xfs: allocate delayed extents in CoW fork
Modify the writepage handler to find and convert pending delalloc extents to real allocations. Furthermore, when we're doing non-cow writes to a part of a file that already has a CoW reservation (the cowextsz hint that we set up in a subsequent patch facilitates this), promote the write to copy-on-write so that the entire extent can get written out as a single extent on disk, thereby reducing post-CoW fragmentation. Christoph moved the CoW support code in _map_blocks to a separate helper function, refactored other functions, and reduced the number of CoW fork lookups, so I merged those changes here to reduce churn. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
parent
60b4984fc3
commit
ef4736678f
4 changed files with 170 additions and 19 deletions
|
@ -31,6 +31,7 @@
|
|||
#include "xfs_bmap.h"
|
||||
#include "xfs_bmap_util.h"
|
||||
#include "xfs_bmap_btree.h"
|
||||
#include "xfs_reflink.h"
|
||||
#include <linux/gfp.h>
|
||||
#include <linux/mpage.h>
|
||||
#include <linux/pagevec.h>
|
||||
|
@ -341,6 +342,7 @@ xfs_map_blocks(
|
|||
if (XFS_FORCED_SHUTDOWN(mp))
|
||||
return -EIO;
|
||||
|
||||
ASSERT(type != XFS_IO_COW);
|
||||
if (type == XFS_IO_UNWRITTEN)
|
||||
bmapi_flags |= XFS_BMAPI_IGSTATE;
|
||||
|
||||
|
@ -355,6 +357,13 @@ xfs_map_blocks(
|
|||
offset_fsb = XFS_B_TO_FSBT(mp, offset);
|
||||
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
|
||||
imap, &nimaps, bmapi_flags);
|
||||
/*
|
||||
* Truncate an overwrite extent if there's a pending CoW
|
||||
* reservation before the end of this extent. This forces us
|
||||
* to come back to writepage to take care of the CoW.
|
||||
*/
|
||||
if (nimaps && type == XFS_IO_OVERWRITE)
|
||||
xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
|
||||
xfs_iunlock(ip, XFS_ILOCK_SHARED);
|
||||
|
||||
if (error)
|
||||
|
@ -365,8 +374,7 @@ xfs_map_blocks(
|
|||
error = xfs_iomap_write_allocate(ip, XFS_DATA_FORK, offset,
|
||||
imap);
|
||||
if (!error)
|
||||
trace_xfs_map_blocks_alloc(ip, offset, count, type,
|
||||
imap);
|
||||
trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
|
||||
return error;
|
||||
}
|
||||
|
||||
|
@ -739,6 +747,56 @@ xfs_aops_discard_page(
|
|||
return;
|
||||
}
|
||||
|
||||
static int
|
||||
xfs_map_cow(
|
||||
struct xfs_writepage_ctx *wpc,
|
||||
struct inode *inode,
|
||||
loff_t offset,
|
||||
unsigned int *new_type)
|
||||
{
|
||||
struct xfs_inode *ip = XFS_I(inode);
|
||||
struct xfs_bmbt_irec imap;
|
||||
bool is_cow = false, need_alloc = false;
|
||||
int error;
|
||||
|
||||
/*
|
||||
* If we already have a valid COW mapping keep using it.
|
||||
*/
|
||||
if (wpc->io_type == XFS_IO_COW) {
|
||||
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, offset);
|
||||
if (wpc->imap_valid) {
|
||||
*new_type = XFS_IO_COW;
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Else we need to check if there is a COW mapping at this offset.
|
||||
*/
|
||||
xfs_ilock(ip, XFS_ILOCK_SHARED);
|
||||
is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap, &need_alloc);
|
||||
xfs_iunlock(ip, XFS_ILOCK_SHARED);
|
||||
|
||||
if (!is_cow)
|
||||
return 0;
|
||||
|
||||
/*
|
||||
* And if the COW mapping has a delayed extent here we need to
|
||||
* allocate real space for it now.
|
||||
*/
|
||||
if (need_alloc) {
|
||||
error = xfs_iomap_write_allocate(ip, XFS_COW_FORK, offset,
|
||||
&imap);
|
||||
if (error)
|
||||
return error;
|
||||
}
|
||||
|
||||
wpc->io_type = *new_type = XFS_IO_COW;
|
||||
wpc->imap_valid = true;
|
||||
wpc->imap = imap;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* We implement an immediate ioend submission policy here to avoid needing to
|
||||
* chain multiple ioends and hence nest mempool allocations which can violate
|
||||
|
@ -771,6 +829,7 @@ xfs_writepage_map(
|
|||
int error = 0;
|
||||
int count = 0;
|
||||
int uptodate = 1;
|
||||
unsigned int new_type;
|
||||
|
||||
bh = head = page_buffers(page);
|
||||
offset = page_offset(page);
|
||||
|
@ -791,22 +850,13 @@ xfs_writepage_map(
|
|||
continue;
|
||||
}
|
||||
|
||||
if (buffer_unwritten(bh)) {
|
||||
if (wpc->io_type != XFS_IO_UNWRITTEN) {
|
||||
wpc->io_type = XFS_IO_UNWRITTEN;
|
||||
wpc->imap_valid = false;
|
||||
}
|
||||
} else if (buffer_delay(bh)) {
|
||||
if (wpc->io_type != XFS_IO_DELALLOC) {
|
||||
wpc->io_type = XFS_IO_DELALLOC;
|
||||
wpc->imap_valid = false;
|
||||
}
|
||||
} else if (buffer_uptodate(bh)) {
|
||||
if (wpc->io_type != XFS_IO_OVERWRITE) {
|
||||
wpc->io_type = XFS_IO_OVERWRITE;
|
||||
wpc->imap_valid = false;
|
||||
}
|
||||
} else {
|
||||
if (buffer_unwritten(bh))
|
||||
new_type = XFS_IO_UNWRITTEN;
|
||||
else if (buffer_delay(bh))
|
||||
new_type = XFS_IO_DELALLOC;
|
||||
else if (buffer_uptodate(bh))
|
||||
new_type = XFS_IO_OVERWRITE;
|
||||
else {
|
||||
if (PageUptodate(page))
|
||||
ASSERT(buffer_mapped(bh));
|
||||
/*
|
||||
|
@ -819,6 +869,17 @@ xfs_writepage_map(
|
|||
continue;
|
||||
}
|
||||
|
||||
if (xfs_is_reflink_inode(XFS_I(inode))) {
|
||||
error = xfs_map_cow(wpc, inode, offset, &new_type);
|
||||
if (error)
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (wpc->io_type != new_type) {
|
||||
wpc->io_type = new_type;
|
||||
wpc->imap_valid = false;
|
||||
}
|
||||
|
||||
if (wpc->imap_valid)
|
||||
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
|
||||
offset);
|
||||
|
|
|
@ -28,13 +28,15 @@ enum {
|
|||
XFS_IO_DELALLOC, /* covers delalloc region */
|
||||
XFS_IO_UNWRITTEN, /* covers allocated but uninitialized data */
|
||||
XFS_IO_OVERWRITE, /* covers already allocated extent */
|
||||
XFS_IO_COW, /* covers copy-on-write extent */
|
||||
};
|
||||
|
||||
#define XFS_IO_TYPES \
|
||||
{ XFS_IO_INVALID, "invalid" }, \
|
||||
{ XFS_IO_DELALLOC, "delalloc" }, \
|
||||
{ XFS_IO_UNWRITTEN, "unwritten" }, \
|
||||
{ XFS_IO_OVERWRITE, "overwrite" }
|
||||
{ XFS_IO_OVERWRITE, "overwrite" }, \
|
||||
{ XFS_IO_COW, "CoW" }
|
||||
|
||||
/*
|
||||
* Structure for buffered I/O completions.
|
||||
|
|
|
@ -328,3 +328,87 @@ xfs_reflink_reserve_cow_range(
|
|||
|
||||
return error;
|
||||
}
|
||||
|
||||
/*
|
||||
* Find the CoW reservation (and whether or not it needs block allocation)
|
||||
* for a given byte offset of a file.
|
||||
*/
|
||||
bool
|
||||
xfs_reflink_find_cow_mapping(
|
||||
struct xfs_inode *ip,
|
||||
xfs_off_t offset,
|
||||
struct xfs_bmbt_irec *imap,
|
||||
bool *need_alloc)
|
||||
{
|
||||
struct xfs_bmbt_irec irec;
|
||||
struct xfs_ifork *ifp;
|
||||
struct xfs_bmbt_rec_host *gotp;
|
||||
xfs_fileoff_t bno;
|
||||
xfs_extnum_t idx;
|
||||
|
||||
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
|
||||
ASSERT(xfs_is_reflink_inode(ip));
|
||||
|
||||
/* Find the extent in the CoW fork. */
|
||||
ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
|
||||
bno = XFS_B_TO_FSBT(ip->i_mount, offset);
|
||||
gotp = xfs_iext_bno_to_ext(ifp, bno, &idx);
|
||||
if (!gotp)
|
||||
return false;
|
||||
|
||||
xfs_bmbt_get_all(gotp, &irec);
|
||||
if (bno >= irec.br_startoff + irec.br_blockcount ||
|
||||
bno < irec.br_startoff)
|
||||
return false;
|
||||
|
||||
trace_xfs_reflink_find_cow_mapping(ip, offset, 1, XFS_IO_OVERWRITE,
|
||||
&irec);
|
||||
|
||||
/* If it's still delalloc, we must allocate later. */
|
||||
*imap = irec;
|
||||
*need_alloc = !!(isnullstartblock(irec.br_startblock));
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
/*
|
||||
* Trim an extent to end at the next CoW reservation past offset_fsb.
|
||||
*/
|
||||
int
|
||||
xfs_reflink_trim_irec_to_next_cow(
|
||||
struct xfs_inode *ip,
|
||||
xfs_fileoff_t offset_fsb,
|
||||
struct xfs_bmbt_irec *imap)
|
||||
{
|
||||
struct xfs_bmbt_irec irec;
|
||||
struct xfs_ifork *ifp;
|
||||
struct xfs_bmbt_rec_host *gotp;
|
||||
xfs_extnum_t idx;
|
||||
|
||||
if (!xfs_is_reflink_inode(ip))
|
||||
return 0;
|
||||
|
||||
/* Find the extent in the CoW fork. */
|
||||
ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
|
||||
gotp = xfs_iext_bno_to_ext(ifp, offset_fsb, &idx);
|
||||
if (!gotp)
|
||||
return 0;
|
||||
xfs_bmbt_get_all(gotp, &irec);
|
||||
|
||||
/* This is the extent before; try sliding up one. */
|
||||
if (irec.br_startoff < offset_fsb) {
|
||||
idx++;
|
||||
if (idx >= ifp->if_bytes / sizeof(xfs_bmbt_rec_t))
|
||||
return 0;
|
||||
gotp = xfs_iext_get_ext(ifp, idx);
|
||||
xfs_bmbt_get_all(gotp, &irec);
|
||||
}
|
||||
|
||||
if (irec.br_startoff >= imap->br_startoff + imap->br_blockcount)
|
||||
return 0;
|
||||
|
||||
imap->br_blockcount = irec.br_startoff - imap->br_startoff;
|
||||
trace_xfs_reflink_trim_irec(ip, imap);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
|
@ -28,5 +28,9 @@ extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,
|
|||
|
||||
extern int xfs_reflink_reserve_cow_range(struct xfs_inode *ip,
|
||||
xfs_off_t offset, xfs_off_t count);
|
||||
extern bool xfs_reflink_find_cow_mapping(struct xfs_inode *ip, xfs_off_t offset,
|
||||
struct xfs_bmbt_irec *imap, bool *need_alloc);
|
||||
extern int xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
|
||||
xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);
|
||||
|
||||
#endif /* __XFS_REFLINK_H */
|
||||
|
|
Loading…
Add table
Reference in a new issue