> > Hi Namjae, Hi Brian, > > Here are some review notes. I haven't got to any of the test code or > played around with it just yet... Thanks for your reivew :)
> > > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > > index 79c9819..da01890 100644 > > --- a/fs/xfs/libxfs/xfs_bmap.c > > +++ b/fs/xfs/libxfs/xfs_bmap.c > > @@ -5528,56 +5528,87 @@ xfs_bmse_shift_one( > > FYI, you're probably going to need to rebase the xfs_bmse_shift_one() > bits on top of Dave's recent cleanup here: > > http://oss.sgi.com/archives/xfs/2014-11/msg00458.html okay. > > > int *current_ext, > > struct xfs_bmbt_rec_host *gotp, > > struct xfs_btree_cur *cur, > > - int *logflags) > > + int *logflags, > > + enum SHIFT_DIRECTION SHIFT) > > { > > 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; > > 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_GOTO(!isnullstartblock(got.br_startblock), > > out_error); > > > > - /* > > - * If this is the first extent in the file, make sure there's enough > > - * room at the start of the file and jump right to the shift as there's > > - * no left extent to merge. > > - */ > > - if (*current_ext == 0) { > > - if (got.br_startoff < offset_shift_fsb) > > + if (SHIFT == SHIFT_LEFT) { > > + startoff = got.br_startoff - offset_shift_fsb; > > + /* > > + * If this is the first extent in the file, make sure there's > > + * enough room at the start of the file and jump right to the > > + * shift as there's no left extent to merge. > > + */ > > + if (*current_ext == 0) { > > + if (got.br_startoff < offset_shift_fsb) > > + return -EINVAL; > > + goto shift_extent; > > + } > > + > > + /* 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; > > - goto shift_extent; > > - } > > > > - /* 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); > > + /* check whether to merge the extent or shift it down */ > > + if (!xfs_bmse_can_merge(&cont, &got, offset_shift_fsb)) > > + goto shift_extent; > > > > - if (startoff < left.br_startoff + left.br_blockcount) > > - return -EINVAL; > > + return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, > > + *current_ext, gotp, contp, cur, logflags); > > + } else { > > + startoff = got.br_startoff + offset_shift_fsb; > > + /* > > + * If this is the last extent in the file, make sure there's > > + * enough room at the end of the file and jump right to the > > + * shift as there's no right extent to merge. > > + */ > > + if (*current_ext == (total_extents - 1)) > > + goto shift_extent; > > > > - /* check whether to merge the extent or shift it down */ > > - if (!xfs_bmse_can_merge(&left, &got, offset_shift_fsb)) > > - goto shift_extent; > > + /* grab the right extent and check for a large enough hole */ > > + contp = xfs_iext_get_ext(ifp, *current_ext + 1); > > + xfs_bmbt_get_all(contp, &cont); > > > > - return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, *current_ext, > > - gotp, leftp, cur, logflags); > > + if (startoff > cont.br_startoff) > > + return -EINVAL; > > Shouldn't this be 'if (startoff + got.br_blockount > cont.br_startoff)'? True, I will fix. > > > + > > + if (!xfs_bmse_can_merge(&got, &cont, offset_shift_fsb)) > > + goto shift_extent; > > + > > + return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, > > + *current_ext + 1, contp, gotp, cur, > > + logflags); > > It doesn't look like xfs_bmse_merge() is bidirectional in this sense. > The can_merge() helper might work Ok since we're just checking whether > the extents line up. The merge code, however, will always extend the > block count of the left extent and delete the right. The left extent is > gotp in this case, which is the extent we want to shift right. In other > words, it seems like we should adjust the start offset of the right > extent to the right-shifted start offset of the left and delete the > left. Right, I will change. > > That said, I wonder whether we even care about a merge in the right > shift case since we haven't punched a hole in the file and thus have not > changed the "neighbors" of any of the extents we're shuffling around. I > would think any extents that are already contiguous as such are already > a single extent. yes, in case of insert range it is highly unlikely that a merge is required. But we have kept this code as part of a generic API for shifting extents. > > > + } > > > > shift_extent: > > /* > > * 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)++; > > + if (SHIFT == SHIFT_LEFT) > > + (*current_ext)++; > > + else > > + (*current_ext)--; > > xfs_bmbt_set_startoff(gotp, startoff); > > *logflags |= XFS_ILOG_CORE; > > if (!cur) { > > @@ -5604,10 +5635,10 @@ out_error: > > } > > > > /* > > - * 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 > > @@ -5617,12 +5648,13 @@ int > > xfs_bmap_shift_extents( > > struct xfs_trans *tp, > > struct xfs_inode *ip, > > - xfs_fileoff_t start_fsb, > > + xfs_fileoff_t stop_fsb, > > xfs_fileoff_t offset_shift_fsb, > > int *done, > > xfs_fileoff_t *next_fsb, > > xfs_fsblock_t *firstblock, > > struct xfs_bmap_free *flist, > > + enum SHIFT_DIRECTION SHIFT, > > int num_exts) > > { > > struct xfs_btree_cur *cur = NULL; > > @@ -5636,6 +5668,7 @@ xfs_bmap_shift_extents( > > int whichfork = XFS_DATA_FORK; > > int logflags = 0; > > int total_extents; > > + int stop_extent; > > > > if (unlikely(XFS_TEST_ERROR( > > (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS && > > @@ -5651,6 +5684,7 @@ 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)) { > > @@ -5668,43 +5702,87 @@ 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); > > + 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); > > + 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; > > + goto del_cursor; > > + } > > It looks like stop_extent is exclusive for left shifts (== total_extents > rather than the last extent number) and inclusive for right shifts. > Could we be consistent between the two? Right, we can change stop_extent = total_extents - 1 in case of collapse to make it consistent. > > > + > > + 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; > > - > > - /* update total extent count and grab the next record */ > > + /* > > + * In case there was an extent merge after shifting extent, > > + * extent numbers would change. > > + * Update total extent count and grab the next record. > > + */ > > total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t); > > - if (current_ext >= total_extents) > > - break; > > + if (SHIFT == SHIFT_RIGHT) { > > + gotp = xfs_iext_bno_to_ext(ifp, stop_fsb, &stop_extent); > > + if (current_ext < stop_extent) { > > + *done = 1; > > + break; > > + } > > + } else { > > + stop_extent = total_extents; > > + if (current_ext == stop_extent) { > > + *done = 1; > > + break; > > + } > > ... and if we can make stop_extent consistently exclusive, it looks like > we could use 'if (current_ext == stop_extent)' as a stop condition for > both cases, yes? Yes. Right. > > > + } > > 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; > > } > > Might be good to set next_fsb to NULLFSBLOCK or some such value if we > are done. Okay. > > + > > + /* > > + * 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; > > + > > + /* We are going to change core inode */ > > + logflags = XFS_ILOG_CORE; > > + > > + 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; > > + } else { > > + cur = NULL; > > + logflags |= XFS_ILOG_DEXT; > > + } > > This looks like it suffers from a similar problem as the bmap shift code > with regard to logflags and error handling. Check out the subsequent fix > for reference: > > ca446d88 xfs: don't log inode unless extent shift makes extent modifications > > We basically init. logflags to 0 and delay setting the actual flags as > long as possible, until we actually make a change to the extent tree or > bmap btree. > > Otherwise, if the following lookup were to fail, for example, we'd still > log the inode even though we haven't changed anything and ultimately the > fs will shutdown on transaction cancel. True, I will update. > > + } > > + > > + /* > > + * Convert to a btree if necessary. > > + */ > > + if (xfs_bmap_needs_btree(ip, whichfork)) { > > + int tmp_logflags; /* partial log flag return val */ > > + > > + ASSERT(cur == NULL); > > + error = xfs_bmap_extents_to_btree(tp, ip, firstfsb, free_list, > > + &cur, 0, &tmp_logflags, whichfork); > > + logflags |= tmp_logflags; > > + } > > Hmm, looks Ok, but it would be nice if we had a test case for this > convert to btree scenario. I suspect something that falloc's just the > right number extents for a known fs format and does an insert range > right in the middle of one would suffice (and probably only require a > few seconds to run). Okay, I will prepare a testcase for convert to btree scenario of insert range. for collapse range we have generic/017 which tests multiple collapse calls on same file. I can write same test for insert range which will insert a single block hole at every alternate block in the file. Each insert range call will split the extent into 2 extents. This test need not be fs specfic so can be used for ext4 also. > > > + > > +del_cursor: > > + if (cur) { > > + cur->bc_private.b.allocated = 0; > > + xfs_btree_del_cursor(cur, > > + error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR); > > + } > > + xfs_trans_log_inode(tp, ip, logflags); > > + return error; > > +} > > + > > +int > > +xfs_bmap_split_extent( > > + struct xfs_inode *ip, > > + xfs_fileoff_t split_fsb) > > You can line up the above params with the local vars below. Okay. > > > +{ > > + struct xfs_mount *mp = ip->i_mount; > > + struct xfs_trans *tp; > > + struct xfs_bmap_free free_list; > > + xfs_fsblock_t firstfsb; > > + int committed; > > + int error; > > + > > + tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT); > > + error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, > > + XFS_DIOSTRAT_SPACE_RES(mp, 0), 0); > > + if (error) { > > + xfs_trans_cancel(tp, 0); > > + return error; > > + } > > + > > + xfs_ilock(ip, XFS_ILOCK_EXCL); > > + error = xfs_trans_reserve_quota(tp, mp, ip->i_udquot, > > + ip->i_gdquot, ip->i_pdquot, > > + XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, > > + XFS_QMOPT_RES_REGBLKS); > > + if (error) > > + goto out; > > + > > + xfs_trans_ijoin(tp, ip, 0); > > Might as well transfer the lock to the tp here? That avoids the need for > the unlocks below. We just need to make sure we order things correctly > such that the inode is unlocked on error conditions. Could you elaborate more ? Acutally, I can not find what is problem.. > > - * > > + * @next_fsb will keep track of the extent currently undergoing shift. > > + * @stop_fsb will keep track of the extent at which we have to stop. > > + * If we are shifting left, we will start with block (offset + len) and > > + * shift each extent till last extent. > > + * If we are shifting right, we will start with last extent inside file > > space > > + * and continue until we reach the block corresponding to offset. > > + * If right shift, delegate the work of > > + * initialization of next_fsb to xfs_bmap_shift_extent as it has ilock > > held. > > Could you move the bit of the comment about the next_fsb right-shift > init down where we set it to NULLFSBLOCK? That way it is a bit more > clear. Okay. > > + > > while (!error && !done) { > > tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT); > > /* > > @@ -1475,10 +1478,9 @@ xfs_collapse_file_space( > > * We are using the write transaction in which max 2 bmbt > > * updates are allowed > > */ > > - start_fsb = next_fsb; > > - error = xfs_bmap_shift_extents(tp, ip, start_fsb, shift_fsb, > > + error = xfs_bmap_shift_extents(tp, ip, stop_fsb, shift_fsb, > > Nice clean up, but could we reorder next_fsb prior to stop_fsb to be a > bit more clean? Yes, We could. > > } > > > > /* > > + > > + new_size = i_size_read(inode) + len; > > + do_file_insert = 1; > > } else { > > if (!(mode & FALLOC_FL_KEEP_SIZE) && > > offset + len > i_size_read(inode)) { > > There's a check that sets XFS_DIFLAG_PREALLOC down after this hunk but > before the next that we probably want to update to exclude insert range > (it already handles collapse). Okay. Thanks! > > Brian > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
