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| author | Paulo Alcantara <pcacjr@gmail.com> | 2011-08-29 05:49:32 +0000 |
|---|---|---|
| committer | Paulo Alcantara <pcacjr@gmail.com> | 2011-09-11 04:09:59 +0000 |
| commit | 8edf44b7fb1a4f29029b93c63285c4431358bbe1 (patch) | |
| tree | fafa9b1d8620e202986d1b13692de879ede2ef3d | |
| parent | c65a32b86a09f997cf443149c0dc9acfb6d20186 (diff) | |
| download | syslinux-8edf44b7fb1a4f29029b93c63285c4431358bbe1.tar.gz syslinux-8edf44b7fb1a4f29029b93c63285c4431358bbe1.tar.xz syslinux-8edf44b7fb1a4f29029b93c63285c4431358bbe1.zip | |
ntfs: don't start lookup from the same block in ntfs_mft_record_lookup()
ntfs_mft_record_lookup() always started its lookup from the same block,
which was though a mistake. So the lookup became very slow. Now
determine its starting block number from the calculated MFT record's LCN
number.
Signed-off-by: Paulo Alcantara <pcacjr@gmail.com>
| -rw-r--r-- | core/fs/ntfs/ntfs.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/core/fs/ntfs/ntfs.c b/core/fs/ntfs/ntfs.c index 51557eef..14c275b9 100644 --- a/core/fs/ntfs/ntfs.c +++ b/core/fs/ntfs/ntfs.c @@ -167,10 +167,13 @@ static MFT_RECORD *ntfs_mft_record_lookup(struct fs_info *fs, uint32_t file, blo { const uint64_t mft_record_size = NTFS_SB(fs)->mft_record_size; uint8_t *buf; + const block_t mft_blk = NTFS_SB(fs)->mft_blk; block_t cur_blk; block_t right_blk; uint64_t offset = 0; uint64_t next_offset; + const unsigned mft_record_shift = ilog2(mft_record_size); + const unsigned clust_byte_shift = NTFS_SB(fs)->clust_byte_shift; uint64_t lcn = NTFS_SB(fs)->mft_lcn; int err; MFT_RECORD *mrec; @@ -179,9 +182,11 @@ static MFT_RECORD *ntfs_mft_record_lookup(struct fs_info *fs, uint32_t file, blo if (!buf) malloc_error("uint8_t *"); - cur_blk = blk ? *blk : 0; + /* determine MFT record's LCN and block number */ + lcn = NTFS_SB(fs)->mft_lcn + (file << mft_record_shift >> clust_byte_shift); + cur_blk = (lcn << clust_byte_shift >> BLOCK_SHIFT(fs)) - mft_blk - 1; for (;;) { - right_blk = cur_blk + NTFS_SB(fs)->mft_blk; + right_blk = cur_blk + mft_blk; err = ntfs_read(fs, buf, mft_record_size, mft_record_size, &right_blk, &offset, &next_offset, &lcn); if (err) { @@ -202,10 +207,10 @@ static MFT_RECORD *ntfs_mft_record_lookup(struct fs_info *fs, uint32_t file, blo if (next_offset >= BLOCK_SIZE(fs)) { /* try the next FS block */ offset = 0; - cur_blk = right_blk - NTFS_SB(fs)->mft_blk + 1; + cur_blk = right_blk - mft_blk + 1; } else { /* there's still content to fetch in the current block */ - cur_blk = right_blk - NTFS_SB(fs)->mft_blk; + cur_blk = right_blk - mft_blk; offset = next_offset; /* update FS block offset */ } } @@ -751,7 +756,6 @@ static uint32_t ntfs_getfssec(struct file *file, char *buf, int sectors, free(mrec); } - return ret; out: |