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tell what an inode is

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rsc 2007-08-27 14:23:48 +00:00
parent a505fd6651
commit 6c34f97cb8
1 changed files with 9 additions and 4 deletions
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11
fs.c
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@ -98,7 +98,12 @@ bfree(int dev, uint b)
brelse(bp);
}
// Inodes
// Inodes.
//
// An inode is a single, unnamed file in the file system.
// The inode disk structure holds metadata (the type, device numbers,
// and data size) along with a list of blocks where the associated
// data can be found.
//
// The inodes are laid out sequentially on disk immediately after
// the superblock. The kernel keeps a cache of the in-use
@ -110,9 +115,9 @@ bfree(int dev, uint b)
// When ip->ref falls to zero, the inode is no longer cached.
// It is an error to use an inode without holding a reference to it.
//
// Inodes can be locked with I_BUSY (like bufs and B_BUSY).
// Processes are only allowed to read and write inode
// metadata and contents when holding the inode's lock.
// metadata and contents when holding the inode's lock,
// represented by the I_BUSY flag in the in-memory copy.
// Because inode locks are held during disk accesses,
// they are implemented using a flag rather than with
// spin locks. Callers are responsible for locking