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-rw-r--r--fs/xfs/xfs_buf_item.c1155
1 files changed, 1155 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
new file mode 100644
index 000000000..092d652bc
--- /dev/null
+++ b/fs/xfs/xfs_buf_item.c
@@ -0,0 +1,1155 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_trans_priv.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_log.h"
+
+
+kmem_zone_t *xfs_buf_item_zone;
+
+static inline struct xfs_buf_log_item *BUF_ITEM(struct xfs_log_item *lip)
+{
+ return container_of(lip, struct xfs_buf_log_item, bli_item);
+}
+
+STATIC void xfs_buf_do_callbacks(struct xfs_buf *bp);
+
+static inline int
+xfs_buf_log_format_size(
+ struct xfs_buf_log_format *blfp)
+{
+ return offsetof(struct xfs_buf_log_format, blf_data_map) +
+ (blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));
+}
+
+/*
+ * This returns the number of log iovecs needed to log the
+ * given buf log item.
+ *
+ * It calculates this as 1 iovec for the buf log format structure
+ * and 1 for each stretch of non-contiguous chunks to be logged.
+ * Contiguous chunks are logged in a single iovec.
+ *
+ * If the XFS_BLI_STALE flag has been set, then log nothing.
+ */
+STATIC void
+xfs_buf_item_size_segment(
+ struct xfs_buf_log_item *bip,
+ struct xfs_buf_log_format *blfp,
+ int *nvecs,
+ int *nbytes)
+{
+ struct xfs_buf *bp = bip->bli_buf;
+ int next_bit;
+ int last_bit;
+
+ last_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
+ if (last_bit == -1)
+ return;
+
+ /*
+ * initial count for a dirty buffer is 2 vectors - the format structure
+ * and the first dirty region.
+ */
+ *nvecs += 2;
+ *nbytes += xfs_buf_log_format_size(blfp) + XFS_BLF_CHUNK;
+
+ while (last_bit != -1) {
+ /*
+ * This takes the bit number to start looking from and
+ * returns the next set bit from there. It returns -1
+ * if there are no more bits set or the start bit is
+ * beyond the end of the bitmap.
+ */
+ next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
+ last_bit + 1);
+ /*
+ * If we run out of bits, leave the loop,
+ * else if we find a new set of bits bump the number of vecs,
+ * else keep scanning the current set of bits.
+ */
+ if (next_bit == -1) {
+ break;
+ } else if (next_bit != last_bit + 1) {
+ last_bit = next_bit;
+ (*nvecs)++;
+ } else if (xfs_buf_offset(bp, next_bit * XFS_BLF_CHUNK) !=
+ (xfs_buf_offset(bp, last_bit * XFS_BLF_CHUNK) +
+ XFS_BLF_CHUNK)) {
+ last_bit = next_bit;
+ (*nvecs)++;
+ } else {
+ last_bit++;
+ }
+ *nbytes += XFS_BLF_CHUNK;
+ }
+}
+
+/*
+ * This returns the number of log iovecs needed to log the given buf log item.
+ *
+ * It calculates this as 1 iovec for the buf log format structure and 1 for each
+ * stretch of non-contiguous chunks to be logged. Contiguous chunks are logged
+ * in a single iovec.
+ *
+ * Discontiguous buffers need a format structure per region that that is being
+ * logged. This makes the changes in the buffer appear to log recovery as though
+ * they came from separate buffers, just like would occur if multiple buffers
+ * were used instead of a single discontiguous buffer. This enables
+ * discontiguous buffers to be in-memory constructs, completely transparent to
+ * what ends up on disk.
+ *
+ * If the XFS_BLI_STALE flag has been set, then log nothing but the buf log
+ * format structures.
+ */
+STATIC void
+xfs_buf_item_size(
+ struct xfs_log_item *lip,
+ int *nvecs,
+ int *nbytes)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ int i;
+
+ ASSERT(atomic_read(&bip->bli_refcount) > 0);
+ if (bip->bli_flags & XFS_BLI_STALE) {
+ /*
+ * The buffer is stale, so all we need to log
+ * is the buf log format structure with the
+ * cancel flag in it.
+ */
+ trace_xfs_buf_item_size_stale(bip);
+ ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
+ *nvecs += bip->bli_format_count;
+ for (i = 0; i < bip->bli_format_count; i++) {
+ *nbytes += xfs_buf_log_format_size(&bip->bli_formats[i]);
+ }
+ return;
+ }
+
+ ASSERT(bip->bli_flags & XFS_BLI_LOGGED);
+
+ if (bip->bli_flags & XFS_BLI_ORDERED) {
+ /*
+ * The buffer has been logged just to order it.
+ * It is not being included in the transaction
+ * commit, so no vectors are used at all.
+ */
+ trace_xfs_buf_item_size_ordered(bip);
+ *nvecs = XFS_LOG_VEC_ORDERED;
+ return;
+ }
+
+ /*
+ * the vector count is based on the number of buffer vectors we have
+ * dirty bits in. This will only be greater than one when we have a
+ * compound buffer with more than one segment dirty. Hence for compound
+ * buffers we need to track which segment the dirty bits correspond to,
+ * and when we move from one segment to the next increment the vector
+ * count for the extra buf log format structure that will need to be
+ * written.
+ */
+ for (i = 0; i < bip->bli_format_count; i++) {
+ xfs_buf_item_size_segment(bip, &bip->bli_formats[i],
+ nvecs, nbytes);
+ }
+ trace_xfs_buf_item_size(bip);
+}
+
+static inline void
+xfs_buf_item_copy_iovec(
+ struct xfs_log_vec *lv,
+ struct xfs_log_iovec **vecp,
+ struct xfs_buf *bp,
+ uint offset,
+ int first_bit,
+ uint nbits)
+{
+ offset += first_bit * XFS_BLF_CHUNK;
+ xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BCHUNK,
+ xfs_buf_offset(bp, offset),
+ nbits * XFS_BLF_CHUNK);
+}
+
+static inline bool
+xfs_buf_item_straddle(
+ struct xfs_buf *bp,
+ uint offset,
+ int next_bit,
+ int last_bit)
+{
+ return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) !=
+ (xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) +
+ XFS_BLF_CHUNK);
+}
+
+static void
+xfs_buf_item_format_segment(
+ struct xfs_buf_log_item *bip,
+ struct xfs_log_vec *lv,
+ struct xfs_log_iovec **vecp,
+ uint offset,
+ struct xfs_buf_log_format *blfp)
+{
+ struct xfs_buf *bp = bip->bli_buf;
+ uint base_size;
+ int first_bit;
+ int last_bit;
+ int next_bit;
+ uint nbits;
+
+ /* copy the flags across from the base format item */
+ blfp->blf_flags = bip->__bli_format.blf_flags;
+
+ /*
+ * Base size is the actual size of the ondisk structure - it reflects
+ * the actual size of the dirty bitmap rather than the size of the in
+ * memory structure.
+ */
+ base_size = xfs_buf_log_format_size(blfp);
+
+ first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
+ if (!(bip->bli_flags & XFS_BLI_STALE) && first_bit == -1) {
+ /*
+ * If the map is not be dirty in the transaction, mark
+ * the size as zero and do not advance the vector pointer.
+ */
+ return;
+ }
+
+ blfp = xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BFORMAT, blfp, base_size);
+ blfp->blf_size = 1;
+
+ if (bip->bli_flags & XFS_BLI_STALE) {
+ /*
+ * The buffer is stale, so all we need to log
+ * is the buf log format structure with the
+ * cancel flag in it.
+ */
+ trace_xfs_buf_item_format_stale(bip);
+ ASSERT(blfp->blf_flags & XFS_BLF_CANCEL);
+ return;
+ }
+
+
+ /*
+ * Fill in an iovec for each set of contiguous chunks.
+ */
+ last_bit = first_bit;
+ nbits = 1;
+ for (;;) {
+ /*
+ * This takes the bit number to start looking from and
+ * returns the next set bit from there. It returns -1
+ * if there are no more bits set or the start bit is
+ * beyond the end of the bitmap.
+ */
+ next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
+ (uint)last_bit + 1);
+ /*
+ * If we run out of bits fill in the last iovec and get out of
+ * the loop. Else if we start a new set of bits then fill in
+ * the iovec for the series we were looking at and start
+ * counting the bits in the new one. Else we're still in the
+ * same set of bits so just keep counting and scanning.
+ */
+ if (next_bit == -1) {
+ xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
+ first_bit, nbits);
+ blfp->blf_size++;
+ break;
+ } else if (next_bit != last_bit + 1 ||
+ xfs_buf_item_straddle(bp, offset, next_bit, last_bit)) {
+ xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
+ first_bit, nbits);
+ blfp->blf_size++;
+ first_bit = next_bit;
+ last_bit = next_bit;
+ nbits = 1;
+ } else {
+ last_bit++;
+ nbits++;
+ }
+ }
+}
+
+/*
+ * This is called to fill in the vector of log iovecs for the
+ * given log buf item. It fills the first entry with a buf log
+ * format structure, and the rest point to contiguous chunks
+ * within the buffer.
+ */
+STATIC void
+xfs_buf_item_format(
+ struct xfs_log_item *lip,
+ struct xfs_log_vec *lv)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ struct xfs_log_iovec *vecp = NULL;
+ uint offset = 0;
+ int i;
+
+ ASSERT(atomic_read(&bip->bli_refcount) > 0);
+ ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
+ (bip->bli_flags & XFS_BLI_STALE));
+ ASSERT((bip->bli_flags & XFS_BLI_STALE) ||
+ (xfs_blft_from_flags(&bip->__bli_format) > XFS_BLFT_UNKNOWN_BUF
+ && xfs_blft_from_flags(&bip->__bli_format) < XFS_BLFT_MAX_BUF));
+
+
+ /*
+ * If it is an inode buffer, transfer the in-memory state to the
+ * format flags and clear the in-memory state.
+ *
+ * For buffer based inode allocation, we do not transfer
+ * this state if the inode buffer allocation has not yet been committed
+ * to the log as setting the XFS_BLI_INODE_BUF flag will prevent
+ * correct replay of the inode allocation.
+ *
+ * For icreate item based inode allocation, the buffers aren't written
+ * to the journal during allocation, and hence we should always tag the
+ * buffer as an inode buffer so that the correct unlinked list replay
+ * occurs during recovery.
+ */
+ if (bip->bli_flags & XFS_BLI_INODE_BUF) {
+ if (xfs_sb_version_hascrc(&lip->li_mountp->m_sb) ||
+ !((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) &&
+ xfs_log_item_in_current_chkpt(lip)))
+ bip->__bli_format.blf_flags |= XFS_BLF_INODE_BUF;
+ bip->bli_flags &= ~XFS_BLI_INODE_BUF;
+ }
+
+ if ((bip->bli_flags & (XFS_BLI_ORDERED|XFS_BLI_STALE)) ==
+ XFS_BLI_ORDERED) {
+ /*
+ * The buffer has been logged just to order it. It is not being
+ * included in the transaction commit, so don't format it.
+ */
+ trace_xfs_buf_item_format_ordered(bip);
+ return;
+ }
+
+ for (i = 0; i < bip->bli_format_count; i++) {
+ xfs_buf_item_format_segment(bip, lv, &vecp, offset,
+ &bip->bli_formats[i]);
+ offset += bp->b_maps[i].bm_len;
+ }
+
+ /*
+ * Check to make sure everything is consistent.
+ */
+ trace_xfs_buf_item_format(bip);
+}
+
+/*
+ * This is called to pin the buffer associated with the buf log item in memory
+ * so it cannot be written out.
+ *
+ * We also always take a reference to the buffer log item here so that the bli
+ * is held while the item is pinned in memory. This means that we can
+ * unconditionally drop the reference count a transaction holds when the
+ * transaction is completed.
+ */
+STATIC void
+xfs_buf_item_pin(
+ struct xfs_log_item *lip)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+
+ ASSERT(atomic_read(&bip->bli_refcount) > 0);
+ ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
+ (bip->bli_flags & XFS_BLI_ORDERED) ||
+ (bip->bli_flags & XFS_BLI_STALE));
+
+ trace_xfs_buf_item_pin(bip);
+
+ atomic_inc(&bip->bli_refcount);
+ atomic_inc(&bip->bli_buf->b_pin_count);
+}
+
+/*
+ * This is called to unpin the buffer associated with the buf log
+ * item which was previously pinned with a call to xfs_buf_item_pin().
+ *
+ * Also drop the reference to the buf item for the current transaction.
+ * If the XFS_BLI_STALE flag is set and we are the last reference,
+ * then free up the buf log item and unlock the buffer.
+ *
+ * If the remove flag is set we are called from uncommit in the
+ * forced-shutdown path. If that is true and the reference count on
+ * the log item is going to drop to zero we need to free the item's
+ * descriptor in the transaction.
+ */
+STATIC void
+xfs_buf_item_unpin(
+ struct xfs_log_item *lip,
+ int remove)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ xfs_buf_t *bp = bip->bli_buf;
+ struct xfs_ail *ailp = lip->li_ailp;
+ int stale = bip->bli_flags & XFS_BLI_STALE;
+ int freed;
+
+ ASSERT(bp->b_fspriv == bip);
+ ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+ trace_xfs_buf_item_unpin(bip);
+
+ freed = atomic_dec_and_test(&bip->bli_refcount);
+
+ if (atomic_dec_and_test(&bp->b_pin_count))
+ wake_up_all(&bp->b_waiters);
+
+ if (freed && stale) {
+ ASSERT(bip->bli_flags & XFS_BLI_STALE);
+ ASSERT(xfs_buf_islocked(bp));
+ ASSERT(XFS_BUF_ISSTALE(bp));
+ ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
+
+ trace_xfs_buf_item_unpin_stale(bip);
+
+ if (remove) {
+ /*
+ * If we are in a transaction context, we have to
+ * remove the log item from the transaction as we are
+ * about to release our reference to the buffer. If we
+ * don't, the unlock that occurs later in
+ * xfs_trans_uncommit() will try to reference the
+ * buffer which we no longer have a hold on.
+ */
+ if (lip->li_desc)
+ xfs_trans_del_item(lip);
+
+ /*
+ * Since the transaction no longer refers to the buffer,
+ * the buffer should no longer refer to the transaction.
+ */
+ bp->b_transp = NULL;
+ }
+
+ /*
+ * If we get called here because of an IO error, we may
+ * or may not have the item on the AIL. xfs_trans_ail_delete()
+ * will take care of that situation.
+ * xfs_trans_ail_delete() drops the AIL lock.
+ */
+ if (bip->bli_flags & XFS_BLI_STALE_INODE) {
+ xfs_buf_do_callbacks(bp);
+ bp->b_fspriv = NULL;
+ bp->b_iodone = NULL;
+ } else {
+ spin_lock(&ailp->xa_lock);
+ xfs_trans_ail_delete(ailp, lip, SHUTDOWN_LOG_IO_ERROR);
+ xfs_buf_item_relse(bp);
+ ASSERT(bp->b_fspriv == NULL);
+ }
+ xfs_buf_relse(bp);
+ } else if (freed && remove) {
+ /*
+ * There are currently two references to the buffer - the active
+ * LRU reference and the buf log item. What we are about to do
+ * here - simulate a failed IO completion - requires 3
+ * references.
+ *
+ * The LRU reference is removed by the xfs_buf_stale() call. The
+ * buf item reference is removed by the xfs_buf_iodone()
+ * callback that is run by xfs_buf_do_callbacks() during ioend
+ * processing (via the bp->b_iodone callback), and then finally
+ * the ioend processing will drop the IO reference if the buffer
+ * is marked XBF_ASYNC.
+ *
+ * Hence we need to take an additional reference here so that IO
+ * completion processing doesn't free the buffer prematurely.
+ */
+ xfs_buf_lock(bp);
+ xfs_buf_hold(bp);
+ bp->b_flags |= XBF_ASYNC;
+ xfs_buf_ioerror(bp, -EIO);
+ XFS_BUF_UNDONE(bp);
+ xfs_buf_stale(bp);
+ xfs_buf_ioend(bp);
+ }
+}
+
+/*
+ * Buffer IO error rate limiting. Limit it to no more than 10 messages per 30
+ * seconds so as to not spam logs too much on repeated detection of the same
+ * buffer being bad..
+ */
+
+static DEFINE_RATELIMIT_STATE(xfs_buf_write_fail_rl_state, 30 * HZ, 10);
+
+STATIC uint
+xfs_buf_item_push(
+ struct xfs_log_item *lip,
+ struct list_head *buffer_list)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ uint rval = XFS_ITEM_SUCCESS;
+
+ if (xfs_buf_ispinned(bp))
+ return XFS_ITEM_PINNED;
+ if (!xfs_buf_trylock(bp)) {
+ /*
+ * If we have just raced with a buffer being pinned and it has
+ * been marked stale, we could end up stalling until someone else
+ * issues a log force to unpin the stale buffer. Check for the
+ * race condition here so xfsaild recognizes the buffer is pinned
+ * and queues a log force to move it along.
+ */
+ if (xfs_buf_ispinned(bp))
+ return XFS_ITEM_PINNED;
+ return XFS_ITEM_LOCKED;
+ }
+
+ ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+
+ trace_xfs_buf_item_push(bip);
+
+ /* has a previous flush failed due to IO errors? */
+ if ((bp->b_flags & XBF_WRITE_FAIL) &&
+ ___ratelimit(&xfs_buf_write_fail_rl_state, "XFS: Failing async write")) {
+ xfs_warn(bp->b_target->bt_mount,
+"Failing async write on buffer block 0x%llx. Retrying async write.",
+ (long long)bp->b_bn);
+ }
+
+ if (!xfs_buf_delwri_queue(bp, buffer_list))
+ rval = XFS_ITEM_FLUSHING;
+ xfs_buf_unlock(bp);
+ return rval;
+}
+
+/*
+ * Release the buffer associated with the buf log item. If there is no dirty
+ * logged data associated with the buffer recorded in the buf log item, then
+ * free the buf log item and remove the reference to it in the buffer.
+ *
+ * This call ignores the recursion count. It is only called when the buffer
+ * should REALLY be unlocked, regardless of the recursion count.
+ *
+ * We unconditionally drop the transaction's reference to the log item. If the
+ * item was logged, then another reference was taken when it was pinned, so we
+ * can safely drop the transaction reference now. This also allows us to avoid
+ * potential races with the unpin code freeing the bli by not referencing the
+ * bli after we've dropped the reference count.
+ *
+ * If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item
+ * if necessary but do not unlock the buffer. This is for support of
+ * xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't
+ * free the item.
+ */
+STATIC void
+xfs_buf_item_unlock(
+ struct xfs_log_item *lip)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ bool clean;
+ bool aborted;
+ int flags;
+
+ /* Clear the buffer's association with this transaction. */
+ bp->b_transp = NULL;
+
+ /*
+ * If this is a transaction abort, don't return early. Instead, allow
+ * the brelse to happen. Normally it would be done for stale
+ * (cancelled) buffers at unpin time, but we'll never go through the
+ * pin/unpin cycle if we abort inside commit.
+ */
+ aborted = (lip->li_flags & XFS_LI_ABORTED) ? true : false;
+ /*
+ * Before possibly freeing the buf item, copy the per-transaction state
+ * so we can reference it safely later after clearing it from the
+ * buffer log item.
+ */
+ flags = bip->bli_flags;
+ bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED);
+
+ /*
+ * If the buf item is marked stale, then don't do anything. We'll
+ * unlock the buffer and free the buf item when the buffer is unpinned
+ * for the last time.
+ */
+ if (flags & XFS_BLI_STALE) {
+ trace_xfs_buf_item_unlock_stale(bip);
+ ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
+ if (!aborted) {
+ atomic_dec(&bip->bli_refcount);
+ return;
+ }
+ }
+
+ trace_xfs_buf_item_unlock(bip);
+
+ /*
+ * If the buf item isn't tracking any data, free it, otherwise drop the
+ * reference we hold to it. If we are aborting the transaction, this may
+ * be the only reference to the buf item, so we free it anyway
+ * regardless of whether it is dirty or not. A dirty abort implies a
+ * shutdown, anyway.
+ *
+ * Ordered buffers are dirty but may have no recorded changes, so ensure
+ * we only release clean items here.
+ */
+ clean = (flags & XFS_BLI_DIRTY) ? false : true;
+ if (clean) {
+ int i;
+ for (i = 0; i < bip->bli_format_count; i++) {
+ if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map,
+ bip->bli_formats[i].blf_map_size)) {
+ clean = false;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Clean buffers, by definition, cannot be in the AIL. However, aborted
+ * buffers may be dirty and hence in the AIL. Therefore if we are
+ * aborting a buffer and we've just taken the last refernce away, we
+ * have to check if it is in the AIL before freeing it. We need to free
+ * it in this case, because an aborted transaction has already shut the
+ * filesystem down and this is the last chance we will have to do so.
+ */
+ if (atomic_dec_and_test(&bip->bli_refcount)) {
+ if (clean)
+ xfs_buf_item_relse(bp);
+ else if (aborted) {
+ ASSERT(XFS_FORCED_SHUTDOWN(lip->li_mountp));
+ if (lip->li_flags & XFS_LI_IN_AIL) {
+ spin_lock(&lip->li_ailp->xa_lock);
+ xfs_trans_ail_delete(lip->li_ailp, lip,
+ SHUTDOWN_LOG_IO_ERROR);
+ }
+ xfs_buf_item_relse(bp);
+ }
+ }
+
+ if (!(flags & XFS_BLI_HOLD))
+ xfs_buf_relse(bp);
+}
+
+/*
+ * This is called to find out where the oldest active copy of the
+ * buf log item in the on disk log resides now that the last log
+ * write of it completed at the given lsn.
+ * We always re-log all the dirty data in a buffer, so usually the
+ * latest copy in the on disk log is the only one that matters. For
+ * those cases we simply return the given lsn.
+ *
+ * The one exception to this is for buffers full of newly allocated
+ * inodes. These buffers are only relogged with the XFS_BLI_INODE_BUF
+ * flag set, indicating that only the di_next_unlinked fields from the
+ * inodes in the buffers will be replayed during recovery. If the
+ * original newly allocated inode images have not yet been flushed
+ * when the buffer is so relogged, then we need to make sure that we
+ * keep the old images in the 'active' portion of the log. We do this
+ * by returning the original lsn of that transaction here rather than
+ * the current one.
+ */
+STATIC xfs_lsn_t
+xfs_buf_item_committed(
+ struct xfs_log_item *lip,
+ xfs_lsn_t lsn)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+
+ trace_xfs_buf_item_committed(bip);
+
+ if ((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) && lip->li_lsn != 0)
+ return lip->li_lsn;
+ return lsn;
+}
+
+STATIC void
+xfs_buf_item_committing(
+ struct xfs_log_item *lip,
+ xfs_lsn_t commit_lsn)
+{
+}
+
+/*
+ * This is the ops vector shared by all buf log items.
+ */
+static const struct xfs_item_ops xfs_buf_item_ops = {
+ .iop_size = xfs_buf_item_size,
+ .iop_format = xfs_buf_item_format,
+ .iop_pin = xfs_buf_item_pin,
+ .iop_unpin = xfs_buf_item_unpin,
+ .iop_unlock = xfs_buf_item_unlock,
+ .iop_committed = xfs_buf_item_committed,
+ .iop_push = xfs_buf_item_push,
+ .iop_committing = xfs_buf_item_committing
+};
+
+STATIC int
+xfs_buf_item_get_format(
+ struct xfs_buf_log_item *bip,
+ int count)
+{
+ ASSERT(bip->bli_formats == NULL);
+ bip->bli_format_count = count;
+
+ if (count == 1) {
+ bip->bli_formats = &bip->__bli_format;
+ return 0;
+ }
+
+ bip->bli_formats = kmem_zalloc(count * sizeof(struct xfs_buf_log_format),
+ KM_SLEEP);
+ if (!bip->bli_formats)
+ return -ENOMEM;
+ return 0;
+}
+
+STATIC void
+xfs_buf_item_free_format(
+ struct xfs_buf_log_item *bip)
+{
+ if (bip->bli_formats != &bip->__bli_format) {
+ kmem_free(bip->bli_formats);
+ bip->bli_formats = NULL;
+ }
+}
+
+/*
+ * Allocate a new buf log item to go with the given buffer.
+ * Set the buffer's b_fsprivate field to point to the new
+ * buf log item. If there are other item's attached to the
+ * buffer (see xfs_buf_attach_iodone() below), then put the
+ * buf log item at the front.
+ */
+void
+xfs_buf_item_init(
+ xfs_buf_t *bp,
+ xfs_mount_t *mp)
+{
+ xfs_log_item_t *lip = bp->b_fspriv;
+ xfs_buf_log_item_t *bip;
+ int chunks;
+ int map_size;
+ int error;
+ int i;
+
+ /*
+ * Check to see if there is already a buf log item for
+ * this buffer. If there is, it is guaranteed to be
+ * the first. If we do already have one, there is
+ * nothing to do here so return.
+ */
+ ASSERT(bp->b_target->bt_mount == mp);
+ if (lip != NULL && lip->li_type == XFS_LI_BUF)
+ return;
+
+ bip = kmem_zone_zalloc(xfs_buf_item_zone, KM_SLEEP);
+ xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
+ bip->bli_buf = bp;
+ xfs_buf_hold(bp);
+
+ /*
+ * chunks is the number of XFS_BLF_CHUNK size pieces the buffer
+ * can be divided into. Make sure not to truncate any pieces.
+ * map_size is the size of the bitmap needed to describe the
+ * chunks of the buffer.
+ *
+ * Discontiguous buffer support follows the layout of the underlying
+ * buffer. This makes the implementation as simple as possible.
+ */
+ error = xfs_buf_item_get_format(bip, bp->b_map_count);
+ ASSERT(error == 0);
+
+ for (i = 0; i < bip->bli_format_count; i++) {
+ chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
+ XFS_BLF_CHUNK);
+ map_size = DIV_ROUND_UP(chunks, NBWORD);
+
+ bip->bli_formats[i].blf_type = XFS_LI_BUF;
+ bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
+ bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
+ bip->bli_formats[i].blf_map_size = map_size;
+ }
+
+ /*
+ * Put the buf item into the list of items attached to the
+ * buffer at the front.
+ */
+ if (bp->b_fspriv)
+ bip->bli_item.li_bio_list = bp->b_fspriv;
+ bp->b_fspriv = bip;
+}
+
+
+/*
+ * Mark bytes first through last inclusive as dirty in the buf
+ * item's bitmap.
+ */
+static void
+xfs_buf_item_log_segment(
+ uint first,
+ uint last,
+ uint *map)
+{
+ uint first_bit;
+ uint last_bit;
+ uint bits_to_set;
+ uint bits_set;
+ uint word_num;
+ uint *wordp;
+ uint bit;
+ uint end_bit;
+ uint mask;
+
+ /*
+ * Convert byte offsets to bit numbers.
+ */
+ first_bit = first >> XFS_BLF_SHIFT;
+ last_bit = last >> XFS_BLF_SHIFT;
+
+ /*
+ * Calculate the total number of bits to be set.
+ */
+ bits_to_set = last_bit - first_bit + 1;
+
+ /*
+ * Get a pointer to the first word in the bitmap
+ * to set a bit in.
+ */
+ word_num = first_bit >> BIT_TO_WORD_SHIFT;
+ wordp = &map[word_num];
+
+ /*
+ * Calculate the starting bit in the first word.
+ */
+ bit = first_bit & (uint)(NBWORD - 1);
+
+ /*
+ * First set any bits in the first word of our range.
+ * If it starts at bit 0 of the word, it will be
+ * set below rather than here. That is what the variable
+ * bit tells us. The variable bits_set tracks the number
+ * of bits that have been set so far. End_bit is the number
+ * of the last bit to be set in this word plus one.
+ */
+ if (bit) {
+ end_bit = MIN(bit + bits_to_set, (uint)NBWORD);
+ mask = ((1 << (end_bit - bit)) - 1) << bit;
+ *wordp |= mask;
+ wordp++;
+ bits_set = end_bit - bit;
+ } else {
+ bits_set = 0;
+ }
+
+ /*
+ * Now set bits a whole word at a time that are between
+ * first_bit and last_bit.
+ */
+ while ((bits_to_set - bits_set) >= NBWORD) {
+ *wordp |= 0xffffffff;
+ bits_set += NBWORD;
+ wordp++;
+ }
+
+ /*
+ * Finally, set any bits left to be set in one last partial word.
+ */
+ end_bit = bits_to_set - bits_set;
+ if (end_bit) {
+ mask = (1 << end_bit) - 1;
+ *wordp |= mask;
+ }
+}
+
+/*
+ * Mark bytes first through last inclusive as dirty in the buf
+ * item's bitmap.
+ */
+void
+xfs_buf_item_log(
+ xfs_buf_log_item_t *bip,
+ uint first,
+ uint last)
+{
+ int i;
+ uint start;
+ uint end;
+ struct xfs_buf *bp = bip->bli_buf;
+
+ /*
+ * walk each buffer segment and mark them dirty appropriately.
+ */
+ start = 0;
+ for (i = 0; i < bip->bli_format_count; i++) {
+ if (start > last)
+ break;
+ end = start + BBTOB(bp->b_maps[i].bm_len);
+ if (first > end) {
+ start += BBTOB(bp->b_maps[i].bm_len);
+ continue;
+ }
+ if (first < start)
+ first = start;
+ if (end > last)
+ end = last;
+
+ xfs_buf_item_log_segment(first, end,
+ &bip->bli_formats[i].blf_data_map[0]);
+
+ start += bp->b_maps[i].bm_len;
+ }
+}
+
+
+/*
+ * Return 1 if the buffer has been logged or ordered in a transaction (at any
+ * point, not just the current transaction) and 0 if not.
+ */
+uint
+xfs_buf_item_dirty(
+ xfs_buf_log_item_t *bip)
+{
+ return (bip->bli_flags & XFS_BLI_DIRTY);
+}
+
+STATIC void
+xfs_buf_item_free(
+ xfs_buf_log_item_t *bip)
+{
+ xfs_buf_item_free_format(bip);
+ kmem_zone_free(xfs_buf_item_zone, bip);
+}
+
+/*
+ * This is called when the buf log item is no longer needed. It should
+ * free the buf log item associated with the given buffer and clear
+ * the buffer's pointer to the buf log item. If there are no more
+ * items in the list, clear the b_iodone field of the buffer (see
+ * xfs_buf_attach_iodone() below).
+ */
+void
+xfs_buf_item_relse(
+ xfs_buf_t *bp)
+{
+ xfs_buf_log_item_t *bip = bp->b_fspriv;
+
+ trace_xfs_buf_item_relse(bp, _RET_IP_);
+ ASSERT(!(bip->bli_item.li_flags & XFS_LI_IN_AIL));
+
+ bp->b_fspriv = bip->bli_item.li_bio_list;
+ if (bp->b_fspriv == NULL)
+ bp->b_iodone = NULL;
+
+ xfs_buf_rele(bp);
+ xfs_buf_item_free(bip);
+}
+
+
+/*
+ * Add the given log item with its callback to the list of callbacks
+ * to be called when the buffer's I/O completes. If it is not set
+ * already, set the buffer's b_iodone() routine to be
+ * xfs_buf_iodone_callbacks() and link the log item into the list of
+ * items rooted at b_fsprivate. Items are always added as the second
+ * entry in the list if there is a first, because the buf item code
+ * assumes that the buf log item is first.
+ */
+void
+xfs_buf_attach_iodone(
+ xfs_buf_t *bp,
+ void (*cb)(xfs_buf_t *, xfs_log_item_t *),
+ xfs_log_item_t *lip)
+{
+ xfs_log_item_t *head_lip;
+
+ ASSERT(xfs_buf_islocked(bp));
+
+ lip->li_cb = cb;
+ head_lip = bp->b_fspriv;
+ if (head_lip) {
+ lip->li_bio_list = head_lip->li_bio_list;
+ head_lip->li_bio_list = lip;
+ } else {
+ bp->b_fspriv = lip;
+ }
+
+ ASSERT(bp->b_iodone == NULL ||
+ bp->b_iodone == xfs_buf_iodone_callbacks);
+ bp->b_iodone = xfs_buf_iodone_callbacks;
+}
+
+/*
+ * We can have many callbacks on a buffer. Running the callbacks individually
+ * can cause a lot of contention on the AIL lock, so we allow for a single
+ * callback to be able to scan the remaining lip->li_bio_list for other items
+ * of the same type and callback to be processed in the first call.
+ *
+ * As a result, the loop walking the callback list below will also modify the
+ * list. it removes the first item from the list and then runs the callback.
+ * The loop then restarts from the new head of the list. This allows the
+ * callback to scan and modify the list attached to the buffer and we don't
+ * have to care about maintaining a next item pointer.
+ */
+STATIC void
+xfs_buf_do_callbacks(
+ struct xfs_buf *bp)
+{
+ struct xfs_log_item *lip;
+
+ while ((lip = bp->b_fspriv) != NULL) {
+ bp->b_fspriv = lip->li_bio_list;
+ ASSERT(lip->li_cb != NULL);
+ /*
+ * Clear the next pointer so we don't have any
+ * confusion if the item is added to another buf.
+ * Don't touch the log item after calling its
+ * callback, because it could have freed itself.
+ */
+ lip->li_bio_list = NULL;
+ lip->li_cb(bp, lip);
+ }
+}
+
+/*
+ * This is the iodone() function for buffers which have had callbacks
+ * attached to them by xfs_buf_attach_iodone(). It should remove each
+ * log item from the buffer's list and call the callback of each in turn.
+ * When done, the buffer's fsprivate field is set to NULL and the buffer
+ * is unlocked with a call to iodone().
+ */
+void
+xfs_buf_iodone_callbacks(
+ struct xfs_buf *bp)
+{
+ struct xfs_log_item *lip = bp->b_fspriv;
+ struct xfs_mount *mp = lip->li_mountp;
+ static ulong lasttime;
+ static xfs_buftarg_t *lasttarg;
+
+ if (likely(!bp->b_error))
+ goto do_callbacks;
+
+ /*
+ * If we've already decided to shutdown the filesystem because of
+ * I/O errors, there's no point in giving this a retry.
+ */
+ if (XFS_FORCED_SHUTDOWN(mp)) {
+ xfs_buf_stale(bp);
+ XFS_BUF_DONE(bp);
+ trace_xfs_buf_item_iodone(bp, _RET_IP_);
+ goto do_callbacks;
+ }
+
+ if (bp->b_target != lasttarg ||
+ time_after(jiffies, (lasttime + 5*HZ))) {
+ lasttime = jiffies;
+ xfs_buf_ioerror_alert(bp, __func__);
+ }
+ lasttarg = bp->b_target;
+
+ /*
+ * If the write was asynchronous then no one will be looking for the
+ * error. Clear the error state and write the buffer out again.
+ *
+ * XXX: This helps against transient write errors, but we need to find
+ * a way to shut the filesystem down if the writes keep failing.
+ *
+ * In practice we'll shut the filesystem down soon as non-transient
+ * errors tend to affect the whole device and a failing log write
+ * will make us give up. But we really ought to do better here.
+ */
+ if (XFS_BUF_ISASYNC(bp)) {
+ ASSERT(bp->b_iodone != NULL);
+
+ trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
+
+ xfs_buf_ioerror(bp, 0); /* errno of 0 unsets the flag */
+
+ if (!(bp->b_flags & (XBF_STALE|XBF_WRITE_FAIL))) {
+ bp->b_flags |= XBF_WRITE | XBF_ASYNC |
+ XBF_DONE | XBF_WRITE_FAIL;
+ xfs_buf_submit(bp);
+ } else {
+ xfs_buf_relse(bp);
+ }
+
+ return;
+ }
+
+ /*
+ * If the write of the buffer was synchronous, we want to make
+ * sure to return the error to the caller of xfs_bwrite().
+ */
+ xfs_buf_stale(bp);
+ XFS_BUF_DONE(bp);
+
+ trace_xfs_buf_error_relse(bp, _RET_IP_);
+
+do_callbacks:
+ xfs_buf_do_callbacks(bp);
+ bp->b_fspriv = NULL;
+ bp->b_iodone = NULL;
+ xfs_buf_ioend(bp);
+}
+
+/*
+ * This is the iodone() function for buffers which have been
+ * logged. It is called when they are eventually flushed out.
+ * It should remove the buf item from the AIL, and free the buf item.
+ * It is called by xfs_buf_iodone_callbacks() above which will take
+ * care of cleaning up the buffer itself.
+ */
+void
+xfs_buf_iodone(
+ struct xfs_buf *bp,
+ struct xfs_log_item *lip)
+{
+ struct xfs_ail *ailp = lip->li_ailp;
+
+ ASSERT(BUF_ITEM(lip)->bli_buf == bp);
+
+ xfs_buf_rele(bp);
+
+ /*
+ * If we are forcibly shutting down, this may well be
+ * off the AIL already. That's because we simulate the
+ * log-committed callbacks to unpin these buffers. Or we may never
+ * have put this item on AIL because of the transaction was
+ * aborted forcibly. xfs_trans_ail_delete() takes care of these.
+ *
+ * Either way, AIL is useless if we're forcing a shutdown.
+ */
+ spin_lock(&ailp->xa_lock);
+ xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
+ xfs_buf_item_free(BUF_ITEM(lip));
+}