Date: Tue, 14 Sep 2010 18:04:05 +0000 (UTC) From: Kirk McKusick <mckusick@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r212617 - head/sys/ufs/ffs Message-ID: <201009141804.o8EI45kp088466@svn.freebsd.org>
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Author: mckusick Date: Tue Sep 14 18:04:05 2010 New Revision: 212617 URL: http://svn.freebsd.org/changeset/base/212617 Log: Update comments in soft updates code to more fully describe the addition of journalling. Only functional change is to tighten a KASSERT. Reviewed by: jeff Roberson Modified: head/sys/ufs/ffs/ffs_softdep.c head/sys/ufs/ffs/fs.h head/sys/ufs/ffs/softdep.h Modified: head/sys/ufs/ffs/ffs_softdep.c ============================================================================== --- head/sys/ufs/ffs/ffs_softdep.c Tue Sep 14 17:22:06 2010 (r212616) +++ head/sys/ufs/ffs/ffs_softdep.c Tue Sep 14 18:04:05 2010 (r212617) @@ -2378,7 +2378,8 @@ remove_from_journal(wk) /* * We emulate a TAILQ to save space in most structures which do not * require TAILQ semantics. Here we must update the tail position - * when removing the tail which is not the final entry. + * when removing the tail which is not the final entry. This works + * only if the worklist linkage are at the beginning of the structure. */ if (ump->softdep_journal_tail == wk) ump->softdep_journal_tail = @@ -2605,7 +2606,7 @@ jremref_write(jremref, jseg, data) inoref_write(&jremref->jr_ref, jseg, rec); } -static void +static void jmvref_write(jmvref, jseg, data) struct jmvref *jmvref; struct jseg *jseg; @@ -2906,9 +2907,9 @@ complete_jseg(jseg) waiting = wk->wk_state & IOWAITING; wk->wk_state &= ~(IOSTARTED | IOWAITING); wk->wk_state |= COMPLETE; - KASSERT(i < jseg->js_cnt, + KASSERT(i++ < jseg->js_cnt, ("handle_written_jseg: overflow %d >= %d", - i, jseg->js_cnt)); + i - 1, jseg->js_cnt)); switch (wk->wk_type) { case D_JADDREF: handle_written_jaddref(WK_JADDREF(wk)); @@ -7492,7 +7493,7 @@ handle_written_sbdep(sbdep, bp) if (inodedep_lookup(mp, fs->fs_sujfree, 0, &inodedep) == 0) panic("handle_written_sbdep: lost inodedep"); /* - * Now that we have a record of this indode in stable store allow it + * Now that we have a record of this inode in stable store allow it * to be written to free up pending work. Inodes may see a lot of * write activity after they are unlinked which we must not hold up. */ @@ -7509,8 +7510,7 @@ handle_written_sbdep(sbdep, bp) } /* - * Mark an inodedep has unlinked and insert it into the in-memory unlinked - * list. + * Mark an inodedep as unlinked and insert it into the in-memory unlinked list. */ static void unlinked_inodedep(mp, inodedep) @@ -7576,7 +7576,7 @@ clear_unlinked_inodedep(inodedep) * link before us, whether it be the superblock or an inode. * Unfortunately the list may change while we're waiting * on the buf lock for either resource so we must loop until - * we lock. the right one. If both the superblock and an + * we lock the right one. If both the superblock and an * inode point to this inode we must clear the inode first * followed by the superblock. */ @@ -9094,7 +9094,7 @@ handle_jwork(wkhd) /* * Handle the bufwait list on an inode when it is safe to release items * held there. This normally happens after an inode block is written but - * may be delayed and handle later if there are pending journal items that + * may be delayed and handled later if there are pending journal items that * are not yet safe to be released. */ static struct freefile * Modified: head/sys/ufs/ffs/fs.h ============================================================================== --- head/sys/ufs/ffs/fs.h Tue Sep 14 17:22:06 2010 (r212616) +++ head/sys/ufs/ffs/fs.h Tue Sep 14 18:04:05 2010 (r212617) @@ -661,7 +661,7 @@ lbn_level(ufs_lbn_t lbn) /* * Size of the segment record header. There is at most one for each disk - * block n the journal. The segment header is followed by an array of + * block in the journal. The segment header is followed by an array of * records. fsck depends on the first element in each record being 'op' * and the second being 'ino'. Segments may span multiple disk blocks but * the header is present on each. Modified: head/sys/ufs/ffs/softdep.h ============================================================================== --- head/sys/ufs/ffs/softdep.h Tue Sep 14 17:22:06 2010 (r212616) +++ head/sys/ufs/ffs/softdep.h Tue Sep 14 18:04:05 2010 (r212617) @@ -107,6 +107,15 @@ * * The ONWORKLIST flag shows whether the structure is currently linked * onto a worklist. + * + * The UNLINK* flags track the progress of updating the on-disk linked + * list of active but unlinked inodes. When an inode is first unlinked + * it is marked as UNLINKED. When its on-disk di_freelink has been + * written its UNLINKNEXT flags is set. When its predecessor in the + * list has its di_freelink pointing at us its UNLINKPREV is set. + * When the on-disk list can reach it from the superblock, its + * UNLINKONLIST flag is set. Once all of these flags are set, it + * is safe to let its last name be removed. */ #define ATTACHED 0x000001 #define UNDONE 0x000002 @@ -353,20 +362,22 @@ struct bmsafemap { * or fragment is allocated from a cylinder group. Its state is set to * DEPCOMPLETE when its cylinder group map is written. It is converted to * an allocdirect or allocindir allocation once the allocator calls the - * appropriate setup function. + * appropriate setup function. It will initially be linked onto a bmsafemap + * list. Once converted it can be linked onto the lists described for + * allocdirect or allocindir as described below. */ struct newblk { - struct worklist nb_list; + struct worklist nb_list; /* See comment above. */ # define nb_state nb_list.wk_state - LIST_ENTRY(newblk) nb_hash; /* hashed lookup */ - LIST_ENTRY(newblk) nb_deps; /* bmsafemap's list of newblks */ + LIST_ENTRY(newblk) nb_hash; /* Hashed lookup. */ + LIST_ENTRY(newblk) nb_deps; /* Bmsafemap's list of newblks. */ struct jnewblk *nb_jnewblk; /* New block journal entry. */ - struct bmsafemap *nb_bmsafemap;/* cylgrp dep (if pending) */ - struct freefrag *nb_freefrag; /* fragment to be freed (if any) */ + struct bmsafemap *nb_bmsafemap;/* Cylgrp dep (if pending). */ + struct freefrag *nb_freefrag; /* Fragment to be freed (if any). */ struct indirdephd nb_indirdeps; /* Children indirect blocks. */ - struct workhead nb_newdirblk; /* dir block to notify when written */ + struct workhead nb_newdirblk; /* Dir block to notify when written. */ struct workhead nb_jwork; /* Journal work pending. */ - ufs2_daddr_t nb_newblkno; /* new value of block pointer */ + ufs2_daddr_t nb_newblkno; /* New value of block pointer. */ }; /* @@ -517,16 +528,16 @@ struct freeblks { /* * A "freework" structure handles the release of a tree of blocks or a single * block. Each indirect block in a tree is allocated its own freework - * structure so that the indrect block may be freed only when all of its + * structure so that the indirect block may be freed only when all of its * children are freed. In this way we enforce the rule that an allocated * block must have a valid path to a root that is journaled. Each child * block acquires a reference and when the ref hits zero the parent ref * is decremented. If there is no parent the freeblks ref is decremented. */ struct freework { - struct worklist fw_list; + struct worklist fw_list; /* Delayed worklist. */ # define fw_state fw_list.wk_state - LIST_ENTRY(freework) fw_next; /* Queue for freeblksk. */ + LIST_ENTRY(freework) fw_next; /* Queue for freeblk list. */ struct freeblks *fw_freeblks; /* Root of operation. */ struct freework *fw_parent; /* Parent indirect. */ ufs2_daddr_t fw_blkno; /* Our block #. */ @@ -545,7 +556,7 @@ struct freework { * to be freed as well. */ struct freedep { - struct worklist fd_list; + struct worklist fd_list; /* Delayed worklist. */ struct freework *fd_freework; /* Parent freework. */ }; @@ -705,10 +716,10 @@ struct newdirblk { * so they may easily be queued in-order on the inodedep. */ struct inoref { - struct worklist if_list; + struct worklist if_list; /* Journal pending or jseg entries. */ # define if_state if_list.wk_state TAILQ_ENTRY(inoref) if_deps; /* Links for inodedep. */ - struct jsegdep *if_jsegdep; + struct jsegdep *if_jsegdep; /* Will track our journal record. */ off_t if_diroff; /* Directory offset. */ ino_t if_ino; /* Inode number. */ ino_t if_parent; /* Parent inode number. */ @@ -731,8 +742,8 @@ struct inoref { * ultimately released when the file is freed or the link is dropped again. */ struct jaddref { - struct inoref ja_ref; -# define ja_list ja_ref.if_list /* Journal pending or jseg entries. */ + struct inoref ja_ref; /* see inoref above. */ +# define ja_list ja_ref.if_list /* Jrnl pending, id_inowait, dm_jwork.*/ # define ja_state ja_ref.if_list.wk_state LIST_ENTRY(jaddref) ja_bmdeps; /* Links for bmsafemap. */ union { @@ -754,21 +765,28 @@ struct jaddref { * may proceed as normal. */ struct jremref { - struct inoref jr_ref; -# define jr_list jr_ref.if_list /* Journal pending or jseg entries. */ + struct inoref jr_ref; /* see inoref above. */ +# define jr_list jr_ref.if_list /* Linked to softdep_journal_pending. */ # define jr_state jr_ref.if_list.wk_state - LIST_ENTRY(jremref) jr_deps; /* Links for pagdep. */ + LIST_ENTRY(jremref) jr_deps; /* Links for dirrem. */ struct dirrem *jr_dirrem; /* Back pointer to dirrem. */ }; +/* + * A "jmvref" structure tracks a name relocations within the same + * directory block that occur as a result of directory compaction. + * It prevents the updated directory entry from being written to disk + * until the journal entry is written. Once the journal has been + * written the compacted directory may be written to disk. + */ struct jmvref { - struct worklist jm_list; - LIST_ENTRY(jmvref) jm_deps; - struct pagedep *jm_pagedep; - ino_t jm_parent; - ino_t jm_ino; - off_t jm_oldoff; - off_t jm_newoff; + struct worklist jm_list; /* Linked to softdep_journal_pending. */ + LIST_ENTRY(jmvref) jm_deps; /* Jmvref on pagedep. */ + struct pagedep *jm_pagedep; /* Back pointer to pagedep. */ + ino_t jm_parent; /* Containing directory inode number. */ + ino_t jm_ino; /* Inode number of our entry. */ + off_t jm_oldoff; /* Our old offset in directory. */ + off_t jm_newoff; /* Our new offset in directory. */ }; /* @@ -780,36 +798,37 @@ struct jmvref { * write the jnewblk structure is maintained to prevent the bitmaps from * reaching the disk. Ultimately the jnewblk structure will be passed * to the free routine as the in memory cg is modified back to the free - * state at which time it can be released. + * state at which time it can be released. It may be held on any of the + * fx_jwork, fw_jwork, fb_jwork, ff_jwork, nb_jwork, or ir_jwork lists. */ struct jnewblk { - struct worklist jn_list; + struct worklist jn_list; /* See lists above. */ # define jn_state jn_list.wk_state - struct jsegdep *jn_jsegdep; - LIST_ENTRY(jnewblk) jn_deps; /* All jnewblks on bmsafemap */ - struct newblk *jn_newblk; - ino_t jn_ino; - ufs_lbn_t jn_lbn; - ufs2_daddr_t jn_blkno; - int jn_oldfrags; - int jn_frags; + struct jsegdep *jn_jsegdep; /* Will track our journal record. */ + LIST_ENTRY(jnewblk) jn_deps; /* Jnewblks on sm_jnewblkhd. */ + struct newblk *jn_newblk; /* Back pointer to newblk. */ + ino_t jn_ino; /* Ino to which allocated. */ + ufs_lbn_t jn_lbn; /* Lbn to which allocated. */ + ufs2_daddr_t jn_blkno; /* Blkno allocated */ + int jn_oldfrags; /* Previous fragments when extended. */ + int jn_frags; /* Number of fragments. */ }; /* * A "jfreeblk" structure tracks the journal write for freeing a block * or tree of blocks. The block pointer must not be cleared in the inode - * or indirect prior to the jfreeblk being written. + * or indirect prior to the jfreeblk being written to the journal. */ struct jfreeblk { - struct worklist jf_list; + struct worklist jf_list; /* Linked to softdep_journal_pending. */ # define jf_state jf_list.wk_state - struct jsegdep *jf_jsegdep; - struct freeblks *jf_freeblks; - LIST_ENTRY(jfreeblk) jf_deps; - ino_t jf_ino; - ufs_lbn_t jf_lbn; - ufs2_daddr_t jf_blkno; - int jf_frags; + struct jsegdep *jf_jsegdep; /* Will track our journal record. */ + struct freeblks *jf_freeblks; /* Back pointer to freeblks. */ + LIST_ENTRY(jfreeblk) jf_deps; /* Jfreeblk on fb_jfreeblkhd. */ + ino_t jf_ino; /* Ino from which blocks freed. */ + ufs_lbn_t jf_lbn; /* Lbn from which blocks freed. */ + ufs2_daddr_t jf_blkno; /* Blkno being freed. */ + int jf_frags; /* Number of frags being freed. */ }; /* @@ -818,14 +837,14 @@ struct jfreeblk { * freeblks operation. */ struct jfreefrag { - struct worklist fr_list; + struct worklist fr_list; /* Linked to softdep_journal_pending. */ # define fr_state fr_list.wk_state - struct jsegdep *fr_jsegdep; - struct freefrag *fr_freefrag; - ino_t fr_ino; - ufs_lbn_t fr_lbn; - ufs2_daddr_t fr_blkno; - int fr_frags; + struct jsegdep *fr_jsegdep; /* Will track our journal record. */ + struct freefrag *fr_freefrag; /* Back pointer to freefrag. */ + ino_t fr_ino; /* Ino from which frag freed. */ + ufs_lbn_t fr_lbn; /* Lbn from which frag freed. */ + ufs2_daddr_t fr_blkno; /* Blkno being freed. */ + int fr_frags; /* Size of frag being freed. */ }; /* @@ -835,42 +854,45 @@ struct jfreefrag { * is complete and the truncated inode is fsync'd. */ struct jtrunc { - struct worklist jt_list; - struct jsegdep *jt_jsegdep; - ino_t jt_ino; - off_t jt_size; - int jt_extsize; + struct worklist jt_list; /* Linked to softdep_journal_pending. */ + struct jsegdep *jt_jsegdep; /* Will track our journal record. */ + ino_t jt_ino; /* Ino being truncated. */ + off_t jt_size; /* Final file size. */ + int jt_extsize; /* Final extent size. */ }; /* * A "jsegdep" structure tracks a single reference to a written journal * segment so the journal space can be reclaimed when all dependencies - * have been written. + * have been written. It can hang off of id_inowait, dm_jwork, da_jwork, + * nb_jwork, ff_jwork, or fb_jwork lists. */ struct jsegdep { - struct worklist jd_list; + struct worklist jd_list; /* See above for lists. */ # define jd_state jd_list.wk_state - struct jseg *jd_seg; + struct jseg *jd_seg; /* Our journal record. */ }; /* * A "jseg" structure contains all of the journal records written in a - * single disk write. jaddref and jremref structures are linked into + * single disk write. The jaddref and jremref structures are linked into * js_entries so thay may be completed when the write completes. The - * js_deps array contains as many entries as there are ref counts to - * reduce the number of allocations required per journal write to one. + * js_entries also include the write dependency structures: jmvref, + * jnewblk, jfreeblk, jfreefrag, and jtrunc. The js_refs field counts + * the number of entries on the js_entries list. Thus there is a single + * jseg entry to describe each journal write. */ struct jseg { struct worklist js_list; /* b_deps link for journal */ # define js_state js_list.wk_state struct workhead js_entries; /* Entries awaiting write */ - TAILQ_ENTRY(jseg) js_next; + TAILQ_ENTRY(jseg) js_next; /* List of all unfinished segments. */ struct jblocks *js_jblocks; /* Back pointer to block/seg list */ struct buf *js_buf; /* Buffer while unwritten */ - uint64_t js_seq; - int js_size; /* Allocated size in bytes */ - int js_cnt; /* Total items allocated */ - int js_refs; /* Count of items pending completion */ + uint64_t js_seq; /* Journal record sequence number. */ + int js_size; /* Size of journal record in bytes. */ + int js_cnt; /* Total items allocated. */ + int js_refs; /* Count of js_entries items. */ }; /* @@ -878,10 +900,11 @@ struct jseg { * superblock writes. This makes sure the superblock is always pointing at * the first possible unlinked inode for the suj recovery process. If a * block write completes and we discover a new head is available the buf - * is dirtied and the dep is kept. + * is dirtied and the dep is kept. See the description of the UNLINK* + * flags above for more details. */ struct sbdep { struct worklist sb_list; /* b_dep linkage */ struct fs *sb_fs; /* Filesystem pointer within buf. */ - struct ufsmount *sb_ump; + struct ufsmount *sb_ump; /* Our mount structure */ };
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