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GFS2: Clean up quota slot allocation 

Quota slot allocation has historically used a vector of pages
and a set of homegrown find/test/set/clear bit functions. Since
the size of the bitmap is likely to be based on the default
qc file size, thats a couple of pages at most. So we ought
to be able to allocate that as a single chunk, with a vmalloc
fallback, just in case of memory fragmentation.

We are then able to use the kernel's own find/test/set/clear
bit functions, rather than rolling our own.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
This commit is contained in:
Steven Whitehouse 2013-12-12 17:29:32 +00:00
parent 8ad151c2ac
commit ee2411a8db
2 changed files with 30 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/gfs2/incore.h
View File

@ -733,8 +733,7 @@ struct gfs2_sbd {
spinlock_t sd_trunc_lock;
unsigned int sd_quota_slots;
unsigned int sd_quota_chunks;
unsigned char **sd_quota_bitmap;
unsigned long *sd_quota_bitmap;
u64 sd_quota_sync_gen;

100
fs/gfs2/quota.c
View File

@ -315,50 +315,30 @@ static void qd_put(struct gfs2_quota_data *qd)
static int slot_get(struct gfs2_quota_data *qd)
{
struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
unsigned int c, o = 0, b;
unsigned char byte = 0;
struct gfs2_sbd *sdp = qd->qd_sbd;
unsigned int bit;
int error = 0;
spin_lock(&qd_lock);
if (qd->qd_slot_count != 0)
goto out;
if (qd->qd_slot_count++) {
spin_unlock(&qd_lock);
return 0;
error = -ENOSPC;
bit = find_first_zero_bit(sdp->sd_quota_bitmap, sdp->sd_quota_slots);
if (bit < sdp->sd_quota_slots) {
set_bit(bit, sdp->sd_quota_bitmap);
qd->qd_slot = bit;
out:
qd->qd_slot_count++;
}
for (c = 0; c < sdp->sd_quota_chunks; c++)
for (o = 0; o < PAGE_SIZE; o++) {
byte = sdp->sd_quota_bitmap[c][o];
if (byte != 0xFF)
goto found;
}
goto fail;
found:
for (b = 0; b < 8; b++)
if (!(byte & (1 << b)))
break;
qd->qd_slot = c * (8 * PAGE_SIZE) + o * 8 + b;
if (qd->qd_slot >= sdp->sd_quota_slots)
goto fail;
sdp->sd_quota_bitmap[c][o] |= 1 << b;
spin_unlock(&qd_lock);
return 0;
fail:
qd->qd_slot_count--;
spin_unlock(&qd_lock);
return -ENOSPC;
return error;
}
static void slot_hold(struct gfs2_quota_data *qd)
{
struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
struct gfs2_sbd *sdp = qd->qd_sbd;
spin_lock(&qd_lock);
gfs2_assert(sdp, qd->qd_slot_count);
@ -366,34 +346,14 @@ static void slot_hold(struct gfs2_quota_data *qd)
spin_unlock(&qd_lock);
}
static void gfs2_icbit_munge(struct gfs2_sbd *sdp, unsigned char **bitmap,
unsigned int bit, int new_value)
{
unsigned int c, o, b = bit;
int old_value;
c = b / (8 * PAGE_SIZE);
b %= 8 * PAGE_SIZE;
o = b / 8;
b %= 8;
old_value = (bitmap[c][o] & (1 << b));
gfs2_assert_withdraw(sdp, !old_value != !new_value);
if (new_value)
bitmap[c][o] |= 1 << b;
else
bitmap[c][o] &= ~(1 << b);
}
static void slot_put(struct gfs2_quota_data *qd)
{
struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
struct gfs2_sbd *sdp = qd->qd_sbd;
spin_lock(&qd_lock);
gfs2_assert(sdp, qd->qd_slot_count);
if (!--qd->qd_slot_count) {
gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, qd->qd_slot, 0);
BUG_ON(!test_and_clear_bit(qd->qd_slot, sdp->sd_quota_bitmap));
qd->qd_slot = -1;
}
spin_unlock(&qd_lock);
@ -1269,6 +1229,7 @@ int gfs2_quota_init(struct gfs2_sbd *sdp)
unsigned int x, slot = 0;
unsigned int found = 0;
unsigned int hash;
unsigned int bm_size;
u64 dblock;
u32 extlen = 0;
int error;
@ -1277,20 +1238,16 @@ int gfs2_quota_init(struct gfs2_sbd *sdp)
return -EIO;
sdp->sd_quota_slots = blocks * sdp->sd_qc_per_block;
sdp->sd_quota_chunks = DIV_ROUND_UP(sdp->sd_quota_slots, 8 * PAGE_SIZE);
bm_size = DIV_ROUND_UP(sdp->sd_quota_slots, 8 * sizeof(unsigned long));
bm_size *= sizeof(unsigned long);
error = -ENOMEM;
sdp->sd_quota_bitmap = kcalloc(sdp->sd_quota_chunks,
sizeof(unsigned char *), GFP_NOFS);
sdp->sd_quota_bitmap = kmalloc(bm_size, GFP_NOFS|__GFP_NOWARN);
if (sdp->sd_quota_bitmap == NULL)
sdp->sd_quota_bitmap = __vmalloc(bm_size, GFP_NOFS, PAGE_KERNEL);
if (!sdp->sd_quota_bitmap)
return error;
for (x = 0; x < sdp->sd_quota_chunks; x++) {
sdp->sd_quota_bitmap[x] = kzalloc(PAGE_SIZE, GFP_NOFS);
if (!sdp->sd_quota_bitmap[x])
goto fail;
}
memset(sdp->sd_quota_bitmap, 0, bm_size);
for (x = 0; x < blocks; x++) {
struct buffer_head *bh;
@ -1339,7 +1296,7 @@ int gfs2_quota_init(struct gfs2_sbd *sdp)
qd->qd_slot_count = 1;
spin_lock(&qd_lock);
gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, slot, 1);
BUG_ON(test_and_set_bit(slot, sdp->sd_quota_bitmap));
list_add(&qd->qd_list, &sdp->sd_quota_list);
atomic_inc(&sdp->sd_quota_count);
spin_unlock(&qd_lock);
@ -1370,7 +1327,6 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
{
struct list_head *head = &sdp->sd_quota_list;
struct gfs2_quota_data *qd;
unsigned int x;
spin_lock(&qd_lock);
while (!list_empty(head)) {
@ -1401,9 +1357,11 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
gfs2_assert_warn(sdp, !atomic_read(&sdp->sd_quota_count));
if (sdp->sd_quota_bitmap) {
for (x = 0; x < sdp->sd_quota_chunks; x++)
kfree(sdp->sd_quota_bitmap[x]);
kfree(sdp->sd_quota_bitmap);
if (is_vmalloc_addr(sdp->sd_quota_bitmap))
vfree(sdp->sd_quota_bitmap);
else
kfree(sdp->sd_quota_bitmap);
sdp->sd_quota_bitmap = NULL;
}
}