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-rw-r--r--fs/xfs/xfs_buf_item.c1090
1 files changed, 1090 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
new file mode 100644
index 0000000000..023d4e0385
--- /dev/null
+++ b/fs/xfs/xfs_buf_item.c
@@ -0,0 +1,1090 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_mount.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_buf_item.h"
+#include "xfs_inode.h"
+#include "xfs_inode_item.h"
+#include "xfs_quota.h"
+#include "xfs_dquot_item.h"
+#include "xfs_dquot.h"
+#include "xfs_trace.h"
+#include "xfs_log.h"
+#include "xfs_log_priv.h"
+
+
+struct kmem_cache *xfs_buf_item_cache;
+
+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);
+}
+
+/* Is this log iovec plausibly large enough to contain the buffer log format? */
+bool
+xfs_buf_log_check_iovec(
+ struct xfs_log_iovec *iovec)
+{
+ struct xfs_buf_log_format *blfp = iovec->i_addr;
+ char *bmp_end;
+ char *item_end;
+
+ if (offsetof(struct xfs_buf_log_format, blf_data_map) > iovec->i_len)
+ return false;
+
+ item_end = (char *)iovec->i_addr + iovec->i_len;
+ bmp_end = (char *)&blfp->blf_data_map[blfp->blf_map_size];
+ return bmp_end <= item_end;
+}
+
+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]));
+}
+
+static inline bool
+xfs_buf_item_straddle(
+ struct xfs_buf *bp,
+ uint offset,
+ int first_bit,
+ int nbits)
+{
+ void *first, *last;
+
+ first = xfs_buf_offset(bp, offset + (first_bit << XFS_BLF_SHIFT));
+ last = xfs_buf_offset(bp,
+ offset + ((first_bit + nbits) << XFS_BLF_SHIFT));
+
+ if (last - first != nbits * XFS_BLF_CHUNK)
+ return true;
+ return false;
+}
+
+/*
+ * Return the number of log iovecs and space needed to log the given buf log
+ * item segment.
+ *
+ * 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.
+ */
+STATIC void
+xfs_buf_item_size_segment(
+ struct xfs_buf_log_item *bip,
+ struct xfs_buf_log_format *blfp,
+ uint offset,
+ int *nvecs,
+ int *nbytes)
+{
+ struct xfs_buf *bp = bip->bli_buf;
+ int first_bit;
+ int nbits;
+ int next_bit;
+ int last_bit;
+
+ first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
+ if (first_bit == -1)
+ return;
+
+ (*nvecs)++;
+ *nbytes += xfs_buf_log_format_size(blfp);
+
+ do {
+ nbits = xfs_contig_bits(blfp->blf_data_map,
+ blfp->blf_map_size, first_bit);
+ ASSERT(nbits > 0);
+
+ /*
+ * Straddling a page is rare because we don't log contiguous
+ * chunks of unmapped buffers anywhere.
+ */
+ if (nbits > 1 &&
+ xfs_buf_item_straddle(bp, offset, first_bit, nbits))
+ goto slow_scan;
+
+ (*nvecs)++;
+ *nbytes += nbits * XFS_BLF_CHUNK;
+
+ /*
+ * 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.
+ */
+ first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
+ (uint)first_bit + nbits + 1);
+ } while (first_bit != -1);
+
+ return;
+
+slow_scan:
+ /* Count the first bit we jumped out of the above loop from */
+ (*nvecs)++;
+ *nbytes += XFS_BLF_CHUNK;
+ last_bit = first_bit;
+ 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 ||
+ xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
+ last_bit = next_bit;
+ first_bit = next_bit;
+ (*nvecs)++;
+ nbits = 1;
+ } else {
+ last_bit++;
+ nbits++;
+ }
+ *nbytes += XFS_BLF_CHUNK;
+ }
+}
+
+/*
+ * Return the number of log iovecs and space needed to log the given buf log
+ * item.
+ *
+ * Discontiguous buffers need a format structure per region 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. If the item has previously been logged and has dirty
+ * regions, we do not relog them in stale buffers. This has the effect of
+ * reducing the size of the relogged item by the amount of dirty data tracked
+ * by the log item. This can result in the committing transaction reducing the
+ * amount of space being consumed by the CIL.
+ */
+STATIC void
+xfs_buf_item_size(
+ struct xfs_log_item *lip,
+ int *nvecs,
+ int *nbytes)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ int i;
+ int bytes;
+ uint offset = 0;
+
+ 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 as we are never
+ * going to replay the changes tracked in the log item.
+ */
+ 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.
+ */
+ bytes = 0;
+ for (i = 0; i < bip->bli_format_count; i++) {
+ xfs_buf_item_size_segment(bip, &bip->bli_formats[i], offset,
+ nvecs, &bytes);
+ offset += BBTOB(bp->b_maps[i].bm_len);
+ }
+
+ /*
+ * Round up the buffer size required to minimise the number of memory
+ * allocations that need to be done as this item grows when relogged by
+ * repeated modifications.
+ */
+ *nbytes = round_up(bytes, 512);
+ 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 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.
+ */
+ do {
+ ASSERT(first_bit >= 0);
+ nbits = xfs_contig_bits(blfp->blf_data_map,
+ blfp->blf_map_size, first_bit);
+ ASSERT(nbits > 0);
+
+ /*
+ * Straddling a page is rare because we don't log contiguous
+ * chunks of unmapped buffers anywhere.
+ */
+ if (nbits > 1 &&
+ xfs_buf_item_straddle(bp, offset, first_bit, nbits))
+ goto slow_scan;
+
+ xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
+ first_bit, nbits);
+ blfp->blf_size++;
+
+ /*
+ * 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.
+ */
+ first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
+ (uint)first_bit + nbits + 1);
+ } while (first_bit != -1);
+
+ return;
+
+slow_scan:
+ ASSERT(bp->b_addr == NULL);
+ 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, first_bit, nbits)) {
+ 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));
+ ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED) ||
+ (bip->bli_flags & XFS_BLI_STALE));
+
+
+ /*
+ * 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_has_v3inodes(lip->li_log->l_mp) ||
+ !((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;
+ }
+
+ for (i = 0; i < bip->bli_format_count; i++) {
+ xfs_buf_item_format_segment(bip, lv, &vecp, offset,
+ &bip->bli_formats[i]);
+ offset += BBTOB(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 take a reference to the buffer log item here so that the BLI life cycle
+ * extends at least until the buffer is unpinned via xfs_buf_item_unpin() and
+ * inserted into the AIL.
+ *
+ * We also need to take a reference to the buffer itself as the BLI unpin
+ * processing requires accessing the buffer after the BLI has dropped the final
+ * BLI reference. See xfs_buf_item_unpin() for an explanation.
+ * If unpins race to drop the final BLI reference and only the
+ * BLI owns a reference to the buffer, then the loser of the race can have the
+ * buffer fgreed from under it (e.g. on shutdown). Taking a buffer reference per
+ * pin count ensures the life cycle of the buffer extends for as
+ * long as we hold the buffer pin reference in xfs_buf_item_unpin().
+ */
+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);
+
+ xfs_buf_hold(bip->bli_buf);
+ 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(). We enter this function
+ * with a buffer pin count, a buffer reference and a BLI reference.
+ *
+ * We must drop the BLI reference before we unpin the buffer because the AIL
+ * doesn't acquire a BLI reference whenever it accesses it. Therefore if the
+ * refcount drops to zero, the bli could still be AIL resident and the buffer
+ * submitted for I/O at any point before we return. This can result in IO
+ * completion freeing the buffer while we are still trying to access it here.
+ * This race condition can also occur in shutdown situations where we abort and
+ * unpin buffers from contexts other that journal IO completion.
+ *
+ * Hence we have to hold a buffer reference per pin count to ensure that the
+ * buffer cannot be freed until we have finished processing the unpin operation.
+ * The reference is taken in xfs_buf_item_pin(), and we must hold it until we
+ * are done processing the buffer state. In the case of an abort (remove =
+ * true) then we re-use the current pin reference as the IO reference we hand
+ * off to IO failure handling.
+ */
+STATIC void
+xfs_buf_item_unpin(
+ struct xfs_log_item *lip,
+ int remove)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ int stale = bip->bli_flags & XFS_BLI_STALE;
+ int freed;
+
+ ASSERT(bp->b_log_item == 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);
+
+ /*
+ * Nothing to do but drop the buffer pin reference if the BLI is
+ * still active.
+ */
+ if (!freed) {
+ xfs_buf_rele(bp);
+ return;
+ }
+
+ if (stale) {
+ ASSERT(bip->bli_flags & XFS_BLI_STALE);
+ ASSERT(xfs_buf_islocked(bp));
+ ASSERT(bp->b_flags & XBF_STALE);
+ ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
+ ASSERT(list_empty(&lip->li_trans));
+ ASSERT(!bp->b_transp);
+
+ trace_xfs_buf_item_unpin_stale(bip);
+
+ /*
+ * The buffer has been locked and referenced since it was marked
+ * stale so we own both lock and reference exclusively here. We
+ * do not need the pin reference any more, so drop it now so
+ * that we only have one reference to drop once item completion
+ * processing is complete.
+ */
+ xfs_buf_rele(bp);
+
+ /*
+ * 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_item_done(bp);
+ xfs_buf_inode_iodone(bp);
+ ASSERT(list_empty(&bp->b_li_list));
+ } else {
+ xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
+ xfs_buf_item_relse(bp);
+ ASSERT(bp->b_log_item == NULL);
+ }
+ xfs_buf_relse(bp);
+ return;
+ }
+
+ if (remove) {
+ /*
+ * We need to simulate an async IO failures here to ensure that
+ * the correct error completion is run on this buffer. This
+ * requires a reference to the buffer and for the buffer to be
+ * locked. We can safely pass ownership of the pin reference to
+ * the IO to ensure that nothing can free the buffer while we
+ * wait for the lock and then run the IO failure completion.
+ */
+ xfs_buf_lock(bp);
+ bp->b_flags |= XBF_ASYNC;
+ xfs_buf_ioend_fail(bp);
+ return;
+ }
+
+ /*
+ * BLI has no more active references - it will be moved to the AIL to
+ * manage the remaining BLI/buffer life cycle. There is nothing left for
+ * us to do here so drop the pin reference to the buffer.
+ */
+ xfs_buf_rele(bp);
+}
+
+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) {
+ xfs_buf_alert_ratelimited(bp, "XFS: Failing async write",
+ "Failing async write on buffer block 0x%llx. Retrying async write.",
+ (long long)xfs_buf_daddr(bp));
+ }
+
+ if (!xfs_buf_delwri_queue(bp, buffer_list))
+ rval = XFS_ITEM_FLUSHING;
+ xfs_buf_unlock(bp);
+ return rval;
+}
+
+/*
+ * Drop the buffer log item refcount and take appropriate action. This helper
+ * determines whether the bli must be freed or not, since a decrement to zero
+ * does not necessarily mean the bli is unused.
+ *
+ * Return true if the bli is freed, false otherwise.
+ */
+bool
+xfs_buf_item_put(
+ struct xfs_buf_log_item *bip)
+{
+ struct xfs_log_item *lip = &bip->bli_item;
+ bool aborted;
+ bool dirty;
+
+ /* drop the bli ref and return if it wasn't the last one */
+ if (!atomic_dec_and_test(&bip->bli_refcount))
+ return false;
+
+ /*
+ * We dropped the last ref and must free the item if clean or aborted.
+ * If the bli is dirty and non-aborted, the buffer was clean in the
+ * transaction but still awaiting writeback from previous changes. In
+ * that case, the bli is freed on buffer writeback completion.
+ */
+ aborted = test_bit(XFS_LI_ABORTED, &lip->li_flags) ||
+ xlog_is_shutdown(lip->li_log);
+ dirty = bip->bli_flags & XFS_BLI_DIRTY;
+ if (dirty && !aborted)
+ return false;
+
+ /*
+ * The bli is aborted or clean. An aborted item may be in the AIL
+ * regardless of dirty state. For example, consider an aborted
+ * transaction that invalidated a dirty bli and cleared the dirty
+ * state.
+ */
+ if (aborted)
+ xfs_trans_ail_delete(lip, 0);
+ xfs_buf_item_relse(bip->bli_buf);
+ return true;
+}
+
+/*
+ * 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_release(
+ struct xfs_log_item *lip)
+{
+ struct xfs_buf_log_item *bip = BUF_ITEM(lip);
+ struct xfs_buf *bp = bip->bli_buf;
+ bool released;
+ bool hold = bip->bli_flags & XFS_BLI_HOLD;
+ bool stale = bip->bli_flags & XFS_BLI_STALE;
+#if defined(DEBUG) || defined(XFS_WARN)
+ bool ordered = bip->bli_flags & XFS_BLI_ORDERED;
+ bool dirty = bip->bli_flags & XFS_BLI_DIRTY;
+ bool aborted = test_bit(XFS_LI_ABORTED,
+ &lip->li_flags);
+#endif
+
+ trace_xfs_buf_item_release(bip);
+
+ /*
+ * The bli dirty state should match whether the blf has logged segments
+ * except for ordered buffers, where only the bli should be dirty.
+ */
+ ASSERT((!ordered && dirty == xfs_buf_item_dirty_format(bip)) ||
+ (ordered && dirty && !xfs_buf_item_dirty_format(bip)));
+ ASSERT(!stale || (bip->__bli_format.blf_flags & XFS_BLF_CANCEL));
+
+ /*
+ * Clear the buffer's association with this transaction and
+ * per-transaction state from the bli, which has been copied above.
+ */
+ bp->b_transp = NULL;
+ bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED);
+
+ /*
+ * Unref the item and unlock the buffer unless held or stale. Stale
+ * buffers remain locked until final unpin unless the bli is freed by
+ * the unref call. The latter implies shutdown because buffer
+ * invalidation dirties the bli and transaction.
+ */
+ released = xfs_buf_item_put(bip);
+ if (hold || (stale && !released))
+ return;
+ ASSERT(!stale || aborted);
+ xfs_buf_relse(bp);
+}
+
+STATIC void
+xfs_buf_item_committing(
+ struct xfs_log_item *lip,
+ xfs_csn_t seq)
+{
+ return xfs_buf_item_release(lip);
+}
+
+/*
+ * 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 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_release = xfs_buf_item_release,
+ .iop_committing = xfs_buf_item_committing,
+ .iop_committed = xfs_buf_item_committed,
+ .iop_push = xfs_buf_item_push,
+};
+
+STATIC void
+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;
+ }
+
+ bip->bli_formats = kmem_zalloc(count * sizeof(struct xfs_buf_log_format),
+ 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_log_item field to point to the new
+ * buf log item.
+ */
+int
+xfs_buf_item_init(
+ struct xfs_buf *bp,
+ struct xfs_mount *mp)
+{
+ struct xfs_buf_log_item *bip = bp->b_log_item;
+ int chunks;
+ int map_size;
+ int i;
+
+ /*
+ * Check to see if there is already a buf log item for
+ * this buffer. If we do already have one, there is
+ * nothing to do here so return.
+ */
+ ASSERT(bp->b_mount == mp);
+ if (bip) {
+ ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
+ ASSERT(!bp->b_transp);
+ ASSERT(bip->bli_buf == bp);
+ return 0;
+ }
+
+ bip = kmem_cache_zalloc(xfs_buf_item_cache, GFP_KERNEL | __GFP_NOFAIL);
+ xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
+ bip->bli_buf = 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.
+ */
+ xfs_buf_item_get_format(bip, bp->b_map_count);
+
+ 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);
+
+ if (map_size > XFS_BLF_DATAMAP_SIZE) {
+ kmem_cache_free(xfs_buf_item_cache, bip);
+ xfs_err(mp,
+ "buffer item dirty bitmap (%u uints) too small to reflect %u bytes!",
+ map_size,
+ BBTOB(bp->b_maps[i].bm_len));
+ return -EFSCORRUPTED;
+ }
+
+ 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;
+ }
+
+ bp->b_log_item = bip;
+ xfs_buf_hold(bp);
+ return 0;
+}
+
+
+/*
+ * 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;
+
+ ASSERT(first < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
+ ASSERT(last < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
+
+ /*
+ * 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 = ((1U << (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 = (1U << end_bit) - 1;
+ *wordp |= mask;
+ }
+}
+
+/*
+ * Mark bytes first through last inclusive as dirty in the buf
+ * item's bitmap.
+ */
+void
+xfs_buf_item_log(
+ struct xfs_buf_log_item *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) - 1;
+
+ /* skip to the map that includes the first byte to log */
+ if (first > end) {
+ start += BBTOB(bp->b_maps[i].bm_len);
+ continue;
+ }
+
+ /*
+ * Trim the range to this segment and mark it in the bitmap.
+ * Note that we must convert buffer offsets to segment relative
+ * offsets (e.g., the first byte of each segment is byte 0 of
+ * that segment).
+ */
+ if (first < start)
+ first = start;
+ if (end > last)
+ end = last;
+ xfs_buf_item_log_segment(first - start, end - start,
+ &bip->bli_formats[i].blf_data_map[0]);
+
+ start += BBTOB(bp->b_maps[i].bm_len);
+ }
+}
+
+
+/*
+ * Return true if the buffer has any ranges logged/dirtied by a transaction,
+ * false otherwise.
+ */
+bool
+xfs_buf_item_dirty_format(
+ struct xfs_buf_log_item *bip)
+{
+ 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))
+ return true;
+ }
+
+ return false;
+}
+
+STATIC void
+xfs_buf_item_free(
+ struct xfs_buf_log_item *bip)
+{
+ xfs_buf_item_free_format(bip);
+ kmem_free(bip->bli_item.li_lv_shadow);
+ kmem_cache_free(xfs_buf_item_cache, bip);
+}
+
+/*
+ * xfs_buf_item_relse() is called when the buf log item is no longer needed.
+ */
+void
+xfs_buf_item_relse(
+ struct xfs_buf *bp)
+{
+ struct xfs_buf_log_item *bip = bp->b_log_item;
+
+ trace_xfs_buf_item_relse(bp, _RET_IP_);
+ ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
+
+ if (atomic_read(&bip->bli_refcount))
+ return;
+ bp->b_log_item = NULL;
+ xfs_buf_rele(bp);
+ xfs_buf_item_free(bip);
+}
+
+void
+xfs_buf_item_done(
+ struct xfs_buf *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.
+ *
+ * Note that log recovery writes might have buffer items that are not on
+ * the AIL even when the file system is not shut down.
+ */
+ xfs_trans_ail_delete(&bp->b_log_item->bli_item,
+ (bp->b_flags & _XBF_LOGRECOVERY) ? 0 :
+ SHUTDOWN_CORRUPT_INCORE);
+ xfs_buf_item_relse(bp);
+}