On Thu 17-06-21 09:22:40, Darrick J. Wong wrote: > On Tue, Jun 15, 2021 at 11:17:55AM +0200, Jan Kara wrote: > > Convert ext4 to use mapping->invalidate_lock instead of its private > > EXT4_I(inode)->i_mmap_sem. This is mostly search-and-replace. By this > > conversion we fix a long standing race between hole punching and read(2) > > / readahead(2) paths that can lead to stale page cache contents. > > > > CC: <linux-ext4@xxxxxxxxxxxxxxx> > > CC: Ted Tso <tytso@xxxxxxx> > > Hmm, still no ACK from Ted? On ext4 call he mentioned he's fine with the patches and testing has passed for him but he has not given an official tag... > This looks like a pretty straightforward i_mmap_sem conversion, though > in general I'd like /some/ kind of response from anyone in the ext4 > community who has been writing code more recently than me... > > Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx> Yeah, this was basically search-and-replace. Thanks for review! Honza > > --D > > > Signed-off-by: Jan Kara <jack@xxxxxxx> > > --- > > fs/ext4/ext4.h | 10 ---------- > > fs/ext4/extents.c | 25 +++++++++++++----------- > > fs/ext4/file.c | 13 +++++++------ > > fs/ext4/inode.c | 47 +++++++++++++++++----------------------------- > > fs/ext4/ioctl.c | 4 ++-- > > fs/ext4/super.c | 13 +++++-------- > > fs/ext4/truncate.h | 8 +++++--- > > 7 files changed, 50 insertions(+), 70 deletions(-) > > > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > > index 37002663d521..ed64b4b217a1 100644 > > --- a/fs/ext4/ext4.h > > +++ b/fs/ext4/ext4.h > > @@ -1077,15 +1077,6 @@ struct ext4_inode_info { > > * by other means, so we have i_data_sem. > > */ > > struct rw_semaphore i_data_sem; > > - /* > > - * i_mmap_sem is for serializing page faults with truncate / punch hole > > - * operations. We have to make sure that new page cannot be faulted in > > - * a section of the inode that is being punched. We cannot easily use > > - * i_data_sem for this since we need protection for the whole punch > > - * operation and i_data_sem ranks below transaction start so we have > > - * to occasionally drop it. > > - */ > > - struct rw_semaphore i_mmap_sem; > > struct inode vfs_inode; > > struct jbd2_inode *jinode; > > > > @@ -2962,7 +2953,6 @@ extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks); > > extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode, > > loff_t lstart, loff_t lend); > > extern vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf); > > -extern vm_fault_t ext4_filemap_fault(struct vm_fault *vmf); > > extern qsize_t *ext4_get_reserved_space(struct inode *inode); > > extern int ext4_get_projid(struct inode *inode, kprojid_t *projid); > > extern void ext4_da_release_space(struct inode *inode, int to_free); > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > > index cbf37b2cf871..db5d38af9ba8 100644 > > --- a/fs/ext4/extents.c > > +++ b/fs/ext4/extents.c > > @@ -4470,6 +4470,7 @@ static long ext4_zero_range(struct file *file, loff_t offset, > > loff_t len, int mode) > > { > > struct inode *inode = file_inode(file); > > + struct address_space *mapping = file->f_mapping; > > handle_t *handle = NULL; > > unsigned int max_blocks; > > loff_t new_size = 0; > > @@ -4556,17 +4557,17 @@ static long ext4_zero_range(struct file *file, loff_t offset, > > * Prevent page faults from reinstantiating pages we have > > * released from page cache. > > */ > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(mapping); > > > > ret = ext4_break_layouts(inode); > > if (ret) { > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > goto out_mutex; > > } > > > > ret = ext4_update_disksize_before_punch(inode, offset, len); > > if (ret) { > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > goto out_mutex; > > } > > /* Now release the pages and zero block aligned part of pages */ > > @@ -4575,7 +4576,7 @@ static long ext4_zero_range(struct file *file, loff_t offset, > > > > ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, > > flags); > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > if (ret) > > goto out_mutex; > > } > > @@ -5217,6 +5218,7 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, > > static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) > > { > > struct super_block *sb = inode->i_sb; > > + struct address_space *mapping = inode->i_mapping; > > ext4_lblk_t punch_start, punch_stop; > > handle_t *handle; > > unsigned int credits; > > @@ -5270,7 +5272,7 @@ static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) > > * Prevent page faults from reinstantiating pages we have released from > > * page cache. > > */ > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(mapping); > > > > ret = ext4_break_layouts(inode); > > if (ret) > > @@ -5285,15 +5287,15 @@ static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) > > * Write tail of the last page before removed range since it will get > > * removed from the page cache below. > > */ > > - ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset); > > + ret = filemap_write_and_wait_range(mapping, ioffset, offset); > > if (ret) > > goto out_mmap; > > /* > > * Write data that will be shifted to preserve them when discarding > > * page cache below. We are also protected from pages becoming dirty > > - * by i_mmap_sem. > > + * by i_rwsem and invalidate_lock. > > */ > > - ret = filemap_write_and_wait_range(inode->i_mapping, offset + len, > > + ret = filemap_write_and_wait_range(mapping, offset + len, > > LLONG_MAX); > > if (ret) > > goto out_mmap; > > @@ -5346,7 +5348,7 @@ static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) > > ext4_journal_stop(handle); > > ext4_fc_stop_ineligible(sb); > > out_mmap: > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > out_mutex: > > inode_unlock(inode); > > return ret; > > @@ -5363,6 +5365,7 @@ static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) > > static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) > > { > > struct super_block *sb = inode->i_sb; > > + struct address_space *mapping = inode->i_mapping; > > handle_t *handle; > > struct ext4_ext_path *path; > > struct ext4_extent *extent; > > @@ -5421,7 +5424,7 @@ static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) > > * Prevent page faults from reinstantiating pages we have released from > > * page cache. > > */ > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(mapping); > > > > ret = ext4_break_layouts(inode); > > if (ret) > > @@ -5522,7 +5525,7 @@ static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) > > ext4_journal_stop(handle); > > ext4_fc_stop_ineligible(sb); > > out_mmap: > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > out_mutex: > > inode_unlock(inode); > > return ret; > > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > > index 816dedcbd541..d3b4ed91aa68 100644 > > --- a/fs/ext4/file.c > > +++ b/fs/ext4/file.c > > @@ -704,22 +704,23 @@ static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, > > */ > > bool write = (vmf->flags & FAULT_FLAG_WRITE) && > > (vmf->vma->vm_flags & VM_SHARED); > > + struct address_space *mapping = vmf->vma->vm_file->f_mapping; > > pfn_t pfn; > > > > if (write) { > > sb_start_pagefault(sb); > > file_update_time(vmf->vma->vm_file); > > - down_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock_shared(mapping); > > retry: > > handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, > > EXT4_DATA_TRANS_BLOCKS(sb)); > > if (IS_ERR(handle)) { > > - up_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock_shared(mapping); > > sb_end_pagefault(sb); > > return VM_FAULT_SIGBUS; > > } > > } else { > > - down_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock_shared(mapping); > > } > > result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops); > > if (write) { > > @@ -731,10 +732,10 @@ static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, > > /* Handling synchronous page fault? */ > > if (result & VM_FAULT_NEEDDSYNC) > > result = dax_finish_sync_fault(vmf, pe_size, pfn); > > - up_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock_shared(mapping); > > sb_end_pagefault(sb); > > } else { > > - up_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock_shared(mapping); > > } > > > > return result; > > @@ -756,7 +757,7 @@ static const struct vm_operations_struct ext4_dax_vm_ops = { > > #endif > > > > static const struct vm_operations_struct ext4_file_vm_ops = { > > - .fault = ext4_filemap_fault, > > + .fault = filemap_fault, > > .map_pages = filemap_map_pages, > > .page_mkwrite = ext4_page_mkwrite, > > }; > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index fe6045a46599..ee6e69d6f949 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -3950,20 +3950,19 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset, > > return ret; > > } > > > > -static void ext4_wait_dax_page(struct ext4_inode_info *ei) > > +static void ext4_wait_dax_page(struct inode *inode) > > { > > - up_write(&ei->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > schedule(); > > - down_write(&ei->i_mmap_sem); > > + filemap_invalidate_lock(inode->i_mapping); > > } > > > > int ext4_break_layouts(struct inode *inode) > > { > > - struct ext4_inode_info *ei = EXT4_I(inode); > > struct page *page; > > int error; > > > > - if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem))) > > + if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock))) > > return -EINVAL; > > > > do { > > @@ -3974,7 +3973,7 @@ int ext4_break_layouts(struct inode *inode) > > error = ___wait_var_event(&page->_refcount, > > atomic_read(&page->_refcount) == 1, > > TASK_INTERRUPTIBLE, 0, 0, > > - ext4_wait_dax_page(ei)); > > + ext4_wait_dax_page(inode)); > > } while (error == 0); > > > > return error; > > @@ -4005,9 +4004,9 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) > > > > ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); > > if (ext4_has_inline_data(inode)) { > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(mapping); > > ret = ext4_convert_inline_data(inode); > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > if (ret) > > return ret; > > } > > @@ -4058,7 +4057,7 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) > > * Prevent page faults from reinstantiating pages we have released from > > * page cache. > > */ > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(mapping); > > > > ret = ext4_break_layouts(inode); > > if (ret) > > @@ -4131,7 +4130,7 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) > > out_stop: > > ext4_journal_stop(handle); > > out_dio: > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > out_mutex: > > inode_unlock(inode); > > return ret; > > @@ -5426,11 +5425,11 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, > > inode_dio_wait(inode); > > } > > > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(inode->i_mapping); > > > > rc = ext4_break_layouts(inode); > > if (rc) { > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > goto err_out; > > } > > > > @@ -5506,7 +5505,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, > > error = rc; > > } > > out_mmap_sem: > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > } > > > > if (!error) { > > @@ -5983,10 +5982,10 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val) > > * data (and journalled aops don't know how to handle these cases). > > */ > > if (val) { > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(inode->i_mapping); > > err = filemap_write_and_wait(inode->i_mapping); > > if (err < 0) { > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > return err; > > } > > } > > @@ -6019,7 +6018,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val) > > percpu_up_write(&sbi->s_writepages_rwsem); > > > > if (val) > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > > > /* Finally we can mark the inode as dirty. */ > > > > @@ -6063,7 +6062,7 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) > > sb_start_pagefault(inode->i_sb); > > file_update_time(vma->vm_file); > > > > - down_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock_shared(mapping); > > > > err = ext4_convert_inline_data(inode); > > if (err) > > @@ -6176,7 +6175,7 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) > > out_ret: > > ret = block_page_mkwrite_return(err); > > out: > > - up_read(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock_shared(mapping); > > sb_end_pagefault(inode->i_sb); > > return ret; > > out_error: > > @@ -6184,15 +6183,3 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) > > ext4_journal_stop(handle); > > goto out; > > } > > - > > -vm_fault_t ext4_filemap_fault(struct vm_fault *vmf) > > -{ > > - struct inode *inode = file_inode(vmf->vma->vm_file); > > - vm_fault_t ret; > > - > > - down_read(&EXT4_I(inode)->i_mmap_sem); > > - ret = filemap_fault(vmf); > > - up_read(&EXT4_I(inode)->i_mmap_sem); > > - > > - return ret; > > -} > > diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c > > index 31627f7dc5cd..c5ed562b4185 100644 > > --- a/fs/ext4/ioctl.c > > +++ b/fs/ext4/ioctl.c > > @@ -148,7 +148,7 @@ static long swap_inode_boot_loader(struct super_block *sb, > > goto journal_err_out; > > } > > > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_lock(inode->i_mapping); > > err = filemap_write_and_wait(inode->i_mapping); > > if (err) > > goto err_out; > > @@ -256,7 +256,7 @@ static long swap_inode_boot_loader(struct super_block *sb, > > ext4_double_up_write_data_sem(inode, inode_bl); > > > > err_out: > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(inode->i_mapping); > > journal_err_out: > > unlock_two_nondirectories(inode, inode_bl); > > iput(inode_bl); > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > > index d29f6aa7d96e..c3c3cd8b0966 100644 > > --- a/fs/ext4/super.c > > +++ b/fs/ext4/super.c > > @@ -90,12 +90,9 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb, > > /* > > * Lock ordering > > * > > - * Note the difference between i_mmap_sem (EXT4_I(inode)->i_mmap_sem) and > > - * i_mmap_rwsem (inode->i_mmap_rwsem)! > > - * > > * page fault path: > > - * mmap_lock -> sb_start_pagefault -> i_mmap_sem (r) -> transaction start -> > > - * page lock -> i_data_sem (rw) > > + * mmap_lock -> sb_start_pagefault -> invalidate_lock (r) -> transaction start > > + * -> page lock -> i_data_sem (rw) > > * > > * buffered write path: > > * sb_start_write -> i_mutex -> mmap_lock > > @@ -103,8 +100,9 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb, > > * i_data_sem (rw) > > * > > * truncate: > > - * sb_start_write -> i_mutex -> i_mmap_sem (w) -> i_mmap_rwsem (w) -> page lock > > - * sb_start_write -> i_mutex -> i_mmap_sem (w) -> transaction start -> > > + * sb_start_write -> i_mutex -> invalidate_lock (w) -> i_mmap_rwsem (w) -> > > + * page lock > > + * sb_start_write -> i_mutex -> invalidate_lock (w) -> transaction start -> > > * i_data_sem (rw) > > * > > * direct IO: > > @@ -1350,7 +1348,6 @@ static void init_once(void *foo) > > INIT_LIST_HEAD(&ei->i_orphan); > > init_rwsem(&ei->xattr_sem); > > init_rwsem(&ei->i_data_sem); > > - init_rwsem(&ei->i_mmap_sem); > > inode_init_once(&ei->vfs_inode); > > ext4_fc_init_inode(&ei->vfs_inode); > > } > > diff --git a/fs/ext4/truncate.h b/fs/ext4/truncate.h > > index bcbe3668c1d4..ce84aa2786c7 100644 > > --- a/fs/ext4/truncate.h > > +++ b/fs/ext4/truncate.h > > @@ -11,14 +11,16 @@ > > */ > > static inline void ext4_truncate_failed_write(struct inode *inode) > > { > > + struct address_space *mapping = inode->i_mapping; > > + > > /* > > * We don't need to call ext4_break_layouts() because the blocks we > > * are truncating were never visible to userspace. > > */ > > - down_write(&EXT4_I(inode)->i_mmap_sem); > > - truncate_inode_pages(inode->i_mapping, inode->i_size); > > + filemap_invalidate_lock(mapping); > > + truncate_inode_pages(mapping, inode->i_size); > > ext4_truncate(inode); > > - up_write(&EXT4_I(inode)->i_mmap_sem); > > + filemap_invalidate_unlock(mapping); > > } > > > > /* > > -- > > 2.26.2 > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR