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: <[email protected]> > CC: Ted Tso <[email protected]>
Hmm, still no ACK from Ted? 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 <[email protected]> --D > Signed-off-by: Jan Kara <[email protected]> > --- > 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 > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
