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When allocation a ticket for a transaction, the ticket is initialised with the worst case log space usage based on the number of bytes the transaction may consume. Part of this calculation is the number of log headers required for the iclog space used up by the transaction. This calculation makes an undocumented assumption that if the transaction uses the log header space reservation on an iclog, then it consumes either the entire iclog or it completes. That is - the transaction that is first in an iclog is the transaction that the log header reservation is accounted to. If the transaction is larger than the iclog, then it will use the entire iclog itself. Document this assumption. Further, the current calculation uses the rule that we can fit iclog_size bytes of transaction data into an iclog. This is in correct - the amount of space available in an iclog for transaction data is the size of the iclog minus the space used for log record headers. This means that the calculation is out by 512 bytes per 32k of log space the transaction can consume. This is rarely an issue because maximally sized transactions are extremely uncommon, and for 4k block size filesystems maximal transaction reservations are about 400kb. Hence the error in this case is less than the size of an iclog, so that makes it even harder to hit. However, anyone using larger directory blocks (16k directory blocks push the maximum transaction size to approx. 900k on a 4k block size filesystem) or larger block size (e.g. 64k blocks push transactions to the 3-4MB size) could see the error grow to more than an iclog and at this point the transaction is guaranteed to get a reservation underrun and shutdown the filesystem. Fix this by adjusting the calculation to calculate the correct number of iclogs required and account for them all up front. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> |
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| .. | ||
| linux-2.6 | ||
| quota | ||
| support | ||
| Kconfig | ||
| Makefile | ||
| xfs.h | ||
| xfs_acl.h | ||
| xfs_ag.h | ||
| xfs_alloc.c | ||
| xfs_alloc.h | ||
| xfs_alloc_btree.c | ||
| xfs_alloc_btree.h | ||
| xfs_arch.h | ||
| xfs_attr.c | ||
| xfs_attr.h | ||
| xfs_attr_leaf.c | ||
| xfs_attr_leaf.h | ||
| xfs_attr_sf.h | ||
| xfs_bit.c | ||
| xfs_bit.h | ||
| xfs_bmap.c | ||
| xfs_bmap.h | ||
| xfs_bmap_btree.c | ||
| xfs_bmap_btree.h | ||
| xfs_btree.c | ||
| xfs_btree.h | ||
| xfs_btree_trace.c | ||
| xfs_btree_trace.h | ||
| xfs_buf_item.c | ||
| xfs_buf_item.h | ||
| xfs_da_btree.c | ||
| xfs_da_btree.h | ||
| xfs_dfrag.c | ||
| xfs_dfrag.h | ||
| xfs_dinode.h | ||
| xfs_dir2.c | ||
| xfs_dir2.h | ||
| xfs_dir2_block.c | ||
| xfs_dir2_block.h | ||
| xfs_dir2_data.c | ||
| xfs_dir2_data.h | ||
| xfs_dir2_leaf.c | ||
| xfs_dir2_leaf.h | ||
| xfs_dir2_node.c | ||
| xfs_dir2_node.h | ||
| xfs_dir2_sf.c | ||
| xfs_dir2_sf.h | ||
| xfs_dmapi.h | ||
| xfs_dmops.c | ||
| xfs_error.c | ||
| xfs_error.h | ||
| xfs_extfree_item.c | ||
| xfs_extfree_item.h | ||
| xfs_filestream.c | ||
| xfs_filestream.h | ||
| xfs_fs.h | ||
| xfs_fsops.c | ||
| xfs_fsops.h | ||
| xfs_ialloc.c | ||
| xfs_ialloc.h | ||
| xfs_ialloc_btree.c | ||
| xfs_ialloc_btree.h | ||
| xfs_iget.c | ||
| xfs_inode.c | ||
| xfs_inode.h | ||
| xfs_inode_item.c | ||
| xfs_inode_item.h | ||
| xfs_inum.h | ||
| xfs_iomap.c | ||
| xfs_iomap.h | ||
| xfs_itable.c | ||
| xfs_itable.h | ||
| xfs_log.c | ||
| xfs_log.h | ||
| xfs_log_priv.h | ||
| xfs_log_recover.c | ||
| xfs_log_recover.h | ||
| xfs_mount.c | ||
| xfs_mount.h | ||
| xfs_mru_cache.c | ||
| xfs_mru_cache.h | ||
| xfs_quota.h | ||
| xfs_refcache.h | ||
| xfs_rename.c | ||
| xfs_rtalloc.c | ||
| xfs_rtalloc.h | ||
| xfs_rw.c | ||
| xfs_rw.h | ||
| xfs_sb.h | ||
| xfs_trans.c | ||
| xfs_trans.h | ||
| xfs_trans_ail.c | ||
| xfs_trans_buf.c | ||
| xfs_trans_extfree.c | ||
| xfs_trans_inode.c | ||
| xfs_trans_item.c | ||
| xfs_trans_priv.h | ||
| xfs_trans_space.h | ||
| xfs_types.h | ||
| xfs_utils.c | ||
| xfs_utils.h | ||
| xfs_vnodeops.c | ||
| xfs_vnodeops.h | ||