search for: posix_fadv_noreuse

The way we used posix_fadvise was wrong, and yet right! Rich.

...them in places we were calling posix_fadvise directly before. Also in virt-builder we were doing this (and ignoring the result): posix_fadvise (fd, 0, 0, POSIX_FADV_RANDOM|POSIX_FADV_DONTNEED); However the POSIX_FADV_* flags are _not_ bitmasks! In fact POSIX_FADV_RANDOM|POSIX_FADV_DONTNEED == POSIX_FADV_NOREUSE so we were giving a completely different hint from what we thought we were giving. --- builder/pxzcat-c.c | 5 +-- src/guestfs-internal-frontend.h | 5 +++ src/proto.c | 17 +------- src/utils.c | 87 +++++++++++++++++++++++++++++++++++++++++...

...-1; + } + } + else { + /* Open a regular file. */ + fd = open (path, O_RDONLY | O_CLOEXEC); + if (fd == -1) { + reply_with_perror ("%s", orig_path); + return -1; + } + + posix_fadvise (fd, 0, 0, + POSIX_FADV_SEQUENTIAL | + POSIX_FADV_NOREUSE | + POSIX_FADV_DONTNEED); + } + + return 0; +} + +int +do_bmap_file (const char *path) +{ + CLEANUP_FREE char *buf = NULL; + + buf = sysroot_path (path); + if (!buf) { + reply_with_perror ("malloc"); + return -1; + } + + return bmap_prepare (buf, path); +} +...

See http://rwmj.wordpress.com/2014/11/23/mapping-files-to-disk/

...r ("%s", orig_path); > + return -1; > + } Wouldn't be better to just always open the file, stat the fd, and if it's a directory fdopendir + close it? > + > + posix_fadvise (fd, 0, 0, > + POSIX_FADV_SEQUENTIAL | > + POSIX_FADV_NOREUSE | > + POSIX_FADV_DONTNEED); > + } > + > + return 0; > +} > + > +int > +do_bmap_file (const char *path) > +{ > + CLEANUP_FREE char *buf = NULL; > + > + buf = sysroot_path (path); > + if (!buf) { > + reply_with_perror ("malloc&q...

Does *not* incorporate changes suggested by Pino yet. Rich.