jim owens
2010-Mar-05 19:42 UTC
[PATCH 2/2] Btrfs: change dio.c to use dio_min_blocksize instead of 512.
Instead of hard coding the minimum I/O alignment, use the smallest
bdev_logical_blocksize in the filesystem. Also change the alignment
tests to determine the real user request minimum alignment and make
all eof tail and device checks on that user blocksize.
Signed-off-by: jim owens <jim6336@gmail.com>
---
fs/btrfs/dio.c | 144 ++++++++++++++++++++------------------------------------
1 files changed, 51 insertions(+), 93 deletions(-)
diff --git a/fs/btrfs/dio.c b/fs/btrfs/dio.c
index b1beafc..b76b227 100644
--- a/fs/btrfs/dio.c
+++ b/fs/btrfs/dio.c
@@ -134,6 +134,7 @@ struct btrfs_diocb {
struct workspace *workspace;
char *csum_buf;
+ u32 alignment;
int rw;
int error;
int sleeping;
@@ -160,12 +161,10 @@ static void btrfs_dio_write(struct btrfs_diocb *diocb);
static void btrfs_dio_read(struct btrfs_diocb *diocb);
static int btrfs_dio_new_extcb(struct btrfs_dio_extcb **alloc_extcb,
struct btrfs_diocb *diocb, struct extent_map *em);
-static void btrfs_dio_eof_tail(u32 *filetail, int eof,
- struct btrfs_diocb *diocb);
static int btrfs_dio_compressed_read(struct btrfs_diocb *diocb,
struct extent_map *lem, u64 data_len);
static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
- struct extent_map *lem, u64 data_len, int eof);
+ struct extent_map *lem, u64 data_len);
static void btfrs_dio_unplug(struct btrfs_dio_extcb *extcb);
static int btrfs_dio_read_stripes(struct btrfs_dio_extcb *extcb,
u64 *rd_start, u64 *rd_len, int temp_pages);
@@ -180,8 +179,6 @@ static int btrfs_dio_inline_next_in(struct bio_vec *ivec,
struct btrfs_inflate *icb);
static int btrfs_dio_get_user_bvec(struct bio_vec *uv,
struct btrfs_dio_user_mem_control *umc);
-static int btrfs_dio_not_aligned(unsigned long iomask, u32 testlen,
- struct btrfs_dio_user_mem_control *umc);
static void btrfs_dio_put_user_bvec(struct bio_vec *uv,
struct btrfs_dio_user_mem_control *umc);
static void btrfs_dio_release_unused_pages(
@@ -221,29 +218,33 @@ ssize_t btrfs_direct_IO(int rw, struct kiocb *kiocb,
ssize_t done = 0;
struct btrfs_diocb *diocb;
struct inode *inode = kiocb->ki_filp->f_mapping->host;
+ u32 alignment = BTRFS_I(inode)->root->sectorsize;
- /* traditional 512-byte device sector alignment is the
- * minimum required. if they have a larger sector disk
- * (possibly multiple sizes in the filesystem) and need
- * a larger alignment for this I/O, we just fail later.
- */
- if (offset & 511)
- return -EINVAL;
-
- /* check memory alignment, blocks cannot straddle pages.
+ /* check memory alignment, device blocks cannot straddle pages
+ * because special hardware (e.g. iommu) is needed for split dma.
* allow 0-length vectors which are questionable but seem legal.
+ * limit I/O to smaller of request size or available memory.
*/
- for (seg = 0; seg < nr_segs; seg++) {
- if (iov[seg].iov_len &&
- ((unsigned long)iov[seg].iov_base & 511))
- return -EINVAL;
- if (iov[seg].iov_len & 511)
- return -EINVAL;
- done += iov[seg].iov_len;
- }
+ alignment |= offset;
+ for (seg = 0; seg < nr_segs && done < kiocb->ki_left; seg++)
+ if (iov[seg].iov_len) {
+ /* alignment only needed through size of I/O */
+ done += iov[seg].iov_len;
+ done = min_t(ssize_t, done, kiocb->ki_left);
+ alignment |= done | (unsigned long)iov[seg].iov_base;
+ }
- /* limit request size to available memory */
- done = min_t(ssize_t, done, kiocb->ki_left);
+ /* minimum alignment is smallest logical_block_size of all devices in
+ * this fs. this check is not enough if there are larger blocksizes
+ * in the filesystem and we need a larger alignment for this I/O, so
+ * we retest alignment as we build the bio and fail it at that point.
+ * aligning here on largest blocksize would be simpler, but it would
+ * mean applications that were working might fail if the user added a
+ * larger blocksize device even though none of their file was on it.
+ */
+ if (alignment &
+ (BTRFS_I(inode)->root->fs_info->fs_devices->dio_min_blocksize
- 1))
+ return -EINVAL;
/* no write code here so fall back to buffered writes */
if (rw == WRITE)
@@ -253,6 +254,14 @@ ssize_t btrfs_direct_IO(int rw, struct kiocb *kiocb,
if (!diocb)
return -ENOMEM;
+ /* determine minimum user alignment block size across entire I/O
+ * so we can use it for eof tail handling and testing each device
+ */
+ diocb->alignment +
BTRFS_I(inode)->root->fs_info->fs_devices->dio_min_blocksize;
+ while (!(alignment & diocb->alignment))
+ diocb->alignment *= 2;
+
diocb->rw = rw;
diocb->kiocb = kiocb;
diocb->start = offset;
@@ -523,8 +532,7 @@ getlock:
}
err = btrfs_dio_compressed_read(diocb, em, len);
} else {
- err = btrfs_dio_extent_read(diocb, em, len,
- len == data_len);
+ err = btrfs_dio_extent_read(diocb, em, len);
}
}
@@ -650,28 +658,13 @@ static int btrfs_dio_compressed_read(struct btrfs_diocb
*diocb,
return err;
}
-/* for consistent eof processing between inline/compressed/normal
- * extents, an unaligned eof gets special treatment, read into temp
- * and memcpy to user on completion the part that does not match
- * the users I/O alignment (for now always 511)
- */
-static void btrfs_dio_eof_tail(u32 *filetail, int eof,
- struct btrfs_diocb *diocb)
-{
- if (eof)
- *filetail &= 511;
- else
- *filetail = 0; /* aligned direct to user memory */
-}
-
/* called with a hard-sector bounded file byte data start/len
* which covers areas of disk data. it might not... be contiguous,
* be on the same device(s), have the same redundancy property.
* get the extent map per contiguous chunk and submit bios.
*/
-
static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
- struct extent_map *lem, u64 data_len, int eof)
+ struct extent_map *lem, u64 data_len)
{
struct extent_map_tree *em_tree = &BTRFS_I(diocb->inode)->
root->fs_info->mapping_tree.map_tree;
@@ -690,9 +683,11 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
csum_after = blocksize - filetail;
}
- /* make post-eof consistent between inline/compressed/normal extents */
- if (filetail)
- btrfs_dio_eof_tail(&filetail, eof, diocb);
+ /* to make eof consistent between inline/compressed/normal extents,
+ * any unaligned bytes at eof get special treatment. those bytes are
+ * read into a kernel temp page and copied to user memory.
+ */
+ filetail &= diocb->alignment - 1;
data_start -= csum_before;
data_len += csum_before + csum_after;
@@ -781,9 +776,7 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
filetail;
else
csum_after = 0;
- if (filetail)
- btrfs_dio_eof_tail(&filetail,
- eof, diocb);
+ filetail &= diocb->alignment - 1;
}
extcb->csum_pg2 = extcb->csum_pg1;
@@ -811,7 +804,7 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
*/
extcb->csum_pg2 = extcb->csum_pg1;
csum_after += filetail;
- csum_after = ALIGN(csum_after, 512); /* for no csum */
+ csum_after = ALIGN(csum_after, diocb->alignment);
err = btrfs_dio_read_stripes(extcb,
&data_start, &csum_after, 1);
if (err)
@@ -867,7 +860,6 @@ static int btrfs_dio_read_stripes(struct btrfs_dio_extcb
*extcb,
while (*rd_len) {
u64 dev_left = *rd_len;
struct btrfs_stripe_info stripe_info;
- unsigned long iomask;
int mirror = 0;
int dvn;
@@ -880,18 +872,16 @@ retry:
btrfs_map_stripe_physical(extcb->em,
stripe_info.stripe_index);
- /* device start and length may not be sector aligned or
- * user memory address/length vectors may not be aligned
- * on a device sector because device sector size is > 512.
- * we might have different size devices in the filesystem,
- * so retry all copies to see if any meet the alignment.
+ /* we can have devices with different logical blocksizes
+ * in the filesystem. the user I/O start and length or
+ * memory address and length may not be sector aligned
+ * on a device with blocksize > dio_min_blocksize.
+ * if the user alignment is not correct for this device,
+ * try other copies to see if any meet their alignment.
*/
- iomask = bdev_logical_block_size(
- btrfs_map_stripe_bdev(extcb->em, dvn)) - 1;
- if ((extcb->diodev[dvn].physical & iomask) ||
- (dev_left & iomask) || (!temp_pages &&
- btrfs_dio_not_aligned(iomask, (u32)dev_left,
- &extcb->diocb->umc))) {
+ if (!temp_pages && extcb->diocb->alignment <
+ bdev_logical_block_size(btrfs_map_stripe_bdev(
+ extcb->em, dvn))) {
if (mirror < btrfs_map_num_copies(extcb->em)) {
mirror++;
goto retry;
@@ -1056,38 +1046,6 @@ static int btrfs_dio_get_user_bvec(struct bio_vec *uv,
return 0;
}
-static int btrfs_dio_not_aligned(unsigned long iomask, u32 testlen,
- struct btrfs_dio_user_mem_control *umc)
-{
- const struct iovec *nuv;
-
- if (!umc) /* temp pages are always good */
- return 0;
-
- if ((unsigned long)umc->work_iov.iov_base & iomask)
- return 1;
- if (testlen <= umc->work_iov.iov_len)
- return 0;
- if (umc->work_iov.iov_len & iomask)
- return 1;
-
- testlen -= umc->work_iov.iov_len;
- nuv = umc->user_iov;
- while (testlen) {
- nuv++;
- while (nuv->iov_len == 0)
- nuv++;
- if ((unsigned long)nuv->iov_base & iomask)
- return 1;
- if (testlen <= nuv->iov_len)
- return 0;
- if (nuv->iov_len & iomask)
- return 1;
- testlen -= nuv->iov_len;
- }
- return 0;
-}
-
/* error processing only, put back the user bvec we could not process
* so we can get it again later or release it properly
*/
--
1.6.3.3
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jim owens
2010-Mar-05 19:51 UTC
[PATCH 2/2] Btrfs: change dio.c to use dio_min_blocksize instead of 512.
Instead of hard coding the minimum I/O alignment, use the smallest
bdev_logical_blocksize in the filesystem. Also change the alignment
tests to determine the real user request minimum alignment and make
all eof tail and device checks on that user blocksize.
Signed-off-by: jim owens <jim6336@gmail.com>
---
fs/btrfs/dio.c | 144 ++++++++++++++++++++------------------------------------
1 files changed, 51 insertions(+), 93 deletions(-)
diff --git a/fs/btrfs/dio.c b/fs/btrfs/dio.c
index b1beafc..b76b227 100644
--- a/fs/btrfs/dio.c
+++ b/fs/btrfs/dio.c
@@ -134,6 +134,7 @@ struct btrfs_diocb {
struct workspace *workspace;
char *csum_buf;
+ u32 alignment;
int rw;
int error;
int sleeping;
@@ -160,12 +161,10 @@ static void btrfs_dio_write(struct btrfs_diocb *diocb);
static void btrfs_dio_read(struct btrfs_diocb *diocb);
static int btrfs_dio_new_extcb(struct btrfs_dio_extcb **alloc_extcb,
struct btrfs_diocb *diocb, struct extent_map *em);
-static void btrfs_dio_eof_tail(u32 *filetail, int eof,
- struct btrfs_diocb *diocb);
static int btrfs_dio_compressed_read(struct btrfs_diocb *diocb,
struct extent_map *lem, u64 data_len);
static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
- struct extent_map *lem, u64 data_len, int eof);
+ struct extent_map *lem, u64 data_len);
static void btfrs_dio_unplug(struct btrfs_dio_extcb *extcb);
static int btrfs_dio_read_stripes(struct btrfs_dio_extcb *extcb,
u64 *rd_start, u64 *rd_len, int temp_pages);
@@ -180,8 +179,6 @@ static int btrfs_dio_inline_next_in(struct bio_vec *ivec,
struct btrfs_inflate *icb);
static int btrfs_dio_get_user_bvec(struct bio_vec *uv,
struct btrfs_dio_user_mem_control *umc);
-static int btrfs_dio_not_aligned(unsigned long iomask, u32 testlen,
- struct btrfs_dio_user_mem_control *umc);
static void btrfs_dio_put_user_bvec(struct bio_vec *uv,
struct btrfs_dio_user_mem_control *umc);
static void btrfs_dio_release_unused_pages(
@@ -221,29 +218,33 @@ ssize_t btrfs_direct_IO(int rw, struct kiocb *kiocb,
ssize_t done = 0;
struct btrfs_diocb *diocb;
struct inode *inode = kiocb->ki_filp->f_mapping->host;
+ u32 alignment = BTRFS_I(inode)->root->sectorsize;
- /* traditional 512-byte device sector alignment is the
- * minimum required. if they have a larger sector disk
- * (possibly multiple sizes in the filesystem) and need
- * a larger alignment for this I/O, we just fail later.
- */
- if (offset & 511)
- return -EINVAL;
-
- /* check memory alignment, blocks cannot straddle pages.
+ /* check memory alignment, device blocks cannot straddle pages
+ * because special hardware (e.g. iommu) is needed for split dma.
* allow 0-length vectors which are questionable but seem legal.
+ * limit I/O to smaller of request size or available memory.
*/
- for (seg = 0; seg < nr_segs; seg++) {
- if (iov[seg].iov_len &&
- ((unsigned long)iov[seg].iov_base & 511))
- return -EINVAL;
- if (iov[seg].iov_len & 511)
- return -EINVAL;
- done += iov[seg].iov_len;
- }
+ alignment |= offset;
+ for (seg = 0; seg < nr_segs && done < kiocb->ki_left; seg++)
+ if (iov[seg].iov_len) {
+ /* alignment only needed through size of I/O */
+ done += iov[seg].iov_len;
+ done = min_t(ssize_t, done, kiocb->ki_left);
+ alignment |= done | (unsigned long)iov[seg].iov_base;
+ }
- /* limit request size to available memory */
- done = min_t(ssize_t, done, kiocb->ki_left);
+ /* minimum alignment is smallest logical_block_size of all devices in
+ * this fs. this check is not enough if there are larger blocksizes
+ * in the filesystem and we need a larger alignment for this I/O, so
+ * we retest alignment as we build the bio and fail it at that point.
+ * aligning here on largest blocksize would be simpler, but it would
+ * mean applications that were working might fail if the user added a
+ * larger blocksize device even though none of their file was on it.
+ */
+ if (alignment &
+ (BTRFS_I(inode)->root->fs_info->fs_devices->dio_min_blocksize
- 1))
+ return -EINVAL;
/* no write code here so fall back to buffered writes */
if (rw == WRITE)
@@ -253,6 +254,14 @@ ssize_t btrfs_direct_IO(int rw, struct kiocb *kiocb,
if (!diocb)
return -ENOMEM;
+ /* determine minimum user alignment block size across entire I/O
+ * so we can use it for eof tail handling and testing each device
+ */
+ diocb->alignment +
BTRFS_I(inode)->root->fs_info->fs_devices->dio_min_blocksize;
+ while (!(alignment & diocb->alignment))
+ diocb->alignment *= 2;
+
diocb->rw = rw;
diocb->kiocb = kiocb;
diocb->start = offset;
@@ -523,8 +532,7 @@ getlock:
}
err = btrfs_dio_compressed_read(diocb, em, len);
} else {
- err = btrfs_dio_extent_read(diocb, em, len,
- len == data_len);
+ err = btrfs_dio_extent_read(diocb, em, len);
}
}
@@ -650,28 +658,13 @@ static int btrfs_dio_compressed_read(struct btrfs_diocb
*diocb,
return err;
}
-/* for consistent eof processing between inline/compressed/normal
- * extents, an unaligned eof gets special treatment, read into temp
- * and memcpy to user on completion the part that does not match
- * the users I/O alignment (for now always 511)
- */
-static void btrfs_dio_eof_tail(u32 *filetail, int eof,
- struct btrfs_diocb *diocb)
-{
- if (eof)
- *filetail &= 511;
- else
- *filetail = 0; /* aligned direct to user memory */
-}
-
/* called with a hard-sector bounded file byte data start/len
* which covers areas of disk data. it might not... be contiguous,
* be on the same device(s), have the same redundancy property.
* get the extent map per contiguous chunk and submit bios.
*/
-
static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
- struct extent_map *lem, u64 data_len, int eof)
+ struct extent_map *lem, u64 data_len)
{
struct extent_map_tree *em_tree = &BTRFS_I(diocb->inode)->
root->fs_info->mapping_tree.map_tree;
@@ -690,9 +683,11 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
csum_after = blocksize - filetail;
}
- /* make post-eof consistent between inline/compressed/normal extents */
- if (filetail)
- btrfs_dio_eof_tail(&filetail, eof, diocb);
+ /* to make eof consistent between inline/compressed/normal extents,
+ * any unaligned bytes at eof get special treatment. those bytes are
+ * read into a kernel temp page and copied to user memory.
+ */
+ filetail &= diocb->alignment - 1;
data_start -= csum_before;
data_len += csum_before + csum_after;
@@ -781,9 +776,7 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
filetail;
else
csum_after = 0;
- if (filetail)
- btrfs_dio_eof_tail(&filetail,
- eof, diocb);
+ filetail &= diocb->alignment - 1;
}
extcb->csum_pg2 = extcb->csum_pg1;
@@ -811,7 +804,7 @@ static int btrfs_dio_extent_read(struct btrfs_diocb *diocb,
*/
extcb->csum_pg2 = extcb->csum_pg1;
csum_after += filetail;
- csum_after = ALIGN(csum_after, 512); /* for no csum */
+ csum_after = ALIGN(csum_after, diocb->alignment);
err = btrfs_dio_read_stripes(extcb,
&data_start, &csum_after, 1);
if (err)
@@ -867,7 +860,6 @@ static int btrfs_dio_read_stripes(struct btrfs_dio_extcb
*extcb,
while (*rd_len) {
u64 dev_left = *rd_len;
struct btrfs_stripe_info stripe_info;
- unsigned long iomask;
int mirror = 0;
int dvn;
@@ -880,18 +872,16 @@ retry:
btrfs_map_stripe_physical(extcb->em,
stripe_info.stripe_index);
- /* device start and length may not be sector aligned or
- * user memory address/length vectors may not be aligned
- * on a device sector because device sector size is > 512.
- * we might have different size devices in the filesystem,
- * so retry all copies to see if any meet the alignment.
+ /* we can have devices with different logical blocksizes
+ * in the filesystem. the user I/O start and length or
+ * memory address and length may not be sector aligned
+ * on a device with blocksize > dio_min_blocksize.
+ * if the user alignment is not correct for this device,
+ * try other copies to see if any meet their alignment.
*/
- iomask = bdev_logical_block_size(
- btrfs_map_stripe_bdev(extcb->em, dvn)) - 1;
- if ((extcb->diodev[dvn].physical & iomask) ||
- (dev_left & iomask) || (!temp_pages &&
- btrfs_dio_not_aligned(iomask, (u32)dev_left,
- &extcb->diocb->umc))) {
+ if (!temp_pages && extcb->diocb->alignment <
+ bdev_logical_block_size(btrfs_map_stripe_bdev(
+ extcb->em, dvn))) {
if (mirror < btrfs_map_num_copies(extcb->em)) {
mirror++;
goto retry;
@@ -1056,38 +1046,6 @@ static int btrfs_dio_get_user_bvec(struct bio_vec *uv,
return 0;
}
-static int btrfs_dio_not_aligned(unsigned long iomask, u32 testlen,
- struct btrfs_dio_user_mem_control *umc)
-{
- const struct iovec *nuv;
-
- if (!umc) /* temp pages are always good */
- return 0;
-
- if ((unsigned long)umc->work_iov.iov_base & iomask)
- return 1;
- if (testlen <= umc->work_iov.iov_len)
- return 0;
- if (umc->work_iov.iov_len & iomask)
- return 1;
-
- testlen -= umc->work_iov.iov_len;
- nuv = umc->user_iov;
- while (testlen) {
- nuv++;
- while (nuv->iov_len == 0)
- nuv++;
- if ((unsigned long)nuv->iov_base & iomask)
- return 1;
- if (testlen <= nuv->iov_len)
- return 0;
- if (nuv->iov_len & iomask)
- return 1;
- testlen -= nuv->iov_len;
- }
- return 0;
-}
-
/* error processing only, put back the user bvec we could not process
* so we can get it again later or release it properly
*/
--
1.6.3.3
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