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author | Robert Morris <[email protected]> | 2011-10-14 10:23:23 -0400 |
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committer | Robert Morris <[email protected]> | 2011-10-14 10:23:23 -0400 |
commit | 12abb1a56164a0d71fb7a76a465c912409f2f60b (patch) | |
tree | bc03592160be0e13960a9c106ecf5d48aadbe897 | |
parent | 38eee5bca75cc16d40101953bc2003bb77d452e7 (diff) | |
download | xv6-labs-12abb1a56164a0d71fb7a76a465c912409f2f60b.tar.gz xv6-labs-12abb1a56164a0d71fb7a76a465c912409f2f60b.tar.bz2 xv6-labs-12abb1a56164a0d71fb7a76a465c912409f2f60b.zip |
don't let dirty blocks be evicted from cache!
-rw-r--r-- | bio.c | 4 | ||||
-rw-r--r-- | file.c | 8 | ||||
-rw-r--r-- | log.c | 1 | ||||
-rw-r--r-- | sysfile.c | 6 |
4 files changed, 15 insertions, 4 deletions
@@ -79,9 +79,9 @@ bget(uint dev, uint sector) } } - // Not cached; recycle some existing buffer. + // Not cached; recycle some non-busy and clean buffer. for(b = bcache.head.prev; b != &bcache.head; b = b->prev){ - if((b->flags & B_BUSY) == 0){ + if((b->flags & B_BUSY) == 0 && (b->flags & B_DIRTY) == 0){ b->dev = dev; b->sector = sector; b->flags = B_BUSY; @@ -1,3 +1,7 @@ +// +// File descriptors +// + #include "types.h" #include "defs.h" #include "param.h" @@ -87,7 +91,7 @@ filestat(struct file *f, struct stat *st) return -1; } -// Read from file f. Addr is kernel address. +// Read from file f. int fileread(struct file *f, char *addr, int n) { @@ -108,7 +112,7 @@ fileread(struct file *f, char *addr, int n) } //PAGEBREAK! -// Write to file f. Addr is kernel address. +// Write to file f. int filewrite(struct file *f, char *addr, int n) { @@ -177,6 +177,7 @@ log_write(struct buf *b) brelse(lbuf); if (i == log.lh.n) log.lh.n++; + b->flags |= B_DIRTY; // XXX prevent eviction } //PAGEBREAK! @@ -1,3 +1,9 @@ +// +// File-system system calls. +// Mostly argument checking, since we don't trust +// user code, and calls into file.c and fs.c. +// + #include "types.h" #include "defs.h" #include "param.h" |