// SPDX-License-Identifier: GPL-2.0
/*
 * Interface between ext4 and JBD
 */

#include "ext4_jbd2.h"

#include <trace/events/ext4.h>

int ext4_inode_journal_mode(struct inode *inode)
{
        if (EXT4_JOURNAL(inode) == NULL)
                return EXT4_INODE_WRITEBACK_DATA_MODE;  /* writeback */
        /* We do not support data journalling with delayed allocation */
        if (!S_ISREG(inode->i_mode) ||
            ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) ||
            test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
            (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
            !test_opt(inode->i_sb, DELALLOC))) {
                /* We do not support data journalling for encrypted data */
                if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode))
                        return EXT4_INODE_ORDERED_DATA_MODE;  /* ordered */
                return EXT4_INODE_JOURNAL_DATA_MODE;    /* journal data */
        }
        if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
                return EXT4_INODE_ORDERED_DATA_MODE;    /* ordered */
        if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
                return EXT4_INODE_WRITEBACK_DATA_MODE;  /* writeback */
        BUG();
}

/* Just increment the non-pointer handle value */
static handle_t *ext4_get_nojournal(void)
{
        handle_t *handle = current->journal_info;
        unsigned long ref_cnt = (unsigned long)handle;

        BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);

        ref_cnt++;
        handle = (handle_t *)ref_cnt;

        current->journal_info = handle;
        return handle;
}


/* Decrement the non-pointer handle value */
static void ext4_put_nojournal(handle_t *handle)
{
        unsigned long ref_cnt = (unsigned long)handle;

        BUG_ON(ref_cnt == 0);

        ref_cnt--;
        handle = (handle_t *)ref_cnt;

        current->journal_info = handle;
}

/*
 * Wrappers for jbd2_journal_start/end.
 */
static int ext4_journal_check_start(struct super_block *sb)
{
        int ret;
        journal_t *journal;

        might_sleep();

        ret = ext4_emergency_state(sb);
        if (unlikely(ret))
                return ret;

        if (WARN_ON_ONCE(sb_rdonly(sb)))
                return -EROFS;

        WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
        journal = EXT4_SB(sb)->s_journal;
        /*
         * Special case here: if the journal has aborted behind our
         * backs (eg. EIO in the commit thread), then we still need to
         * take the FS itself readonly cleanly.
         */
        if (journal && is_journal_aborted(journal)) {
                ext4_abort(sb, -journal->j_errno, "Detected aborted journal");
                return -EROFS;
        }
        return 0;
}

handle_t *__ext4_journal_start_sb(struct inode *inode,
                                  struct super_block *sb, unsigned int line,
                                  int type, int blocks, int rsv_blocks,
                                  int revoke_creds)
{
        journal_t *journal;
        int err;
        if (inode)
                trace_ext4_journal_start_inode(inode, blocks, rsv_blocks,
                                        revoke_creds, type,
                                        _RET_IP_);
        else
                trace_ext4_journal_start_sb(sb, blocks, rsv_blocks,
                                        revoke_creds, type,
                                        _RET_IP_);
        err = ext4_journal_check_start(sb);
        if (err < 0)
                return ERR_PTR(err);

        journal = EXT4_SB(sb)->s_journal;
        if (!journal || (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
                return ext4_get_nojournal();
        return jbd2__journal_start(journal, blocks, rsv_blocks, revoke_creds,
                                   GFP_NOFS, type, line);
}

int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
{
        struct super_block *sb;
        int err;
        int rc;

        if (!ext4_handle_valid(handle)) {
                ext4_put_nojournal(handle);
                return 0;
        }

        err = handle->h_err;
        if (!handle->h_transaction) {
                rc = jbd2_journal_stop(handle);
                return err ? err : rc;
        }

        sb = handle->h_transaction->t_journal->j_private;
        rc = jbd2_journal_stop(handle);

        if (!err)
                err = rc;
        if (err)
                __ext4_std_error(sb, where, line, err);
        return err;
}

handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
                                        int type)
{
        struct super_block *sb;
        int err;

        if (!ext4_handle_valid(handle))
                return ext4_get_nojournal();

        sb = handle->h_journal->j_private;
        trace_ext4_journal_start_reserved(sb,
                                jbd2_handle_buffer_credits(handle), _RET_IP_);
        err = ext4_journal_check_start(sb);
        if (err < 0) {
                jbd2_journal_free_reserved(handle);
                return ERR_PTR(err);
        }

        err = jbd2_journal_start_reserved(handle, type, line);
        if (err < 0)
                return ERR_PTR(err);
        return handle;
}

int __ext4_journal_ensure_credits(handle_t *handle, int check_cred,
                                  int extend_cred, int revoke_cred)
{
        if (!ext4_handle_valid(handle))
                return 0;
        if (is_handle_aborted(handle))
                return -EROFS;
        if (jbd2_handle_buffer_credits(handle) >= check_cred &&
            handle->h_revoke_credits >= revoke_cred)
                return 0;
        extend_cred = max(0, extend_cred - jbd2_handle_buffer_credits(handle));
        revoke_cred = max(0, revoke_cred - handle->h_revoke_credits);
        return ext4_journal_extend(handle, extend_cred, revoke_cred);
}

static void ext4_journal_abort_handle(const char *caller, unsigned int line,
                                      const char *err_fn,
                                      struct buffer_head *bh,
                                      handle_t *handle, int err)
{
        char nbuf[16];
        const char *errstr = ext4_decode_error(NULL, err, nbuf);

        BUG_ON(!ext4_handle_valid(handle));

        if (bh)
                BUFFER_TRACE(bh, "abort");

        if (!handle->h_err)
                handle->h_err = err;

        if (is_handle_aborted(handle))
                return;

        printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
               caller, line, errstr, err_fn);

        jbd2_journal_abort_handle(handle);
}

static void ext4_check_bdev_write_error(struct super_block *sb)
{
        struct address_space *mapping = sb->s_bdev->bd_mapping;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        int err;

        /*
         * If the block device has write error flag, it may have failed to
         * async write out metadata buffers in the background. In this case,
         * we could read old data from disk and write it out again, which
         * may lead to on-disk filesystem inconsistency.
         */
        if (errseq_check(&mapping->wb_err, READ_ONCE(sbi->s_bdev_wb_err))) {
                spin_lock(&sbi->s_bdev_wb_lock);
                err = errseq_check_and_advance(&mapping->wb_err, &sbi->s_bdev_wb_err);
                spin_unlock(&sbi->s_bdev_wb_lock);
                if (err)
                        ext4_error_err(sb, -err,
                                       "Error while async write back metadata");
        }
}

int __ext4_journal_get_write_access(const char *where, unsigned int line,
                                    handle_t *handle, struct super_block *sb,
                                    struct buffer_head *bh,
                                    enum ext4_journal_trigger_type trigger_type)
{
        int err;

        might_sleep();

        if (ext4_handle_valid(handle)) {
                err = jbd2_journal_get_write_access(handle, bh);
                if (err) {
                        ext4_journal_abort_handle(where, line, __func__, bh,
                                                  handle, err);
                        return err;
                }
        } else
                ext4_check_bdev_write_error(sb);
        if (trigger_type == EXT4_JTR_NONE ||
            !ext4_has_feature_metadata_csum(sb))
                return 0;
        BUG_ON(trigger_type >= EXT4_JOURNAL_TRIGGER_COUNT);
        jbd2_journal_set_triggers(bh,
                &EXT4_SB(sb)->s_journal_triggers[trigger_type].tr_triggers);
        return 0;
}

/*
 * The ext4 forget function must perform a revoke if we are freeing data
 * which has been journaled.  Metadata (eg. indirect blocks) must be
 * revoked in all cases.
 *
 * "bh" may be NULL: a metadata block may have been freed from memory
 * but there may still be a record of it in the journal, and that record
 * still needs to be revoked.
 */
int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
                  int is_metadata, struct inode *inode,
                  struct buffer_head *bh, ext4_fsblk_t blocknr)
{
        int err;

        might_sleep();

        trace_ext4_forget(inode, is_metadata, blocknr);
        BUFFER_TRACE(bh, "enter");

        ext4_debug("forgetting bh %p: is_metadata=%d, mode %o, data mode %x\n",
                  bh, is_metadata, inode->i_mode,
                  test_opt(inode->i_sb, DATA_FLAGS));

        /*
         * In the no journal case, we should wait for the ongoing buffer
         * to complete and do a forget.
         */
        if (!ext4_handle_valid(handle)) {
                if (bh) {
                        clear_buffer_dirty(bh);
                        wait_on_buffer(bh);
                        __bforget(bh);
                }
                return 0;
        }

        /* Never use the revoke function if we are doing full data
         * journaling: there is no need to, and a V1 superblock won't
         * support it.  Otherwise, only skip the revoke on un-journaled
         * data blocks. */

        if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
            (!is_metadata && !ext4_should_journal_data(inode))) {
                if (bh) {
                        BUFFER_TRACE(bh, "call jbd2_journal_forget");
                        err = jbd2_journal_forget(handle, bh);
                        if (err)
                                ext4_journal_abort_handle(where, line, __func__,
                                                          bh, handle, err);
                        return err;
                }
                return 0;
        }

        /*
         * data!=journal && (is_metadata || should_journal_data(inode))
         */
        BUFFER_TRACE(bh, "call jbd2_journal_revoke");
        err = jbd2_journal_revoke(handle, blocknr, bh);
        if (err) {
                ext4_journal_abort_handle(where, line, __func__,
                                          bh, handle, err);
                __ext4_error(inode->i_sb, where, line, true, -err, 0,
                             "error %d when attempting revoke", err);
        }
        BUFFER_TRACE(bh, "exit");
        return err;
}

int __ext4_journal_get_create_access(const char *where, unsigned int line,
                                handle_t *handle, struct super_block *sb,
                                struct buffer_head *bh,
                                enum ext4_journal_trigger_type trigger_type)
{
        int err;

        if (!ext4_handle_valid(handle))
                return 0;

        err = jbd2_journal_get_create_access(handle, bh);
        if (err) {
                ext4_journal_abort_handle(where, line, __func__, bh, handle,
                                          err);
                return err;
        }
        if (trigger_type == EXT4_JTR_NONE ||
            !ext4_has_feature_metadata_csum(sb))
                return 0;
        BUG_ON(trigger_type >= EXT4_JOURNAL_TRIGGER_COUNT);
        jbd2_journal_set_triggers(bh,
                &EXT4_SB(sb)->s_journal_triggers[trigger_type].tr_triggers);
        return 0;
}

int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
                                 handle_t *handle, struct inode *inode,
                                 struct buffer_head *bh)
{
        int err = 0;

        might_sleep();

        set_buffer_meta(bh);
        set_buffer_prio(bh);
        set_buffer_uptodate(bh);
        if (ext4_handle_valid(handle)) {
                err = jbd2_journal_dirty_metadata(handle, bh);
                /* Errors can only happen due to aborted journal or a nasty bug */
                if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) {
                        ext4_journal_abort_handle(where, line, __func__, bh,
                                                  handle, err);
                        if (inode == NULL) {
                                pr_err("EXT4: jbd2_journal_dirty_metadata "
                                       "failed: handle type %u started at "
                                       "line %u, credits %u/%u, errcode %d",
                                       handle->h_type,
                                       handle->h_line_no,
                                       handle->h_requested_credits,
                                       jbd2_handle_buffer_credits(handle), err);
                                return err;
                        }
                        ext4_error_inode(inode, where, line,
                                         bh->b_blocknr,
                                         "journal_dirty_metadata failed: "
                                         "handle type %u started at line %u, "
                                         "credits %u/%u, errcode %d",
                                         handle->h_type,
                                         handle->h_line_no,
                                         handle->h_requested_credits,
                                         jbd2_handle_buffer_credits(handle),
                                         err);
                }
        } else {
                if (inode)
                        mark_buffer_dirty_inode(bh, inode);
                else
                        mark_buffer_dirty(bh);
                if (inode && inode_needs_sync(inode)) {
                        sync_dirty_buffer(bh);
                        if (buffer_req(bh) && !buffer_uptodate(bh)) {
                                ext4_error_inode_err(inode, where, line,
                                                     bh->b_blocknr, EIO,
                                        "IO error syncing itable block");
                                err = -EIO;
                        }
                }
        }
        return err;
}