On Tue, Oct 31, 2017 at 04:22:27PM +0200, Christoph Hellwig wrote:
> Supporting a small bit of data inside the inode fork blows up the fork size
> a lot, removing the 32 bytes of inline data halves the effective size of
> the inode fork (and it still has a lot of unused padding left), and the
> performance of a single kmalloc doesn't show up compared to the size to read
> an inode or create one.
Do you see any secondary effects, such as increased slab fragmentation
because of the extra kmem_allocs? In general I think this should be ok,
I just worry slightly that whatever reason we had for having
if_inline_data is still around and will blow up in weird ways if we get
rid of it.
(I will go play with scrub on a big filesystem to see if it runs
noticeably slower or goes whacky.)
Code-wise,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
>
> It also simplifies the fork management code a lot.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/libxfs/xfs_inode_fork.c | 185 +++--------------------------------------
> fs/xfs/libxfs/xfs_inode_fork.h | 11 ---
> fs/xfs/xfs_bmap_util.c | 15 ----
> 3 files changed, 13 insertions(+), 198 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
> index c9e10d4818b7..5ac341d2b093 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.c
> +++ b/fs/xfs/libxfs/xfs_inode_fork.c
> @@ -269,19 +269,14 @@ xfs_init_local_fork(
> if (zero_terminate)
> mem_size++;
>
> - if (size == 0)
> - ifp->if_u1.if_data = NULL;
> - else if (mem_size <= sizeof(ifp->if_u2.if_inline_data))
> - ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
> - else {
> + if (size) {
> real_size = roundup(mem_size, 4);
> ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS);
> - }
> -
> - if (size) {
> memcpy(ifp->if_u1.if_data, data, size);
> if (zero_terminate)
> ifp->if_u1.if_data[size] = '\0';
> + } else {
> + ifp->if_u1.if_data = NULL;
> }
>
> ifp->if_bytes = size;
> @@ -292,13 +287,6 @@ xfs_init_local_fork(
>
> /*
> * The file is in-lined in the on-disk inode.
> - * If it fits into if_inline_data, then copy
> - * it there, otherwise allocate a buffer for it
> - * and copy the data there. Either way, set
> - * if_data to point at the data.
> - * If we allocate a buffer for the data, make
> - * sure that its size is a multiple of 4 and
> - * record the real size in i_real_bytes.
> */
> STATIC int
> xfs_iformat_local(
> @@ -328,9 +316,7 @@ xfs_iformat_local(
>
> /*
> * The file consists of a set of extents all of which fit into the on-disk
> - * inode. If there are few enough extents to fit into the if_inline_ext, then
> - * copy them there. Otherwise allocate a buffer for them and copy them into it.
> - * Either way, set if_extents to point at the extents.
> + * inode.
> */
> STATIC int
> xfs_iformat_extents(
> @@ -362,8 +348,6 @@ xfs_iformat_extents(
> ifp->if_real_bytes = 0;
> if (nex == 0)
> ifp->if_u1.if_extents = NULL;
> - else if (nex <= XFS_INLINE_EXTS)
> - ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
> else
> xfs_iext_add(ifp, 0, nex);
>
> @@ -618,26 +602,9 @@ xfs_idata_realloc(
> ASSERT(new_size >= 0);
>
> if (new_size == 0) {
> - if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
> - kmem_free(ifp->if_u1.if_data);
> - }
> + kmem_free(ifp->if_u1.if_data);
> ifp->if_u1.if_data = NULL;
> real_size = 0;
> - } else if (new_size <= sizeof(ifp->if_u2.if_inline_data)) {
> - /*
> - * If the valid extents/data can fit in if_inline_ext/data,
> - * copy them from the malloc'd vector and free it.
> - */
> - if (ifp->if_u1.if_data == NULL) {
> - ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
> - } else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
> - ASSERT(ifp->if_real_bytes != 0);
> - memcpy(ifp->if_u2.if_inline_data, ifp->if_u1.if_data,
> - new_size);
> - kmem_free(ifp->if_u1.if_data);
> - ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
> - }
> - real_size = 0;
> } else {
> /*
> * Stuck with malloc/realloc.
> @@ -651,7 +618,7 @@ xfs_idata_realloc(
> ASSERT(ifp->if_real_bytes == 0);
> ifp->if_u1.if_data = kmem_alloc(real_size,
> KM_SLEEP | KM_NOFS);
> - } else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
> + } else {
> /*
> * Only do the realloc if the underlying size
> * is really changing.
> @@ -662,12 +629,6 @@ xfs_idata_realloc(
> real_size,
> KM_SLEEP | KM_NOFS);
> }
> - } else {
> - ASSERT(ifp->if_real_bytes == 0);
> - ifp->if_u1.if_data = kmem_alloc(real_size,
> - KM_SLEEP | KM_NOFS);
> - memcpy(ifp->if_u1.if_data, ifp->if_u2.if_inline_data,
> - ifp->if_bytes);
> }
> }
> ifp->if_real_bytes = real_size;
> @@ -695,8 +656,7 @@ xfs_idestroy_fork(
> * so check and free it up if we do.
> */
> if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
> - if ((ifp->if_u1.if_data != ifp->if_u2.if_inline_data) &&
> - (ifp->if_u1.if_data != NULL)) {
> + if (ifp->if_u1.if_data != NULL) {
> ASSERT(ifp->if_real_bytes != 0);
> kmem_free(ifp->if_u1.if_data);
> ifp->if_u1.if_data = NULL;
> @@ -704,13 +664,11 @@ xfs_idestroy_fork(
> }
> } else if ((ifp->if_flags & XFS_IFEXTENTS) &&
> ((ifp->if_flags & XFS_IFEXTIREC) ||
> - ((ifp->if_u1.if_extents != NULL) &&
> - (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)))) {
> + (ifp->if_u1.if_extents != NULL))) {
> ASSERT(ifp->if_real_bytes != 0);
> xfs_iext_destroy(ifp);
> }
> - ASSERT(ifp->if_u1.if_extents == NULL ||
> - ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext);
> + ASSERT(ifp->if_u1.if_extents == NULL);
> ASSERT(ifp->if_real_bytes == 0);
> if (whichfork == XFS_ATTR_FORK) {
> kmem_zone_free(xfs_ifork_zone, ip->i_afp);
> @@ -943,28 +901,14 @@ xfs_iext_add(
> ASSERT((idx >= 0) && (idx <= nextents));
> byte_diff = ext_diff * sizeof(xfs_bmbt_rec_t);
> new_size = ifp->if_bytes + byte_diff;
> +
> /*
> - * If the new number of extents (nextents + ext_diff)
> - * fits inside the inode, then continue to use the inline
> - * extent buffer.
> - */
> - if (nextents + ext_diff <= XFS_INLINE_EXTS) {
> - if (idx < nextents) {
> - memmove(&ifp->if_u2.if_inline_ext[idx + ext_diff],
> - &ifp->if_u2.if_inline_ext[idx],
> - (nextents - idx) * sizeof(xfs_bmbt_rec_t));
> - memset(&ifp->if_u2.if_inline_ext[idx], 0, byte_diff);
> - }
> - ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
> - ifp->if_real_bytes = 0;
> - }
> - /*
> - * Otherwise use a linear (direct) extent list.
> + * Use a linear (direct) extent list.
> * If the extents are currently inside the inode,
> * xfs_iext_realloc_direct will switch us from
> * inline to direct extent allocation mode.
> */
> - else if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
> + if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
> xfs_iext_realloc_direct(ifp, new_size);
> if (idx < nextents) {
> memmove(&ifp->if_u1.if_extents[idx + ext_diff],
> @@ -1172,43 +1116,10 @@ xfs_iext_remove(
> xfs_iext_remove_indirect(ifp, cur->idx, ext_diff);
> } else if (ifp->if_real_bytes) {
> xfs_iext_remove_direct(ifp, cur->idx, ext_diff);
> - } else {
> - xfs_iext_remove_inline(ifp, cur->idx, ext_diff);
> }
> ifp->if_bytes = new_size;
> }
>
> -/*
> - * This removes ext_diff extents from the inline buffer, beginning
> - * at extent index idx.
> - */
> -void
> -xfs_iext_remove_inline(
> - xfs_ifork_t *ifp, /* inode fork pointer */
> - xfs_extnum_t idx, /* index to begin removing exts */
> - int ext_diff) /* number of extents to remove */
> -{
> - int nextents; /* number of extents in file */
> -
> - ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
> - ASSERT(idx < XFS_INLINE_EXTS);
> - nextents = xfs_iext_count(ifp);
> - ASSERT(((nextents - ext_diff) > 0) &&
> - (nextents - ext_diff) < XFS_INLINE_EXTS);
> -
> - if (idx + ext_diff < nextents) {
> - memmove(&ifp->if_u2.if_inline_ext[idx],
> - &ifp->if_u2.if_inline_ext[idx + ext_diff],
> - (nextents - (idx + ext_diff)) *
> - sizeof(xfs_bmbt_rec_t));
> - memset(&ifp->if_u2.if_inline_ext[nextents - ext_diff],
> - 0, ext_diff * sizeof(xfs_bmbt_rec_t));
> - } else {
> - memset(&ifp->if_u2.if_inline_ext[idx], 0,
> - ext_diff * sizeof(xfs_bmbt_rec_t));
> - }
> -}
> -
> /*
> * This removes ext_diff extents from a linear (direct) extent list,
> * beginning at extent index idx. If the extents are being removed
> @@ -1351,16 +1262,7 @@ xfs_iext_realloc_direct(
> /* Free extent records */
> if (new_size == 0) {
> xfs_iext_destroy(ifp);
> - }
> - /* Resize direct extent list and zero any new bytes */
> - else if (ifp->if_real_bytes) {
> - /* Check if extents will fit inside the inode */
> - if (new_size <= XFS_INLINE_EXTS * sizeof(xfs_bmbt_rec_t)) {
> - xfs_iext_direct_to_inline(ifp, new_size /
> - (uint)sizeof(xfs_bmbt_rec_t));
> - ifp->if_bytes = new_size;
> - return;
> - }
> + } else {
> if (!is_power_of_2(new_size)){
> rnew_size = roundup_pow_of_two(new_size);
> }
> @@ -1375,63 +1277,10 @@ xfs_iext_realloc_direct(
> rnew_size - ifp->if_real_bytes);
> }
> }
> - /* Switch from the inline extent buffer to a direct extent list */
> - else {
> - if (!is_power_of_2(new_size)) {
> - rnew_size = roundup_pow_of_two(new_size);
> - }
> - xfs_iext_inline_to_direct(ifp, rnew_size);
> - }
> ifp->if_real_bytes = rnew_size;
> ifp->if_bytes = new_size;
> }
>
> -/*
> - * Switch from linear (direct) extent records to inline buffer.
> - */
> -void
> -xfs_iext_direct_to_inline(
> - xfs_ifork_t *ifp, /* inode fork pointer */
> - xfs_extnum_t nextents) /* number of extents in file */
> -{
> - ASSERT(ifp->if_flags & XFS_IFEXTENTS);
> - ASSERT(nextents <= XFS_INLINE_EXTS);
> - /*
> - * The inline buffer was zeroed when we switched
> - * from inline to direct extent allocation mode,
> - * so we don't need to clear it here.
> - */
> - memcpy(ifp->if_u2.if_inline_ext, ifp->if_u1.if_extents,
> - nextents * sizeof(xfs_bmbt_rec_t));
> - kmem_free(ifp->if_u1.if_extents);
> - ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
> - ifp->if_real_bytes = 0;
> -}
> -
> -/*
> - * Switch from inline buffer to linear (direct) extent records.
> - * new_size should already be rounded up to the next power of 2
> - * by the caller (when appropriate), so use new_size as it is.
> - * However, since new_size may be rounded up, we can't update
> - * if_bytes here. It is the caller's responsibility to update
> - * if_bytes upon return.
> - */
> -void
> -xfs_iext_inline_to_direct(
> - xfs_ifork_t *ifp, /* inode fork pointer */
> - int new_size) /* number of extents in file */
> -{
> - ifp->if_u1.if_extents = kmem_alloc(new_size, KM_NOFS);
> - memset(ifp->if_u1.if_extents, 0, new_size);
> - if (ifp->if_bytes) {
> - memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
> - ifp->if_bytes);
> - memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
> - sizeof(xfs_bmbt_rec_t));
> - }
> - ifp->if_real_bytes = new_size;
> -}
> -
> /*
> * Resize an extent indirection array to new_size bytes.
> */
> @@ -1511,9 +1360,6 @@ xfs_iext_destroy(
> xfs_iext_irec_remove_all(ifp);
> } else if (ifp->if_real_bytes) {
> kmem_free(ifp->if_u1.if_extents);
> - } else if (ifp->if_bytes) {
> - memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
> - sizeof(xfs_bmbt_rec_t));
> }
> ifp->if_u1.if_extents = NULL;
> ifp->if_real_bytes = 0;
> @@ -1708,8 +1554,6 @@ xfs_iext_irec_init(
>
> if (nextents == 0) {
> ifp->if_u1.if_extents = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
> - } else if (!ifp->if_real_bytes) {
> - xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
> } else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
> xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
> }
> @@ -1829,9 +1673,6 @@ xfs_iext_irec_compact(
>
> if (nextents == 0) {
> xfs_iext_destroy(ifp);
> - } else if (nextents <= XFS_INLINE_EXTS) {
> - xfs_iext_indirect_to_direct(ifp);
> - xfs_iext_direct_to_inline(ifp, nextents);
> } else if (nextents <= XFS_LINEAR_EXTS) {
> xfs_iext_indirect_to_direct(ifp);
> } else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index dc347dd9dc78..508f13784334 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -51,8 +51,6 @@ typedef struct xfs_ext_irec {
> */
> #define XFS_IEXT_BUFSZ 4096
> #define XFS_LINEAR_EXTS (XFS_IEXT_BUFSZ / (uint)sizeof(xfs_bmbt_rec_t))
> -#define XFS_INLINE_EXTS 2
> -#define XFS_INLINE_DATA 32
> typedef struct xfs_ifork {
> int if_bytes; /* bytes in if_u1 */
> int if_real_bytes; /* bytes allocated in if_u1 */
> @@ -64,12 +62,6 @@ typedef struct xfs_ifork {
> xfs_ext_irec_t *if_ext_irec; /* irec map file exts */
> char *if_data; /* inline file data */
> } if_u1;
> - union {
> - xfs_bmbt_rec_host_t if_inline_ext[XFS_INLINE_EXTS];
> - /* very small file extents */
> - char if_inline_data[XFS_INLINE_DATA];
> - /* very small file data */
> - } if_u2;
> } xfs_ifork_t;
>
> /*
> @@ -158,12 +150,9 @@ void xfs_iext_add_indirect_multi(struct xfs_ifork *, int,
> xfs_extnum_t, int);
> void xfs_iext_remove(struct xfs_inode *, struct xfs_iext_cursor *,
> int, int);
> -void xfs_iext_remove_inline(struct xfs_ifork *, xfs_extnum_t, int);
> void xfs_iext_remove_direct(struct xfs_ifork *, xfs_extnum_t, int);
> void xfs_iext_remove_indirect(struct xfs_ifork *, xfs_extnum_t, int);
> void xfs_iext_realloc_direct(struct xfs_ifork *, int);
> -void xfs_iext_direct_to_inline(struct xfs_ifork *, xfs_extnum_t);
> -void xfs_iext_inline_to_direct(struct xfs_ifork *, int);
> void xfs_iext_destroy(struct xfs_ifork *);
> struct xfs_bmbt_rec_host *
> xfs_iext_bno_to_ext(struct xfs_ifork *, xfs_fileoff_t, int *);
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index b6b954d5cf54..c2f8e40a3e1f 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1709,7 +1709,6 @@ xfs_swap_extent_forks(
> xfs_filblks_t aforkblks = 0;
> xfs_filblks_t taforkblks = 0;
> xfs_extnum_t junk;
> - xfs_extnum_t nextents;
> uint64_t tmp;
> int error;
>
> @@ -1784,13 +1783,6 @@ xfs_swap_extent_forks(
>
> switch (ip->i_d.di_format) {
> case XFS_DINODE_FMT_EXTENTS:
> - /*
> - * If the extents fit in the inode, fix the pointer. Otherwise
> - * it's already NULL or pointing to the extent.
> - */
> - nextents = xfs_iext_count(&ip->i_df);
> - if (nextents <= XFS_INLINE_EXTS)
> - ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
> (*src_log_flags) |= XFS_ILOG_DEXT;
> break;
> case XFS_DINODE_FMT_BTREE:
> @@ -1802,13 +1794,6 @@ xfs_swap_extent_forks(
>
> switch (tip->i_d.di_format) {
> case XFS_DINODE_FMT_EXTENTS:
> - /*
> - * If the extents fit in the inode, fix the pointer. Otherwise
> - * it's already NULL or pointing to the extent.
> - */
> - nextents = xfs_iext_count(&tip->i_df);
> - if (nextents <= XFS_INLINE_EXTS)
> - tifp->if_u1.if_extents = tifp->if_u2.if_inline_ext;
> (*target_log_flags) |= XFS_ILOG_DEXT;
> break;
> case XFS_DINODE_FMT_BTREE:
> --
> 2.14.2
>
> --
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