diff options
Diffstat (limited to 'fs/xfs/xfs_buf_item.c')
| -rw-r--r-- | fs/xfs/xfs_buf_item.c | 1090 |
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); +} |