From de94eb558b542873d3f6f9ede1b8575fb5662248 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Tue, 22 Jul 2008 13:06:20 +0300 Subject: [PATCH] UBIFS: optimize deletions Every time anything is deleted, UBIFS writes the deletion inode node twice - once in 'ubifs_jnl_update()' and the second time in 'ubifs_jnl_write_inode()'. However, the second write is not needed if no commit happened after 'ubifs_jnl_update()'. This patch checks that condition and avoids writing the deletion inode for the second time. Signed-off-by: Artem Bityutskiy --- fs/ubifs/journal.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++ fs/ubifs/super.c | 6 +++-- fs/ubifs/ubifs.h | 12 +++++++--- 3 files changed, 73 insertions(+), 5 deletions(-) diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c index 3bc3fc9470..0bcee7d221 100644 --- a/fs/ubifs/journal.c +++ b/fs/ubifs/journal.c @@ -604,6 +604,7 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir, release_head(c, BASEHD); goto out_finish; } + ui->del_cmtno = c->cmt_no; } err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, sync); @@ -820,6 +821,64 @@ out_free: return err; } +/** + * ubifs_jnl_write_inode - delete an inode. + * @c: UBIFS file-system description object + * @inode: inode to delete + * + * This function deletes inode @inode which includes removing it from orphans, + * deleting it from TNC and, in some cases, writing a deletion inode to the + * journal. + * + * When regular file inodes are unlinked or a directory inode is removed, the + * 'ubifs_jnl_update()' function write corresponding deletion inode and + * direntry to the media, and adds the inode to orphans. After this, when the + * last reference to this inode has been dropped, this function is called. In + * general, it has to write one more deletion inode to the media, because if + * a commit happened between 'ubifs_jnl_update()' and + * 'ubifs_jnl_delete_inode()', the deletion inode is not in the journal + * anymore, and in fact it might be not on the flash anymore, becouse it might + * have been garbage-collected already. And for optimization reasond UBIFS does + * not read the orphan area if it has been unmounted cleanly, so it would have + * no indication in the journal that there is a deleted inode which has to be + * removed from TNC. + * + * However, if there was no commit between 'ubifs_jnl_update()' and + * 'ubifs_jnl_delete_inode()', then there is no need to write the deletion + * inode to the media for the second time. And this is quite typical case. + * + * This function returns zero in case of success and a negative error code in + * case of failure. + */ +int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode) +{ + int err; + struct ubifs_inode *ui = ubifs_inode(inode); + + ubifs_assert(inode->i_nlink == 0); + + if (ui->del_cmtno != c->cmt_no) + /* A commit happened for sure */ + return ubifs_jnl_write_inode(c, inode); + + down_read(&c->commit_sem); + /* + * Check commit number again, because the first test has been done + * without @c->commit_sem, so a commit might have happened. + */ + if (ui->del_cmtno != c->cmt_no) { + up_read(&c->commit_sem); + return ubifs_jnl_write_inode(c, inode); + } + + ubifs_delete_orphan(c, inode->i_ino); + err = ubifs_tnc_remove_ino(c, inode->i_ino); + if (err) + ubifs_ro_mode(c, err); + up_read(&c->commit_sem); + return err; +} + /** * ubifs_jnl_rename - rename a directory entry. * @c: UBIFS file-system description object @@ -928,6 +987,7 @@ int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir, release_head(c, BASEHD); goto out_finish; } + new_ui->del_cmtno = c->cmt_no; } err = write_head(c, BASEHD, dent, len, &lnum, &offs, sync); diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index cf1fb6cffa..6cc4175f23 100644 --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -341,13 +341,15 @@ static void ubifs_delete_inode(struct inode *inode) goto out; ui->ui_size = inode->i_size = 0; - err = ubifs_jnl_write_inode(c, inode); + err = ubifs_jnl_delete_inode(c, inode); if (err) /* * Worst case we have a lost orphan inode wasting space, so a * simple error message is ok here. */ - ubifs_err("can't write inode %lu, error %d", inode->i_ino, err); + ubifs_err("can't delete inode %lu, error %d", + inode->i_ino, err); + out: if (ui->dirty) ubifs_release_dirty_inode_budget(c, ui); diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 21502b6040..dfb4b93614 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -322,6 +322,8 @@ struct ubifs_gced_idx_leb { * struct ubifs_inode - UBIFS in-memory inode description. * @vfs_inode: VFS inode description object * @creat_sqnum: sequence number at time of creation + * @del_cmtno: commit number corresponding to the time the inode was deleted, + * protected by @c->commit_sem; * @xattr_size: summarized size of all extended attributes in bytes * @xattr_cnt: count of extended attributes this inode has * @xattr_names: sum of lengths of all extended attribute names belonging to @@ -372,7 +374,10 @@ struct ubifs_gced_idx_leb { */ struct ubifs_inode { struct inode vfs_inode; - unsigned long long creat_sqnum; + union { + unsigned long long creat_sqnum; + unsigned long long del_cmtno; + }; unsigned int xattr_size; unsigned int xattr_cnt; unsigned int xattr_names; @@ -779,7 +784,7 @@ struct ubifs_compressor { /** * struct ubifs_budget_req - budget requirements of an operation. * - * @fast: non-zero if the budgeting should try to aquire budget quickly and + * @fast: non-zero if the budgeting should try to acquire budget quickly and * should not try to call write-back * @recalculate: non-zero if @idx_growth, @data_growth, and @dd_growth fields * have to be re-calculated @@ -860,7 +865,7 @@ struct ubifs_mount_opts { * struct ubifs_info - UBIFS file-system description data structure * (per-superblock). * @vfs_sb: VFS @struct super_block object - * @bdi: backing device info object to make VFS happy and disable readahead + * @bdi: backing device info object to make VFS happy and disable read-ahead * * @highest_inum: highest used inode number * @vfs_gen: VFS inode generation counter @@ -1402,6 +1407,7 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir, int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode, const union ubifs_key *key, const void *buf, int len); int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode); +int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode); int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir, const struct dentry *old_dentry, const struct inode *new_dir, -- 2.39.5