| Message ID | 20240430124926.1775355-11-hch@lst.de (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [01/16] xfs: allow non-empty forks in xfs_bmap_local_to_extents_empty | expand |
On Tue, Apr 30, 2024 at 02:49:20PM +0200, Christoph Hellwig wrote: > When removing the last 8-byte inode, xfs_dir2_sf_removename calls > xfs_dir2_sf_toino4 after removing the entry. This is rather inefficient > as it causes two buffer realloacations. Instead of that pass a bool > argument to xfs_dir2_sf_toino4 so that it can remove the entry pointed > to by args as part of the conversion and use that to shortcut the > process. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/libxfs/xfs_dir2_sf.c | 41 ++++++++++++++++++++++++++++--------- > 1 file changed, 31 insertions(+), 10 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c > index 3b6d6dda92f29f..21e04594606b89 100644 > --- a/fs/xfs/libxfs/xfs_dir2_sf.c > +++ b/fs/xfs/libxfs/xfs_dir2_sf.c > @@ -34,7 +34,7 @@ static void xfs_dir2_sf_check(xfs_da_args_t *args); > #define xfs_dir2_sf_check(args) > #endif /* DEBUG */ > > -static void xfs_dir2_sf_toino4(xfs_da_args_t *args); > +static void xfs_dir2_sf_toino4(struct xfs_da_args *args, bool remove); > static void xfs_dir2_sf_toino8(xfs_da_args_t *args); > > int > @@ -935,6 +935,15 @@ xfs_dir2_sf_removename( > ASSERT(dp->i_df.if_bytes == oldsize); > ASSERT(oldsize >= xfs_dir2_sf_hdr_size(sfp->i8count)); > > + /* > + * If this is the last 8-byte, directly convert to the 4-byte format > + * and just skip the removed entry when building the new fork. > + */ > + if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && sfp->i8count == 1) { > + xfs_dir2_sf_toino4(args, true); > + return 0; > + } > + > /* > * Loop over the old directory entries. > * Find the one we're deleting. > @@ -980,10 +989,8 @@ xfs_dir2_sf_removename( > * Are we changing inode number size? > */ > if (args->inumber > XFS_DIR2_MAX_SHORT_INUM) { > - if (sfp->i8count == 1) > - xfs_dir2_sf_toino4(args); > - else > - sfp->i8count--; > + ASSERT(sfp->i8count > 1); > + sfp->i8count--; > } > xfs_dir2_sf_check(args); > xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA); > @@ -1087,7 +1094,7 @@ xfs_dir2_sf_replace( > if (i == sfp->count) { > ASSERT(args->op_flags & XFS_DA_OP_OKNOENT); > if (i8elevated) > - xfs_dir2_sf_toino4(args); > + xfs_dir2_sf_toino4(args, false); > return -ENOENT; > } > } > @@ -1100,7 +1107,7 @@ xfs_dir2_sf_replace( > * And the old count was one, so need to convert to small. > */ > if (sfp->i8count == 1) > - xfs_dir2_sf_toino4(args); > + xfs_dir2_sf_toino4(args, false); > else > sfp->i8count--; > } > @@ -1128,7 +1135,8 @@ xfs_dir2_sf_replace( > */ > static void > xfs_dir2_sf_toino4( > - xfs_da_args_t *args) /* operation arguments */ > + struct xfs_da_args *args, > + bool remove) > { > struct xfs_inode *dp = args->dp; > struct xfs_mount *mp = dp->i_mount; > @@ -1148,6 +1156,8 @@ xfs_dir2_sf_toino4( > * Compute the new inode size. > */ > newsize = oldsize - (oldsfp->count + 1) * XFS_INO64_DIFF; > + if (remove) > + newsize -= xfs_dir2_sf_entsize(mp, oldsfp, args->namelen); > > dp->i_df.if_data = sfp = kmalloc(newsize, GFP_KERNEL | __GFP_NOFAIL); > dp->i_df.if_bytes = newsize; > @@ -1166,11 +1176,22 @@ xfs_dir2_sf_toino4( > i < sfp->count; > i++, sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep), > oldsfep = xfs_dir2_sf_nextentry(mp, oldsfp, oldsfep)) { > + xfs_ino_t ino = xfs_dir2_sf_get_ino(mp, oldsfp, oldsfep); > + > + /* > + * Just skip over the entry that is removed if there is one. > + */ > + if (remove && args->inumber == ino) { > + oldsfep = xfs_dir2_sf_nextentry(mp, oldsfp, oldsfep); > + sfp->count--; > + if (++i == sfp->count) > + break; > + } What happens if a shortform directory contains two entries to the same file? I think @remove really means that the caller has verified that the sf directory only contains one link @args->inumber? If that's so, then the comment for this function should say that. --D > + > sfep->namelen = oldsfep->namelen; > memcpy(sfep->offset, oldsfep->offset, sizeof(sfep->offset)); > memcpy(sfep->name, oldsfep->name, sfep->namelen); > - xfs_dir2_sf_put_ino(mp, sfp, sfep, > - xfs_dir2_sf_get_ino(mp, oldsfp, oldsfep)); > + xfs_dir2_sf_put_ino(mp, sfp, sfep, ino); > xfs_dir2_sf_put_ftype(mp, sfep, > xfs_dir2_sf_get_ftype(mp, oldsfep)); > } > -- > 2.39.2 > >
On Wed, May 01, 2024 at 02:25:19PM -0700, Darrick J. Wong wrote: > What happens if a shortform directory contains two entries to the same > file? I think @remove really means that the caller has verified that > the sf directory only contains one link @args->inumber? If that's so, > then the comment for this function should say that. No, I don't think there is such a validation. But given that i8count is 1 and the entry we are removing has a 4-byte inode when we call this, we can't by definition have two entries pointing to this inode, as then i8count would be 2. But I only thought about that now, and is is far to subtle (and I need to check if the above is true for whiteouts). I'll either clearly document it, or change it to a name comparison.
diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c index 3b6d6dda92f29f..21e04594606b89 100644 --- a/fs/xfs/libxfs/xfs_dir2_sf.c +++ b/fs/xfs/libxfs/xfs_dir2_sf.c @@ -34,7 +34,7 @@ static void xfs_dir2_sf_check(xfs_da_args_t *args); #define xfs_dir2_sf_check(args) #endif /* DEBUG */ -static void xfs_dir2_sf_toino4(xfs_da_args_t *args); +static void xfs_dir2_sf_toino4(struct xfs_da_args *args, bool remove); static void xfs_dir2_sf_toino8(xfs_da_args_t *args); int @@ -935,6 +935,15 @@ xfs_dir2_sf_removename( ASSERT(dp->i_df.if_bytes == oldsize); ASSERT(oldsize >= xfs_dir2_sf_hdr_size(sfp->i8count)); + /* + * If this is the last 8-byte, directly convert to the 4-byte format + * and just skip the removed entry when building the new fork. + */ + if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && sfp->i8count == 1) { + xfs_dir2_sf_toino4(args, true); + return 0; + } + /* * Loop over the old directory entries. * Find the one we're deleting. @@ -980,10 +989,8 @@ xfs_dir2_sf_removename( * Are we changing inode number size? */ if (args->inumber > XFS_DIR2_MAX_SHORT_INUM) { - if (sfp->i8count == 1) - xfs_dir2_sf_toino4(args); - else - sfp->i8count--; + ASSERT(sfp->i8count > 1); + sfp->i8count--; } xfs_dir2_sf_check(args); xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA); @@ -1087,7 +1094,7 @@ xfs_dir2_sf_replace( if (i == sfp->count) { ASSERT(args->op_flags & XFS_DA_OP_OKNOENT); if (i8elevated) - xfs_dir2_sf_toino4(args); + xfs_dir2_sf_toino4(args, false); return -ENOENT; } } @@ -1100,7 +1107,7 @@ xfs_dir2_sf_replace( * And the old count was one, so need to convert to small. */ if (sfp->i8count == 1) - xfs_dir2_sf_toino4(args); + xfs_dir2_sf_toino4(args, false); else sfp->i8count--; } @@ -1128,7 +1135,8 @@ xfs_dir2_sf_replace( */ static void xfs_dir2_sf_toino4( - xfs_da_args_t *args) /* operation arguments */ + struct xfs_da_args *args, + bool remove) { struct xfs_inode *dp = args->dp; struct xfs_mount *mp = dp->i_mount; @@ -1148,6 +1156,8 @@ xfs_dir2_sf_toino4( * Compute the new inode size. */ newsize = oldsize - (oldsfp->count + 1) * XFS_INO64_DIFF; + if (remove) + newsize -= xfs_dir2_sf_entsize(mp, oldsfp, args->namelen); dp->i_df.if_data = sfp = kmalloc(newsize, GFP_KERNEL | __GFP_NOFAIL); dp->i_df.if_bytes = newsize; @@ -1166,11 +1176,22 @@ xfs_dir2_sf_toino4( i < sfp->count; i++, sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep), oldsfep = xfs_dir2_sf_nextentry(mp, oldsfp, oldsfep)) { + xfs_ino_t ino = xfs_dir2_sf_get_ino(mp, oldsfp, oldsfep); + + /* + * Just skip over the entry that is removed if there is one. + */ + if (remove && args->inumber == ino) { + oldsfep = xfs_dir2_sf_nextentry(mp, oldsfp, oldsfep); + sfp->count--; + if (++i == sfp->count) + break; + } + sfep->namelen = oldsfep->namelen; memcpy(sfep->offset, oldsfep->offset, sizeof(sfep->offset)); memcpy(sfep->name, oldsfep->name, sfep->namelen); - xfs_dir2_sf_put_ino(mp, sfp, sfep, - xfs_dir2_sf_get_ino(mp, oldsfp, oldsfep)); + xfs_dir2_sf_put_ino(mp, sfp, sfep, ino); xfs_dir2_sf_put_ftype(mp, sfep, xfs_dir2_sf_get_ftype(mp, oldsfep)); }
When removing the last 8-byte inode, xfs_dir2_sf_removename calls xfs_dir2_sf_toino4 after removing the entry. This is rather inefficient as it causes two buffer realloacations. Instead of that pass a bool argument to xfs_dir2_sf_toino4 so that it can remove the entry pointed to by args as part of the conversion and use that to shortcut the process. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/libxfs/xfs_dir2_sf.c | 41 ++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 10 deletions(-)