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readahead: use the right parameter order when checking the range

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In some cases the offset and size arguments were flipped when checking to
see if a range had already been read.  This would have been OK as long as
the same mistake had been made consistently, since `bees_readahead_check`
only does a cache lookup on the parameters, it doesn't try to use them to
read a file.  Alas, there was one case where the correct order was used,
albeit a relatively rare one.

Fix all the calls to use the correct order.

Also fix a comment:  the recent request cache is global to all threads.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
This commit is contained in:
Zygo Blaxell
2024-12-04 11:11:13 -05:00
parent 1dd96f20c6
commit e40339856f
1 changed files with 4 additions and 4 deletions
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8
src/bees.cc
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@@ -220,7 +220,7 @@ bees_readahead_check(int const fd, off_t const offset, size_t const size)
{
// FIXME: the rest of the code calls this function more often than necessary,
// usually back-to-back calls on the same range in a loop.
// Simply discard requests that are identical to recent requests from the same thread.
// Simply discard requests that are identical to recent requests.
const Stat stat_rv(fd);
auto tup = make_tuple(offset, size, stat_rv.st_dev, stat_rv.st_ino);
static mutex s_recent_mutex;
@@ -242,7 +242,7 @@ static
void
bees_readahead_nolock(int const fd, const off_t offset, const size_t size)
{
if (!bees_readahead_check(fd, size, offset)) return;
if (!bees_readahead_check(fd, offset, size)) return;
Timer readahead_timer;
BEESNOTE("readahead " << name_fd(fd) << " offset " << to_hex(offset) << " len " << pretty(size));
BEESTOOLONG("readahead " << name_fd(fd) << " offset " << to_hex(offset) << " len " << pretty(size));
@@ -278,7 +278,7 @@ static mutex s_only_one;
void
bees_readahead_pair(int fd, off_t offset, size_t size, int fd2, off_t offset2, size_t size2)
{
if (!bees_readahead_check(fd, size, offset) && !bees_readahead_check(fd2, offset2, size2)) return;
if (!bees_readahead_check(fd, offset, size) && !bees_readahead_check(fd2, offset2, size2)) return;
BEESNOTE("waiting to readahead " << name_fd(fd) << " offset " << to_hex(offset) << " len " << pretty(size) << ","
<< "\n\t" << name_fd(fd2) << " offset " << to_hex(offset2) << " len " << pretty(size2));
unique_lock<mutex> m_lock(s_only_one);
@@ -289,7 +289,7 @@ bees_readahead_pair(int fd, off_t offset, size_t size, int fd2, off_t offset2, s
void
bees_readahead(int const fd, const off_t offset, const size_t size)
{
if (!bees_readahead_check(fd, size, offset)) return;
if (!bees_readahead_check(fd, offset, size)) return;
BEESNOTE("waiting to readahead " << name_fd(fd) << " offset " << to_hex(offset) << " len " << pretty(size));
unique_lock<mutex> m_lock(s_only_one);
bees_readahead_nolock(fd, offset, size);