exofs: Prepare for groups
* Rename _offset_dev_unit_off() to _calc_stripe_info() and recieve a struct for the output params * In _prepare_for_striping we only need to call _calc_stripe_info() once. The other componets are easy to calculate from that. This code was inspired by what's done in truncate. * Some code shifts that make sense now but will make more sense when group support is added. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
This commit is contained in:
Boaz Harrosh
parent
96391e2bae
commit
b367e78bd1
161
fs/exofs/ios.c
161
fs/exofs/ios.c
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@ -259,28 +259,46 @@ int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
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return acumulated_lin_err;
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}
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/* REMOVEME: After review
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Some quoteing from the standard
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/*
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* L - logical offset into the file
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*
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* U - The number of bytes in a full stripe
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*
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* U = stripe_unit * group_width
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*
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* N - The stripe number
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*
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* N = L / U
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*
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* C - The component index coresponding to L
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*
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* C = (L - (N*U)) / stripe_unit
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*
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* O - The component offset coresponding to L
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*
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* (N*stripe_unit)+(L%stripe_unit)
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*/
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L = logical offset into the file
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W = number of data components in a stripe
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S = W * stripe_unit (S is Stripe length)
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N = L / S (N is the stripe Number)
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C = (L-(N*S)) / stripe_unit (C is the component)
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O = (N*stripe_unit)+(L%stripe_unit) (O is the object's offset)
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*/
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struct _striping_info {
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u64 obj_offset;
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unsigned dev;
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unsigned unit_off;
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};
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static void _offset_dev_unit_off(struct exofs_io_state *ios, u64 file_offset,
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u64 *obj_offset, unsigned *dev, unsigned *unit_off)
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static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
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struct _striping_info *si)
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{
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unsigned stripe_unit = ios->layout->stripe_unit;
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unsigned stripe_length = stripe_unit * ios->layout->group_width;
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u64 stripe_no = file_offset;
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unsigned stripe_mod = do_div(stripe_no, stripe_length);
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u32 stripe_unit = ios->layout->stripe_unit;
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u32 group_width = ios->layout->group_width;
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u32 U = stripe_unit * group_width;
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*unit_off = stripe_mod % stripe_unit;
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*obj_offset = stripe_no * stripe_unit + *unit_off;
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*dev = stripe_mod / stripe_unit * ios->layout->mirrors_p1;
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u32 LmodU;
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u64 N = div_u64_rem(file_offset, U, &LmodU);
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si->unit_off = LmodU % stripe_unit;
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si->obj_offset = N * stripe_unit + si->unit_off;
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si->dev = LmodU / stripe_unit;
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si->dev *= ios->layout->mirrors_p1;
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}
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static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_pg,
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@ -327,65 +345,88 @@ static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_pg,
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return 0;
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}
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static int _prepare_for_striping(struct exofs_io_state *ios)
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static int _prepare_pages(struct exofs_io_state *ios,
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struct _striping_info *si)
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{
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u64 length = ios->length;
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u64 offset = ios->offset;
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unsigned stripe_unit = ios->layout->stripe_unit;
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unsigned mirrors_p1 = ios->layout->mirrors_p1;
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unsigned dev = si->dev;
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unsigned comp = 0;
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unsigned stripes = 0;
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unsigned cur_pg = 0;
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int ret = 0;
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if (!ios->pages) {
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if (ios->kern_buff) {
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struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
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unsigned unit_off;
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_offset_dev_unit_off(ios, offset, &per_dev->offset,
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&per_dev->dev, &unit_off);
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/* no cross device without page array */
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BUG_ON((ios->layout->group_width > 1) &&
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(unit_off + length > stripe_unit));
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}
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ios->numdevs = ios->layout->mirrors_p1;
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return 0;
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}
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while (length) {
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struct exofs_per_dev_state *per_dev = &ios->per_dev[comp];
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unsigned cur_len, page_off;
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unsigned cur_len, page_off = 0;
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if (!per_dev->length) {
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unsigned unit_off;
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_offset_dev_unit_off(ios, offset, &per_dev->offset,
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&per_dev->dev, &unit_off);
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stripes++;
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cur_len = min_t(u64, stripe_unit - unit_off, length);
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offset += cur_len;
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page_off = unit_off & ~PAGE_MASK;
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BUG_ON(page_off != ios->pgbase);
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} else {
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cur_len = min_t(u64, stripe_unit, length);
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page_off = 0;
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per_dev->dev = dev;
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if (dev < si->dev) {
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per_dev->offset = si->obj_offset + stripe_unit -
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si->unit_off;
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cur_len = stripe_unit;
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} else if (dev == si->dev) {
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per_dev->offset = si->obj_offset;
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cur_len = stripe_unit - si->unit_off;
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page_off = si->unit_off & ~PAGE_MASK;
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BUG_ON(page_off && (page_off != ios->pgbase));
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} else { /* dev > si->dev */
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per_dev->offset = si->obj_offset - si->unit_off;
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cur_len = stripe_unit;
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}
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stripes++;
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dev += mirrors_p1;
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dev %= ios->layout->s_numdevs;
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} else {
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cur_len = stripe_unit;
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}
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if (cur_len >= length)
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cur_len = length;
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ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
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cur_len);
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if (unlikely(ret))
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goto out;
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comp += ios->layout->mirrors_p1;
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comp += mirrors_p1;
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comp %= ios->layout->s_numdevs;
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length -= cur_len;
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}
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out:
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ios->numdevs = stripes * ios->layout->mirrors_p1;
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ios->numdevs = stripes * mirrors_p1;
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return ret;
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}
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static int _prepare_for_striping(struct exofs_io_state *ios)
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{
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struct _striping_info si;
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_calc_stripe_info(ios, ios->offset, &si);
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if (!ios->pages) {
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if (ios->kern_buff) {
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struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
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per_dev->offset = si.obj_offset;
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per_dev->dev = si.dev;
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/* no cross device without page array */
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BUG_ON((ios->layout->group_width > 1) &&
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(si.unit_off + ios->length >
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ios->layout->stripe_unit));
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}
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ios->numdevs = ios->layout->mirrors_p1;
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return 0;
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}
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return _prepare_pages(ios, &si);
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}
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int exofs_sbi_create(struct exofs_io_state *ios)
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{
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int i, ret;
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@ -648,9 +689,7 @@ int exofs_oi_truncate(struct exofs_i_info *oi, u64 size)
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struct osd_attr attr;
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__be64 newsize;
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} *size_attrs;
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u64 this_obj_size;
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unsigned dev;
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unsigned unit_off;
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struct _striping_info si;
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int i, ret;
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ret = exofs_get_io_state(&sbi->layout, &ios);
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@ -668,19 +707,19 @@ int exofs_oi_truncate(struct exofs_i_info *oi, u64 size)
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ios->cred = oi->i_cred;
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ios->numdevs = ios->layout->s_numdevs;
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_offset_dev_unit_off(ios, size, &this_obj_size, &dev, &unit_off);
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_calc_stripe_info(ios, size, &si);
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for (i = 0; i < ios->layout->group_width; ++i) {
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struct exofs_trunc_attr *size_attr = &size_attrs[i];
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u64 obj_size;
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if (i < dev)
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obj_size = this_obj_size +
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ios->layout->stripe_unit - unit_off;
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else if (i == dev)
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obj_size = this_obj_size;
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else /* i > dev */
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obj_size = this_obj_size - unit_off;
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if (i < si.dev)
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obj_size = si.obj_offset +
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ios->layout->stripe_unit - si.unit_off;
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else if (i == si.dev)
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obj_size = si.obj_offset;
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else /* i > si.dev */
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obj_size = si.obj_offset - si.unit_off;
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size_attr->newsize = cpu_to_be64(obj_size);
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size_attr->attr = g_attr_logical_length;
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