From: Dave Chinner Subject: Re: [PATCH RESEND 2/12] xfs: Add support FALLOC_FL_INSERT_RANGE for fallocate Date: Tue, 17 Feb 2015 11:54:08 +1100 Message-ID: <20150217005408.GE4251@dastard> References: <1424101680-3301-1-git-send-email-linkinjeon@gmail.com> <1424101680-3301-3-git-send-email-linkinjeon@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: tytso-3s7WtUTddSA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org, a.sangwan-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, bfoster-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Namjae Jeon To: Namjae Jeon Return-path: Content-Disposition: inline In-Reply-To: <1424101680-3301-3-git-send-email-linkinjeon-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On Tue, Feb 17, 2015 at 12:47:49AM +0900, Namjae Jeon wrote: > From: Namjae Jeon > > This patch implements fallocate's FALLOC_FL_INSERT_RANGE for XFS. > > 1) Make sure that both offset and len are block size aligned. > 2) Update the i_size of inode by len bytes. > 3) Compute the file's logical block number against offset. If the computed > block number is not the starting block of the extent, split the extent > such that the block number is the starting block of the extent. > 4) Shift all the extents which are lying bewteen [offset, last allocated extent] > towards right by len bytes. This step will make a hole of len bytes > at offset. > > Signed-off-by: Namjae Jeon > Signed-off-by: Ashish Sangwan > Reviewed-by: Brian Foster > --- > fs/xfs/libxfs/xfs_bmap.c | 358 ++++++++++++++++++++++++++++++++++++++++------ > fs/xfs/libxfs/xfs_bmap.h | 13 +- > fs/xfs/xfs_bmap_util.c | 126 +++++++++++----- > fs/xfs/xfs_bmap_util.h | 2 + > fs/xfs/xfs_file.c | 38 ++++- > fs/xfs/xfs_trace.h | 1 + > 6 files changed, 455 insertions(+), 83 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index 61ec015..6699e53 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -5518,50 +5518,86 @@ xfs_bmse_shift_one( > int *current_ext, > struct xfs_bmbt_rec_host *gotp, > struct xfs_btree_cur *cur, > - int *logflags) > + int *logflags, > + enum SHIFT_DIRECTION SHIFT) Please don't shout. ;) Lower case for types and variables, upper case for the enum values. I also think the "shift" variable should be named "direction", too, so the code reads "if (direction == SHIFT_LEFT)" and so is clearly self documenting... (only commenting once on this, please change it in other places) as well ;) > { > struct xfs_ifork *ifp; > xfs_fileoff_t startoff; > - struct xfs_bmbt_rec_host *leftp; > + struct xfs_bmbt_rec_host *contp; > struct xfs_bmbt_irec got; > - struct xfs_bmbt_irec left; > + struct xfs_bmbt_irec cont; Not sure what "cont" is short for. It's used as the "adjacent extent" record, so that would be a better name IMO. > int error; > int i; > + int total_extents; > > ifp = XFS_IFORK_PTR(ip, whichfork); > + total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > > xfs_bmbt_get_all(gotp, &got); > - startoff = got.br_startoff - offset_shift_fsb; > > /* delalloc extents should be prevented by caller */ > XFS_WANT_CORRUPTED_RETURN(!isnullstartblock(got.br_startblock)); > > - /* > - * Check for merge if we've got an extent to the left, otherwise make > - * sure there's enough room at the start of the file for the shift. > - */ > - if (*current_ext) { > - /* grab the left extent and check for a large enough hole */ > - leftp = xfs_iext_get_ext(ifp, *current_ext - 1); > - xfs_bmbt_get_all(leftp, &left); > + if (SHIFT == SHIFT_LEFT) { > + startoff = got.br_startoff - offset_shift_fsb; > > - if (startoff < left.br_startoff + left.br_blockcount) > + /* > + * Check for merge if we've got an extent to the left, > + * otherwise make sure there's enough room at the start > + * of the file for the shift. > + */ > + if (*current_ext) { > + /* > + * grab the left extent and check for a large > + * enough hole. > + */ > + contp = xfs_iext_get_ext(ifp, *current_ext - 1); > + xfs_bmbt_get_all(contp, &cont); > + > + if (startoff < cont.br_startoff + cont.br_blockcount) > + return -EINVAL; > + > + /* check whether to merge the extent or shift it down */ > + if (xfs_bmse_can_merge(&cont, &got, offset_shift_fsb)) { > + return xfs_bmse_merge(ip, whichfork, > + offset_shift_fsb, > + *current_ext, gotp, contp, > + cur, logflags); > + } > + } else if (got.br_startoff < offset_shift_fsb) > return -EINVAL; This would be better written: if (!*current_ext) { if (got.br_startoff < offset_shift_fsb) return -EINVAL; goto update_current_ext; } and then the rest of the code in the shift left branch can drop a level of indent and hence become less congested and easier to read. > + } else { > + startoff = got.br_startoff + offset_shift_fsb; > + /* > + * If this is not the last extent in the file, make sure there's > + * enough room between current extent and next extent for > + * accommodating the shift. > + */ > + if (*current_ext < (total_extents - 1)) { > + contp = xfs_iext_get_ext(ifp, *current_ext + 1); > + xfs_bmbt_get_all(contp, &cont); > + if (startoff + got.br_blockcount > cont.br_startoff) > + return -EINVAL; > > - /* check whether to merge the extent or shift it down */ > - if (xfs_bmse_can_merge(&left, &got, offset_shift_fsb)) { > - return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, > - *current_ext, gotp, leftp, cur, > - logflags); > + /* > + * Unlike a left shift (which involves a hole punch), > + * a right shift does not modify extent neighbors > + * in any way. We should never find mergeable extents > + * in this scenario. Check anyways and warn if we > + * encounter two extents that could be one. > + */ > + if (xfs_bmse_can_merge(&got, &cont, offset_shift_fsb)) > + WARN_ON_ONCE(1); > } Similarly: /* nothing to move if this is the last extent */ if (*current_ext >= total_extents) goto update_current_ext; > - } else if (got.br_startoff < offset_shift_fsb) > - return -EINVAL; > - > + } > /* > * Increment the extent index for the next iteration, update the start > * offset of the in-core extent and update the btree if applicable. > */ > - (*current_ext)++; update_current_ext: > + if (SHIFT == SHIFT_LEFT) > + (*current_ext)++; > + else > + (*current_ext)--; > xfs_bmbt_set_startoff(gotp, startoff); > *logflags |= XFS_ILOG_CORE; > if (!cur) { > @@ -5581,10 +5617,10 @@ xfs_bmse_shift_one( > } > > /* > - * Shift extent records to the left to cover a hole. > + * Shift extent records to the left/right to cover/create a hole. > * > * The maximum number of extents to be shifted in a single operation is > - * @num_exts. @start_fsb specifies the file offset to start the shift and the > + * @num_exts. @stop_fsb specifies the file offset at which to stop shift and the > * file offset where we've left off is returned in @next_fsb. @offset_shift_fsb > * is the length by which each extent is shifted. If there is no hole to shift > * the extents into, this will be considered invalid operation and we abort > @@ -5594,12 +5630,13 @@ int > xfs_bmap_shift_extents( > struct xfs_trans *tp, > struct xfs_inode *ip, > - xfs_fileoff_t start_fsb, > + xfs_fileoff_t *next_fsb, > xfs_fileoff_t offset_shift_fsb, > int *done, > - xfs_fileoff_t *next_fsb, > + xfs_fileoff_t stop_fsb, > xfs_fsblock_t *firstblock, > struct xfs_bmap_free *flist, > + enum SHIFT_DIRECTION SHIFT, > int num_exts) > { > struct xfs_btree_cur *cur = NULL; > @@ -5609,10 +5646,11 @@ xfs_bmap_shift_extents( > struct xfs_ifork *ifp; > xfs_extnum_t nexts = 0; > xfs_extnum_t current_ext; > + xfs_extnum_t total_extents; > + xfs_extnum_t stop_extent; > int error = 0; > int whichfork = XFS_DATA_FORK; > int logflags = 0; > - int total_extents; > > if (unlikely(XFS_TEST_ERROR( > (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS && > @@ -5628,6 +5666,7 @@ xfs_bmap_shift_extents( > > ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL)); > ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); > + ASSERT(SHIFT == SHIFT_LEFT || SHIFT == SHIFT_RIGHT); > > ifp = XFS_IFORK_PTR(ip, whichfork); > if (!(ifp->if_flags & XFS_IFEXTENTS)) { > @@ -5645,43 +5684,85 @@ xfs_bmap_shift_extents( > } > > /* > + * There may be delalloc extents in the data fork before the range we > + * are collapsing out, so we cannot use the count of real extents here. > + * Instead we have to calculate it from the incore fork. > + */ > + total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > + if (total_extents == 0) { > + *done = 1; > + goto del_cursor; > + } > + > + /* > + * In case of first right shift, we need to initialize next_fsb > + */ > + if (*next_fsb == NULLFSBLOCK) { > + ASSERT(SHIFT == SHIFT_RIGHT); This should be at the top of the function. i.e. ASSERT(*next_fsb != NULLFSBLOCK || direction == SHIFT_RIGHT) > + gotp = xfs_iext_get_ext(ifp, total_extents - 1); > + xfs_bmbt_get_all(gotp, &got); > + *next_fsb = got.br_startoff; > + if (stop_fsb > *next_fsb) { > + *done = 1; > + goto del_cursor; > + } > + } > + > + /* Lookup the extent index at which we have to stop */ > + if (SHIFT == SHIFT_RIGHT) { > + gotp = xfs_iext_bno_to_ext(ifp, stop_fsb, &stop_extent); > + /* Make stop_extent exclusive of shift range */ > + stop_extent--; > + } else > + stop_extent = total_extents; > + > + /* > * Look up the extent index for the fsb where we start shifting. We can > * henceforth iterate with current_ext as extent list changes are locked > * out via ilock. > * > * gotp can be null in 2 cases: 1) if there are no extents or 2) > - * start_fsb lies in a hole beyond which there are no extents. Either > + * *next_fsb lies in a hole beyond which there are no extents. Either > * way, we are done. > */ > - gotp = xfs_iext_bno_to_ext(ifp, start_fsb, ¤t_ext); > + gotp = xfs_iext_bno_to_ext(ifp, *next_fsb, ¤t_ext); > if (!gotp) { > *done = 1; > goto del_cursor; > } > > - /* > - * There may be delalloc extents in the data fork before the range we > - * are collapsing out, so we cannot use the count of real extents here. > - * Instead we have to calculate it from the incore fork. > - */ > - total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > - while (nexts++ < num_exts && current_ext < total_extents) { > + /* some sanity checking before we finally start shifting extents */ > + if ((SHIFT == SHIFT_LEFT && current_ext >= stop_extent) || > + (SHIFT == SHIFT_RIGHT && current_ext <= stop_extent)) { > + error = EIO; error = -EIO; > + goto del_cursor; > + } > + > + while (nexts++ < num_exts) { > error = xfs_bmse_shift_one(ip, whichfork, offset_shift_fsb, > - ¤t_ext, gotp, cur, &logflags); > + ¤t_ext, gotp, cur, &logflags, > + SHIFT); > if (error) > goto del_cursor; > + /* > + * In case there was an extent merge after shifting extent, > + * extent numbers would change. > + * Update total extent count and grab the next record. > + */ /* * If there was an extent merge during the shift, the extent * count can change. Update the total and grade the next record. */ > + if (SHIFT == SHIFT_LEFT) { > + total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > + stop_extent = total_extents; > + } > > - /* update total extent count and grab the next record */ > - total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > - if (current_ext >= total_extents) > + if (current_ext == stop_extent) { > + *done = 1; > + *next_fsb = NULLFSBLOCK; > break; > + } > gotp = xfs_iext_get_ext(ifp, current_ext); > } > > - /* Check if we are done */ > - if (current_ext == total_extents) { > - *done = 1; > - } else if (next_fsb) { > + if (!*done) { > xfs_bmbt_get_all(gotp, &got); > *next_fsb = got.br_startoff; > } > @@ -5696,3 +5777,192 @@ del_cursor: > > return error; > } > + > +/* > + * Splits an extent into two extents at split_fsb block that it is > + * the first block of the current_ext. @current_ext is a target extent > + * to be split. @split_fsb is a block where the extents is split. > + * If split_fsb lies in a hole or the first block of extents, just return 0. > + */ > +STATIC int > +xfs_bmap_split_extent_at( > + struct xfs_trans *tp, > + struct xfs_inode *ip, > + xfs_fileoff_t split_fsb, > + xfs_fsblock_t *firstfsb, > + struct xfs_bmap_free *free_list) > +{ > + int whichfork = XFS_DATA_FORK; > + struct xfs_btree_cur *cur = NULL; > + struct xfs_bmbt_rec_host *gotp; > + struct xfs_bmbt_irec got; > + struct xfs_bmbt_irec new; /* split extent */ > + struct xfs_mount *mp = ip->i_mount; > + struct xfs_ifork *ifp; > + xfs_fsblock_t gotblkcnt; /* new block count for got */ > + xfs_extnum_t current_ext; > + int error = 0; > + int logflags = 0; > + int i = 0; > + > + if (unlikely(XFS_TEST_ERROR( > + (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS && > + XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE), > + mp, XFS_ERRTAG_BMAPIFORMAT, XFS_RANDOM_BMAPIFORMAT))) { > + XFS_ERROR_REPORT("xfs_bmap_split_extent_at", > + XFS_ERRLEVEL_LOW, mp); > + return -EFSCORRUPTED; > + } > + > + if (XFS_FORCED_SHUTDOWN(mp)) > + return -EIO; > + > + ifp = XFS_IFORK_PTR(ip, whichfork); > + if (!(ifp->if_flags & XFS_IFEXTENTS)) { > + /* Read in all the extents */ > + error = xfs_iread_extents(tp, ip, whichfork); > + if (error) > + return error; > + } > + > + gotp = xfs_iext_bno_to_ext(ifp, split_fsb, ¤t_ext); > + /* > + * gotp can be null in 2 cases: 1) if there are no extents > + * or 2) split_fsb lies in a hole beyond which there are > + * no extents. Either way, we are done. > + */ > + if (!gotp) > + return 0; Comment can go before the call to xfs_iext_bno_to_ext(). > + > + xfs_bmbt_get_all(gotp, &got); > + > + /* > + * Check split_fsb lies in a hole or the start boundary offset > + * of the extent. > + */ > + if (got.br_startoff >= split_fsb) > + return 0; > + > + gotblkcnt = split_fsb - got.br_startoff; > + new.br_startoff = split_fsb; > + new.br_startblock = got.br_startblock + gotblkcnt; > + new.br_blockcount = got.br_blockcount - gotblkcnt; > + new.br_state = got.br_state; > + > + if (ifp->if_flags & XFS_IFBROOT) { > + cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork); > + cur->bc_private.b.firstblock = *firstfsb; > + cur->bc_private.b.flist = free_list; > + cur->bc_private.b.flags = 0; > + } > + > + if (cur) { No need to close the XFS_IFBROOT branch and then check for cur; we just allocated it inside the XFS_IFBROOT branch! > + error = xfs_bmbt_lookup_eq(cur, got.br_startoff, > + got.br_startblock, > + got.br_blockcount, > + &i); > + if (error) > + goto del_cursor; > + XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor); > + } .... > @@ -1427,20 +1429,23 @@ xfs_collapse_file_space( > > /* > * Writeback and invalidate cache for the remainder of the file as we're > - * about to shift down every extent from the collapse range to EOF. The > - * free of the collapse range above might have already done some of > - * this, but we shouldn't rely on it to do anything outside of the range > - * that was freed. > + * about to shift down every extent from offset to EOF. > */ > error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, > - offset + len, -1); > + offset, -1); > if (error) > return error; > error = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, > - (offset + len) >> PAGE_CACHE_SHIFT, -1); > + offset >> PAGE_CACHE_SHIFT, -1); > if (error) > return error; > > + if (SHIFT == SHIFT_RIGHT) { > + error = xfs_bmap_split_extent(ip, stop_fsb); > + if (error) > + return error; > + } This needs a comment explaining why we are splitting an extent here. > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 1cdba95..222a91a 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -823,11 +823,13 @@ xfs_file_fallocate( > long error; > enum xfs_prealloc_flags flags = 0; > loff_t new_size = 0; > + int do_file_insert = 0; bool rather than int. > > if (!S_ISREG(inode->i_mode)) > return -EINVAL; > if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | > - FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE)) > + FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | > + FALLOC_FL_INSERT_RANGE)) > return -EOPNOTSUPP; This should use a local define before the function such as: #define XFS_FALLOC_FL_SUPPORTED \ (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \ FALLOC_FL_INSERT_RANGE) This is similar to how we define supported checks for FIEMAP operations in xfs_vn_fiemap(). > > xfs_ilock(ip, XFS_IOLOCK_EXCL); > @@ -857,6 +859,28 @@ xfs_file_fallocate( > error = xfs_collapse_file_space(ip, offset, len); > if (error) > goto out_unlock; > + } else if (mode & FALLOC_FL_INSERT_RANGE) { > + unsigned blksize_mask = (1 << inode->i_blkbits) - 1; > + > + if (offset & blksize_mask || len & blksize_mask) { > + error = -EINVAL; > + goto out_unlock; > + } > + > + /* Check for wrap through zero */ > + if (inode->i_size + len > inode->i_sb->s_maxbytes) { > + error = -EFBIG; > + goto out_unlock; > + } At first I thought that was a duplicate check of what is in vfs_fallocate() (i.e. off + len > s_maxbytes). Can you change the comment to read something like: /* check the new inode size does not wrap through zero */ > + > + /* Offset should be less than i_size */ > + if (offset >= i_size_read(inode)) { > + error = -EINVAL; > + goto out_unlock; > + } > + > + new_size = i_size_read(inode) + len; > + do_file_insert = 1; Why do you use inode->i_size onthe wrap check, yet i_size_read() twice here? > } else { > flags |= XFS_PREALLOC_SET; > > @@ -891,8 +915,20 @@ xfs_file_fallocate( > iattr.ia_valid = ATTR_SIZE; > iattr.ia_size = new_size; > error = xfs_setattr_size(ip, &iattr); > + if (error) > + goto out_unlock; > } > > + /* > + * Some operations are performed after the inode size is updated. For > + * example, insert range expands the address space of the file, shifts > + * all subsequent extents to create a hole inside the file. Updating > + * the size first ensures that shifted extents aren't left hanging > + * past EOF in the event of a crash or failure. > + */ /* * Perform hole insertion now that the file size has been * updated so that if we crash during the operation we don't * leave shifted extents past EOF and hence losing access to * the data that is contained within them. */ > + if (do_file_insert) > + error = xfs_insert_file_space(ip, offset, len); > + > out_unlock: > xfs_iunlock(ip, XFS_IOLOCK_EXCL); > return error; Cheers, Dave. -- Dave Chinner david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html