the buffer already belongs to the |
| * current committing transaction (in which case we should have frozen |
| * data present for that commit). In that case, we don't relink the |
| * buffer: that only gets done when the old transaction finally |
| * completes its commit. |
| */ |
| int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| struct journal_head *jh; |
| int ret = 0; |
| |
| if (!buffer_jbd(bh)) |
| return -EUCLEAN; |
| |
| /* |
| * We don't grab jh reference here since the buffer must be part |
| * of the running transaction. |
| */ |
| jh = bh2jh(bh); |
| jbd2_debug(5, "journal_head %p\n", jh); |
| JBUFFER_TRACE(jh, "entry"); |
| |
| /* |
| * This and the following assertions are unreliable since we may see jh |
| * in inconsistent state unless we grab bh_state lock. But this is |
| * crucial to catch bugs so let's do a reliable check until the |
| * lockless handling is fully proven. |
| */ |
| if (data_race(jh->b_transaction != transaction && |
| jh->b_next_transaction != transaction)) { |
| spin_lock(&jh->b_state_lock); |
| J_ASSERT_JH(jh, jh->b_transaction == transaction || |
| jh->b_next_transaction == transaction); |
| spin_unlock(&jh->b_state_lock); |
| } |
| if (jh->b_modified == 1) { |
| /* If it's in our transaction it must be in BJ_Metadata list. */ |
| if (data_race(jh->b_transaction == transaction && |
| jh->b_jlist != BJ_Metadata)) { |
| spin_lock(&jh->b_state_lock); |
| if (jh->b_transaction == transaction && |
| jh->b_jlist != BJ_Metadata) |
| pr_err("JBD2: assertion failure: h_type=%u " |
| "h_line_no=%u block_no=%llu jlist=%u\n", |
| handle->h_type, handle->h_line_no, |
| (unsigned long long) bh->b_blocknr, |
| jh->b_jlist); |
| J_ASSERT_JH(jh, jh->b_transaction != transaction || |
| jh->b_jlist == BJ_Metadata); |
| spin_unlock(&jh->b_state_lock); |
| } |
| goto out; |
| } |
| |
| journal = transaction->t_journal; |
| spin_lock(&jh->b_state_lock); |
| |
| if (is_handle_aborted(handle)) { |
| /* |
| * Check journal aborting with @jh->b_state_lock locked, |
| * since 'jh->b_transaction' could be replaced with |
| * 'jh->b_next_transaction' during old transaction |
| * committing if journal aborted, which may fail |
| * assertion on 'jh->b_frozen_data == NULL'. |
| */ |
| ret = -EROFS; |
| goto out_unlock_bh; |
| } |
| |
| if (jh->b_modified == 0) { |
| /* |
| * This buffer's got modified and becoming part |
| * of the transaction. This needs to be done |
| * once a transaction -bzzz |
| */ |
| if (WARN_ON_ONCE(jbd2_handle_buffer_credits(handle) <= 0)) { |
| ret = -ENOSPC; |
| goto out_unlock_bh; |
| } |
| jh->b_modified = 1; |
| handle->h_total_credits--; |
| } |
| |
| /* |
| * fastpath, to avoid expensive locking. If this buffer is already |
| * on the running transaction's metadata list there is nothing to do. |
| * Nobody can take it off again because there is a handle open. |
| * I _think_ we're OK here with SMP barriers - a mistaken decision will |
| * result in this test being false, so we go in and take the locks. |
| */ |
| if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { |
| JBUFFER_TRACE(jh, "fastpath"); |
| if (unlikely(jh->b_transaction != |
| journal->j_running_transaction)) { |
| printk(KERN_ERR "JBD2: %s: " |
| "jh->b_transaction (%llu, %p, %u) != " |
| "journal->j_running_transaction (%p, %u)\n", |
| journal->j_devname, |
| (unsigned long long) bh->b_blocknr, |
| jh->b_transaction, |
| jh->b_transaction ? jh->b_transaction->t_tid : 0, |
| journal->j_running_transaction, |
| journal->j_running_transaction ? |
| journal->j_running_transaction->t_tid : 0); |
| ret = -EINVAL; |
| } |
| goto out_unlock_bh; |
| } |
| |
| set_buffer_jbddirty(bh); |
| |
| /* |
| * Metadata already on the current transaction list doesn't |
| * need to be filed. Metadata on another transaction's list must |
| * be committing, and will be refiled once the commit completes: |
| * leave it alone for now. |
| */ |
| if (jh->b_transaction != transaction) { |
| JBUFFER_TRACE(jh, "already on other transaction"); |
| if (unlikely(((jh->b_transaction != |
| journal->j_committing_transaction)) || |
| (jh->b_next_transaction != transaction))) { |
| printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: " |
| "bad jh for block %llu: " |
| "transaction (%p, %u), " |
| "jh->b_transaction (%p, %u), " |
| "jh->b_next_transaction (%p, %u), jlist %u\n", |
| journal->j_devname, |
| (unsigned long long) bh->b_blocknr, |
| transaction, transaction->t_tid, |
| jh->b_transaction, |
| jh->b_transaction ? |
| jh->b_transaction->t_tid : 0, |
| jh->b_next_transaction, |
| jh->b_next_transaction ? |
| jh->b_next_transaction->t_tid : 0, |
| jh->b_jlist); |
| WARN_ON(1); |
| ret = -EINVAL; |
| } |
| /* And this case is illegal: we can't reuse another |
| * transaction's data buffer, ever. */ |
| goto out_unlock_bh; |
| } |
| |
| /* That test should have eliminated the following case: */ |
| J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
| |
| JBUFFER_TRACE(jh, "file as BJ_Metadata"); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata); |
| spin_unlock(&journal->j_list_lock); |
| out_unlock_bh: |
| spin_unlock(&jh->b_state_lock); |
| out: |
| JBUFFER_TRACE(jh, "exit"); |
| return ret; |
| } |
| |
| /** |
| * jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
| * @handle: transaction handle |
| * @bh: bh to 'forget' |
| * |
| * We can only do the bforget if there are no commits pending against the |
| * buffer. If the buffer is dirty in the current running transaction we |
| * can safely unlink it. |
| * |
| * bh may not be a journalled buffer at all - it may be a non-JBD |
| * buffer which came off the hashtable. Check for this. |
| * |
| * Decrements bh->b_count by one. |
| * |
| * Allow this call even if the handle has aborted --- it may be part of |
| * the caller's cleanup after an abort. |
| */ |
| int jbd2_journal_forget(handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| struct journal_head *jh; |
| int drop_reserve = 0; |
| int err = 0; |
| int was_modified = 0; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| journal = transaction->t_journal; |
| |
| BUFFER_TRACE(bh, "entry"); |
| |
| jh = jbd2_journal_grab_journal_head(bh); |
| if (!jh) { |
| __bforget(bh); |
| return 0; |
| } |
| |
| spin_lock(&jh->b_state_lock); |
| |
| /* Critical error: attempting to delete a bitmap buffer, maybe? |
| * Don't do any jbd operations, and return an error. */ |
| if (!J_EXPECT_JH(jh, !jh->b_committed_data, |
| "inconsistent data on disk")) { |
| err = -EIO; |
| goto drop; |
| } |
| |
| /* keep track of whether or not this transaction modified us */ |
| was_modified = jh->b_modified; |
| |
| /* |
| * The buffer's going from the transaction, we must drop |
| * all references -bzzz |
| */ |
| jh->b_modified = 0; |
| |
| if (jh->b_transaction == transaction) { |
| J_ASSERT_JH(jh, !jh->b_frozen_data); |
| |
| /* If we are forgetting a buffer which is already part |
| * of this transaction, then we can just drop it from |
| * the transaction immediately. */ |
| clear_buffer_dirty(bh); |
| clear_buffer_jbddirty(bh); |
| |
| JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); |
| |
| /* |
| * we only want to drop a reference if this transaction |
| * modified the buffer |
| */ |
| if (was_modified) |
| drop_reserve = 1; |
| |
| /* |
| * We are no longer going to journal this buffer. |
| * However, the commit of this transaction is still |
| * important to the buffer: the delete that we are now |
| * processing might obsolete an old log entry, so by |
| * committing, we can satisfy the buffer's checkpoint. |
| * |
| * So, if we have a checkpoint on the buffer, we should |
| * now refile the buffer on our BJ_Forget list so that |
| * we know to remove the checkpoint after we commit. |
| */ |
| |
| spin_lock(&journal->j_list_lock); |
| if (jh->b_cp_transaction) { |
| __jbd2_journal_temp_unlink_buffer(jh); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
| } else { |
| __jbd2_journal_unfile_buffer(jh); |
| jbd2_journal_put_journal_head(jh); |
| } |
| spin_unlock(&journal->j_list_lock); |
| } else if (jh->b_transaction) { |
| J_ASSERT_JH(jh, (jh->b_transaction == |
| journal->j_committing_transaction)); |
| /* However, if the buffer is still owned by a prior |
| * (committing) transaction, we can't drop it yet... */ |
| JBUFFER_TRACE(jh, "belongs to older transaction"); |
| /* ... but we CAN drop it from the new transaction through |
| * marking the buffer as freed and set j_next_transaction to |
| * the new transaction, so that not only the commit code |
| * knows it should clear dirty bits when it is done with the |
| * buffer, but also the buffer can be checkpointed only |
| * after the new transaction commits. */ |
| |
| set_buffer_freed(bh); |
| |
| if (!jh->b_next_transaction) { |
| spin_lock(&journal->j_list_lock); |
| jh->b_next_transaction = transaction; |
| spin_unlock(&journal->j_list_lock); |
| } else { |
| J_ASSERT(jh->b_next_transaction == transaction); |
| |
| /* |
| * only drop a reference if this transaction modified |
| * the buffer |
| */ |
| if (was_modified) |
| drop_reserve = 1; |
| } |
| } else { |
| /* |
| * Finally, if the buffer is not belongs to any |
| * transaction, we can just drop it now if it has no |
| * checkpoint. |
| */ |
| spin_lock(&journal->j_list_lock); |
| if (!jh->b_cp_transaction) { |
| JBUFFER_TRACE(jh, "belongs to none transaction"); |
| spin_unlock(&journal->j_list_lock); |
| goto drop; |
| } |
| |
| /* |
| * Otherwise, if the buffer has been written to disk, |
| * it is safe to remove the checkpoint and drop it. |
| */ |
| if (!buffer_dirty(bh)) { |
| __jbd2_journal_remove_checkpoint(jh); |
| spin_unlock(&journal->j_list_lock); |
| goto drop; |
| } |
| |
| /* |
| * The buffer is still not written to disk, we should |
| * attach this buffer to current transaction so that the |
| * buffer can be checkpointed only after the current |
| * transaction commits. |
| */ |
| clear_buffer_dirty(bh); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
| spin_unlock(&journal->j_list_lock); |
| } |
| drop: |
| __brelse(bh); |
| spin_unlock(&jh->b_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| if (drop_reserve) { |
| /* no need to reserve log space for this block -bzzz */ |
| handle->h_total_credits++; |
| } |
| return err; |
| } |
| |
| /** |
| * jbd2_journal_stop() - complete a transaction |
| * @handle: transaction to complete. |
| * |
| * All done for a particular handle. |
| * |
| * There is not much action needed here. We just return any remaining |
| * buffer credits to the transaction and remove the handle. The only |
| * complication is that we need to start a commit operation if the |
| * filesystem is marked for synchronous update. |
| * |
| * jbd2_journal_stop itself will not usually return an error, but it may |
| * do so in unusual circumstances. In particular, expect it to |
| * return -EIO if a jbd2_journal_abort has been executed since the |
| * transaction began. |
| */ |
| int jbd2_journal_stop(handle_t *handle) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| int err = 0, wait_for_commit = 0; |
| tid_t tid; |
| pid_t pid; |
| |
| if (--handle->h_ref > 0) { |
| jbd2_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, |
| handle->h_ref); |
| if (is_handle_aborted(handle)) |
| return -EIO; |
| return 0; |
| } |
| if (!transaction) { |
| /* |
| * Handle is already detached from the transaction so there is |
| * nothing to do other than free the handle. |
| */ |
| memalloc_nofs_restore(handle->saved_alloc_context); |
| goto free_and_exit; |
| } |
| journal = transaction->t_journal; |
| tid = transaction->t_tid; |
| |
| if (is_handle_aborted(handle)) |
| err = -EIO; |
| |
| jbd2_debug(4, "Handle %p going down\n", handle); |
| trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev, |
| tid, handle->h_type, handle->h_line_no, |
| jiffies - handle->h_start_jiffies, |
| handle->h_sync, handle->h_requested_credits, |
| (handle->h_requested_credits - |
| handle->h_total_credits)); |
| |
| /* |
| * Implement synchronous transaction batching. If the handle |
| * was synchronous, don't force a commit immediately. Let's |
| * yield and let another thread piggyback onto this |
| * transaction. Keep doing that while new threads continue to |
| * arrive. It doesn't cost much - we're about to run a commit |
| * and sleep on IO anyway. Speeds up many-threaded, many-dir |
| * operations by 30x or more... |
| * |
| * We try and optimize the sleep time against what the |
| * underlying disk can do, instead of having a static sleep |
| * time. This is useful for the case where our storage is so |
| * fast that it is more optimal to go ahead and force a flush |
| * and wait for the transaction to be committed than it is to |
| * wait for an arbitrary amount of time for new writers to |
| * join the transaction. We achieve this by measuring how |
| * long it takes to commit a transaction, and compare it with |
| * how long this transaction has been running, and if run time |
| * < commit time then we sleep for the delta and commit. This |
| * greatly helps super fast disks that would see slowdowns as |
| * more threads started doing fsyncs. |
| * |
| * But don't do this if this process was the most recent one |
| * to perform a synchronous write. We do this to detect the |
| * case where a single process is doing a stream of sync |
| * writes. No point in waiting for joiners in that case. |
| * |
| * Setting max_batch_time to 0 disables this completely. |
| */ |
| pid = current->pid; |
| if (handle->h_sync && journal->j_last_sync_writer != pid && |
| journal->j_max_batch_time) { |
| u64 commit_time, trans_time; |
| |
| journal->j_last_sync_writer = pid; |
| |
| read_lock(&journal->j_state_lock); |
| commit_time = journal->j_average_commit_time; |
| read_unlock(&journal->j_state_lock); |
| |
| trans_time = ktime_to_ns(ktime_sub(ktime_get(), |
| transaction->t_start_time)); |
| |
| commit_time = max_t(u64, commit_time, |
| 1000*journal->j_min_batch_time); |
| commit_time = min_t(u64, commit_time, |
| 1000*journal->j_max_batch_time); |
| |
| if (trans_time < commit_time) { |
| ktime_t expires = ktime_add_ns(ktime_get(), |
| commit_time); |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); |
| } |
| } |
| |
| if (handle->h_sync) |
| transaction->t_synchronous_commit = 1; |
| |
| /* |
| * If the handle is marked SYNC, we need to set another commit |
| * going! We also want to force a commit if the transaction is too |
| * old now. |
| */ |
| if (handle->h_sync || |
| time_after_eq(jiffies, transaction->t_expires)) { |
| /* Do this even for aborted journals: an abort still |
| * completes the commit thread, it just doesn't write |
| * anything to disk. */ |
| |
| jbd2_debug(2, "transaction too old, requesting commit for " |
| "handle %p\n", handle); |
| /* This is non-blocking */ |
| jbd2_log_start_commit(journal, tid); |
| |
| /* |
| * Special case: JBD2_SYNC synchronous updates require us |
| * to wait for the commit to complete. |
| */ |
| if (handle->h_sync && !(current->flags & PF_MEMALLOC)) |
| wait_for_commit = 1; |
| } |
| |
| /* |
| * Once stop_this_handle() drops t_updates, the transaction could start |
| * committing on us and eventually disappear. So we must not |
| * dereference transaction pointer again after calling |
| * stop_this_handle(). |
| */ |
| stop_this_handle(handle); |
| |
| if (wait_for_commit) |
| err = jbd2_log_wait_commit(journal, tid); |
| |
| free_and_exit: |
| if (handle->h_rsv_handle) |
| jbd2_free_handle(handle->h_rsv_handle); |
| jbd2_free_handle(handle); |
| return err; |
| } |
| |
| /* |
| * |
| * List management code snippets: various functions for manipulating the |
| * transaction buffer lists. |
| * |
| */ |
| |
| /* |
| * Append a buffer to a transaction list, given the transaction's list head |
| * pointer. |
| * |
| * j_list_lock is held. |
| * |
| * jh->b_state_lock is held. |
| */ |
| |
| static inline void |
| __blist_add_buffer(struct journal_head **list, struct journal_head *jh) |
| { |
| if (!*list) { |
| jh->b_tnext = jh->b_tprev = jh; |
| *list = jh; |
| } else { |
| /* Insert at the tail of the list to preserve order */ |
| struct journal_head *first = *list, *last = first->b_tprev; |
| jh->b_tprev = last; |
| jh->b_tnext = first; |
| last->b_tnext = first->b_tprev = jh; |
| } |
| } |
| |
| /* |
| * Remove a buffer from a transaction list, given the transaction's list |
| * head pointer. |
| * |
| * Called with j_list_lock held, and the journal may not be locked. |
| * |
| * jh->b_state_lock is held. |
| */ |
| |
| static inline void |
| __blist_del_buffer(struct journal_head **list, struct journal_head *jh) |
| { |
| if (*list == jh) { |
| *list = jh->b_tnext; |
| if (*list == jh) |
| *list = NULL; |
| } |
| jh->b_tprev->b_tnext = jh->b_tnext; |
| jh->b_tnext->b_tprev = jh->b_tprev; |
| } |
| |
| /* |
| * Remove a buffer from the appropriate transaction list. |
| * |
| * Note that this function can *change* the value of |
| * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or |
| * t_reserved_list. If the caller is holding onto a copy of one of these |
| * pointers, it could go bad. Generally the caller needs to re-read the |
| * pointer from the transaction_t. |
| * |
| * Called under j_list_lock. |
| */ |
| static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
| { |
| struct journal_head **list = NULL; |
| transaction_t *transaction; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| lockdep_assert_held(&jh->b_state_lock); |
| transaction = jh->b_transaction; |
| if (transaction) |
| assert_spin_locked(&transaction->t_journal->j_list_lock); |
| |
| J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); |
| if (jh->b_jlist != BJ_None) |
| J_ASSERT_JH(jh, transaction != NULL); |
| |
| switch (jh->b_jlist) { |
| case BJ_None: |
| return; |
| case BJ_Metadata: |
| transaction->t_nr_buffers--; |
| J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); |
| list = &transaction->t_buffers; |
| break; |
| case BJ_Forget: |
| list = &transaction->t_forget; |
| break; |
| case BJ_Shadow: |
| list = &transaction->t_shadow_list; |
| break; |
| case BJ_Reserved: |
| list = &transaction->t_reserved_list; |
| break; |
| } |
| |
| __blist_del_buffer(list, jh); |
| jh->b_jlist = BJ_None; |
| if (transaction && is_journal_aborted(transaction->t_journal)) |
| clear_buffer_jbddirty(bh); |
| else if (test_clear_buffer_jbddirty(bh)) |
| mark_buffer_dirty(bh); /* Expose it to the VM */ |
| } |
| |
| /* |
| * Remove buffer from all transactions. The caller is responsible for dropping |
| * the jh reference that belonged to the transaction. |
| * |
| * Called with bh_state lock and j_list_lock |
| */ |
| static void __jbd2_journal_unfile_buffer(struct journal_head *jh) |
| { |
| J_ASSERT_JH(jh, jh->b_transaction != NULL); |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| |
| __jbd2_journal_temp_unlink_buffer(jh); |
| jh->b_transaction = NULL; |
| } |
| |
| void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
| { |
| struct buffer_head *bh = jh2bh(jh); |
| |
| /* Get reference so that buffer cannot be freed before we unlock it */ |
| get_bh(bh); |
| spin_lock(&jh->b_state_lock); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_unfile_buffer(jh); |
| spin_unlock(&journal->j_list_lock); |
| spin_unlock(&jh->b_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| __brelse(bh); |
| } |
| |
| /* |
| * Called from jbd2_journal_try_to_free_buffers(). |
| * |
| * Called under jh->b_state_lock |
| */ |
| static void |
| __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) |
| { |
| struct journal_head *jh; |
| |
| jh = bh2jh(bh); |
| |
| if (buffer_locked(bh) || buffer_dirty(bh)) |
| goto out; |
| |
| if (jh->b_next_transaction != NULL || jh->b_transaction != NULL) |
| goto out; |
| |
| spin_lock(&journal->j_list_lock); |
| if (jh->b_cp_transaction != NULL) { |
| /* written-back checkpointed metadata buffer */ |
| JBUFFER_TRACE(jh, "remove from checkpoint list"); |
| __jbd2_journal_remove_checkpoint(jh); |
| } |
| spin_unlock(&journal->j_list_lock); |
| out: |
| return; |
| } |
| |
| /** |
| * jbd2_journal_try_to_free_buffers() - try to free page buffers. |
| * @journal: journal for operation |
| * @folio: Folio to detach data from. |
| * |
| * For all the buffers on this page, |
| * if they are fully written out ordered data, move them onto BUF_CLEAN |
| * so try_to_free_buffers() can reap them. |
| * |
| * This function returns non-zero if we wish try_to_free_buffers() |
| * to be called. We do this if the page is releasable by try_to_free_buffers(). |
| * We also do it if the page has locked or dirty buffers and the caller wants |
| * us to perform sync or async writeout. |
| * |
| * This complicates JBD locking somewhat. We aren't protected by the |
| * BKL here. We wish to remove the buffer from its committing or |
| * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
| * |
| * This may *change* the value of transaction_t->t_datalist, so anyone |
| * who looks at t_datalist needs to lock against this function. |
| * |
| * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
| * buffer. So we need to lock against that. jbd2_journal_dirty_data() |
| * will come out of the lock with the buffer dirty, which makes it |
| * ineligible for release here. |
| * |
| * Who else is affected by this? hmm... Really the only contender |
| * is do_get_write_access() - it could be looking at the buffer while |
| * journal_try_to_free_buffer() is changing its state. But that |
| * cannot happen because we never reallocate freed data as metadata |
| * while the data is part of a transaction. Yes? |
| * |
| * Return false on failure, true on success |
| */ |
| bool jbd2_journal_try_to_free_buffers(journal_t *journal, struct folio *folio) |
| { |
| struct buffer_head *head; |
| struct buffer_head *bh; |
| bool ret = false; |
| |
| J_ASSERT(folio_test_locked(folio)); |
| |
| head = folio_buffers(folio); |
| bh = head; |
| do { |
| struct journal_head *jh; |
| |
| /* |
| * We take our own ref against the journal_head here to avoid |
| * having to add tons of locking around each instance of |
| * jbd2_journal_put_journal_head(). |
| */ |
| jh = jbd2_journal_grab_journal_head(bh); |
| if (!jh) |
| continue; |
| |
| spin_lock(&jh->b_state_lock); |
| __journal_try_to_free_buffer(journal, bh); |
| spin_unlock(&jh->b_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| if (buffer_jbd(bh)) |
| goto busy; |
| } while ((bh = bh->b_this_page) != head); |
| |
| ret = try_to_free_buffers(folio); |
| busy: |
| return ret; |
| } |
| |
| /* |
| * This buffer is no longer needed. If it is on an older transaction's |
| * checkpoint list we need to record it on this transaction's forget list |
| * to pin this buffer (and hence its checkpointing transaction) down until |
| * this transaction commits. If the buffer isn't on a checkpoint list, we |
| * release it. |
| * Returns non-zero if JBD no longer has an interest in the buffer. |
| * |
| * Called under j_list_lock. |
| * |
| * Called under jh->b_state_lock. |
| */ |
| static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) |
| { |
| int may_free = 1; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| if (jh->b_cp_transaction) { |
| JBUFFER_TRACE(jh, "on running+cp transaction"); |
| __jbd2_journal_temp_unlink_buffer(jh); |
| /* |
| * We don't want to write the buffer anymore, clear the |
| * bit so that we don't confuse checks in |
| * __journal_file_buffer |
| */ |
| clear_buffer_dirty(bh); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
| may_free = 0; |
| } else { |
| JBUFFER_TRACE(jh, "on running transaction"); |
| __jbd2_journal_unfile_buffer(jh); |
| jbd2_journal_put_journal_head(jh); |
| } |
| return may_free; |
| } |
| |
| /* |
| * jbd2_journal_invalidate_folio |
| * |
| * This code is tricky. It has a number of cases to deal with. |
| * |
| * There are two invariants which this code relies on: |
| * |
| * i_size must be updated on disk before we start calling invalidate_folio |
| * on the data. |
| * |
| * This is done in ext3 by defining an ext3_setattr method which |
| * updates i_size before truncate gets going. By maintaining this |
| * invariant, we can be sure that it is safe to throw away any buffers |
| * attached to the current transaction: once the transaction commits, |
| * we know that the data will not be needed. |
| * |
| * Note however that we can *not* throw away data belonging to the |
| * previous, committing transaction! |
| * |
| * Any disk blocks which *are* part of the previous, committing |
| * transaction (and which therefore cannot be discarded immediately) are |
| * not going to be reused in the new running transaction |
| * |
| * The bitmap committed_data images guarantee this: any block which is |
| * allocated in one transaction and removed in the next will be marked |
| * as in-use in the committed_data bitmap, so cannot be reused until |
| * the next transaction to delete the block commits. This means that |
| * leaving committing buffers dirty is quite safe: the disk blocks |
| * cannot be reallocated to a different file and so buffer aliasing is |
| * not possible. |
| * |
| * |
| * The above applies mainly to ordered data mode. In writeback mode we |
| * don't make guarantees about the order in which data hits disk --- in |
| * particular we don't guarantee that new dirty data is flushed before |
| * transaction commit --- so it is always safe just to discard data |
| * immediately in that mode. --sct |
| */ |
| |
| /* |
| * The journal_unmap_buffer helper function returns zero if the buffer |
| * concerned remains pinned as an anonymous buffer belonging to an older |
| * transaction. |
| * |
| * We're outside-transaction here. Either or both of j_running_transaction |
| * and j_committing_transaction may be NULL. |
| */ |
| static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, |
| int partial_page) |
| { |
| transaction_t *transaction; |
| struct journal_head *jh; |
| int may_free = 1; |
| |
| BUFFER_TRACE(bh, "entry"); |
| |
| /* |
| * It is safe to proceed here without the j_list_lock because the |
| * buffers cannot be stolen by try_to_free_buffers as long as we are |
| * holding the page lock. --sct |
| */ |
| |
| jh = jbd2_journal_grab_journal_head(bh); |
| if (!jh) |
| goto zap_buffer_unlocked; |
| |
| /* OK, we have data buffer in journaled mode */ |
| write_lock(&journal->j_state_lock); |
| spin_lock(&jh->b_state_lock); |
| spin_lock(&journal->j_list_lock); |
| |
| /* |
| * We cannot remove the buffer from checkpoint lists until the |
| * transaction adding inode to orphan list (let's call it T) |
| * is committed. Otherwise if the transaction changing the |
| * buffer would be cleaned from the journal before T is |
| * committed, a crash will cause that the correct contents of |
| * the buffer will be lost. On the other hand we have to |
| * clear the buffer dirty bit at latest at the moment when the |
| * transaction marking the buffer as freed in the filesystem |
| * structures is committed because from that moment on the |
| * block can be reallocated and used by a different page. |
| * Since the block hasn't been freed yet but the inode has |
| * already been added to orphan list, it is safe for us to add |
| * the buffer to BJ_Forget list of the newest transaction. |
| * |
| * Also we have to clear buffer_mapped flag of a truncated buffer |
| * because the buffer_head may be attached to the page straddling |
| * i_size (can happen only when blocksize < pagesize) and thus the |
| * buffer_head can be reused when the file is extended again. So we end |
| * up keeping around invalidated buffers attached to transactions' |
| * BJ_Forget list just to stop checkpointing code from cleaning up |
| * the transaction this buffer was modified in. |
| */ |
| transaction = jh->b_transaction; |
| if (transaction == NULL) { |
| /* First case: not on any transaction. If it |
| * has no checkpoint link, then we can zap it: |
| * it's a writeback-mode buffer so we don't care |
| * if it hits disk safely. */ |
| if (!jh->b_cp_transaction) { |
| JBUFFER_TRACE(jh, "not on any transaction: zap"); |
| goto zap_buffer; |
| } |
| |
| if (!buffer_dirty(bh)) { |
| /* bdflush has written it. We can drop it now */ |
| __jbd2_journal_remove_checkpoint(jh); |
| goto zap_buffer; |
| } |
| |
| /* OK, it must be in the journal but still not |
| * written fully to disk: it's metadata or |
| * journaled data... */ |
| |
| if (journal->j_running_transaction) { |
| /* ... and once the current transaction has |
| * committed, the buffer won't be needed any |
| * longer. */ |
| JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); |
| may_free = __dispose_buffer(jh, |
| journal->j_running_transaction); |
| goto zap_buffer; |
| } else { |
| /* There is no currently-running transaction. So the |
| * orphan record which we wrote for this file must have |
| * passed into commit. We must attach this buffer to |
| * the committing transaction, if it exists. */ |
| if (journal->j_committing_transaction) { |
| JBUFFER_TRACE(jh, "give to committing trans"); |
| may_free = __dispose_buffer(jh, |
| journal->j_committing_transaction); |
| goto zap_buffer; |
| } else { |
| /* The orphan record's transaction has |
| * committed. We can cleanse this buffer */ |
| clear_buffer_jbddirty(bh); |
| __jbd2_journal_remove_checkpoint(jh); |
| goto zap_buffer; |
| } |
| } |
| } else if (transaction == journal->j_committing_transaction) { |
| JBUFFER_TRACE(jh, "on committing transaction"); |
| /* |
| * The buffer is committing, we simply cannot touch |
| * it. If the page is straddling i_size we have to wait |
| * for commit and try again. |
| */ |
| if (partial_page) { |
| spin_unlock(&journal->j_list_lock); |
| spin_unlock(&jh->b_state_lock); |
| write_unlock(&journal->j_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| return -EBUSY; |
| } |
| /* |
| * OK, buffer won't be reachable after truncate. We just clear |
| * b_modified to not confuse transaction credit accounting, and |
| * set j_next_transaction to the running transaction (if there |
| * is one) and mark buffer as freed so that commit code knows |
| * it should clear dirty bits when it is done with the buffer. |
| */ |
| set_buffer_freed(bh); |
| if (journal->j_running_transaction && buffer_jbddirty(bh)) |
| jh->b_next_transaction = journal->j_running_transaction; |
| jh->b_modified = 0; |
| spin_unlock(&journal->j_list_lock); |
| spin_unlock(&jh->b_state_lock); |
| write_unlock(&journal->j_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| return 0; |
| } else { |
| /* Good, the buffer belongs to the running transaction. |
| * We are writing our own transaction's data, not any |
| * previous one's, so it is safe to throw it away |
| * (remember that we expect the filesystem to have set |
| * i_size already for this truncate so recovery will not |
| * expose the disk blocks we are discarding here.) */ |
| J_ASSERT_JH(jh, transaction == journal->j_running_transaction); |
| JBUFFER_TRACE(jh, "on running transaction"); |
| may_free = __dispose_buffer(jh, transaction); |
| } |
| |
| zap_buffer: |
| /* |
| * This is tricky. Although the buffer is truncated, it may be reused |
| * if blocksize < pagesize and it is attached to the page straddling |
| * EOF. Since the buffer might have been added to BJ_Forget list of the |
| * running transaction, journal_get_write_access() won't clear |
| * b_modified and credit accounting gets confused. So clear b_modified |
| * here. |
| */ |
| jh->b_modified = 0; |
| spin_unlock(&journal->j_list_lock); |
| spin_unlock(&jh->b_state_lock); |
| write_unlock(&journal->j_state_lock); |
| jbd2_journal_put_journal_head(jh); |
| zap_buffer_unlocked: |
| clear_buffer_dirty(bh); |
| J_ASSERT_BH(bh, !buffer_jbddirty(bh)); |
| clear_buffer_mapped(bh); |
| clear_buffer_req(bh); |
| clear_buffer_new(bh); |
| clear_buffer_delay(bh); |
| clear_buffer_unwritten(bh); |
| bh->b_bdev = NULL; |
| return may_free; |
| } |
| |
| /** |
| * jbd2_journal_invalidate_folio() |
| * @journal: journal to use for flush... |
| * @folio: folio to flush |
| * @offset: start of the range to invalidate |
| * @length: length of the range to invalidate |
| * |
| * Reap page buffers containing data after in the specified range in page. |
| * Can return -EBUSY if buffers are part of the committing transaction and |
| * the page is straddling i_size. Caller then has to wait for current commit |
| * and try again. |
| */ |
| int jbd2_journal_invalidate_folio(journal_t *journal, struct folio *folio, |
| size_t offset, size_t length) |
| { |
| struct buffer_head *head, *bh, *next; |
| unsigned int stop = offset + length; |
| unsigned int curr_off = 0; |
| int partial_page = (offset || length < folio_size(folio)); |
| int may_free = 1; |
| int ret = 0; |
| |
| if (!folio_test_locked(folio)) |
| BUG(); |
| head = folio_buffers(folio); |
| if (!head) |
| return 0; |
| |
| BUG_ON(stop > folio_size(folio) || stop < length); |
| |
| /* We will potentially be playing with lists other than just the |
| * data lists (especially for journaled data mode), so be |
| * cautious in our locking. */ |
| |
| bh = head; |
| do { |
| unsigned int next_off = curr_off + bh->b_size; |
| next = bh->b_this_page; |
| |
| if (next_off > stop) |
| return 0; |
| |
| if (offset <= curr_off) { |
| /* This block is wholly outside the truncation point */ |
| lock_buffer(bh); |
| ret = journal_unmap_buffer(journal, bh, partial_page); |
| unlock_buffer(bh); |
| if (ret < 0) |
| return ret; |
| may_free &= ret; |
| } |
| curr_off = next_off; |
| bh = next; |
| |
| } while (bh != head); |
| |
| if (!partial_page) { |
| if (may_free && try_to_free_buffers(folio)) |
| J_ASSERT(!folio_buffers(folio)); |
| } |
| return 0; |
| } |
| |
| /* |
| * File a buffer on the given transaction list. |
| */ |
| void __jbd2_journal_file_buffer(struct journal_head *jh, |
| transaction_t *transaction, int jlist) |
| { |
| struct journal_head **list = NULL; |
| int was_dirty = 0; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| lockdep_assert_held(&jh->b_state_lock); |
| assert_spin_locked(&transaction->t_journal->j_list_lock); |
| |
| J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); |
| J_ASSERT_JH(jh, jh->b_transaction == transaction || |
| jh->b_transaction == NULL); |
| |
| if (jh->b_transaction && jh->b_jlist == jlist) |
| return; |
| |
| if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
| jlist == BJ_Shadow || jlist == BJ_Forget) { |
| /* |
| * For metadata buffers, we track dirty bit in buffer_jbddirty |
| * instead of buffer_dirty. We should not see a dirty bit set |
| * here because we clear it in do_get_write_access but e.g. |
| * tune2fs can modify the sb and set the dirty bit at any time |
| * so we try to gracefully handle that. |
| */ |
| if (buffer_dirty(bh)) |
| warn_dirty_buffer(bh); |
| if (test_clear_buffer_dirty(bh) || |
| test_clear_buffer_jbddirty(bh)) |
| was_dirty = 1; |
| } |
| |
| if (jh->b_transaction) |
| __jbd2_journal_temp_unlink_buffer(jh); |
| else |
| jbd2_journal_grab_journal_head(bh); |
| jh->b_transaction = transaction; |
| |
| switch (jlist) { |
| case BJ_None: |
| J_ASSERT_JH(jh, !jh->b_committed_data); |
| J_ASSERT_JH(jh, !jh->b_frozen_data); |
| return; |
| case BJ_Metadata: |
| transaction->t_nr_buffers++; |
| list = &transaction->t_buffers; |
| break; |
| case BJ_Forget: |
| list = &transaction->t_forget; |
| break; |
| case BJ_Shadow: |
| list = &transaction->t_shadow_list; |
| break; |
| case BJ_Reserved: |
| list = &transaction->t_reserved_list; |
| break; |
| } |
| |
| __blist_add_buffer(list, jh); |
| jh->b_jlist = jlist; |
| |
| if (was_dirty) |
| set_buffer_jbddirty(bh); |
| } |
| |
| void jbd2_journal_file_buffer(struct journal_head *jh, |
| transaction_t *transaction, int jlist) |
| { |
| spin_lock(&jh->b_state_lock); |
| spin_lock(&transaction->t_journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, jlist); |
| spin_unlock(&transaction->t_journal->j_list_lock); |
| spin_unlock(&jh->b_state_lock); |
| } |
| |
| /* |
| * Remove a buffer from its current buffer list in preparation for |
| * dropping it from its current transaction entirely. If the buffer has |
| * already started to be used by a subsequent transaction, refile the |
| * buffer on that transaction's metadata list. |
| * |
| * Called under j_list_lock |
| * Called under jh->b_state_lock |
| * |
| * When this function returns true, there's no next transaction to refile to |
| * and the caller has to drop jh reference through |
| * jbd2_journal_put_journal_head(). |
| */ |
| bool __jbd2_journal_refile_buffer(struct journal_head *jh) |
| { |
| int was_dirty, jlist; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| lockdep_assert_held(&jh->b_state_lock); |
| if (jh->b_transaction) |
| assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); |
| |
| /* If the buffer is now unused, just drop it. */ |
| if (jh->b_next_transaction == NULL) { |
| __jbd2_journal_unfile_buffer(jh); |
| return true; |
| } |
| |
| /* |
| * It has been modified by a later transaction: add it to the new |
| * transaction's metadata list. |
| */ |
| |
| was_dirty = test_clear_buffer_jbddirty(bh); |
| __jbd2_journal_temp_unlink_buffer(jh); |
| |
| /* |
| * b_transaction must be set, otherwise the new b_transaction won't |
| * be holding jh reference |
| */ |
| J_ASSERT_JH(jh, jh->b_transaction != NULL); |
| |
| /* |
| * We set b_transaction here because b_next_transaction will inherit |
| * our jh reference and thus __jbd2_journal_file_buffer() must not |
| * take a new one. |
| */ |
| WRITE_ONCE(jh->b_transaction, jh->b_next_transaction); |
| WRITE_ONCE(jh->b_next_transaction, NULL); |
| if (buffer_freed(bh)) |
| jlist = BJ_Forget; |
| else if (jh->b_modified) |
| jlist = BJ_Metadata; |
| else |
| jlist = BJ_Reserved; |
| __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist); |
| J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
| |
| if (was_dirty) |
| set_buffer_jbddirty(bh); |
| return false; |
| } |
| |
| /* |
| * __jbd2_journal_refile_buffer() with necessary locking added. We take our |
| * bh reference so that we can safely unlock bh. |
| * |
| * The jh and bh may be freed by this call. |
| */ |
| void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
| { |
| bool drop; |
| |
| spin_lock(&jh->b_state_lock); |
| spin_lock(&journal->j_list_lock); |
| drop = __jbd2_journal_refile_buffer(jh); |
| spin_unlock(&jh->b_state_lock); |
| spin_unlock(&journal->j_list_lock); |
| if (drop) |
| jbd2_journal_put_journal_head(jh); |
| } |
| |
| /* |
| * File inode in the inode list of the handle's transaction |
| */ |
| static int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode, |
| unsigned long flags, loff_t start_byte, loff_t end_byte) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| journal = transaction->t_journal; |
| |
| jbd2_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, |
| transaction->t_tid); |
| |
| spin_lock(&journal->j_list_lock); |
| jinode->i_flags |= flags; |
| |
| if (jinode->i_dirty_end) { |
| jinode->i_dirty_start = min(jinode->i_dirty_start, start_byte); |
| jinode->i_dirty_end = max(jinode->i_dirty_end, end_byte); |
| } else { |
| jinode->i_dirty_start = start_byte; |
| jinode->i_dirty_end = end_byte; |
| } |
| |
| /* Is inode already attached where we need it? */ |
| if (jinode->i_transaction == transaction || |
| jinode->i_next_transaction == transaction) |
| goto done; |
| |
| /* |
| * We only ever set this variable to 1 so the test is safe. Since |
| * t_need_data_flush is likely to be set, we do the test to save some |
| * cacheline bouncing |
| */ |
| if (!transaction->t_need_data_flush) |
| transaction->t_need_data_flush = 1; |
| /* On some different transaction's list - should be |
| * the committing one */ |
| if (jinode->i_transaction) { |
| J_ASSERT(jinode->i_next_transaction == NULL); |
| J_ASSERT(jinode->i_transaction == |
| journal->j_committing_transaction); |
| jinode->i_next_transaction = transaction; |
| goto done; |
| } |
| /* Not on any transaction list... */ |
| J_ASSERT(!jinode->i_next_transaction); |
| jinode->i_transaction = transaction; |
| list_add(&jinode->i_list, &transaction->t_inode_list); |
| done: |
| spin_unlock(&journal->j_list_lock); |
| |
| return 0; |
| } |
| |
| int jbd2_journal_inode_ranged_write(handle_t *handle, |
| struct jbd2_inode *jinode, loff_t start_byte, loff_t length) |
| { |
| return jbd2_journal_file_inode(handle, jinode, |
| JI_WRITE_DATA | JI_WAIT_DATA, start_byte, |
| start_byte + length - 1); |
| } |
| |
| int jbd2_journal_inode_ranged_wait(handle_t *handle, struct jbd2_inode *jinode, |
| loff_t start_byte, loff_t length) |
| { |
| return jbd2_journal_file_inode(handle, jinode, JI_WAIT_DATA, |
| start_byte, start_byte + length - 1); |
| } |
| |
| /* |
| * File truncate and transaction commit interact with each other in a |
| * non-trivial way. If a transaction writing data block A is |
| * committing, we cannot discard the data by truncate until we have |
| * written them. Otherwise if we crashed after the transaction with |
| * write has committed but before the transaction with truncate has |
| * committed, we could see stale data in block A. This function is a |
| * helper to solve this problem. It starts writeout of the truncated |
| * part in case it is in the committing transaction. |
| * |
| * Filesystem code must call this function when inode is journaled in |
| * ordered mode before truncation happens and after the inode has been |
| * placed on orphan list with the new inode size. The second condition |
| * avoids the race that someone writes new data and we start |
| * committing the transaction after this function has been called but |
| * before a transaction for truncate is started (and furthermore it |
| * allows us to optimize the case where the addition to orphan list |
| * happens in the same transaction as write --- we don't have to write |
| * any data in such case). |
| */ |
| int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
| struct jbd2_inode *jinode, |
| loff_t new_size) |
| { |
| transaction_t *inode_trans, *commit_trans; |
| int ret = 0; |
| |
| /* This is a quick check to avoid locking if not necessary */ |
| if (!jinode->i_transaction) |
| goto out; |
| /* Locks are here just to force reading of recent values, it is |
| * enough that the transaction was not committing before we started |
| * a transaction adding the inode to orphan list */ |
| read_lock(&journal->j_state_lock); |
| commit_trans = journal->j_committing_transaction; |
| read_unlock(&journal->j_state_lock); |
| spin_lock(&journal->j_list_lock); |
| inode_trans = jinode->i_transaction; |
| spin_unlock(&journal->j_list_lock); |
| if (inode_trans == commit_trans) { |
| ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, |
| new_size, LLONG_MAX); |
| if (ret) |
| jbd2_journal_abort(journal, ret); |
| } |
| out: |
| return ret; |
| } |