| Message ID | 20230526090820.64114-1-guochunhai@vivo.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [f2fs-dev,v2] f2fs: Detect looped node chain efficiently | expand |
On 2023/5/26 17:08, Chunhai Guo wrote: > find_fsync_dnodes() detect the looped node chain by comparing the loop > counter with free blocks. While it may take tens of seconds to quit when > the free blocks are large enough. We can use Floyd's cycle detection > algorithm to make the detection more efficient. > > Signed-off-by: Chunhai Guo <guochunhai@vivo.com> > --- > v1 -> v2 : Bail out if a looped is found in a chain and do repair in fsck. > --- > fs/f2fs/recovery.c | 78 ++++++++++++++++++++++++++++++++++------------ > 1 file changed, 58 insertions(+), 20 deletions(-) > > diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c > index 58c1a0096f7d..c1dceda54a4f 100644 > --- a/fs/f2fs/recovery.c > +++ b/fs/f2fs/recovery.c > @@ -360,21 +360,54 @@ static unsigned int adjust_por_ra_blocks(struct f2fs_sb_info *sbi, > return ra_blocks; > } > What about this? return value: - 0: continue the loop - < 0: break and return static int sanity_check_node_chain(struct f2fs_sb_info *sbi, block_t blkaddr, block_t *blkaddr_fast, bool *is_detecting) { if (!is_detecting) return 0; for (i = 0; i < 2; i++) { ... } if (*blkaddr_fast == blkaddr) { f2fs_notice(); return -EINVAL; } return 0; } > +static int find_node_blk_fast(struct f2fs_sb_info *sbi, block_t *blkaddr_fast, > + bool *is_detecting) > +{ > + unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS; > + struct page *page = NULL; > + int i; > + > + for (i = 0; i < 2; i++) { > + if (!f2fs_is_valid_blkaddr(sbi, *blkaddr_fast, META_POR)) { > + *is_detecting = false; > + return 0; > + } > + > + page = f2fs_get_tmp_page(sbi, *blkaddr_fast); > + if (IS_ERR(page)) > + return PTR_ERR(page); > + > + if (!is_recoverable_dnode(page)) { > + f2fs_put_page(page, 1); > + *is_detecting = false; > + return 0; > + } > + > + ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, *blkaddr_fast, > + next_blkaddr_of_node(page)); > + > + *blkaddr_fast = next_blkaddr_of_node(page); > + f2fs_put_page(page, 1); > + > + f2fs_ra_meta_pages_cond(sbi, *blkaddr_fast, ra_blocks); > + } > + > + return 0; > +} > + > static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head, > bool check_only) > { > struct curseg_info *curseg; > struct page *page = NULL; > - block_t blkaddr; > - unsigned int loop_cnt = 0; > - unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS; > - unsigned int free_blocks = MAIN_SEGS(sbi) * sbi->blocks_per_seg - > - valid_user_blocks(sbi); > + block_t blkaddr, blkaddr_fast; > + bool is_detecting = true; > int err = 0; > > /* get node pages in the current segment */ > curseg = CURSEG_I(sbi, CURSEG_WARM_NODE); > blkaddr = NEXT_FREE_BLKADDR(sbi, curseg); > + blkaddr_fast = blkaddr; > > while (1) { > struct fsync_inode_entry *entry; > @@ -431,25 +464,30 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head, > if (IS_INODE(page) && is_dent_dnode(page)) > entry->last_dentry = blkaddr; > next: > - /* sanity check in order to detect looped node chain */ > - if (++loop_cnt >= free_blocks || > - blkaddr == next_blkaddr_of_node(page)) { > - f2fs_notice(sbi, "%s: detect looped node chain, blkaddr:%u, next:%u", > - __func__, blkaddr, > - next_blkaddr_of_node(page)); > - f2fs_put_page(page, 1); > - err = -EINVAL; > - break; > - } > - > - ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr, > - next_blkaddr_of_node(page)); > - > /* check next segment */ > blkaddr = next_blkaddr_of_node(page); > f2fs_put_page(page, 1); > > - f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks); > + /* Below we will detect looped node chain with Floyd's cycle > + * detection algorithm. > + */ > + if (!is_detecting) > + continue; > + > + err = find_node_blk_fast(sbi, &blkaddr_fast, &is_detecting); /* ... */ err = sanity_check_node_chain(); if (err) break; Thanks, > + if (err) > + break; > + > + if (!is_detecting) > + continue; > + > + if (blkaddr_fast == blkaddr) { > + f2fs_notice(sbi, "%s: Detect looped node chain on " > + "blkaddr:%u. Run fsck to fix it.", > + __func__, blkaddr); > + err = -EINVAL; > + break; > + } > } > return err; > }
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index 58c1a0096f7d..c1dceda54a4f 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -360,21 +360,54 @@ static unsigned int adjust_por_ra_blocks(struct f2fs_sb_info *sbi, return ra_blocks; } +static int find_node_blk_fast(struct f2fs_sb_info *sbi, block_t *blkaddr_fast, + bool *is_detecting) +{ + unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS; + struct page *page = NULL; + int i; + + for (i = 0; i < 2; i++) { + if (!f2fs_is_valid_blkaddr(sbi, *blkaddr_fast, META_POR)) { + *is_detecting = false; + return 0; + } + + page = f2fs_get_tmp_page(sbi, *blkaddr_fast); + if (IS_ERR(page)) + return PTR_ERR(page); + + if (!is_recoverable_dnode(page)) { + f2fs_put_page(page, 1); + *is_detecting = false; + return 0; + } + + ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, *blkaddr_fast, + next_blkaddr_of_node(page)); + + *blkaddr_fast = next_blkaddr_of_node(page); + f2fs_put_page(page, 1); + + f2fs_ra_meta_pages_cond(sbi, *blkaddr_fast, ra_blocks); + } + + return 0; +} + static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head, bool check_only) { struct curseg_info *curseg; struct page *page = NULL; - block_t blkaddr; - unsigned int loop_cnt = 0; - unsigned int ra_blocks = RECOVERY_MAX_RA_BLOCKS; - unsigned int free_blocks = MAIN_SEGS(sbi) * sbi->blocks_per_seg - - valid_user_blocks(sbi); + block_t blkaddr, blkaddr_fast; + bool is_detecting = true; int err = 0; /* get node pages in the current segment */ curseg = CURSEG_I(sbi, CURSEG_WARM_NODE); blkaddr = NEXT_FREE_BLKADDR(sbi, curseg); + blkaddr_fast = blkaddr; while (1) { struct fsync_inode_entry *entry; @@ -431,25 +464,30 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head, if (IS_INODE(page) && is_dent_dnode(page)) entry->last_dentry = blkaddr; next: - /* sanity check in order to detect looped node chain */ - if (++loop_cnt >= free_blocks || - blkaddr == next_blkaddr_of_node(page)) { - f2fs_notice(sbi, "%s: detect looped node chain, blkaddr:%u, next:%u", - __func__, blkaddr, - next_blkaddr_of_node(page)); - f2fs_put_page(page, 1); - err = -EINVAL; - break; - } - - ra_blocks = adjust_por_ra_blocks(sbi, ra_blocks, blkaddr, - next_blkaddr_of_node(page)); - /* check next segment */ blkaddr = next_blkaddr_of_node(page); f2fs_put_page(page, 1); - f2fs_ra_meta_pages_cond(sbi, blkaddr, ra_blocks); + /* Below we will detect looped node chain with Floyd's cycle + * detection algorithm. + */ + if (!is_detecting) + continue; + + err = find_node_blk_fast(sbi, &blkaddr_fast, &is_detecting); + if (err) + break; + + if (!is_detecting) + continue; + + if (blkaddr_fast == blkaddr) { + f2fs_notice(sbi, "%s: Detect looped node chain on " + "blkaddr:%u. Run fsck to fix it.", + __func__, blkaddr); + err = -EINVAL; + break; + } } return err; }
find_fsync_dnodes() detect the looped node chain by comparing the loop counter with free blocks. While it may take tens of seconds to quit when the free blocks are large enough. We can use Floyd's cycle detection algorithm to make the detection more efficient. Signed-off-by: Chunhai Guo <guochunhai@vivo.com> --- v1 -> v2 : Bail out if a looped is found in a chain and do repair in fsck. --- fs/f2fs/recovery.c | 78 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 58 insertions(+), 20 deletions(-)