On Friday, January 17, 2020 6:16 AM Darrick J. Wong wrote:
> On Wed, Jan 15, 2020 at 06:24:21PM +0530, Chandan Rajendra wrote:
> > Log space reservation for xattr insert operation can be divided into two
> > parts,
> > 1. Mount time
> > - Inode
> > - Superblock for accounting space allocations
> > - AGF for accounting space used be count, block number, rmapbt and refcnt
> > btrees.
> >
> > 2. The remaining log space can only be calculated at run time because,
> > - A local xattr can be large enough to cause a double split of the dabtree.
> > - The value of the xattr can be large enough to be stored in remote
> > blocks. The contents of the remote blocks are not logged.
> >
> > The log space reservation could be,
> > - 2 * XFS_DA_NODE_MAXDEPTH number of blocks. Additional XFS_DA_NODE_MAXDEPTH
> > number of blocks are required if xattr is large enough to cause another
> > split of the dabtree path from root to leaf block.
> > - BMBT blocks for storing (2 * XFS_DA_NODE_MAXDEPTH) record
> > entries. Additional XFS_DA_NODE_MAXDEPTH number of blocks are required in
> > case of a double split of the dabtree path from root to leaf blocks.
> > - Space for logging blocks of count, block number, rmap and refcnt btrees.
> >
> > Presently, mount time log reservation includes block count required for a
> > single split of the dabtree. The dabtree block count is also taken into
> > account by xfs_attr_calc_size().
> >
> > Also, AGF log space reservation isn't accounted for. Hence log reservation
> > calculation for xattr insert operation gives incorrect value.
> >
> > Apart from the above, xfs_log_calc_max_attrsetm_res() passes a byte count as
> > an argument to XFS_NEXTENTADD_SPACE_RES() instead of block count.
> >
> > To fix these issues, this commit refactors xfs_attr_calc_size() to calculate,
> > 1. The number of dabtree blocks that need to be logged.
> > 2. The number of remote blocks that need to allocated.
> > 3. The number of dabtree blocks that need to allocated.
> >
> > xfs_attr_set() uses this information to compute
> > 1. Number of blocks that needs to allocated during the transaction.
> > 2. Number of bytes that needs to be reserved in the log.
> >
> > This commit also modifies xfs_log_calc_max_attrsetm_res() to invoke
> > xfs_attr_calc_size() to obtain the number of dabtree blocks to be
> > logged which it uses to figure out the total number of blocks to be logged.
> >
> > Signed-off-by: Chandan Rajendra <chandanrlinux@xxxxxxxxx>
> > ---
> > Changelog:
> > V1 -> V2:
> > 1. xfs_attr_calc_size() computes
> > - Number of blocks required to log dabtree blocks.
> > - Number of remote blocks.
> > - Total dabtree blocks to be allocated.
> > 2. Add new function xfs_calc_attr_blocks() to compute the total number of
> > blocks to be allocated during xattr insert operation.
> > 3. Add new function xfs_calc_attr_res() to compute the log space to be
> > reserved during xattr insert operation.
> >
> > fs/xfs/libxfs/xfs_attr.c | 108 +++++++++++++++++++++------------
> > fs/xfs/libxfs/xfs_attr.h | 3 +
> > fs/xfs/libxfs/xfs_log_rlimit.c | 17 +++---
> > fs/xfs/libxfs/xfs_trans_resv.c | 56 +++++++++--------
> > fs/xfs/libxfs/xfs_trans_resv.h | 2 +
> > 5 files changed, 113 insertions(+), 73 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> > index 1eae1db74f6c..363b4c47b134 100644
> > --- a/fs/xfs/libxfs/xfs_attr.c
> > +++ b/fs/xfs/libxfs/xfs_attr.c
> > @@ -183,43 +183,6 @@ xfs_attr_get(
> > return 0;
> > }
> >
> > -/*
> > - * Calculate how many blocks we need for the new attribute,
> > - */
> > -STATIC int
> > -xfs_attr_calc_size(
> > - struct xfs_da_args *args,
> > - int *local)
> > -{
> > - struct xfs_mount *mp = args->dp->i_mount;
> > - int size;
> > - int nblks;
> > -
> > - /*
> > - * Determine space new attribute will use, and if it would be
> > - * "local" or "remote" (note: local != inline).
> > - */
> > - size = xfs_attr_leaf_newentsize(mp, args->namelen, args->valuelen,
> > - local);
> > - nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
> > - if (*local) {
> > - if (size > (args->geo->blksize / 2)) {
> > - /* Double split possible */
> > - nblks *= 2;
> > - }
> > - } else {
> > - /*
> > - * Out of line attribute, cannot double split, but
> > - * make room for the attribute value itself.
> > - */
> > - uint dblocks = xfs_attr3_rmt_blocks(mp, args->valuelen);
> > - nblks += dblocks;
> > - nblks += XFS_NEXTENTADD_SPACE_RES(mp, dblocks, XFS_ATTR_FORK);
> > - }
> > -
> > - return nblks;
> > -}
> > -
> > STATIC int
> > xfs_attr_try_sf_addname(
> > struct xfs_inode *dp,
> > @@ -248,6 +211,64 @@ xfs_attr_try_sf_addname(
> > return error ? error : error2;
> > }
> >
> > +STATIC uint
> > +xfs_calc_attr_blocks(
> > + struct xfs_mount *mp,
> > + unsigned int total_dablks,
> > + unsigned int rmt_blks)
> > +{
> > + unsigned int bmbt_blks;
> > +
> > + bmbt_blks = XFS_NEXTENTADD_SPACE_RES(mp, total_dablks + rmt_blks,
> > + XFS_ATTR_FORK);
> > + return total_dablks + rmt_blks + bmbt_blks;
>
> I think this calculation could be added to xfs_attr_calc_size and passed
> back to the caller as another outparam.
>
> At this point we have five different block counts I'm wondering if we
> should create a struct and pass it around...
>
> > +}
> > +
> > +/*
> > + * Calculate how many blocks we need for the new attribute,
> > + */
> > +void
> > +xfs_attr_calc_size(
> > + struct xfs_mount *mp,
> > + int namelen,
> > + int valuelen,
> > + int *local,
> > + unsigned int *log_dablks,
> > + unsigned int *rmt_blks,
> > + unsigned int *total_dablks)
>
> ...something like this? It'll be much easier to remember what each of
> those parameters actually do with a full sentence comment:
>
> struct xfs_attr_set_resv {
> /* Number of blocks in the da btree that we might need to log. */
> unsigned int log_dablks;
>
> /* Number of unlogged blocks needed to store the remote attr value. */
> unsigned int rmt_blks;
>
> /* Blocks we might need to map into the attribute fork. */
> unsigned int total_dablks;
>
> /* Blocks we might need to allocate. */
> unsigned int alloc_blks;
>
> /* Blocks we might need to create all the new attr fork mappings. */
> unsigned int bmbt_blks;
> };
>
> > +{
> > + unsigned int blksize;
> > + int size;
> > +
> > + blksize = mp->m_dir_geo->blksize;
> > + *log_dablks = 0;
> > + *rmt_blks = 0;
> > + *total_dablks = 0;
>
> No need to zero out variables that we're going to set two lines later.
>
> > +
> > + /*
> > + * Determine space new attribute will use, and if it would be
> > + * "local" or "remote" (note: local != inline).
> > + */
> > + size = xfs_attr_leaf_newentsize(mp, namelen, valuelen, local);
> > +
> > + *total_dablks = XFS_DAENTER_BLOCKS(mp, XFS_ATTR_FORK);
> > + *log_dablks = 2 * *total_dablks;
> > +
> > + if (*local) {
> > + if (size > (blksize / 2)) {
> > + /* Double split possible */
> > + *log_dablks += *total_dablks;
> > + *total_dablks *= 2;
> > + }
> > + } else {
> > + /*
> > + * Out of line attribute, cannot double split, but
> > + * make room for the attribute value itself.
> > + */
> > + *rmt_blks = xfs_attr3_rmt_blocks(mp, valuelen);
> > + }
> > +}
> > +
> > /*
> > * Set the attribute specified in @args.
> > */
> > @@ -346,6 +367,9 @@ xfs_attr_set(
> > struct xfs_mount *mp = dp->i_mount;
> > struct xfs_da_args args;
> > struct xfs_trans_res tres;
> > + unsigned int log_dablks;
> > + unsigned int rmt_blks;
> > + unsigned int total_dablks;
> > int rsvd = (flags & ATTR_ROOT) != 0;
> > int error, local;
> >
> > @@ -361,7 +385,11 @@ xfs_attr_set(
> > args.value = value;
> > args.valuelen = valuelen;
> > args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
> > - args.total = xfs_attr_calc_size(&args, &local);
> > +
> > + xfs_attr_calc_size(mp, args.namelen, args.valuelen, &local,
> > + &log_dablks, &rmt_blks, &total_dablks);
> > +
> > + args.total = xfs_calc_attr_blocks(mp, total_dablks, rmt_blks);
> >
> > error = xfs_qm_dqattach(dp);
> > if (error)
> > @@ -380,8 +408,8 @@ xfs_attr_set(
> > return error;
> > }
> >
> > - tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
> > - M_RES(mp)->tr_attrsetrt.tr_logres * args.total;
> > + tres.tr_logres = xfs_calc_attr_res(mp, log_dablks, rmt_blks,
> > + total_dablks);
> > tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
> > tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
> >
> > diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> > index 94badfa1743e..a1c77618802b 100644
> > --- a/fs/xfs/libxfs/xfs_attr.h
> > +++ b/fs/xfs/libxfs/xfs_attr.h
> > @@ -154,5 +154,8 @@ int xfs_attr_remove_args(struct xfs_da_args *args);
> > int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
> > int flags, struct attrlist_cursor_kern *cursor);
> > bool xfs_attr_namecheck(const void *name, size_t length);
> > +void xfs_attr_calc_size(struct xfs_mount *mp, int namelen, int valuelen,
> > + int *local, unsigned int *log_dablks,
> > + unsigned int *rmt_blks, unsigned int *total_dablks);
> >
> > #endif /* __XFS_ATTR_H__ */
> > diff --git a/fs/xfs/libxfs/xfs_log_rlimit.c b/fs/xfs/libxfs/xfs_log_rlimit.c
> > index 7f55eb3f3653..33b805411f72 100644
> > --- a/fs/xfs/libxfs/xfs_log_rlimit.c
> > +++ b/fs/xfs/libxfs/xfs_log_rlimit.c
> > @@ -10,6 +10,7 @@
> > #include "xfs_log_format.h"
> > #include "xfs_trans_resv.h"
> > #include "xfs_mount.h"
> > +#include "xfs_attr.h"
> > #include "xfs_da_format.h"
> > #include "xfs_trans_space.h"
> > #include "xfs_da_btree.h"
> > @@ -23,17 +24,19 @@ STATIC int
> > xfs_log_calc_max_attrsetm_res(
> > struct xfs_mount *mp)
> > {
> > - int size;
> > - int nblks;
> > + int size;
> > + int local;
> > + unsigned int total_dablks;
> > + unsigned int rmt_blks;
> > + unsigned int log_dablks;
> >
> > size = xfs_attr_leaf_entsize_local_max(mp->m_attr_geo->blksize) -
> > MAXNAMELEN - 1;
> > - nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
> > - nblks += XFS_B_TO_FSB(mp, size);
> > - nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
> > + xfs_attr_calc_size(mp, size, 0, &local, &log_dablks, &rmt_blks,
> > + &total_dablks);
> > + ASSERT(local == 1);
> >
> > - return M_RES(mp)->tr_attrsetm.tr_logres +
> > - M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
> > + return xfs_calc_attr_res(mp, log_dablks, rmt_blks, total_dablks);
> > }
> >
> > /*
> > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
> > index 824073a839ac..8a0fea655358 100644
> > --- a/fs/xfs/libxfs/xfs_trans_resv.c
> > +++ b/fs/xfs/libxfs/xfs_trans_resv.c
> > @@ -701,12 +701,10 @@ xfs_calc_attrinval_reservation(
> > * Setting an attribute at mount time.
> > * the inode getting the attribute
> > * the superblock for allocations
> > - * the agfs extents are allocated from
> > - * the attribute btree * max depth
> > - * the inode allocation btree
> > + * the agf extents are allocated from
> > * Since attribute transaction space is dependent on the size of the attribute,
> > * the calculation is done partially at mount time and partially at runtime(see
> > - * below).
> > + * xfs_attr_calc_size()).
> > */
> > STATIC uint
> > xfs_calc_attrsetm_reservation(
> > @@ -714,27 +712,7 @@ xfs_calc_attrsetm_reservation(
> > {
> > return XFS_DQUOT_LOGRES(mp) +
> > xfs_calc_inode_res(mp, 1) +
> > - xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) +
> > - xfs_calc_buf_res(XFS_DA_NODE_MAXDEPTH, XFS_FSB_TO_B(mp, 1));
> > -}
> > -
> > -/*
> > - * Setting an attribute at runtime, transaction space unit per block.
> > - * the superblock for allocations: sector size
> > - * the inode bmap btree could join or split: max depth * block size
> > - * Since the runtime attribute transaction space is dependent on the total
> > - * blocks needed for the 1st bmap, here we calculate out the space unit for
> > - * one block so that the caller could figure out the total space according
> > - * to the attibute extent length in blocks by:
> > - * ext * M_RES(mp)->tr_attrsetrt.tr_logres
> > - */
> > -STATIC uint
> > -xfs_calc_attrsetrt_reservation(
> > - struct xfs_mount *mp)
> > -{
> > - return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) +
> > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK),
> > - XFS_FSB_TO_B(mp, 1));
> > + xfs_calc_buf_res(2, mp->m_sb.sb_sectsize);
>
> What effect does changing these reservation calculations have on the
> computed minimum log size?
>
> > }
> >
> > /*
> > @@ -832,6 +810,32 @@ xfs_calc_sb_reservation(
> > return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize);
> > }
> >
> > +uint
> > +xfs_calc_attr_res(
> > + struct xfs_mount *mp,
> > + unsigned int log_dablks,
> > + unsigned int rmt_blks,
> > + unsigned int total_dablks)
> > +{
> > + unsigned int da_blksize;
> > + unsigned int fs_blksize;
> > + unsigned int bmbt_blks;
> > + unsigned int space_blks;
> > +
> > + bmbt_blks = XFS_NEXTENTADD_SPACE_RES(mp, total_dablks + rmt_blks,
> > + XFS_ATTR_FORK);
>
> Pass in the resv structure above and you won't need to calculate this
> again.
>
> > + space_blks = xfs_allocfree_log_count(mp,
> > + total_dablks + rmt_blks + bmbt_blks);
>
> Only two levels of indent needed here:
>
> space_blks = xfs_allocfree_log_count(mp,
> total_dablks + rmt_blks + bmbt_blks);
>
> > +
> > + da_blksize = mp->m_attr_geo->blksize;
> > + fs_blksize = mp->m_sb.sb_blocksize;
>
> You could probably pass these to xfs_calc_buf_res directly.
>
> I'll give this a spin and see how it does.
>
> --D
>
> > +
> > + return M_RES(mp)->tr_attrsetm.tr_logres +
> > + xfs_calc_buf_res(log_dablks, da_blksize) +
> > + xfs_calc_buf_res(bmbt_blks, fs_blksize) +
> > + xfs_calc_buf_res(space_blks, fs_blksize);
> > +}
> > +
> > void
> > xfs_trans_resv_calc(
> > struct xfs_mount *mp,
> > @@ -942,7 +946,7 @@ xfs_trans_resv_calc(
> > resp->tr_ichange.tr_logres = xfs_calc_ichange_reservation(mp);
> > resp->tr_fsyncts.tr_logres = xfs_calc_swrite_reservation(mp);
> > resp->tr_writeid.tr_logres = xfs_calc_writeid_reservation(mp);
> > - resp->tr_attrsetrt.tr_logres = xfs_calc_attrsetrt_reservation(mp);
> > + resp->tr_attrsetrt.tr_logres = 0;
> > resp->tr_clearagi.tr_logres = xfs_calc_clear_agi_bucket_reservation(mp);
> > resp->tr_growrtzero.tr_logres = xfs_calc_growrtzero_reservation(mp);
> > resp->tr_growrtfree.tr_logres = xfs_calc_growrtfree_reservation(mp);
> > diff --git a/fs/xfs/libxfs/xfs_trans_resv.h b/fs/xfs/libxfs/xfs_trans_resv.h
> > index 7241ab28cf84..48ceba72fb12 100644
> > --- a/fs/xfs/libxfs/xfs_trans_resv.h
> > +++ b/fs/xfs/libxfs/xfs_trans_resv.h
> > @@ -91,6 +91,8 @@ struct xfs_trans_resv {
> > #define XFS_ATTRSET_LOG_COUNT 3
> > #define XFS_ATTRRM_LOG_COUNT 3
> >
> > +uint xfs_calc_attr_res(struct xfs_mount *mp, unsigned int log_dablks,
> > + unsigned int rmt_blks, unsigned int total_dablks);
> > void xfs_trans_resv_calc(struct xfs_mount *mp, struct xfs_trans_resv *resp);
> > uint xfs_allocfree_log_count(struct xfs_mount *mp, uint num_ops);
> >
>
Hi Darrick,
I agree to the changes you have suggested. I will apply them and post the next
version soon.
I will also figure out the effect of this patch on minimum log size.
--
chandan
