Andreas Dilger
2017-Jun-15 00:11 UTC
[Ocfs2-devel] [PATCH v2 26/28] ext4: cleanup transaction restarts during inode deletion
On Jun 14, 2017, at 8:17 AM, Tahsin Erdogan <tahsin at google.com> wrote:> > During inode deletion, journal credits that will be needed are hard to > determine, that is why we have journal extend/restart calls in several > places. Whenever a transaction is restarted, filesystem must be in a > consistent state because there is no atomicity guarantee beyond a > restart call. > > Add ext4_xattr_ensure_credits() helper function which takes care of > journal extend/restart logic. It also handles getting jbd2 write access > and dirty metadata calls. This function is called at every iteration of > handling an ea_inode reference.Another option that might be less complex is to just add the xattr inodes to the orphan list in the main transaction (which should be a fixed number of credits), and then truncate/unlink the xattr inodes after the main transaction has completed rather than making the transactions arbitrarily large. At one point we even had a separate unlink thread to handle this in the background to reduce the unlink latency for very large files, which also avoids issues with nested transactions. Cheers, Andreas> Signed-off-by: Tahsin Erdogan <tahsin at google.com> > --- > v2: made ext4_xattr_ensure_credits() static > > fs/ext4/inode.c | 66 ++++----------- > fs/ext4/xattr.c | 257 ++++++++++++++++++++++++++++++++++++-------------------- > fs/ext4/xattr.h | 3 +- > 3 files changed, 183 insertions(+), 143 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index cf91532765a4..4d6936f0d8a4 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode) > */ > sb_start_intwrite(inode->i_sb); > > - handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits); > + if (!IS_NOQUOTA(inode)) > + extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb); > + > + handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, > + ext4_blocks_for_truncate(inode)+extra_credits); > if (IS_ERR(handle)) { > ext4_std_error(inode->i_sb, PTR_ERR(handle)); > /* > @@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode) > sb_end_intwrite(inode->i_sb); > goto no_delete; > } > + > if (IS_SYNC(inode)) > ext4_handle_sync(handle); > - > - /* > - * Delete xattr inode before deleting the main inode. > - */ > - err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array); > - if (err) { > - ext4_warning(inode->i_sb, > - "couldn't delete inode's xattr (err %d)", err); > - goto stop_handle; > - } > - > - if (!IS_NOQUOTA(inode)) > - extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb); > - > - if (!ext4_handle_has_enough_credits(handle, > - ext4_blocks_for_truncate(inode) + extra_credits)) { > - err = ext4_journal_extend(handle, > - ext4_blocks_for_truncate(inode) + extra_credits); > - if (err > 0) > - err = ext4_journal_restart(handle, > - ext4_blocks_for_truncate(inode) + extra_credits); > - if (err != 0) { > - ext4_warning(inode->i_sb, > - "couldn't extend journal (err %d)", err); > - goto stop_handle; > - } > - } > - > inode->i_size = 0; > err = ext4_mark_inode_dirty(handle, inode); > if (err) { > @@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode) > } > } > > - /* > - * ext4_ext_truncate() doesn't reserve any slop when it > - * restarts journal transactions; therefore there may not be > - * enough credits left in the handle to remove the inode from > - * the orphan list and set the dtime field. > - */ > - if (!ext4_handle_has_enough_credits(handle, extra_credits)) { > - err = ext4_journal_extend(handle, extra_credits); > - if (err > 0) > - err = ext4_journal_restart(handle, extra_credits); > - if (err != 0) { > - ext4_warning(inode->i_sb, > - "couldn't extend journal (err %d)", err); > - stop_handle: > - ext4_journal_stop(handle); > - ext4_orphan_del(NULL, inode); > - sb_end_intwrite(inode->i_sb); > - goto no_delete; > - } > + /* Remove xattr references. */ > + err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array, > + extra_credits); > + if (err) { > + ext4_warning(inode->i_sb, "xattr delete (err %d)", err); > + stop_handle: > + ext4_journal_stop(handle); > + ext4_orphan_del(NULL, inode); > + sb_end_intwrite(inode->i_sb); > + ext4_xattr_inode_array_free(ea_inode_array); > + goto no_delete; > } > > /* > @@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode) > ext4_clear_inode(inode); > else > ext4_free_inode(handle, inode); > - > ext4_journal_stop(handle); > sb_end_intwrite(inode->i_sb); > ext4_xattr_inode_array_free(ea_inode_array); > diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c > index 3ee7e2f68476..abc7d5f84e5f 100644 > --- a/fs/ext4/xattr.c > +++ b/fs/ext4/xattr.c > @@ -108,6 +108,10 @@ const struct xattr_handler *ext4_xattr_handlers[] = { > #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \ > inode->i_sb->s_fs_info)->s_mb_cache) > > +static int > +ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array, > + struct inode *inode); > + > #ifdef CONFIG_LOCKDEP > void ext4_xattr_inode_set_class(struct inode *ea_inode) > { > @@ -653,6 +657,127 @@ static void ext4_xattr_update_super_block(handle_t *handle, > } > } > > +static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode, > + int credits, struct buffer_head *bh, > + bool dirty, bool block_csum) > +{ > + int error; > + > + if (!ext4_handle_valid(handle)) > + return 0; > + > + if (handle->h_buffer_credits >= credits) > + return 0; > + > + error = ext4_journal_extend(handle, credits - handle->h_buffer_credits); > + if (!error) > + return 0; > + if (error < 0) { > + ext4_warning(inode->i_sb, "Extend journal (error %d)", error); > + return error; > + } > + > + if (bh && dirty) { > + if (block_csum) > + ext4_xattr_block_csum_set(inode, bh); > + error = ext4_handle_dirty_metadata(handle, NULL, bh); > + if (error) { > + ext4_warning(inode->i_sb, "Handle metadata (error %d)", > + error); > + return error; > + } > + } > + > + error = ext4_journal_restart(handle, credits); > + if (error) { > + ext4_warning(inode->i_sb, "Restart journal (error %d)", error); > + return error; > + } > + > + if (bh) { > + error = ext4_journal_get_write_access(handle, bh); > + if (error) { > + ext4_warning(inode->i_sb, > + "Get write access failed (error %d)", > + error); > + return error; > + } > + } > + return 0; > +} > + > +static void > +ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent, > + struct buffer_head *bh, > + struct ext4_xattr_entry *first, bool block_csum, > + struct ext4_xattr_inode_array **ea_inode_array, > + int extra_credits) > +{ > + struct inode *ea_inode; > + struct ext4_xattr_entry *entry; > + bool dirty = false; > + unsigned int ea_ino; > + int err; > + int credits; > + > + /* One credit for dec ref on ea_inode, one for orphan list addition, */ > + credits = 2 + extra_credits; > + > + for (entry = first; !IS_LAST_ENTRY(entry); > + entry = EXT4_XATTR_NEXT(entry)) { > + if (!entry->e_value_inum) > + continue; > + ea_ino = le32_to_cpu(entry->e_value_inum); > + err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode); > + if (err) > + continue; > + > + err = ext4_expand_inode_array(ea_inode_array, ea_inode); > + if (err) { > + ext4_warning_inode(ea_inode, > + "Expand inode array err=%d", err); > + iput(ea_inode); > + continue; > + } > + > + err = ext4_xattr_ensure_credits(handle, parent, credits, bh, > + dirty, block_csum); > + if (err) { > + ext4_warning_inode(ea_inode, "Ensure credits err=%d", > + err); > + continue; > + } > + > + inode_lock(ea_inode); > + clear_nlink(ea_inode); > + ext4_orphan_add(handle, ea_inode); > + inode_unlock(ea_inode); > + > + /* > + * Forget about ea_inode within the same transaction that decrements the ref > + * count. This avoids duplicate decrements in case the rest of the work > + * spills over to subsequent transactions. > + */ > + entry->e_value_inum = 0; > + entry->e_value_size = 0; > + > + dirty = true; > + } > + > + if (dirty) { > + /* > + * Note that we are deliberately skipping csum calculation for > + * the final update because we do not expect any journal > + * restarts until xattr block is freed. > + */ > + > + err = ext4_handle_dirty_metadata(handle, NULL, bh); > + if (err) > + ext4_warning_inode(parent, > + "handle dirty metadata err=%d", err); > + } > +} > + > /* > * Release the xattr block BH: If the reference count is > 1, decrement it; > * otherwise free the block. > @@ -1985,42 +2110,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array, > return 0; > } > > -/** > - * Add xattr inode to orphan list > - */ > -static int > -ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits, > - struct ext4_xattr_inode_array *ea_inode_array) > -{ > - int idx = 0, error = 0; > - struct inode *ea_inode; > - > - if (ea_inode_array == NULL) > - return 0; > - > - for (; idx < ea_inode_array->count; ++idx) { > - if (!ext4_handle_has_enough_credits(handle, credits)) { > - error = ext4_journal_extend(handle, credits); > - if (error > 0) > - error = ext4_journal_restart(handle, credits); > - > - if (error != 0) { > - ext4_warning(inode->i_sb, > - "couldn't extend journal " > - "(err %d)", error); > - return error; > - } > - } > - ea_inode = ea_inode_array->inodes[idx]; > - inode_lock(ea_inode); > - ext4_orphan_add(handle, ea_inode); > - inode_unlock(ea_inode); > - /* the inode's i_count will be released by caller */ > - } > - > - return 0; > -} > - > /* > * ext4_xattr_delete_inode() > * > @@ -2033,16 +2122,23 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits, > */ > int > ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, > - struct ext4_xattr_inode_array **ea_inode_array) > + struct ext4_xattr_inode_array **ea_inode_array, > + int extra_credits) > { > struct buffer_head *bh = NULL; > struct ext4_xattr_ibody_header *header; > struct ext4_inode *raw_inode; > - struct ext4_iloc iloc; > - struct ext4_xattr_entry *entry; > - struct inode *ea_inode; > - unsigned int ea_ino; > - int credits = 3, error = 0; > + struct ext4_iloc iloc = { .bh = NULL }; > + int error; > + > + error = ext4_xattr_ensure_credits(handle, inode, extra_credits, > + NULL /* bh */, > + false /* dirty */, > + false /* block_csum */); > + if (error) { > + EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error); > + goto cleanup; > + } > > if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) > goto delete_external_ea; > @@ -2050,31 +2146,20 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, > error = ext4_get_inode_loc(inode, &iloc); > if (error) > goto cleanup; > + > + error = ext4_journal_get_write_access(handle, iloc.bh); > + if (error) > + goto cleanup; > + > raw_inode = ext4_raw_inode(&iloc); > header = IHDR(inode, raw_inode); > - for (entry = IFIRST(header); !IS_LAST_ENTRY(entry); > - entry = EXT4_XATTR_NEXT(entry)) { > - if (!entry->e_value_inum) > - continue; > - ea_ino = le32_to_cpu(entry->e_value_inum); > - error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode); > - if (error) > - continue; > - error = ext4_expand_inode_array(ea_inode_array, ea_inode); > - if (error) { > - iput(ea_inode); > - brelse(iloc.bh); > - goto cleanup; > - } > - entry->e_value_inum = 0; > - } > - brelse(iloc.bh); > + ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header), > + false /* block_csum */, ea_inode_array, > + extra_credits); > > delete_external_ea: > if (!EXT4_I(inode)->i_file_acl) { > - /* add xattr inode to orphan list */ > - error = ext4_xattr_inode_orphan_add(handle, inode, credits, > - *ea_inode_array); > + error = 0; > goto cleanup; > } > bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); > @@ -2092,46 +2177,32 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, > goto cleanup; > } > > - for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry); > - entry = EXT4_XATTR_NEXT(entry)) { > - if (!entry->e_value_inum) > - continue; > - ea_ino = le32_to_cpu(entry->e_value_inum); > - error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode); > - if (error) > - continue; > - error = ext4_expand_inode_array(ea_inode_array, ea_inode); > - if (error) > - goto cleanup; > - entry->e_value_inum = 0; > - } > - > - /* add xattr inode to orphan list */ > - error = ext4_xattr_inode_orphan_add(handle, inode, credits, > - *ea_inode_array); > - if (error) > - goto cleanup; > - > - if (!IS_NOQUOTA(inode)) > - credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb); > - > - if (!ext4_handle_has_enough_credits(handle, credits)) { > - error = ext4_journal_extend(handle, credits); > - if (error > 0) > - error = ext4_journal_restart(handle, credits); > + if (ext4_has_feature_ea_inode(inode->i_sb)) { > + error = ext4_journal_get_write_access(handle, bh); > if (error) { > - ext4_warning(inode->i_sb, > - "couldn't extend journal (err %d)", error); > + EXT4_ERROR_INODE(inode, "write access %llu", > + EXT4_I(inode)->i_file_acl); > goto cleanup; > } > + ext4_xattr_inode_remove_all(handle, inode, bh, > + BFIRST(bh), > + true /* block_csum */, > + ea_inode_array, > + extra_credits); > } > > ext4_xattr_release_block(handle, inode, bh); > + /* Update i_file_acl within the same transaction that releases block. */ > EXT4_I(inode)->i_file_acl = 0; > - > + error = ext4_mark_inode_dirty(handle, inode); > + if (error) { > + EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)", > + error); > + goto cleanup; > + } > cleanup: > + brelse(iloc.bh); > brelse(bh); > - > return error; > } > > diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h > index adf761518a73..b2005a2716d9 100644 > --- a/fs/ext4/xattr.h > +++ b/fs/ext4/xattr.h > @@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len); > > extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino); > extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, > - struct ext4_xattr_inode_array **array); > + struct ext4_xattr_inode_array **array, > + int extra_credits); > extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array); > > extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, > -- > 2.13.1.508.gb3defc5cc-goog >Cheers, Andreas -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 195 bytes Desc: Message signed with OpenPGP Url : http://oss.oracle.com/pipermail/ocfs2-devel/attachments/20170614/9174eb88/attachment.bin